Browse Topic: Vibration

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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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
Optimization Using Analytic Sensitivities Derived from an Advanced Coupling Framework: Applications to Rotor Blade TwistF-0082-2026-02345/5/2026
An advanced coupling framework was leveraged to assemble analytic sensitivities of lifting line theory aerodynamic loads with respect to externally-defined blade geometry parameters for optimization of main rotor performance of conventional helicopter configurations. Three vehicle weights and two flat-plate-equivalent drag configurations were examined across the flight envelope from hover to an advance ratio of 0.3. Two types of twist controls were investigated: quasi-static and fully active. Power savings were strongly correlated to the forward flight to hover power, ranging between 1.5 and 3.5% for quasi-static geometries and 2.0 and 4.5% for fully active controls when the installed power is twice of that required in hover. Blade twists optimized at higher power ratios were observed to favor high shaft tilt angles. Optimal twist deformation relative to hover-optimized designs is nonlinear across the blade span. Minimal penalties to aerodynamic vibrations were incurred through the use of either quasi-static or fully active twist controls as measured with a vibration intrusion index.
Hansen, Josh, Reveles, Nicolas
Dynamic Testing and Component Inspection of a Pericyclic Drive SystemF-0082-2026-01945/5/2026
After four decades of research and 3.5 year prototype testing campaign, Penn State's pericyclic transmission technology demonstrator, dubbed the 'Pericycler', has achieved its operating speed of 5,000 RPM at 17 HP. The characterization of this system by experimental efficiency and vibration represents a major milestone in pericyclic gear technology. A post-test inspection procedure was performed to analyze component wear and validate hypotheses on mesh behavior. This work concludes with structural, tribological, and instrumentation modifications to the Pericycler for future testing.
McGovern, Jeremy, Eicholtz, Keith, DeSmidt, Hans, Darmstadt, Patrick, Mathur, Tanmay, Stevens, Mark, Smith, Edward, Schroen, Erik, Mitsingas, Constandinos
Hierarchical Control Strategy Evaluation and Migration for a Four-Degree-of-Freedom Quarter Commercial Vehicle02-19-03-00144/9/2026
In order to improve the comfort performance in commercial vehicles, this study proposes a hierarchical control strategy that integrates the evaluation and migration of control algorithms. First, a quarter-vehicle model with four-degree-of-freedom (4-DOF) is constructed, incorporating the dynamics of the wheel, frame, driver’s cab, and seat. The key modal characteristics of the model are then verified through amplitude–frequency analysis, confirming their consistency with the typical vibration patterns observed in actual commercial vehicles, which provides the foundation for subsequent control strategy evaluation and migration. Then, based on a standard two-degree-of-freedom (2-DOF) suspension model, a weighted comprehensive evaluation function is developed to account for comfort, structural safety, handling stability, and both time- and frequency-domain performance indicators. Using this evaluation function, various control algorithms—including Skyhook control (SH), acceleration-based damping control (ADD), and proportional–integral–derivative control (PID)—are systematically assessed. The control algorithm is migrated to the 4-DOF model to carry out the hierarchical collaborative control. The results show that this method can effectively inhibit vibration transmission to enhance ride comfort and improve structural safety at the same time, while maintaining an acceptable level of handling performance. The transferability and applicability of the hierarchical control method are validated for the considered vertical dynamics scenarios. This article provides a new theoretical method and technical pathway for the comfort-oriented performance optimization of commercial vehicles.
Pan, Ting, Pang, Jianzhong, Wu, Jinglai, Zhang, Jiuxiang, Kang, Gong, Zhang, Yunqing
Predicting Electric Vehicle Interior Noise Quality from Drive Unit End-of-Line Vibration Testing2026-01-02234/7/2026
The Noise, Vibration, and Harshness (NVH) quality of electric vehicles (EVs) is heavily influenced by the performance of the electric drive unit. As a critical step in production, End-of-Line (EOL) testing of drive units is used to assess and control component-level NVH before vehicle assembly. However, the correlation between EOL test results and final vehicle interior noise quality, which directly impacts customer satisfaction, is not always fully understood. This paper presents a methodology for characterizing and predicting vehicle interior noise quality based on data from drive unit EOL vibration testing. Our study investigates the intricate relationship between drive unit assembly variations, component tolerances, and the resulting vibration response. We establish a robust correlation between these drive unit characteristics and both objective vehicle interior noise levels and subjective customer perception. The findings provide a framework for using EOL data to proactively identify critical manufacturing risks and optimize processes. This approach not only facilitates the delivery of a superior, noise-concern-free product but also contributes to reducing manufacturing costs by minimizing scrap and rework. This research advances NVH quality assessment for EVs and provides manufacturers with a vital tool to enhance customer experience and satisfaction in a competitive market.
Arvanitis, Anastasios, Jangid, Kuldeep
Machine Learning-Based Gear Defect Detection in Electric Vehicle Drive Units Using End-of-Line Vibration Analysis2026-01-06374/7/2026
The final assembly of electric vehicle (EV) drive units includes an essential End-of-Line (EOL) test to ensure both component integrity and Noise, Vibration, and Harshness (NVH) quality. This screening process, which uses dynamometers to measure vibration signals, is critical for identifying defects before a drive unit is installed in a vehicle. A significant source of failure during this test is gear defects, which can arise from manufacturing or handling issues. Traditional EOL testing methods rely on time-domain analysis and the impulsiveness of vibration signatures to detect these defects, a technique with inherent limitations in accuracy. This paper introduces and evaluates a novel approach using Machine Learning (ML) to analyze vibration signals for improved gear defect detection. We discuss the methodologies of both the traditional time-domain and the proposed ML-based techniques. Finally, we provide a comprehensive comparison of their respective efficiency and accuracy, demonstrating the superior performance of the machine learning method for this application.
Arvanitis, Anastasios, Michaloliakos, Anargyros
Reliability-Based Vibration Design of Vehicle Systems with Tuned Mass Dampers (TMD)2026-01-01394/7/2026
Tuned Mass Dampers (TMDs) are widely used in the automotive industry to mitigate Noise, Vibration, and Harshness (NVH) issues across various vehicle systems. These passive devices are particularly effective in reducing structural vibrations in components subjected to resonant excitation. However, real-world applications often face challenges due to manufacturing variability and system-level build differences, which can cause deviations in both the TMD’s tuned frequency (up to ±15%) and the vibration characteristics of the host structure. These uncertainties—in both the TMD properties and the vehicle subsystem dynamics—can be modeled using statistical distributions. This paper presents a generalized methodology for vibration analysis and design under uncertainty, combining reliability engineering with dynamic vibration modeling. The approach formulates a unified mathematical framework that incorporates probabilistic and stochastic modeling to assess TMD performance under a range of build and environmental conditions. As a case study, the method is applied to assess steering column vibrations, with a focus on quantifying the probability that system performance meets specified NVH targets. Multiple statistical distribution models are considered to predict the likelihood that vibrations exceed customer acceptance thresholds, potentially leading to unfavorable subjective and objective ratings. The results are validated using population-level vehicle data. While demonstrated on the steering system, the proposed methodology is applicable to any vehicle subsystem equipped with a TMD, provided that the relevant random variables—such as modal properties, excitation inputs, and build tolerances—are properly characterized. This enables robust TMD design across vehicle domains, ensuring performance consistency despite system variability.
Abbas, Ahmad, Haider, Syed, d'Souza, Suneel
NVH Characterization of New Pulse Width Modulation Strategies2026-01-02244/7/2026
Pulse Width Modulation (PWM) is needed to supply AC motors from DC voltages, but it creates high-frequency sideband harmonics that contribute negatively to sound quality. Several strategies were developed in the last decades to reduce the total harmonic distortion and switching losses, including discontinuous PWM. A new formulation of discontinuous PWM waveforms is proposed. It eases the implementation of PWM in simulation models and on experimental platforms, but it also enables the creation of new strategies. This study aims at assessing the NVH performance of six new strategies proposed by the authors. The goal is not to enhance the electrical performance but to seek new sound attributes, to change the sound quality of the machine. All strategies were tested on a test bench to characterize their current, vibration, and noise level on the full modulation index range. The measurements performed with the new strategies present some contrast. Semi-discontinuous strategies, which present a constant segment twice as short as that of existing discontinuous strategies, allow new sound attributes to appear. They also reduce the number of commutations compared to the classic sinusoidal strategy. The method adopted therefore seems relevant for creating new strategies but requires a complete characterization to assess the compromise between electrical and acoustic performance.
Wanty, Salomé, Delpoux, Romain, Glesser, Martin, Totaro, Nicolas, Parizet, Etienne, Degrendele, Karine
Lightweight Bubble Sheet Panel To Reduce Inverter Noise and Vibration for Electric Vehicles2026-01-04424/7/2026
Inverters are typically integrated into electric drive units for electric vehicles (EVs) to reduce packaging size and cost. However, coupled vibrations from the electric motor and gears are transmitted to the inverter, which can become a dominant noise source due to its large radiative panel. Metal panels are required for electromagnetic interference (EMI) compliance, yet these covers usually lack sufficient stiffness or damping for noise control. Adding ribs and applying damping treatments result in excessive mass, cost, and packaging challenges. A new bubble sheet panel design has been developed to enhance the structural strength and damping performance of the inverter cover while significantly reducing its mass. A thin sheet of aluminum is welded onto the cover in an optimized pattern that enhances stiffness and damping performance while accommodating packaging requirements. The welding pattern can include logos or artistic designs to improve the panel’s appearance. The metal sheets are blown apart between the welds to form a 3D structure that is three times stiffer and twice as strong as a flat monolithic sheet of the same thickness. The composite dual bubble sheets can effectively reduce structural vibration. Damping materials, such as liquid-applied sound deadener (LASD), can be injected into the bubble sheet cavities to significantly improve its damping performance. Prototype bubble sheets have been designed, analyzed, and tested for an integrated inverter used in front-wheel-drive (FWD) electric drive unit for EV applications. Analysis and modal tests show a reduction of 10 to 15 dB at panel resonances with close to 30% reduction in mass. The bubble sheet panel is installed on an integrated inverter and tested in the electric drive unit. Sound power measurements confirm a reduction of up to 10 dB in inverter panel vibration.
He, Song, Bobel, Andrew, Naismith, Gregory, Yi, Wenwen, Patruni, Pavan Kumar
Modal Analysis Approach on Vehicle Transient Behavior Considering Roll and Pitch Dynamics2026-01-02104/7/2026
When a vehicle performs planar motion, the tire side force induces a jacking-up effect determined by the suspension roll center height governed by suspension geometry. These jacking forces also excite pitching motion. In this study, the pitching degree of freedom, along with roll degree of freedom, was incorporated in the bicycle model of the vehicle motion, hence it becomes four-degree-of-freedom model, and a new analytical method that applies modal analysis method to the model decomposes the motion of the sprung mass of the vehicle into mutually independent vibration modes. Since the superposition of these vibration modes can reproduce vehicle motion, these vibration modes are the fundamental factors governing sprung-mass behavior. Therefore, understanding how these vibration modes respond to design parameters provides a theoretical foundation to design desired vehicle dynamics from the early stage of car development. This report presents, by conducting modal analysis of the four-degree-of-freedom model, that the pitching dominant mode and the mode associated with planar motion and roll, which constitute a three-degree-of-freedom system, are mutually independent dynamically. Furthermore, the suspension design method that controls the pitch-dominant mode can ameliorate the initial turn-in response of the sprung mass in the desirable direction. The insight presented in this report can offer a systematic understanding of the essential characteristics of sprung mass dynamics and can provide new theoretical framework for vehicle dynamics performance design.
Kusaka, Kaoru, Yuhara, Takahiro, Koakutsu, Shingo
Dog Clutch Actuator Control to Mitigate NVH2026-01-00034/7/2026
Dog clutches have long been employed in the automotive industry across various applications, including transmission systems, transfer cases, axle disconnects, and hybrid driveline architectures. Their ability to provide direct mechanical engagement makes it ideal for torque transmission with minimal energy loss. However, the transition between engaged and disengaged states can introduce noise, vibration, and harshness (NVH), which may be perceptible to vehicle occupants and affect overall driving comfort. A typical dog clutch relies on interlocking teeth for torque transfer, and its actuation can result in NVH due to factors such as friction between mating surfaces, backlash between engagement components, teeth-on-teeth contact during synchronization, and impact forces during clutch engagement. This paper presents Stellantis’s approach to controlling the actuator system to mitigate NVH effects during clutch engagement and disengagement, focusing on strategies that enhance drivability and system refinement in electrified vehicle platforms.
Xu, Chengyi, Madireddy, Krishna Chaitanya, Verhun, Brandon
Acoustic Improvements to a Passenger Service Unit Panel with Core Filler and Facesheet Patches using Topology Optimization2026-01-05114/7/2026
Passenger comfort is becoming the forefront of luxury private jets where noise needs to be kept to a minimum. One source of structure-borne noise is the vibration of the Passenger Service Unit (PSU) panel. These vibrations originate from the outer skin, excited by turbulent boundary layer, and are transmitted through the fuselage frame to the PSU panel. This panel resides overhead of passenger seating, it is composed of a corrugated honeycomb core sandwiched between thin face-sheets. This paper presents a systematic approach to improve the vibro-acoustic performance of a honeycomb core sandwich structure by employing core filler and facesheet patches. Topology Optimization (TO) is used to determine the optimal layouts of these design modifications. The vibro-acoustic performance of the PSU panel with facesheet patches and core filler is evaluated using a frequency response analysis in the commercial finite element solver OptiStruct. The effectiveness of vibration reduction will be quantified by using the Dynamic Stiffness (DS) and velocity response of the PSU panel measured using the Frequency Response Function (FRF). Validation used excitations from 500 to 3000 Hz and indicated that using the TO interpreted layout of core filler and facesheet patches, separately improved the DS of the panel by 402% and 198%, and the velocity response by -35% and -18%, while increasing the weight by 0.1% and 4.7% respectively. Their combined effect has also been tested and found to provide an additional 445% improvement to DS and a -39% improvement in velocity response with 4.8% of additional material, though overall behavior varies depending on frequency range.
Russo, Connor, Whetstone, Isobel, Patel, Anuj, Wotten, Erik, Kim, Il Yong
Analyzing Effects of Cell to Chassis Technology on Sound Transmission Loss of Skateboard- Sharing Vehicles2026-01-50243/30/2026
Limited published research has critically examined the impact of Cell-to-Chassis (CTC) structures on the Noise, Vibration, and Harshness (NVH) performance of electric vehicles (EVs), with most studies focusing on conventional Cell-to-Pack (CTP) systems. A concern is that vehicles employing CTC architectures may exhibit compromised NVH performance due to the absence of a dedicated floor panel. To investigate the NVH performance implications of the CTC structure, this study adopts a comprehensive methodology encompassing: (1) theoretical Sound Transmission Loss (STL) analysis utilizing mass law and double-panel principles, (2) finite element (FE) modeling of STL, (3) in-vehicle Acoustic Transfer Function (ATF) testing, and (4) interior noise measurements conducted at a constant 60 km/h on a smooth asphalt road. Simulation results demonstrate that, compared to a conventional CTP floor system, the studied CTC structure achieves a 5–40 dB increase in STL across the 200–2000 Hz frequency range. This finding is consistent with theoretical calculations. Furthermore, experimental results from in-vehicle ATF and interior noise tests reveal no significant acoustic difference in the 400–1400 Hz frequency range, which is primarily associated with tire noise, between a configuration with complete floor insulation (including carpeting) and one with insulation (including carpeting) removed from the CTC area. This research validates an effective simulation method for floor system STL and demonstrates that the acoustic insulation performance of the CTC structure enables potential cost and weight reductions by minimizing the requirement for traditional carpeting and sound insulation pads. This approach also suggests a pathway to reducing Volatile Organic Compound (VOC) emissions from these ancillary materials.
Xu, Xueying, Wang, Xiaoming, Ma, Caijun, Li, Guofu
Experimental Vibroacoustic Measurement of Thin Steel Panels Coated with Different Liquid-Applied Spray Damping Layer Thickness10-10-02-00172/23/2026
This study investigates the effect of liquid-applied spray damping (LASD) thickness on the vibration and sound radiation of thin steel panels. Although LASD is widely used to enhance structural damping, its influence on radiated sound and the role of coating thickness have not been systematically studied. Five steel panels with varying LASD thicknesses were evaluated using two experimental approaches. An impact-based method in a hemi-anechoic chamber measured the structural mobility and noise transfer functions, while a reciprocal method in a reverberation chamber under acoustic excitation measured the radiated sound power transfer function. A thickness ratio was found beyond which additional LASD thickness yielded diminishing improvements in noise and vibration reductions. The effect of LASD thickness on radiation efficiency was also assessed in both narrowband and one-third octave bands.
Neihguk, David, Suh, Sam, Herrin, David W.
Vibration Analysis of Rectangular and Circular Plates with Fixed Edges: Analytical and Computational Validation2026-28-01082/12/2026
This study presents a comparative investigation of the vibration characteristics of rectangular and circular plates with fixed edges using analytical, numerical, and computational approaches. Analytical models based on classical plate theory were employed to calculate natural frequencies and mode shapes, while finite element analysis (FEA) was performed in a CAE tool to provide high-fidelity simulation results. A detailed mesh convergence study confirmed numerical stability, with frequency variations below 1% between successive refinements. Analytical predictions showed excellent agreement with simulation results for lower modes, with errors as low as 0.25% for the rectangular plate and 2.65% for the circular plate. However, higher modes exhibited significant deviations, with errors reaching up to 29.01% for rectangular and 181.52% for circular geometries, highlighting the limitations of closed-form solutions in capturing complex vibrational behavior. Python-based computational tools were developed to automate frequency calculations and visualize mode shapes, bridging theoretical formulations with practical applications. The integration of analytical, numerical, and computational methods provides a robust framework for understanding plate vibrations, demonstrating that analytical solutions remain effective for fundamental modes, while FEM ensures accuracy for higher-order behavior.
N, Suhas, R, Sanjay, Bhaskara Rao, Lokavarapu
Vibration Dynamics of a Half-Car Model Considering Tire–Road Separation02-19-04-00212/9/2026
The vibrating half-car model is used to represent the dynamic behavior of a truck’s dependent suspension system, capturing four degrees of freedom. This research investigates time and frequency responses of vibration behavior of half-car model with possible tire–road separation. This investigation is significant because all previously reported analyses based on the tire-road attachment were incorrect, particularly regarding the tire-road separation phenomenon. The differential equations are extended to enhance the accuracy of the model, incorporating tire–road separation conditions for both wheels. A numerical approach is applied to simulate the vertical and roll dynamics of the system under the separation assumption. The simulation results are validated through experiments conducted using ADAMS View software. Integrating the tire–road separation into the model results in dynamic responses that closely reflect real-world behavior. These findings provide valuable guidance for designing more effective suspension systems and for developing control strategies aimed at reducing rollover risk and enhancing lateral stability.
Nguyen, Quy Dang, Jazar, Reza
Establish Relation of Car Door Window Glass Opening on Door Assembly Dynamic and Vibrational Behavior2026-01-50062/2/2026
Window glass is a component of the side door assembly of cars. It provides a clear vision for passengers and outsiders. It functions as a temporary opening and ventilation system for the car. It is a part of a car’s aesthetics; it adds stiffness to the door and protects the occupants from different weather conditions. The objectives of this study were to understand the effect of fully and partially opened or closed window glass on the dynamic behaviors of door assemblies and to develop a process to assess these dynamic behaviors. An assessment methodology was developed to determine the effects of various window glass positions on the dynamic behavior of the door assembly. An authenticated finite element (FE) model was used to complete this investigation. The finite element model of the door assembly was validated by correlating the modal frequencies with their corresponding mode shapes. The correlated FE model with the window glass fully closed was called the baseline (W0), and eight other models with the window glass partially and fully opened were analyzed and assessed. The baseline and eight models were assessed in terms of modal results and total vibrations. The investigation was based on modal analysis, frequency response, and total vibrations, which were calculated based on the area under the curve using the trapezoidal rule. The total vibrations were evaluated at all 15 critical locations. The discussion and interpretation led to a few conclusions. There is a minor effect on the natural frequency, mode shape, and number of modes between 0 Hz and 100 Hz. There was a significant increase in vibration around the window glass and a negligible effect on locations away from the window glass. Finally, the work was concluded with suggestions for door designers and a few recommendations for car drivers.
Jadhav, Pandurang Maruti, Waghulde, Kishor B., Bhortake, Rupesh V.
Simulation of Higher Harmonic Vibration Control System Considering Actuator Amplitude LimitSM-2026-VLADA-51661/27/2026
A comprehensive numerical study was conducted to reduce helicopter rotor hub vibratory loads and fuselage vibrations using the Higher Harmonic Control (HHC) technique. A CAMRAD II model of a medium utility helicopter was developed for aeromechanical simulation, and a linear system model representing both hub vibratory load and fuselage vibration characteristics was identified offline. Optimal control inputs were then computed to minimize vibration responses under different weightings on hub vibratory load and fuselage vibration in the objective function. The predicted performance was verified through CAMRAD II simulations. Additionally, a closed-loop HHC system incorporating actuator amplitude limitations was investigated. A control algorithm regulated actuator amplitudes while maintaining phase consistency, dynamically adjusting control inputs after each iteration. The results demonstrate that the amplitude-limited closed-loop control limits excessive pitch link loads while maintaining effective vibration suppression, thereby maintaining structural safety and ensuring practical feasibility for real-world helicopter applications.
Kim, Do-Hyung, Park, Jae-Sang, Kang, Woo-Ram
Dual-Stage Compressor Bracket NVH Optimization for High-Performance 4×4 Electric Vehicles2026-26-03271/16/2026
The rising demand for high-performance 4x4 electric vehicles (EVs) has necessitated development in Noise, vibration and harshness (NVH) optimization, especially in critical components such as compressor bracket. This study focuses on NVH optimization of a dual-stage compressor bracket, comparing its performance against conventional single stage isolation bracket. The dual-stage bracket is evaluated for isolation effectiveness, modal frequency alignment, and overall NVH performance, while ensuring compliance with stiffness targets. Additionally, dual-stage design meets stringent stiffness requirement, confirming structural integrity under dynamic loads. Modal analysis results reveal that the dual-stage configuration effectively shifts critical frequencies away from operational ranges, reducing resonance risks. The results highlight the dual-stage bracket's ability to address NVH challenges in high-performance 4x4 EVs, offering a robust solution for improving cabin comfort and vehicle refinement. This study provides insights for engineers seeking to optimize NVH performance in EV powertrain components, emphasizing the trade-offs between isolation effectiveness, modal behavior, and structural stiffness.
Hazra, Sandip, Tangadpalliwar, Sonali
Refinement of Road Induced Steering Wheel Vibration in Electric Vehicle2026-26-03371/16/2026
Nowadays, customers expect excellent cabin insulation and superior ride comfort in electric vehicles. OEMs focus on fine tuning the suspension system in electric vehicle to isolate the road induced shocks which finally offers superior ride quality. This paper focuses on enhancing the ride comfort by reducing the road excitation which originates mainly due to road inputs. Higher steering wheel vibration is perceived on the test vehicle on rough road surfaces. To determine the predominant force transfer path, Multi reference Transfer Path Analysis (MTPA) is performed on the front and rear suspension. Based on the finding from MTPA, various recommendations are explored and the effect of each modification is discussed. Apart from this, Operational Deflection Shape (ODS) analysis is used to determine the deflection shape on the entire steering system . Based on ODS findings, recommendations like dynamic stiffness improvements on the steering column and steering wheel are explored and the impact on the steering wheel vibration is discussed. With all the counter measures proposed, steering wheel vibration levels are reduced by ~ 7 dB . Component level modal targets are proposed to avoid the vibration concern due to road excitation.
S, Nataraja Moorthy, Rao, Manchi, Selvam, Ebinezer, Raghavendran, Prasath
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