Browse Topic: Vibration

Items (3,917)
Find
Further Investigation of Brake Squeal: Effect of (Inboard/Outboard) Pads Property Differential2026-01-07999/14/2026
It was reported earlier that the wear differential between the inboard pad and the outboard pad leads to brake squeal generation. The (inboard/outboard) pads wear differential can occur due to hardware issues such as brake pad drag and/or two different wear rates of the (I/O) pads, which is caused by two different material properties of the pads although the pad formula may be the same. It is found that (I/O) pads compressibility differential/hardness differential/friction differential are all interrelated and that they contribute to brake squeal generation in addition to the inboard pad tangential/radial taper wear. A method has been found to separate the inboard pad friction and the outboard pad friction and to estimate each friction coefficient.
Liu, Richard, Wu, Shane, Wu, Godot, Zou, Tianlang
Influence of Ferritic Nitrocarburizing with Smart-ONC® on the Modal and Damping Behavior of Gray Cast Iron Brake Rotors2026-01-07989/14/2026
Ferritic nitrocarburizing (FNC) with in-process post-oxidation has been developed as a production-capable surface engineering solution for gray cast iron (GCI) brake rotors to meet the Euro 7 non-exhaust particulate emission limits. While prior investigations have demonstrated significant PM₁₀ reduction, improved corrosion resistance, and stable braking performance, the influence of FNC on noise, vibration, and harshness (NVH) performance requires systematic evaluation. This study quantified the relative contributions of the alloy composition, rotor geometry, and FNC treatment to the modal frequency and damping behavior. Seven ventilated disc types from multiple foundries were characterized to assess the composition-driven variability. In addition, 120 production discs (ventilated and solid) were measured before and after FNC processing to isolate the treatment effects. Modal properties were obtained using impulse-hammer testing under free–free boundary conditions in accordance with VDA 301, and damping was evaluated using the half-power bandwidth method (Q-factor). The results show that the natural frequency is governed primarily by geometric parameters, scaling with the friction-ring thickness and disc diameter. In contrast, the damping behavior is dominated by the alloy composition and graphite morphology. Variations in silicon, chromium, and carbon equivalent produced a 3–4× difference in the Q-factor across foundries. FNC treatment had a negligible effect on the natural frequency (<1%) but produced a measurable increase in the Q-factor, typically 7–10% for solid discs and 22–32% for ventilated discs. The findings establish a clear hierarchy of influence: composition controls the damping, geometry controls the frequency, and the FNC introduces a secondary shift. Within production-relevant composition windows, FNC + Smart-ONC® does not represent a limiting factor for the NVH performance of Euro 7–compliant brake systems.
Awe, Samuel Ayowole, Holly, Mike, Winter, Karl-Michael
A Multi-Body Dynamic Analysis of Click Noise Generated in Rear Brake Caliper2026-01-08159/14/2026
As customer awareness of brake-related NVH (Noise, Vibration and Harshness) continues to increase across the automotive industry, noise originating from braking systems is increasingly regarded as important indicator of vehicle quality. Among these issues, intermittent click noise from rear brake caliper is commonly noticed during low-speed driving and initial brake application and is frequently associated with customer dissatisfaction. In the automotive industry, this noise has primarily been addressed through empirical design modifications and component-level testing. However, due to its low reproducibility and impulsive response characteristics, making quantitative prediction and root-cause identification during the design phase difficult. While most previous brake NVH research has mainly focused on continuous vibration phenomena such as squeal and groan, fewer studies have examined single-event impact noise related to pad-to-carrier clearances, contact transitions, and frictional nonlinearity from a simulation-based perspective. In this study, rear brake caliper click noise is defined as a dynamic phenomenon inherent to conventional caliper mechanical architecture. A Multi-Body-Dynamic model was developed using RecurDyn to reproduce the observed behavior incorporating pad-to-carrier clearance, friction characteristics, and component compliance. Brake dynamometer testing was conducted to measure acceleration and noise response, and correlation with simulation results was performed. Simulation and tests were carried out using a caliper geometry whose improvement effectiveness had been confirmed in prior applications, demonstrating that the applied approach can qualitatively and reproduce the occurrence tendencies and key characteristics of rear caliper click noise. The simulation-test integrated approach is applicable to early-stage NVH risk assessment and to the validation of countermeasures for click noise in production vehicles. Future work will focus on improving analytical modeling and prediction of click noise through development of a new model incorporating key design parameters.
Choi, Hyeontae, Kim, Sangbum, Park, Ilho, Kim, Taeuk, Kwon, Yongsik, Yang, Soonhong, Ma, Jaehyeon, Kim, Jinwook
Experimental Study on Ultrasonic Drilling of CFRP Based on Ultrasonic Tools2026-99-14139/11/2026
To investigate the influence of laws of rotational speed, ultrasonic vibration, and feed speed on burr length, splitting length, and hole roundness of carbon fiber reinforced plastic (CFRP), drilling experiments using ultrasonic tools designed based on the dagger drill principle were carried out on CFRP materials. This study aims to explore methods for improving the hole-making quality of CFRP and further enhancing its hole-making efficiency. The results show that a high rotational speed can effectively reduce the burr length by 60% and the splitting length by 50%. Ultrasonic vibration can reduce the burr length and splitting length by about 70% and increase the hole roundness by about 10%. The higher the feed speed, the lower the hole-making quality, while an excessively low feed speed will impair the hole-making efficiency. In this study, the optimal hole-making quality was achieved when the rotational speed was set at 18500 r/min, ultrasonic vibration was activated, and the feed speed was controlled at 40 mm/min. The research results provide valuable references for the research, popularization, and application of ultrasonic tools and related technologies.
Xiang, Hui, Xiao, Liuwei, Song, Jinhui, Chen, Songlin, Liu, Zhichun, Liu, Yihong, Xiao, Huan, Zhang, Cheng, Ran, Qiuyue, Luo, Jiang
Study on Nonlinear Dynamic Characteristics of High-Speed Train Braking Systems2026-99-11419/11/2026
To address the oversimplification in prior brake system models, this study develops a 10-degree-of-freedom (DOF) dynamic model of a disc brake system. A control-variable approach is employed to numerically simulate the effects of braking force, rotational inertia, brake pad tangential stiffness, suspension stiffness, and damping. The vibration responses under different braking conditions and in the presence of multi-parameter coupling are analyzed through bifurcation diagrams, phase trajectories, and Poincaré sections. The main findings indicate: (1) Increasing braking force induces a transition from period-1 to higher-order periodic motions (e.g., period-6), accompanied by significant vibration amplification; (2) Enhanced brake pad tangential stiffness suppresses vibration amplitude but extends the sticking phase duration; (3) Exceeding a critical primary suspension stiffness threshold triggers system instability. These results suggest that structural optimization of suspensions and reasonable selection of brake pad support stiffness are important measures to prevent stick-slip vibrations.
Li, Songge, Wang, Jingyue
Research on an Evaluation Method and Application of Autonomous Vehicles in Traffic Flow Environment2026-99-15629/11/2026
Traffic flow environment testing is indispensable in the research and evaluation process of intelligent vehicles. However, the current vehicle evaluation systems mostly focus on simple dynamic scenarios and lack a comprehensive assessment of vehicle performance in complex traffic flow environments. In view of this, this paper constructs a multi-dimensional comprehensive performance evaluation system for vehicles in traffic flow environments. Firstly, based on the randomness and dynamics of traffic flow, four core evaluation dimensions covering safety, comfort, efficiency, and economy are constructed. In terms of security, the collision time and Predicted Safety Metrics are adopted. This enables the dual quantification of immediate collision risks and dynamic obstacle avoidance capabilities. The comfort evaluation focuses on the impact of vibration frequency on the human body and constructs a graded quantitative index. Efficiency and economy evaluation models are built through time cost and energy consumption cost. The verification is carried out under different traffic flow scenarios, and the final results demonstrate the consistency between the evaluation method of this paper and the expert evaluation method, thereby verifying the rationality of the evaluation system presented in this paper.
Wang, Guangyu, Song, Shiping, Zhang, Cheng, Qu, Ge, Yu, Xiaojun
Study on the Vehicle Unsteady Vibration Control with a Semi-Active Strut2026-99-12319/4/2026
Unsteady vibrations of vehicles, which can be easily perceived by the human body, may affect the driving experience and compromise driving comfort. However, the conventional three-point powertrain mounting system (PMS) often fails to offer a satisfactory solution. Here, a novel four-point PMS was proposed by introducing a semi-active strut (SAS), which can provide stronger damping in a low-frequency range to resolve this problem. Specifically, a thirteen degrees of freedom (DoFs) vehicle dynamic model (VDM) with four mounts was constructed, and the evaluation indices for unsteady vibration responses of the vehicle were determined and analyzed; Next, the PMS optimization design approach was employed to identify the proper position of installation and dynamic stiffness of the SAS, and meanwhile the 13 DoFs VDM and the force-sharing principle were used to identify the structural parameters of the strut; Last, comparative experiments were performed to analyze the effect of the strut on alleviating the unsteady vibration of the vehicle under varied unsteady vehicle states. The results showed that the SAS has significantly reduced the seat rail peak acceleration, verifying the effectiveness of our novel PMS in alleviating the unsteady vibration. The research provided a feasible solution to alleviate the unsteady vibration of vehicles and improve the driving experience.
Wang, Daoyong, Liu, Yongjiang, Ma, Bo
A Method of Hamiltonian System for the Vibration Problem of Cracked Plates with Piecewise Boundaries2026-99-12599/4/2026
This paper focuses on analytical solutions for studying the vibrations of partially cracked orthotropic plates with piecewise boundaries using the symplectic elasticity method. Crack compliance coefficients are derived from the line spring model and introduced into the governing equations. In this paper, by establishing the Hamiltonian system and solving the Hamiltonian canonical equations, the vibration problem of cracked plates with piecewise boundaries can be reduced to finding the symplectic eigenvalues and symplectic eigensolutions. In the Hamiltonian system, the problem is transformed into seeking the solution of an algebraic equation system by the aid of symplectic eigensolutions and the adjoint symplectic orthogonal relations between the eigensolutions. Thus, for orthotropic plates with cracks under piecewise boundary conditions, this work presents a set of analytical solutions. Specifically, expressions for the free vibration behavior are derived. Furthermore, the steady-state response is determined. Finally, the transient dynamic response is also formulated and solved. The numerical results show that this method is effective and the natural frequency obtained in this paper is consistent with experimental results. A parametric investigation is performed, with the aim of comprehensively investigating the dynamic behavior of cracked plates subjected to piecewise boundaries. Significant findings include how aspect ratio, piecewise boundary conditions, and crack length affect structural vibration characteristics. For the plates containing cracks under piecewise boundaries, the frequency-response and the time-history curves for the forced vibration are plotted. These curves clearly illustrate the corresponding vibration characteristics of the plates. Some of the results can provide benchmarks for validating numerical or approximate methods. The method presented in this paper can provide a pathway for solving similar problems in the field.
Qu, Jianlong, Yu, Qinyu, Jia, Jufang, Xu, Xinsheng
Study on the “Vibration-Differential Pressure” Coupled Environment Test Technology for Airborne Equipment Vibration Isolation Systems2026-99-12519/4/2026
The stable operation of airborne equipment determines the functionality and performance standards of aircraft. Installing vibration isolation systems on such equipment aims to improve its performance. With the advancement of aircraft capabilities, future evaluations of airborne equipment’s vibration isolation systems will require increasingly real-world experimental assessment. Achieving a ground-based simulation of the complex coupling environment encountered by airborne equipment at high altitudes presents a huge challenge. This paper proposes a method utilizing air springs to simulate differential pressure forces, successfully enabling ground-based testing of “vibration-differential pressure” coupled environments for airborne equipment. The results verify the effectiveness of this approach, and it can be used for this type of environmental testing.
Qin, Xiaomeng, Xing, Xiaoming, Mou, Haowen, Wang, Jianzhong
Optimized Design of Vibration Reduction for the Frame Structure of Metering, Considering Ground Impact Load2026-99-12339/4/2026
To effectively mitigate the adverse effects of impact loads on the operational quality of a planter, this paper focuses on precision metering with dual planting chambers, and a novel approach is proposed to concurrently consider static and impact loads in the design of the frame structure, aiming to achieve a balanced design that combines load-bearing capacity and vibration reduction effects. The methodology employs a dual-layer cyclic process, where the outer layer calculates equivalent static loads based on the structural nonlinear dynamic response, and the inner layer introduces these equivalent static loads into the objective function of the optimization model using a weight method. The design of the frame structure, which simultaneously accounts for static and impact loads, is established through a topology optimization model based on the parametric level-set method. The simulation-optimization results indicate that, within the two-dimensional plane, the optimized seed metering frame achieves a marked reduction in volume fraction while its compliance remains almost unchanged. When the solution is expanded from 2-D to 3-D, and the optimized volume is increased to match the original volume, the optimized stiffness becomes 1.92 times the initial stiffness. This demonstrates that the frame is substantially lightened yet its stiffness is effectively enhanced, confirming that the design concurrently offers improved vibration attenuation and load-bearing capacity. The proposed structural optimization method can provide a viable design for improving the quality of precision metering. Although physical tests are still lacking, the soundness and consistency of both the simulation outcomes and numerical analyses provide strong evidence for the feasibility of the proposed method. Future tests can further verify its effectiveness.
Zhang, Wenpeng, Zeng, Shan, Zang, Ying, Wang, Yu
A Simultaneous Impulse and Oscillatory Component Decomposition Method for Fault Diagnosis of Rolling Bearings2026-99-12049/4/2026
Due to the interference of oscillatory components and noise, the periodic impulses associated with localized bearing faults become difficult to extract, leading to unreliable diagnostic performance. To solve this problem, the study proposes a simultaneous impulse and oscillatory component decomposition method (SIOCD). The method designs and solves a novel optimization model to decompose oscillatory components and fault impulse components from noisy vibration signals. To achieve component separation in the optimization model, distinct penalty functions are introduced for oscillatory and impulse components. For oscillatory components, a regularization term is applied to achieve their extraction by minimizing the component bandwidth in the frequency domain. For impulse components, a penalty function is designed to achieve their decomposition by enhancing both sparsity within groups (SWG) and sparsity across groups (SAG) in the time domain. Then, an iterative solver is derived using an alternating minimization framework and the majorization-minimization (MM) algorithm. Finally, the proposed method’s effectiveness is demonstrated through comprehensive simulation and experimental analyses, and the results demonstrate that it achieves superior performance over existing approaches in fault feature extraction and enhancement.
Sun, Haoran, Zhang, Jinduo, Han, Tianyu, Shi, Xi
Comprehensive Analysis of Torsional Vibration Response in Marine Propulsion Shafting Systems2026-99-12749/4/2026
The marine propulsion shafting system serves as the core component of ship power transmission, wherein torsional vibrations can easily lead to shaft cracking and failure. Thus, avoiding shafting resonance is vital for ship safety. Previous research primarily focuses on a single vibration mechanism of diesel engine propulsion shafting systems, lacking a comprehensive analysis of modal characteristics, frequency, and transient responses. This paper systematically investigates the torsional vibration characteristics of shafting systems, constructs a mathematical model for torsional vibrations, deduces a method for solving natural frequencies, and establishes a frequency-domain transfer function matrix using the Laplace Transform to theoretically derive the transient response of damped forced vibrations. Taking the propulsion shafting system of a low-speed diesel engine in a 10,000-ton oil tanker as an example, a multi-condition analysis based on a simplified shafting model is conducted. This includes modal solution analysis, 0–2000 Hz frequency sweep tests, and comparative experiments on transient responses under different excitation frequencies with a 1000 Nm torque. The study reveals the influence mechanism of the coupling between excitation frequency and natural frequency on the dynamic characteristics of the shafting system. By investigating torsional vibration patterns, this research provides a theoretical basis for vibration reduction design and resonance avoidance in marine propulsion shafting systems.
Zhang, Jiayi
Dynamic Characteristics Analysis of Conical-Cylindrical Shell Structure2026-99-12789/4/2026
In the context of aerospace development towards lightweight, high reliability, and long life directions, such materials have become the core materials of key load-bearing structures for advanced aircraft, and their structural dynamic characteristics are directly related to the flight safety and service stability of the aircraft. This article uses uniform artificial springs to simulate the stiffness coupling effect and boundary conditions of the entire structure. In the stage of theoretical modeling, classical shell theory is used, and orthogonal polynomials are introduced as displacement functions. Is solved by the Lagrange energy equation. On this basis, the effect of external size parameters on structural vibration frequency is deeply discussed. With the change in structural natural frequency with the taper of the conical shell, the ratio of cylindrical shell length to diameter and the ratio of diameter to thickness are analyzed.
Zhao, Yunhao, Chen, Jie
Research on Online Zero-Point Calibration Technique for Ω-Shaped Coriolis Flowmeters in CCUS Applications2026-99-12379/4/2026
The Ω-shaped Coriolis flowmeter, owing to its suitability for high-pressure and wide-temperature conditions, has become the preferred device for CO2 metering in CCUS-EOR projects. In practical applications, however, the volatile nature of operating pressures and temperatures triggers a persistent zero-point drift. This instability creates a ripple effect: it not only degrades metering precision but also fundamentally undermines the equitable basis of carbon trading markets. This study, through theoretical analysis, fluid-structure coupling simulation, and experiments, deeply investigates the patterns of zero-point drift in Ω-shaped Coriolis flowmeters and corresponding correction methods. The research reveals that the asymmetry of the measuring tube structure is the primary cause of zero-point drift, with changes in the vibration frequency of the measuring tube directly influencing the zero-point value, leading to the establishment of a related zero-point drift model. Based on the asymmetric structure of a DN15 Ω-shaped Coriolis flowmeter, simulations were performed to model the zero-point variation patterns under different pressures and temperatures using CO2 as the fluid, thereby verifying the effectiveness of the zero-point drift model. To validate our approach, we executed targeted zero-point experiments, employing the proposed model to predict zero-point shifts across a broad spectrum of pressures and temperatures. By integrating these predictions into a refined correction framework, we successfully neutralized drift-induced errors. These findings offer both a robust theoretical pillar and a practical toolkit for high-precision CO2 accounting, ultimately safeguarding the economic integrity of carbon trading within CCUS-EOR initiatives.
Yu, Haobo, Hua, Chenquan, Yu, Wenxin, Zhao, Zerun
A Study on the Dynamic Characteristics of Long-Span Single Conductors Using Meshfree Methods2026-99-04248/28/2026
The free vibration characteristics of long-span transmission conductors form the fundamental basis for vibration control design, as their natural frequencies and mode shapes directly affect line safety and the selection of vibration suppression devices. In this study, the three-dimensional linear free vibration governing equations were derived through functional integration of the kinetic and potential energies by using Hamilton’s variational principle. Compared with the conventional integral transform method, an improved meshfree discretization strategy is proposed: the shape functions are constructed using the moving least squares (MLS) method, while the boundary conditions are treated with a fully transformed approach, thereby converting the partial differential equations into ordinary differential equations. Subsequently, a corresponding eigenvalue problem is solved to calculate the first few frequencies of the system, and the effect of conductor natural parameters on these frequencies for the transmission conductor is investigated. The results indicate that the natural frequency decreases when the conductor length becomes larger, and the rate of decrease becomes more gradual as the length increases; it decreases with increasing cross-sectional diameter; it decreases linearly with increasing material density; and it increases linearly with increasing elastic modulus. These findings demonstrate that conductor length, cross-sectional diameter, material density, and elastic modulus all have significant effects on the natural frequency. Among them, length and diameter affect the frequency by altering the conductor’s inertia and structural characteristics, whereas density and elastic modulus govern the frequency from the perspectives of inertia and stiffness, respectively.
Li, Chen, Cheng, Yongfeng, Li, Danyu, Qiu, Gang
Objective Quantification of Harmonic Impulsive Sounds and Interval Prediction of Sound Quality in Hybrid Vehicle Engines10-11-01-00038/28/2026
Steady advancement is observed in global research on eco-friendly and sustainable transportation. Rapid technological evolution of hybrid electric vehicles (HEVs) is documented. Lower overall noise output and more compact structures are achieved in HEV engines relative to conventional internal combustion engines. The perceptibility of harmonic impulsive sounds is significantly enhanced by these design characteristics. A close correlation is observed between these acoustic phenomena and negative human auditory perceptions. These events are treated as a core focus for HEV noise, vibration, and harshness optimization. Accurate quantification of harmonic impulsive sounds is not achieved by conventional objective indicators. A favorable balance between reliability and accuracy is not established by existing subjective prediction models. Practical engineering applications of these methods are severely restricted. A novel objective quantification method for harmonic impulsive sounds is proposed in this study. The method is established based on time–frequency masking theory and tonal strength. Bench tests in a semi-anechoic chamber and subjective evaluation experiments with standardized rating scales are performed for data collection. Collected sound signals are decomposed through an integrated approach of wavelet transform and variational mode decomposition. Targeted feature extraction is completed for harmonic impulsive sounds. A quantitative index incorporating human auditory temporal and frequency masking effects is developed. The proposed index exhibits a significantly stronger correlation with subjective evaluation results than traditional objective metrics, confirming its superior ability to reflect actual perceived sound quality. An interval prediction model for sound quality evaluation is established based on support vector machines and kernel density estimation. Traditional objective metrics and the proposed index are introduced as key input parameters. Effective and reliable prediction of HEV engine noise subjective satisfaction is achieved by the model.
Lin, Xu, Liang, Xingyu, Shi, Zhiyuan
Vibration Simulation of Guide Mechanism Based on Rigid-Flexible Coupling Dynamics2026-99-03108/14/2026
For vibration issues induced by coupling effects between flexible barrel guide mechanisms and moving bodies in high-speed dynamic systems, this study investigated their interaction mechanism using flexible multibody dynamics principles. A solid model was developed in 3D CAD software. The modal neutral file (MNF) of the guide mechanism was generated in ABAQUS, and its contact dynamics with the moving body were simulated in ADAMS via flexible contact theory and the modal superposition method. Comparative simulations revealed that incorporating structural flexibility yielded smoother fluctuations in the moving body’s axis inclination angle, providing more accurate system behaviour characterization. Exit velocity and spin rate errors remained below 5% against theoretical values, demonstrating model reliability.
Zhu, Qing, Cheng, Zixiang, Zhuo, Changfei
Structural Optimization Design and Experimental Study of a Shipboard Cabinet2026-99-09018/7/2026
The shipboard cabinet is an important carrier of radar equipment. It is necessary to ensure a good working environment and provide maximum support and protection for the internal equipment. In this paper, a shipboard cabinet that can realize a parallel heat dissipation architecture was taken as the object. The natural frequency and mode were used to find the area where the cabinet was prone to high-frequency vibration under impact excitation. The response characteristics of the cabinet under strong impact conditions were studied using a nonlinear transient dynamic analysis method. The weak links in the cabinet structure were identified, and the structural reinforcement design was carried out. After optimization, the maximum stress value of the cabinet was significantly reduced, and the safety factor was greater than 1.5. Finally, the effectiveness of the structural optimization was verified through experiments. The cabinet vibration isolation system was optimized and selected to ensure that it has good vibration isolation characteristics and impact response. The vibration isolation performance of the wire mesh isolator and the non-resonant peak isolator in the shipboard vibration and impact environment was verified by experiments. The impact transmissibility is less than 0.3, and the vibration transmissibility is less than 1.5, which can further improve the vibration and impact resistance of the shipboard cabinet.
Ni, Xiaokang, Jiang, Bo, Zhang, Liangjuan, Wu, Jingkai
Analysis of the Impact on Ride Comfort from Splitting the Unsprung Mass in Vehicle Modeling2026-01-50578/6/2026
The study was conducted to investigate the differences in ride comfort analysis between treating the unsprung mass as a whole and modeling it separately. A classical two-degrees-of-freedom single-wheel vehicle vibration model and a three-degrees-of-freedom single-wheel vehicle vibration model with split unsprung mass were established, with their state-space descriptions determined. The fundamental vibration response quantities of both models were identified, and time-domain simulations under random road excitation were performed using MATLAB/Simulink. The results indicate that the two modeling approaches exhibit minimal differences in ride comfort analysis for the sprung mass, but there are certain differences for the unsprung mass. Additionally, for the three-degrees-of-freedom single-wheel vehicle vibration model with split unsprung mass, the axle-to-wheel mass ratio was introduced to analyze the changes in the fundamental vibration response quantities when the unsprung mass increases by a fixed value and is distributed differently between the axle and the wheel. The results show that variations in the axle-to-wheel mass ratio have no significant impact on the vibration characteristics of the sprung mass. Reducing the mass ratio, i.e., transferring part of the unsprung mass to the wheel, can somewhat reduce the vertical acceleration of the unsprung mass, but it will slightly increase the relative dynamic load on the wheel. Finally, the other two models were simplified by combining the two masses connected by the bearings.
Jie, Li, Wei, Deng, Chengyu, Li
Multi-Objective Optimization Design of Ship Propulsion Shaft System in Ice Area Based on NSWOA Algorithm2026-99-01527/31/2026
Ship propulsion shaft systems are subjected to ice load excitation when ships are navigating in polar ice regions. Compared to conventional hydrodynamic effects, the ice load imposes higher requirements on the shaft system’s ability to withstand torsional stresses. To improve the power of the ship propulsion system when sailing in ice areas and reduce the power loss of the shaft system, while considering the vibration performance. In this paper, a multi-objective optimal design of the shaft system is carried out using the Non-dominated Sorted Whale Optimization Algorithm (NSWOA) to reduce stresses on both the motor shaft and the intermediate shaft. The coupled system model of motor-shaft system-propeller structural components is established, and the system dynamics response model is obtained by solving using the Newmark-β method. Based on the response model, a multi-objective whale optimization algorithm is used to optimize the power and vibration performance of the shaft system simultaneously. The optimized results show that the shaft system transfer efficiency is improved by 0.27%, and the stress at the shaft end is reduced by 11.8% and 12.3% respectively.
Hu, Chuanxi, Li, Yao, Pan, Shuxian, Liu, Zhiyong, Xie, Yuteng, Ye, Jun, Zhou, Ruiping
Research on Sealing and Vibration Reduction Performance of Large Sized Packaging Box2026-99-02027/31/2026
With the continuous development of large precision equipment, the reliability requirement for long-distance transportation is also constantly increasing. Large packaging box with sealing and vibration reduction performance is crucial during transportation. This article introduces the sealing measures for large-sized packaging box, as well as the sealing structure design methods for key parts, vibration reduction measures and the selection and design of vibration dampers. The designed packaging box has been used for long-distance transportation of various types of equipment and the reliability of sealing and vibration reduction performance has been verified in practical applications, providing reference for the design of similar packaging boxes.
Zhang, Ruoyu, Jiang, Shouli
Study on Energy-related Mechanisms of Aeroelastic Instability of Ultra-Long Flexible Wind Turbine Blades Under Various Working Conditions2026-99-01347/31/2026
With the continuous increase in wind turbine power capacity, ultra-long flexible blades face intensified aeroelastic instability risks due to reduced structural stiffness, enhanced modal coupling, and aerodynamic nonlinearity. In addition to the analysis of basic vibration characteristics, this study focuses on energy-related mechanisms of aeroelastic instability under various working conditions. Using a numerical model integrating Dynamic Blade Element Momentum Theory (DBEMT) and Geometrically Exact Beam Theory (GEBT), over 400 time-domain simulations were conducted to characterize instability onset and development. Results reveal four distinct aeroelastic instability regions, each dominated by specific modes. In Region A, flutter dominated by the 2nd flapwise mode is observed. In Region B, flutter dominated by the 1st edgewise mode is observed. In Region C, flutter dominated by the 2nd edgewise mode is observed. While in Region D, where the medial angle of attack (AoA) of the blade has exceeded the stall angle, stall-induced vibration dominated by the 1st flapwise mode is observed. Energy analysis shows aerodynamic work concentration near the blade tip drives instability, with diverse energy exchange patterns across regions. Except for some operating conditions in region C, where instability is dominated by edgewise energy absorption, most aeroelastic instability conditions are dominated by flapwise energy absorption. Torsional degree of freedom contributes minimally to aerodynamic work, but the torsional vibration exerts a notable influence on the AoA. This, in turn, changes the comprehensive aerodynamic forces impacting the blade as well as the general aeroelastic stability. This study clarifies the relationship between operating conditions and energy-driven instability, offering some reference values for the design work and safety assurance of ultra-long flexible blades of the wind turbine.
Wang, Su, Chen, Jiajia, Zhou, Le, Shen, Xin, Li, Chun, Du, Zhaohui
Enhanced Vibration Damping Properties of Novel Mn-Cu Alloy for Ship Structural Applications2026-99-02367/31/2026
Low-frequency vibrations in ships have detrimental effects on the lifespan of onboard equipment and the comfort of crew members, thereby highlighting the importance of developing efficient vibration-damping materials as a critical research area. This study investigates the application of Mn-Cu damping alloys for mitigating vibrations within the 0–1000 Hz frequency range, which is typical of ship environments. The vibration-damping characteristics of the material were examined through a combination of experimental and numerical simulations. A numerical simulation framework was developed to predict the vibration response of manganese-copper damping alloys, incorporating a frequency-dependent damping ratio model derived from experimental characterization. Comparative analyses validated the accuracy of vibration simulations that incorporate frequency-dependent damping ratios and demonstrated the superior vibration attenuation performance of the Mn-Cu damping alloy across the 0-1000 Hz frequency band. Deck application analysis revealed that manganese-copper damping devices reduced the root mean square (RMS) vibration acceleration of the ship deck by up to 17.5% in the 0-1000 Hz frequency range compared to aluminum alloy counterparts. The damping effect was particularly significant in the 400–1000 Hz range, where vibration energy dissipation was most effective due to the material's intrinsic damping mechanisms. Additional engineering evaluation confirmed that the Mn-Cu alloy components maintain structural integrity while providing enhanced damping performance under typical marine environmental conditions. This study establishes a theoretical foundation for the design of ship vibration-damping materials, expands the potential applications of damping alloys in marine engineering, and provides valuable reference data for material selection and vibration control design in shipbuilding and offshore engineering applications.
Yao, Sitong, Tian, Ali, Zhao, Xianghua
Analysis of the Cause of Knocking Noise in a Marine Dual-Power Dual-Branch Transmission Gear System2026-99-16507/24/2026
This study investigates the knocking noise phenomenon in a marine dual-power dual-branch transmission gear system. Vibration mechanisms are analyzed, and potential failure modes are assessed. System vibration data were evaluated using time-domain and frequency-domain methods. Results show that overall vibration levels remained within acceptable limits, with no indication of imminent failure. Physical inspection confirmed that the shaft, gears, bearings, housing, and installation met specifications, with no observed performance degradation or structural damage. By correlating noise occurrence with vessel loading conditions, a strong relationship was identified among gear transmission torque, the power distribution ratio between high-and low-pressure turbines, and the onset of knocking. Specifically, under low-load conditions, uneven power and torque distribution among the four gear branches led to insufficient loading on the low-pressure side. This light-load state induced instability in the low-pressure gears, resulting in periodic tooth disengagement or back-side tooth contact, which is established as the root cause of the knocking noise.
Gu, Chengzhong, Xu, Hanwei, Luo, Rirong, Ren, Fushan
Fatigue Life Analysis of Diesel Engine Filter Seat under Random Vibration Condition2026-99-16567/24/2026
The filter seat of diesel engine fuel filters is a key load-bearing component in the engine fuel system. Its structural integrity directly affects the reliability and safety of fuel delivery. In actual operation, the filter seat is subjected to random vibration loads generated by engine operation and vehicle dynamics, which may cause fatigue failure over time, even when static stresses are below the yield strength. This study employs finite element modeling (FEM) to investigate the structural strength and fatigue life of the diesel engine filter seat under random vibration conditions. The CAD model is simplified and meshed to reflect the main load paths, and boundary conditions, including bolt preload, gravity, and measured vibration PSD spectra are applied. Modal and harmonic response analyses are performed using Abaqus, and the Tovo-Benasciutti frequency-domain method is used in fe-safe to predict fatigue life. The results identify the most fatigue-sensitive areas and reveal that the minimum fatigue life is 10^3.067 cycles under realistic conditions, with the most critical regions located near the bolt connection. The simulation methodology and results provide a reliable basis for structural optimization and life prediction of similar components under random vibration environments.
Gu, Kexuan, Zhu, Yi, Xie, Liang, Wang, Wei
A Novel Rotating Component Comprehensive Diagnostic Network Based on Stacked Auto Encoders and Sparse Filter Combined with Generative Adversarial Network2026-99-05347/10/2026
Nowadays, the majority of intelligent fault diagnosis approaches are still centered on individual faulty components, while only a limited number of models are capable of performing integrated diagnosis for rotating systems that consist of shafts, bearings, and gears. Under variable-speed operating conditions, the large scale of vibration data further complicates the process of effective feature extraction. To improve these challenges, this study develops a comprehensive diagnostic framework for rotating components, termed WGAN-SAFC. The proposed architecture integrates a Wasserstein Generative Adversarial Network (WGAN) with a hybrid structure of stacked autoencoders and sparse filtering (SAFC). SAFC integrates the feature-learning capability of SAE and the sparsity-driven representation of SF, while incorporating adversarial data generation to address sample imbalance and enhance fault diagnosis performance. Experimental verification on collected vibration datasets demonstrates that WGAN-SAFC achieves superior diagnostic accuracy and robustness compared with existing methods.
Li, Shunming, Feng, Mengqi
Analysis and Improvement of Rattle Noise in Manual Transmission2026-99-05277/10/2026
In response to the problem of manual transmission rattle noise in the acceleration process of a truck, the mechanism of the problem is analysed, and the scheme is developed and verified from two aspects: reducing the torsional vibration of the system and reducing the response of the transmission gear. The results show that, on the one hand, reducing the clutch stiffness and optimizing the torsional vibration of the system can reduce the rattle noise of the transmission; On the other hand, it can also reduce the rattle noise of transmission gears by improving the engagement precision of transmission gears and reducing the gear clearance. Considering the improvement effect, cost, and influence on other performance of the two schemes, the appropriate engineering scheme is selected to effectively solve the problem and improve the riding comfort of the product.
Yang, Zhijie, Xu, Binghua
Aircraft Noise Event Identification Technology Based on Single Acoustic Vector Sensor2026-99-05917/10/2026
With the rapid development of China’s civil aviation industry, the problem of airport noise has attracted widespread social attention. The requirement for the real-time monitoring and evaluation of acoustic environment around airports is becoming more and more intense. The identification of aircraft noise events in the complex acoustic environment surrounding the airport is the most critical technical problem in airport noise monitoring. However, the traditional noise source identification technology is difficult to be widely used in real-time monitoring system due to its large errors and complex deployment conditions. This paper presented an aircraft noise source identification technique based on a single acoustic vector sensor. The azimuth parameters of the noise source were estimated by the three-dimensional spatial positioning algorithm of sound pressure and particle vibration velocity combined with information processing, and the three-dimensional footprint of the noise event in the complex acoustic environment was described. Finally, the event was judged as an aircraft noise event by matching the noise footprint with the aircraft flight path. By monitored and analyzed the actual noise events of aircraft departure, the results show that this method can only use a single acoustic vector sensor to locate the aircraft noise source and distinguish the aircraft noise event from the background noise event, which provide a new lightweight method for the real-time airport noise monitoring system to locate the noise source and identify the aircraft noise event
Hou, Jiayu, He, Tianlun, Zhu, Lin, Chen, Ying, Liu, Yinhui, Lv, Lei, Wang, Yuhao, Chen, Da
Design and Testing of a Quasi-Zero-Stiffness Vehicle-Mounted Isolation System with Additional Inerter2026-99-05207/10/2026
Vehicle vibrations during precision instrument transport can cause damage and failure. Existing vibration isolators often lack reliability, mass production feasibility, and easy maintenance. In this paper, we design and analyze a quasi-zero-stiffness vehicle-mounted isolator with an inerter, decreasing dynamic stiffness while raising the effective mass. Theoretical, simulation, and experimental results show improved isolation performance, lower isolation frequency, and a broader isolation bandwidth.
Li, Kai, Lv, Sibo, Sun, Ning, Dai, Shijie
Evaluation of Helicopter Turbine Engine Linear Vibration EnvironmentAIR1289A (Current)6/29/2026
This SAE Aerospace Information Report (AIR) outlines a recommended procedure for evaluation of the vibration environment to which the gas turbine engine powerplant is subjected in the helicopter installation. This analysis of engine vibration is normally demonstrated on a one-time basis upon initial certification, or after a major modification, of an engine/helicopter configuration. This AIR deals with linear vibration as measured on the basic case structure of the engine and not, for example, torsional vibration in drive shafting or vibration of a component within the engine such as a compressor or turbine airfoil. In summary, this AIR discusses the engine manufacturer’s "Installation Test Code" aspects of engine vibration and proposes an appropriate measurement method.
S-12 Powered Lift Propulsion Committee
Holistic Sound Package Design for Optimal NVH and Carbon Footprint of a BEV2026-01-07086/20/2026
Vehicle sound packages are usually designed to provide a given level of vehicle Noise, Vibration, and Harshness (NVH) comfort, within weight and cost constraints. Optimal comfort results can be obtained by considering the interaction of all the parts as a full physical system. So far, extensive research has already been performed and published on optimizing vehicle sound packages to achieve effective noise reduction at lowest cost and weight. Nowadays, due to the urgency of the transition to carbon neutrality, sound packages must also address the reduction of the full vehicle life cycle carbon emissions. Sound package components should use materials that have a low emission impact during production and that are suitable for recycling at the end of the vehicle’s life. This entails reconsidering the material solutions chosen for the sound package as a whole, rather than for each individual component. This article describes possible differentiations in the design of a sound package involving NVH, sustainability, and weight/cost requirements. The study examines how interior and exterior trim components were combined to achieve both optimal NVH and polymer rationalization, through the introduction of mono-material parts and focusing in particular on the use of a new polyester fiber-based floor decoupler, which achieves comparable NVH performance to polyurethane foam without affecting static compression. The article summarizes the vehicle-level performance related to NVH, sustainability, and weight for three sound packages prioritizing either NVH, sustainability or material cost, including a breakdown to analyze the contributions of various components to the overall outcome. A simple metric is introduced to evaluate sustainability, including material, production, use-phase and end-of-life related Greenhouse Gas (GHG) emissions [7–10]. The NVH evaluation involves measuring airborne transfer functions (ATF), complemented by indoor road noise tests. NVH improvements were achieved without an increase in weight, and weight reduction was also possible without negatively impacting NVH performance, both results enhancing the carbon footprint.
Courtois, Theophane, Cardillo, Marco, Criscione, Mattia, Gerges, Youssef, Massocco, Andrea
Automating Component NVH Characterization: A Systematic Approach for Component Test Bench Characterization2026-01-07046/20/2026
Vehicle electrification and accelerated development cycles create a need for virtual Noise, Vibration and Harshness (NVH) development tools which are fast, precise and, seamlessly interchangeable between development sites, suppliers and OEMs. Component-based Transfer Path Analysis (C-TPA), standardized in ISO 20270:2019, enables independent component characterization and integration with virtual models to predict sound and vibration in new assemblies, referred to as Virtual Prototype Assemblies (VPA). However, conventional measurements are labor-intensive, typically restricted to a small number of samples, and overlook production variability. This paper introduces a fully automated, ISO 20270-compliant C-TPA system for non-rigid test benches, featuring a pre-instrumented test fixture with multiple vibration shakers and sensors automatically linked to a data acquisition system for immediate processing. Components can be characterized within minutes, with blocked forces directly integrated into a VPA workflow, replacing time-intensive in-vehicle testing with a repeatable, operator-independent bench procedure. A case study on an automotive steering system demonstrates the method’s accuracy, repeatability, and efficiency, along with its ability to predict realistic interior sound pressure levels and capture production variability, enabling robust virtual NVH evaluation early in the development cycle.
Sturm, Michael, Wienen, Kevin, Brandstetter, Markus, Sorber, Eric, Corbeels, Patrick, Verrecas, Bart, Gonçalves, Vinícius
Methodology Development for Electric Drive Module Vibro-Acoustic Assessment Using Simulation Measurement Comparison and Root Cause Analysis2026-01-06916/20/2026
The virtual development of Electric Drive Modules (EDMs) for Battery Electric Vehicles (BEVs) requires proven and predictive methodologies. One part of the development investigates the vibro-acoustic assessment for the low- and high-frequency ranges within the targeted operating range. The efficient use of such a methodology requires an understanding of the accuracy and validity of the achievable results, as well as the derivation of suitable improvement measures for goals that have not been achieved. The use of reference data from experimental investigations and a detailed root cause analysis (RCA), to directly link a specific response and behavior to the excitations, modal content, and transfer functions, is an essential and non-trivial part of the methodology development. This paper describes the development of such a methodology using the example of a new EDM virtual model for Noise, Vibration and Harshness (NVH) analysis, including the simulation approach, validation, and evaluation procedure. It discusses how RCA can be applied to different observed phenomena in EDM NVH behavior and detected deviations between the initial model and the measurements, the main influencing parameters, and the identified improvement potential for simulation models.
Klarin, Borislav, Pevec, Denis, Resch, Thomas, Esposito, Sara, D'Alessandro, Vincenzo, Spanu, Giorgio
Best-in-Class NVH Optimisation for Electric Powertrains, Holistic Front-Loading Approaches2026-01-06896/20/2026
Achieving best-in-class Noise, Vibration, and Harshness (NVH) in electric powertrains demands a paradigm shift in development methodology. This paper presents a practice-oriented overview of simulation methods in NVH development methodology for electric drive units. This includes target cascading and multi-objective optimisation, and by attacking NVH at the source using KPIs early in the design cycle, significant reductions in development time and reliance on traditional testbed loops are realised. Machine learning (Neural Network) algorithms are utilized to find the best-in-class design, using multi-objective optimisation as well as refining simulation accuracy by adding tolerance effects while target cascading ensures alignment of system-level performance objectives down to subsystem contributions. Combined, these strategies enable rapid and robust NVH optimisation, using simulation for next-generation electric powertrain development. Several applications and real-life examples demonstrate how simulation helped with NVH issue identification or improvement.
Mehrgou, Mehdi, Garcia de Madinabeitia, Inigo, Graf, Bernhard, Gojo, Josef
Vibroacoustic Analysis and Optimisation of an Electric Refrigerant Scroll Compressor2026-01-07226/20/2026
In electrified vehicles, auxiliary components can represent a dominant source of noise, one of which is the refrigerant scroll compressor. Compared with vehicles equipped with internal combustion engines, electrified vehicles require larger refrigerant compressors, as thermal management is needed not only for the passenger compartment but also for the battery and electric drive components. Excitation mechanisms within the compressor, arising from the cyclic compression process and the eccentric motion of the scroll, induce housing vibrations and result in airborne sound radiation. To investigate the vibroacoustic noise generation mechanisms of a scroll compressor, operational vibrations were analysed using accelerometers and three-dimensional laser scanning vibrometry. In addition, the radiated sound was characterised using microphones and near-field sound intensity measurements. The results demonstrate a strong correlation between surface vibrations and airborne sound radiation, with the vibroacoustic behaviour being dominated by speed-dependent tonal components. Pronounced vibration and sound radiation levels occur when excitation orders coincide with rigid-body modes of the mounting system or structural eigenmodes of the compressor housing. Based on these findings, a constrained-layer damping treatment was applied to selected, highly sound-radiating regions of the compressor housing. Although the overall reduction in sound power was limited due to the high stiffness and predominantly rigid-body behaviour of the housing, local vibration and sound radiation reductions were achieved for structurally flexible components, resulting in a perceptible improvement in subjective sound quality. These results highlight the importance of spatially resolved vibroacoustic analysis for understanding noise generation mechanisms and for guiding targeted optimisation measures for refrigerant compressors.
Saur, Lukas, Beer, Gabriel, Fritzsche, Marco, Becker, Stefan
FBS as Key Enabler for Efficient Root Cause Analysis in NVH Simulations2026-01-07106/20/2026
Noise, Vibration, and Harshness (NVH) performance is critical in the automotive development process, yet identifying the true root causes of unwanted dynamic behavior remains a challenge in full vehicle or system-level finite element (FEM) models. This work demonstrates how Frequency Based Substructuring (FBS) provides an efficient framework for understanding NVH phenomena and facilitates new root cause analysis (RCA) types and processes. To begin, we prove the numerical accuracy of the FBS algorithm deployed in the presented investigation by comparing its results with those obtained with superelements and without substructuring. We point out that because the used FBS process starts with a modal representation of the components rather than their frequency response functions (FRF) a different class of RCA type becomes available. Then we introduce new RCA types starting with an analysis named Modal Influence (MI) that reveals the effect of the modes of any component on a certain response. Its key characteristic is that MI analysis is not restricted to the response component opposite to the well-known modal participation factors. Finally, a second novel analysis type is introduced, an advanced variant of Transfer Path Analysis (TPA). While standard TPA assesses the paths between only two system components, the new Expanding TPA is a multi-step process that identifies the most critical path across all components in a fully automated way.
Herbst, Markus
Simulation and Analysis of Flow and Acoustic Induced Structural Vibration2026-01-06966/20/2026
For analysing flow and acoustic induced structural vibration, a fully run time coupled framework combining a hybrid CFD-CAA approach with a modal response simulation was validated and presented at the ISVNH 2022 (SAE Technical Paper 2022-01-0938). In this paper i We apply this CFD–CAA–modal coupling method to a series-representative bonnet geometry and demonstrate its capability to capture flow and aeroacoustically driven vibration with two-way coupling. ii We analyse the modal properties of the bonnet and show that confined air volumes beneath the bonnet can introduce significant fluid loading effects, which are already embedded in experimentally validated FE modal models and must therefore be treated carefully in two-way coupled simulations. iii We validate the fully coupled aeroelastic simulation against wind-tunnel measurements with undisturbed inflow, show close agreement with the measured vibration response and analyse that the dominant excitation is in this case from below the bonnet due to acoustic pressure fluctuations.
Schwertfirm, Florian, Ocker, Joerg, Hartmann, Michael
A Study of Improving Door System Sound Transmission Loss2026-01-06756/20/2026
Recent studies indicate that the door system plays a significant role in the interior noise levels of newly developed vehicles. This research investigates the noise transmission paths through the door system and identifies effective strategies for improvement through a combination of door buck testing and simulation. Specifically, in this study, the finite element method (FEM) was employed for door buck simulation, and the model was validated against vibration test results. Subsequently, acoustic analysis tools were utilized to correlate with noise testing, thereby establishing a process to ensure simulation accuracy. The sound insulation performance for the main areas of the door was experimentally evaluated, and a simulation model with good correlation to these test results was developed. By utilizing both experimental and simulation results, the principal transmission paths were identified, and appropriate improvement strategies for these paths were investigated. The validated improvement strategies are intended to be applied in the development of next-generation vehicles.
Chae, Ki-Sang, Jang, Jinung, Jeong, Hojung, Do, Hyuncheol, Han, Jinwoo, Yi, Jaebok, Bak, Seong-Jae, Jeong, ChanHee
Joint Estimation of Inputs and States for Multi-Axis Vibration Environment Testing2026-01-06836/20/2026
Monitoring inputs and states of a structural dynamic system is often challenging, as direct measurements are costly or even infeasible. A virtual sensing methodology is presented for jointly estimating the input and state of a structure when subjected to multi-directional base excitations. The approach uses a tuned Kalman Filter combined with a model-order reduction of the system model to ensure a low computational cost whilst allowing accurate estimation from a limited number of acceleration measurements. This enables real-time virtual health monitoring strategies and reduction in instrumentation during data acquisition without additional information such as location and direction of application about the inputs. The proposed methodology is validated numerically and experimentally using a notched aluminum beam excited on a multi-directional shaker table, driven simultaneously in two in-plane directions. The study demonstrates accurate full-field estimation of multiple responses along the beam as well as a joint-input-estimation. The results highlight the relevance of multi-axis vibration environments and the importance of multiple-input-multiple-output testing for dynamic characterization and structural health monitoring applications.
Salazar Colunga, Rodrigo, Pandiya, Nimish, Dindorf, Christian, Naets, Frank
A Modular Method for Certified Virtual Validation of NVH Performance in Automotive Platforms2026-01-06846/20/2026
This work presents a modular engineering methodology (DiPhyBa - Digital Physical Balance) for the virtual validation of Noise, Vibration, and Harshness (NVH) performance in automotive development. The approach addresses the inefficiency of repeated physical testing across vehicle variants by introducing a structured two-phase process—Launcher and Reskin—centered on quantitative performance indicators with formal acceptance thresholds. In the Launcher phase, a digital replica of the base vehicle is built and iteratively correlated with physical test data. Validation is governed by objective indicators of confidence, conformity, and correlation, each evaluated against predefined thresholds. Once validated, the model becomes a certified reference, enabling its reuse across derivative configurations in the Reskin phase. Physical testing is only required if indicators fall below threshold, with a final gate test on pre-series vehicles ensuring industrial robustness. DiPhyBa formalizes the decision to replace physical testing with simulation, introducing automation, traceability, and repeatability into the validation workflow. The method is scalable across platforms and adaptable to other technical domains such as durability, thermal, and safety. The long-term industrial ambition is to progressively minimize redundant NVH testing on vehicle variants. Early applications demonstrate significant reductions in development time and cost, while enhancing confidence in simulation-based decisions. DiPhyBa bridges the gap between digital simulation and industrial validation, offering a new standard for virtual engineering in the automotive sector.
Celiberti, Lucia, Camia, Andrea
High-Fidelity NVH Analysis Model Development Process for EV Traction Motors Based on Experimental Correlation2026-01-06856/20/2026
This study presents a high-fidelity NVH (Noise, Vibration, Harshness) analysis model development process for EV traction motors. The proposed process consists of two main components: Path advancement through structural stiffness tuning, and Source advancement, focused on the motor’s excitation mechanisms. Model accuracy was validated through comparison of simulation results with dyno experiment data, with particular focus on the 24th-order electromagnetic vibration observed in an 8-pole, 48-slot motor. Path advancement was achieved through modal correlation between experimental results and finite element (FE) analysis. Nine modal experiment and simulation stages were conducted, ranging from individual components to the complete motor assembly. Mode shapes were compared using the Modal Assurance Criterion (MAC), and natural frequencies were matched within a 5% error margin by adjusting FE material properties. For the 24th-order electromagnetic vibration, simulation results agreed with experiment data within a 7% error margin for natural frequency. However, notable discrepancies remained in vibration amplitude. To resolve these discrepancies, Source advancement was performed. The initial excitation source was derived from idealized electromagnetic analysis, considering radial and tangential force as well as torque ripple. However, rotor eccentricity caused by mechanical assembly tolerances is commonly observed in actual motors. Therefore, the advanced source accounted for rotor–stator eccentricity in the electromagnetic analysis. As a result, the NVH simulation incorporating the advanced source matched the vibration amplitude within a 1% error margin compared to experimental results. The proposed NVH model development process enables more accurate vibration prediction in the early design phase of electric drive motors and is expected to significantly improve NVH performance in future electric drive systems.
Kim, Donghee, Kim, Dong-Jun, Lee, SangHan, Kim, Seon Hyeong, Hwang, Seung Gyu, Valente, Giorgio, Parisouz, Shahriar, Halse, Christopher
Field-Based Evaluation of Physiological Fatigue Reduction in Fuel Cell Refuse Collection Vehicle Using Heart Rate Variability2026-01-06906/20/2026
Understanding the physiological impact of vehicle electrification on operators remains an important but underexplored issue in commercial vehicle research. This study quantitatively evaluates the physiological fatigue of drivers and onboard crew members during real-world operation of commercial refuse-collection vehicles by comparing a diesel-powered vehicle with a fuel cell electric vehicle (FCEV). Both vehicles were operated on the same routes under comparable real-world operating conditions, including similar time periods and operational tasks, during municipal waste collection service. Heart Rate Variability (HRV) metrics were obtained from R-R interval (RRI) data recorded using a Polar heart rate sensor. The Root Mean Square of Successive Differences (RMSSD), a time-domain index reflecting short-term parasympathetic activity, and Poincaré (Lorenz) plot area (LP area), a nonlinear HRV index reflecting overall autonomic nervous system modulation, were calculated. In-cabin vibration and noise levels were also measured as supplementary context to support the interpretation of physiological responses. The results indicate that both RMSSD and LP area were higher during FCEV operation than during diesel vehicle operation. For the driver, RMSSD increased by approximately 61.65% and the LP area by approximately 49.91%. For the onboard crew member, RMSSD increased by approximately 18.79% and the LP area by approximately 46.02%. These findings suggest a consistent association between reduced vibration and noise characteristics in the FCEV and increased HRV indices, indicating reduced physiological fatigue during operation. This study provides quantitative evidence that fuel cell electric commercial vehicles are associated with improved occupational conditions, extending beyond conventional environmental benefits.
Utsumi, Atsuko, Yakoh, Takahiro
A Self-Learning Framework for NVH CAE Analysis2026-01-07186/20/2026
The vibro-acoustic performance of a vehicle is a critical factor in customer perception of quality and comfort, yet optimizing for Noise, Vibration, and Harshness (NVH)—specifically road noise—presents a persistent challenge in the modern automotive development cycle. While advanced Finite Element Method (FEM) analysis is essential, the increasing complexity and volume of CAE simulation data often overwhelm manual interpretation, potentially leading to prolonged development times or compromises in final comfort quality. To address these challenges, this paper introduces the application of CDH/ACE (Autonomous Computational Experiments), a framework that integrates conventional CAE simulation workflows with advanced machine learning in an iterative, cyclic process. This creates an exceptionally user-friendly and self-correcting system that autonomously defines, performs, and learns from computational experiments. By leveraging machine learning algorithms to build robust predictive models from simulation data, the framework intelligently guides design exploration to achieve complex engineering objectives such as design of experiments, multi-objective optimization, and robustness analysis. We demonstrate this methodology through a comprehensive full-vehicle road noise optimization study, detailing the process of defining experiment parameters and configuring acoustic targets within the autonomous learning cycle. The results highlight the effectiveness of this highly automated and intuitive workflow, showing significant reductions in road noise and vehicle mass alongside a substantial decrease in manual engineering effort. Finally, the paper presents the tangible benefits of this approach, assessing current advantages and limitations while providing an outlook on the future application of autonomous, machine-learning-driven methodologies in accelerating modern vehicle development.
Visser, Rene
Feasibility of Hybrid Dynamic Substructuring for Structural Modifications in Automotive Suspension Subsystems2026-01-06976/20/2026
Recent advancements in system-level NVH (Noise, Vibration, and Harshness) development methodologies have improved target cascading and enabled more efficient system-level optimization. Dynamic substructuring facilitates the virtual integration and modification of multiple subsystems and the prediction of changes in overall transfer functions. In practical automotive applications, advanced frequency-based substructuring has been applied to virtually modify system parameters, such as mass and stiffness, at multiple points in a target system, allowing prediction of the resulting effects and optimization of parameter changes without physical intervention. This study extends the methodology by introducing an enhanced substructuring approach capable of addressing not only basic parameter modifications but also large-scale structural changes. The proposed process involves identifying the characteristics of a base system assembly and a target subsystem, decoupling the subsystem from the assembly, incorporating structural modifications, and predicting the resulting transfer function changes. The method was validated through two complementary workflows: a fully experimental test-based workflow and a hybrid workflow. The test-based workflow demonstrated the reliability of substructuring operations, decoupling and coupling, by experimentally evaluating the base assembly, the original subsystem, and the structurally modified subsystem. The hybrid workflow replaced the experimental subsystem models with finite element models, thereby demonstrating the feasibility of substructuring numerical subsystem models with a physical system assembly. Together, these workflows are applied to one of automotive suspension subsystems, cross-member, which can establish the accuracy, flexibility, and practical applicability of the proposed method in supporting system-level NVH development and structural optimization.
Cho, Munhwan, Boelens, Jelle, Reichart, Ron, de Klerk, Dennis, Ahn, Jiho
Influence of Common-Mode Voltage Reduction Techniques on High-Frequency Sideband Vibrations in IPMSM Drives for EVs2026-01-06956/20/2026
Space vector pulse width modulation (SVPWM) induces common-mode voltage (CMV) in three-phase voltage-source inverters, producing steep voltage edges that can lead to high leakage currents. In electric drive applications, these currents accelerate motor bearing degradation and may cause winding insulation failure. Active-zero-state PWM (AZSPWM) and near-state PWM (NSPWM) have been proposed as alternative modulation strategies to mitigate CMV and reduce drive degradation. This paper investigates the noise, vibration, and harshness performance of AZSPWM and NSPWM in comparison with conventional SVPWM. The proposed CMV reduction schemes are evaluated in terms of both CMV mitigation and their impact on high-frequency sideband vibration harmonics. Experimental results demonstrate that the CMV reduction strategies are highly effective in lowering CMV levels relative to SVPWM; however, this benefit is accompanied by an increase in vibration levels, which may adversely affect the mechanical integrity of the drive system despite the reduction in bearing leakage currents.
Khamis, Mahmoud Aly, Tatar, Andrei Alexandru, Repecho, Victor, Doria-Cerezo, Arnau
NVH Design and Refinement of Dedicated Hybrid Engine on Range-Extended Electric Vehicle2026-01-06886/20/2026
Simplicity and electrification of the propulsion system are one of the most important trends in vehicle development and integration process. The complexity of NVH (Noise, Vibration and Harshness) design and refinement is the core challenge to this process. Customers’ expectations of an unnoticeable engine during driving make this challenge more critical [1]. Apart from the overall sound pressure level, the sound quality is even more important due to the lack of noise masking effects [2]. Therefore, the development team has reached an internal consensus that NVH attributes are the top priority in engine development. This paper describes the NVH development process of a dedicated hybrid engine for the range extender electric vehicle (REEV) application, beginning with an introduction to REEV system as well as the operating condition data of long-distance road tests. Based on the road test data, the engine technical specification is defined accordingly and broken down into design targets for all individual components. Subsequently the design target is finally achieved through the definition of engine architecture, hardware selection, and individual component simulation and optimization. With regard to the NVH refinement, the NVH issues such as global crankshaft vibration, start impacts, high-pressure fuel system ticking, and acoustic encapsulations studies are discussed. Finally, the appropriate optimization proposals are summarized and the bench test results are presented.
Wang, Hao, Zhang, Guiqiang
Coupled Loads Analysis of a Single Stage Launch Vehicle for Vibration Test Level Generation2026-26-07416/1/2026
Gaganyaan is an ambitious and recover safety mission for the Indian space program to launch humans into space. The success of the mission depends on the development of required technology and systems. A test vehicle is developed for the technological demonstration for all envisioned abort flight scenarios of Gaganyaan mission. A new configuration of launch vehicle with single liquid stage is planned for multiple flights. Coupled Loads analysis of launch vehicle system is a standard practice to estimate response and loads for the design of structures and generating sine vibration test levels. Usually a vehicle rests on the launch pad through base shroud with horizontal support and no vertical restraint. Upon ignition of the engine, thrust builds up and upon overcoming gravity the vehicle takes off. In the current analysis the launch vehicle is held in position using a holding / retracting mechanism and at a predefined time the vehicle is released. The boundary condition required a novel method to perform response analysis. The responses estimated from pre-flight analysis is correlated with flight response and a good correlation is observed. Additionally response analysis is performed at engine shut-off. Being the first flight, no flight data was available of engine thrust. In the current work, using an analytical thrust, responses are estimated. The analysis also helped in generating levels for vibration test of various sub-assemblies and payload.
Kurudimath, Kottresh Maharudraiah, Jalan, Salil, Rose, Jancy
Retrofit Vibration Mitigation of Launch Vehicle Structures Using Thin Viscoelastic Coatings: Acoustic and Modal Study2026-26-07366/1/2026
Acoustic-induced vibrations pose a significant risk to launch vehicle hardware and payload reliability during critical phases such as lift-off and transonic phase. Reducing such vibrations is especially challenging when the hardware has already been fabricated, limiting the possibility of structural redesign. This study demonstrates a practical post-fabrication solution using a thin viscoelastic polymer coating applied externally to fully assembled hardware. Comprehensive evaluations were conducted using both acoustic testing and Experimental Modal Analysis (EMA) before and after coating application. During acoustic test, a substantial decrease in structure response from 150Hz to 2000Hz, with a reduction of approximately 50% in the grms values was observed for the coated structure demonstrating significant vibration mitigation over a wide frequency range. In contrast, EMA measurements using impact excitation revealed that the response transfer functions did not show a significant reduction within the band considered and modal properties remained largely unchanged upto 200 Hz, indicating that the coating did not significantly alter the structural properties. The apparent enigma calls for a detailed study. A brief overview on the results and the plausible reasons are detailed in the paper. Out of the probable causes, the observed vibration reduction can be primarily attributed to the operational damping and mass addition effects of the PC10 coating. These findings highlight an effective and practical approach for mitigating acoustic-induced vibrations in aerospace structures, with direct application to launch vehicle stages and other aerospace hardware where post-fabrication solutions are critically needed.
Avirah, Nohin K, Panda, Ajay Kumar, Shaikh, Altafhusen
Vibration-Based Methods for Non-Destructive Prediction of Buckling Loads2026-26-07376/1/2026
Using vibration data to estimate buckling loads is proven effective for a wide range of structures, including rods, plates, and shells. The Arbelo formulation of the vibration correlation technique improves prediction reliability for cylindrical and spherical shells. In this study, we introduce a simplified variant of the Arbelo approach that provides higher prediction accuracy while requiring significantly lower pre-load levels. We define a new parameter, the Stiffness Decay Index (SDI), to characterize stiffness degradation by normalizing the loaded natural frequency with respect to the unloaded state. This metric enables accurate buckling prediction without causing structural damage or permanent deformation. We evaluate SDI numerically and experimentally for multiple isotropic geometries and demonstrate its advantages over the Arbelo method, particularly for ellipsoidal domes subjected to external pressure. We conduct experiments on rods, plates, oblate shells, and beverage cans to measure frequency shifts under pre-loading. The results show that when load data above 50% of the critical value is available, the SDI approach predicts the buckling load with accuracy exceeding 90%. These findings confirm that SDI, by directly correlating vibration response with stiffness loss, provides superior buckling-load prediction and serves as a reliable, non-destructive alternative to the Arbelo vibration-correlation method.
Rangarajan, Gopikrishna, V, Vishwajith, Raju, Gangadharan, Dinavahi, Ramkrishna
A Simulation Method for Automotive Door Jitter Containment10-10-03-00225/21/2026
This article describes multi-body dynamics simulation to investigate door jitter issues caused by the limiter during door operations. A simulation model integrating a rigid limiter and a flexible door-body system was developed to replicate the dynamic process of wide-angle door opening/closing. Through iterative refinements—including correlation of simulation results with test data, optimization of internal door connection methods, and solid-element hinge modeling—simulation accuracy was improved to over 89.7%. Using the validated model, quantitative metrics were established to evaluate door jitter severity. Key parameters that influence the door operation smoothness were identified, and an optimization scheme was proposed for a specific vehicle model, incorporating slope-holding performance requirements under hill-parking conditions. Finally, prototype testing validated the approach’s effectiveness. The developed simulation method provides a technical foundation for virtually resolving door jitter issues during vehicle development.
Xiao, Yongfu, Deng, Jianjiao, Li, Jingtan, Yang, Tao, Hou, Hangshen, Han, Chao, Gao, Meng, Wang, Yiqi, Liu, Yihong
Items per page:
1 – 50 of 3917