Browse Topic: Springs

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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
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
A Comprehensive Analysis of a Truck–Semi-Trailer Performance Based on Hierarchical Controller Design to Enhance Driver Comfort and Dynamic Stability02-20-01-00028/18/2026
This study presents an integrated suspension system to improve the ride quality and stability of semi-trailer truck vehicles. The system consists of both an Air/MR-controlled suspension on the driver’s seat and on the truck cab, and an active air main suspension for the truck to improve vehicle stability. All components are connected to the truck and semi-trailer via a series of coupled connections. An analysis of dynamic stability reveals how the truck’s motions affect slosh forces within the semi-trailer during operation. An experimental validation of the new Air/MR suspension damper, developed using ANSYS 2023 R1 Computational Fluid Dynamics (CFD) software, yielded results consistent with prior experimental evidence. The control strategy uses a hierarchical architecture in which an inverse LSTM network controls the MR damper, accurately following the damping forces generated by a higher-level RNN controller implemented in MATLAB. The RNN system adaptively adjusts the stiffness of the cab and driver seat suspension, isolating the cab from vibrations caused by uneven roads. The truck and trailer’s main air suspension uses LQR control, using state inputs to counteract vertical motions caused by road roughness and sloshing. An integrated nonlinear co-simulation model of the truck and semi-trailer—including the truck, sloshing trailer, nonlinear air springs, and CFD-based MR damper demonstrates the control system’s effectiveness. Simulation results compared with a passive suspension system show that the proposed integrated controlled suspension system significantly reduces the truck chassis bending moment, improves ride comfort (49.98%), reduces cab body displacement (63.60%), and increases dynamic stability (57.78%). Maximizing dynamic tire load due to slosh dynamics in both half-loaded and full-loaded tanks does not affect the effective dynamic stability of tire hopping at high frequencies because the stiffness coefficient is adaptively adjusted, thereby synchronizing disturbance rejection and long-term riding comfort in frequency-based control under different road conditions.
Gad, Ahmed Shehata
Failure Analysis of the Safety Valve Spring in a Dangerous Goods Tanker2026-99-03138/14/2026
During the operation, a spring in the built-in safety valve of a dangerous goods tanker. A comprehensive failure analysis of the material was conducted through macroscopic and microscopic inspections, metallographic analysis, energy spectrum analysis (EDS), and hardness tests. The failure mode of the broken spring was brittle fracture. The fracture morphology was like that of ice sugar, and the chemical composition of the spring steel met the specified requirements. The main cause of fracture failure is the mechanical damage to the inner surface during the spring manufacturing process, which leads to stress concentration in the damaged area and ultimately results in fracture. In addition, manufacturers should strengthen and standardize the production process to prevent mechanical damage and select high-purity spring steel to improve the durability of the springs.
Yang, Lijun, Li, Qingshan, Xiong, Mingming, Liu, Mingming, Wu, Junyao, Yu, Lang, Zhang, Zewei, Xie, Xumeng
Solution of Optimal Parameters of Leaf Springs by Firefly Algorithm Based on Penalty Function2026-99-01447/31/2026
The probe is an important component of the precision instrument. During the measurement process, the deformation of the leaf spring directly affects the accuracy of the displacement of the probe. There are many undetermined parameters for the leaf spring, and some parameters have a non-linear impact on the results. This paper proposes a firefly algorithm that combines penalty functions to solve the optimal solution of the objective function for multi parameter leaf springs. Through strategies such as normalizing mapping intervals, setting small populations between cells, and fine-tuning position update formulas, this algorithm quickly obtains the optimal parameters of the leaf spring, and compares it with the orthogonal experimental method to prove the feasibility of this method, providing a certain theoretical reference value for multi parameter solving.
Yu, Jianghao, Shi, Zhaoyao, Song, Huixu
Comfort Study of Air Suspension System Based on MPC Control2026-99-01367/31/2026
Air springs are increasingly replacing traditional shock absorbers in vehicle suspension systems due to their superior mechanical properties, including adjustable stiffness, nonlinear characteristics, and excellent damping performance. To further explore the potential of air suspension in improving ride comfort, this paper focuses on air suspension. We first conducted mechanical characteristic experiments on air springs to obtain their stiffness and damping characteristics under different inflation pressures and excitation frequencies. These tests provide essential mechanical parameters for subsequent modeling and simulation. Based on the experimental data, a simplified 1/4 air suspension simulation model is constructed, taking into account the nonlinear stiffness and damping properties of the air springs. To simulate real-world driving conditions, a random road surface model is introduced as the excitation input. Simulation analysis is conducted to compare the air suspension system with the traditional passive suspension system. The results indicate that, compared to the passive suspension system, the air suspension system integrated with Model Predictive Control(MPC) significantly reduces key performance indicators, including suspension deflection, wheel dynamic load, and sprung mass vertical acceleration. This indicates that the suspension with model predictive control can effectively suppress vehicle vibrations, thereby enhancing ride comfort and driving stability. The results of this study provide an important basis for the optimal design of air suspension systems and have practical application value for improving the suspension performance of the vehicle.
Yin, Zhi
Research on the Influence of Suspension Characteristics on Ride Quality of Railway Wagon2026-99-05117/10/2026
With the country’s economy and people’s consumption capacity increasing, railroad transportation tasks have become more and more frequent, and it is growing the demand for the transportation of high-value goods, fresh produce, etc. Compared with traditional Freight vehicles, express freight vehicles have great advantages in terms of carrying capacity, mobility, and transportation cost, but when it run at a speed of 160 km/h, it often occurs that failure of axle-box rubber springs, primary vertical dampers, secondary lateral dampers, anti-yaw dampers, and air springs. How to ensure the safety and stability of the train under suspension system failure conditions is a problem that needs to be solved during the design process. In this paper, through multi-body system dynamics software, a nonlinear dynamics model of lateral and vertical coupling of the vehicle system is established to analyze the influence of suspension system failure on the stability of 160 km/h express freight vehicles. The analysis results show lowering the operating speeds can meet the Ride Quality of the Vehicles in special conditions.
Gao, Zhixiong, Ma, Kai, Xiao, Yanmei, Chen, Weidong, Wei, Xiao, Sha, Chengyu, Bian, Huihui
A Novel Stiffness Prediction Model of Rolling Lobe Air Springs Considering Irregular Piston Contour Geometry: Development and Experimental Validation15-19-02-00065/18/2026
An accurate air spring model is essential for the design and optimization of air suspension systems to achieve superior performance. This article presents a novel stiffness model for a rolling lobe air spring (RLAS), formulated using stiffness characteristic parameters. Prediction models for these parameters, including effective area and its change rate, as well as effective volume and its change rate, are derived through geometric analysis, based on polynomial fitting of the irregular piston contour. The local contour cone angle of the piston is determined by differentiating the polynomial function, capturing the geometry-dependent variation across the profile. Additionally, a nonlinear hysteresis model for the rubber bellows is integrated, combining a Berg friction component and a Kelvin-Voigt fractional derivative viscoelastic model to represent the amplitude- and frequency-dependent behavior of the RLAS. The proposed model is parameterized through quasi-static and dynamic bench tests under varying amplitudes and frequencies and is validated against both experimental data and an existing modeling approach. Comparative results demonstrate that the proposed model effectively and accurately predicts the static and dynamic responses of the RLAS.
Xia, Xiaojun, Zhang, Hong, Zou, Yi, Ye, Lei, Lu, Yi, Chen, Rui, Zou, Hantong, Wang, Yang
Hingeless Rotor Whirl Flutter Stability Predictions for TRASTF-0082-2026-00775/5/2026
The TiltRotor Aeroelastic Stability Testbed (TRAST) was developed to experimentally investigate whirl-flutter stability of tiltrotor aircraft. Previous wind-tunnel testing focused on configurations representative of current generation tiltrotors utilizing gimballed rotor hubs. The TRAST platform was also designed to support a hingeless rotor system to investigate whirl-flutter mechanisms representative of stiff proprotor configurations. This paper presents analytical whirl-flutter predictions for a hingeless rotor configuration of the TRAST model. Structural mode shapes derived from a NASTRAN finite-element model are combined with comprehensive aeroelastic analyses in CAMRAD II and RCAS. The results show that the dominant whirl-flutter mechanism differs from the gimballed configuration, with instability occurring through the wing in-plane mode rather than the wing vertical bending mode. Parametric studies examining rotor speed, pitch-spring stiffness, rotor flexibility, and diaphragm spring stiffness are conducted to evaluate the sensitivity of the predicted stability boundary. Results indicate that the hingeless configuration is significantly more stable than the equivalent gimballed configuration and exhibits different trends with rotor speed and structural stiffness. These predictions help identify configurations of interest for future wind-tunnel testing and provide insight into whirl-flutter mechanisms for hingeless tiltrotor systems.
Kreshock, Andrew, Cobb, Benjamin, Thornbrugh, Robert
Data-Driven Study on Chassis Suspension Performance Degradation2026-01-05824/7/2026
The performance of chassis suspension mechanisms critically affects vehicle handling, ride comfort, and safety. Implementing real-time health monitoring for chassis systems contributes to preventing severe consequences such as increased body roll or loss of handling stability caused by shock absorber softening or spring stiffness degradation under deteriorating operating conditions, while circumventing the substantial costs associated with professional facility-based chassis inspections. With the rapid development of sensing and data analytics technologies, data-driven approaches are increasingly used in health monitoring. This study aims to achieve online monitoring of chassis suspension performance degradation using a deep neural network (DNN). First, a half-car model incorporating both vertical and pitch motions was established to simulate bumpy road conditions, with the aim of constructing a dataset that includes key vehicle suspension parameters and vehicle states related to their degradation characteristics. Subsequently, a DNN model comprising three hidden layers is developed to assess suspension performance degradation. To optimize model performance, the effects of different numbers of neurons and hidden layers on model accuracy are explored. Experimental results show that the maximum absolute percentage errors of the DNN model in predicting suspension stiffness and damping coefficients are less than 0.13% and 0.17%, respectively, with average absolute percentage errors below 0.046% and 0.06%. The coefficients of determination (R2) exceed 0.999. The proposed method accurately predicts the trend of key suspension parameters, providing robust data support for health management and maintenance decision-making. This is expected to reduce safety risks and maintenance costs while enhancing overall vehicle performance and reliability.
Liao, Yinsheng, Lei, Yisong, Su, Ailin, Wang, Zhenfeng, Shi, Shuai, Zhang, Lei, Zhang, Junzhi, Ma, Changye
Research on Driving Performance of Vehicle Body Control Using Vehicle Height Adjustment System2026-01-06264/7/2026
In recent years, premium vehicles have increasingly incorporated suspension systems capable of adjusting ride height. The primary function of these systems is to enable the vehicle to traverse uneven terrain by elevating the chassis, thereby preventing contact between the underbody and the road surface. Notably, air spring-based mechanisms enhance ride comfort by modulating the wheel rate. The system proposed in this study achieves ride height adjustment through vertical displacement of the spring’s lower seat. By constructing a detailed mechanical topology model using a dynamic simulation tool, this research aims to evaluate the feasibility of improving driving performance not only through height regulation but also by actively controlling the vehicle’s posture during motion.
Park, Jaeyong, Sang Hoon, Lee, Jong Min, Kim, Choi, Jang Han
A Helical Compression Spring Fracture under Impact Velocity in Pump Operation by Theoretical Study and FEA2026-01-02714/7/2026
Helical compression springs have been used widely in various industries from automotive, aerospace and construction to electronics and medical devices. In the automotive industry, they appear in many places such as suspension, valvetrain, etc., as well in the discharge check valve of Gasoline Direct Injection (GDI) pump, which is the subject of study due to a recent fracture in lab testing. A theoretical study is conducted first to establish the equation governing spring dynamic motion under impact velocity, which can be in high magnitude with surging shock wave along spring axis. A new spring shock wave equation is developed for spring axial motion coupled with coil torsional effect. This newly derived shock wave equation has a broader term than the classic spring formula found in most engineering books. In this paper, it shows that the classic spring shock wave equation is only a special case for the general wave equation newly discovered. Then, a theoretical formula on spring shock wave propagation speed and natural frequency are presented, validated by a numerical simulation result by FEA on the spring natural frequency. Next, a FEA tool is employed to study the spring system under transient impact velocity, the spring dynamic stress at fracture location is obtained. It compares closely with the analytical approximate solution. Finally, a fatigue life assessment is performed, back up by the fractured part photo as well as the fatigue life cycles observed in testing. They are found in good agreement.
Pang, Michael L., Gunturu, Srinu, Norkin, Eugene
Improving Semi-Truck Torque Overlay Steering Systems to Boost On-Center Performance: Hardware Design Investigation02-19-02-00122/4/2026
In class 8 semi-trucks, the hydraulic steering gear and torque overlay system are critical components affecting the steering feel design and vehicle control. Transitioning from traditional hydraulic gears to hydraulic gears with torque overlay steering (TOS) systems for increased enhancement of driver comfort is beneficial but has also resulted in drawbacks for on-center steer feel, especially at high vehicle speeds (60+ km/h). This article evaluates the impact of three design mechanisms within hydraulic steering gears of a TOS system that have shown improvement in on-center performance for traditional hydraulic gears. The study compares a standard assembly of TOS, i.e., baseline, and a design-optimized ideal prototype, to evaluate the effectiveness of the three design mechanisms: valve curve performance, on-center friction, and torsion bar stiffness. The two samples underwent high-speed vehicle testing to gather driver feedback and assess potential enhancements to the on-center steering feel. The final design changes on the ideal prototype were based on the best valve curve and on-center friction, as limitations in the torsion bar modification process precluded its use in the vehicle. The vehicle qualification team found insufficient evidence linking these design features to improved overall steering performance. Further research will be conducted to analyze the impact of torsion bar change as well as software controller performance within the TOS as a follow-up study.
Bari, Praful Rajendra, Chaudhuri, Nilankan
Failure Analysis of Dissimilar Metal Weld Joint of an Air Spring Bracket within an Automotive Active Seat Suspension System2026-26-04871/16/2026
In modern four-wheelers, seat suspension systems play a crucial role in enhancing occupant comfort by mitigating the effects of road unevenness and vibrations. Among these systems, active suspension mechanisms offer advanced performance through complex assemblies involving welded, riveted, and bolted joints. This study investigates the failure of an air spring bracket - a critical component of a pneumatic active suspension system - manufactured by Gas Metal Arc Welding (GMAW) of two dissimilar ferrous materials which are likely to be SAPH440 and S355J2. These different materials were used based on mechanical properties required to perform by their particular part. System level validation tests were conducted to ensure the reliability of the seat suspension system. The one of the validation tests is continuous cyclic fatigue test which is carried out on the complete seat assembly. However, during vibration / cyclic endurance testing, premature failures were observed near the weld joints. Detailed failure analysis using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and optical microscopy revealed cracks and discontinuities at the weld interfaces. The microstructure in the heat-affected zone (HAZ) exhibited ferrite-Martensite structure with grain coarsening. The fractography reveals the cleavage type and river type fracture morphology which indicates the part failed due to brittle fracture. Inadequate welding of SAPH440 steel can lead to issues such as cracking, distortion, and poor fusion due to its high carbon content and inadequate heat control. The failure analysis study identified that less fusion control of welding parameters and associated thickness and carbon compositions variation which significantly contributed to the component’s fatigue failure. Preventive strategies, including the optimization of sectional thickness and design changes for uniform stress distribution are proposed to improve the reliability of welded assemblies.
Patale Jr, Reshma, Pinjari, Jayant Namdev, Bali, Shirish
Systematic Study to Understand and Resolve Brake Pull in Commercial Vehicles Using Simulation and Proving Ground Tests2026-26-00831/16/2026
In traditional commercial vehicles with leaf spring suspension and Recirculating Ball Joint (RCBT) steering systems often experience undesirable pulling due to unsymmetrical steering mechanism during braking, especially when the suspension and steering hardpoints are not properly tuned. This work analyzes the mechanisms responsible for pulling tendencies, primarily addressing brake steer and bump steer, which occur due to misalignments in the suspension and steering geometries. Brake steer occurs when braking forces create an imbalance in torque, resulting in the vehicle deviating to one side. On the other hand, bump steer refers to the unwanted changes in the wheel alignment when the suspension undergoes travel, leading to instability or unintended steering input. These two phenomena, if not controlled, can result in undesirable vehicle handling, especially under heavy braking conditions. This work focuses on evaluating these mechanisms and suggests strategies for minimizing their impact through accurate suspension and steering hardpoint tuning. A dedicated methodology was formulated to optimize suspension and steering hardpoints, leveraging Adams Car MBD simulations for fast and accurate predictions of pull direction. Adjustments were made to the front leaf spring pivot and Pitman arm draglink pivot to address bump steer, and the knuckle-to-draglink joint was optimized to minimize brake steer. Simulation outcomes showed that the severe right pull initially observed was reduced to a mild left pull after these changes. Despite offering valuable tuning strategies and directional predictions, the study acknowledges that exact pull magnitude cannot be predicted with certainty due to complex vehicle dynamics. However, the study successfully establishes a method for predicting pull direction, which can serve as a strong foundation for further refining suspension and steering system designs in small commercial vehicles.
Pandhare, Vinay Ramakant, M, Anantha Padmnabhan, Nizampatnam, Balaramakrishna, Londhe, Abhijit, Doundkar, Vikas
Design and Construction of a Bench Test System for Elastomers Suspension2025-36-004112/18/2025
This study presents the design, construction, and experimental validation of a test bench for characterizing elastomer-based torsion suspensions in light vehicle applications. The system replaces conventional spring-damper assemblies with viscoelastic elements that simultaneously absorb and dissipate road-induced vibrations. We developed a scaled prototype instrumented with an Arduino-based data acquisition system and analyzed results using Octave®. The experimental protocol comprised: (1) tribological tests to identify optimal friction pairs through coefficient of friction (μ) and wear rate measurements, and (2) dynamometric evaluations of torque transmission capacity, power output, and efficiency across gear ratios (2.03-6.34). Results indicate that a steel-steel friction pair under a normal force of 250-300 N achieves optimal performance, delivering an output power of 1706 W (84.8% efficiency) and a torque of 30.25 Nm. Comparative analysis shows this configuration reduces wear rates by 42% compared to aluminum-polyurethane pairs while maintaining comparable μ values (0.32±0.03). The system provides a cost-effective platform (75% cheaper than commercial alternatives) for validating Continuous Torque Transmission (CTT) technologies, with direct applications in electric vehicle drivetrains and engineering education.
Silva, Diego Bruno, Grandinetti, Francisco José, Castro, Thais Santos, Dias, Érica Ximenes, Souza Soares, de Álvaro Manoel, Martins, Marcelo Sampaio, Reis de Faria Neto, dos Antônio
Research on the Rotation Resistance Coefficient Experiment Based on the 6 Degree-of-Freedom Rig2025-99-030812/17/2025
The rotational resistance coefficient of the bogie is a critical parameter for assessing the operational safety of vehicles, significantly influencing the stability of the vehicle’s snaking motion and the safety of curve negotiation. This paper conducts measurements of the rotational resistance coefficient using a 6- degree-of-freedom bogie test rig, evaluating the variation patterns of the indicator under different vehicle load conditions and air spring inflation states. By establishing a SIMPACK dynamic model of the 6-DOF platform, it is possible to obtain actuator displacement control curves that comply with the EN 14363 standard. Taking a specific subway trailer bogie as an example, the rotational resistance coefficient under various operating conditions was measured. The test results indicate that under the condition of air spring deflation, the rotational resistance coefficient is significantly higher than that under air spring inflation. Moreover, under the condition of air spring deflation, the effect of vehicle load on the rotational resistance coefficient is negligible. Due to assembly errors and the approximate methods used in calculations, the hysteresis curve of the rotational resistance torque-angle measured by the 6-DOF test rig exhibits minor fluctuations, which have a minimal impact on the results, and there is room for further optimization. The method proposed in this paper can provide a basis for vehicle design optimization, reduce the risk of derailment, and also assist in vehicle maintenance and repair during the operation stage to ensure safe operation. It has been widely applied in the design and operation practice of subway vehicles.
Li, Li, Hu, Jie
Study on Dynamic Performance of Metro Vehicle with Different Air Spring Control Methods2025-99-031312/17/2025
A nonlinear dynamic model of subway trains was developed, and multi-body dynamics simulations were conducted to evaluate how different air spring control strategies affect train performance. The findings indicate that three-point air spring control exhibits direction-dependent effects on vehicle dynamics, whereas two-point and four-point control methods demonstrate more consistent performance across different running conditions.
Dang, Peng, Tian, Fang
Shock Dynamics Analysis of Opening Process of Spring Mechanism for Circuit Breaker2025-99-035412/17/2025
In order to accurately evaluate the strength and stiffness of the key components of the spring mechanism for circuit breakers under strong impact load conditions, and provide strong data support for product design and structural optimization, the impact dynamics analysis method is used to model and simulate the spring mechanism. The dynamic stress test data is used to verify the accuracy of the simulation, and the strength of the key components under impact conditions is obtained. The influence of different stiffness frames on the output shaft offset is analyzed.
Guo, Mingqin, Li, Junfeng, Yin, Tianshuo, Zhang, Pan, Li, Pengzhen, Wang, Pengchao, Ji, Linhao
Automation: How Custom Motion Control Transforms Medical Equipment DesignTBMG-5434012/1/2025
In today’s medical equipment market, reliability is not a luxury — it is a necessity. Every adjustment, every movement, and every interaction with the equipment must be performed flawlessly to ensure patient safety, caregiver efficiency, and long-term service life. Behind this design and precision are highly engineered motion control components, such as gas springs, electric linear actuators, and dampers, that ensure safe, ergonomic operation of medical equipment across a wide range of healthcare applications.
Optimizing Engine Dynamics with Hydraulic Lash Adjusters in Type-5 Valvetrain Systems2025-28-023511/6/2025
For the diesel engines first designed & developed before 2000s, push-rod type valvetrains with mechanical valve lash adjustment were common. For one such legacy diesel engine, first developed for tractors and now applicated for on road vehicles, having push-rod valvetrain architecture & mechanical valve lash adjustment (Type-5 valvetrain system) with flat follower tappet, integrating HLAs for enhancing the NVH & serviceability presented certain challenges. This paper delves into the challenges faced in the design & development phase of HLA integration project on a four-cylinder diesel engine. For integration of HLA, first, the packaging evaluation of valvetrain assembly was done followed by oil flow assessment and necessary changes in the oil pump and circuit. Then, valve lift profile optimizations were done since the ramp rate & seating velocity requirements are different for valvetrains with mechanical lash and HLAs. Numerous iterations were performed for cam-profile design to balance the air flow & volumetric efficiency requirements with the kinematic limitations of higher inertia valvetrain. In parallel, spring force margin was checked for each cam-profile proposal to prevent loss of contact during high speed engine operation and springs with higher preloads & stiffness were evaluated while maintaining the contact stresses at cam nose under material limits. Analytical excel-based calculators were developed for quick first-level assessment of valvetrain kinematics, spring force margin, spring design, cam-profile curve generation from valve lift profile & cam-lobe peak contact stress calculation. For combinations that passed the analytical assessment, 1D simulations were done for checking the engine performance & efficiency while CAE simulation was performed for the valvetrain dynamics. Physical DVP was performed with the finalized valvetrain configuration which included Overloading, High-speed and Cyclic loading tests on engine-level to confirm the performance, functionality & durability with HLA integration.
John, Shijino Shaji, Bagal, Pratik
A Novel Mechanical Model Simulating a Pavement Deflection Measuring System for Non-Invasive Pavement Monitoring Based on a Reliability-Based Optimization Algorithm02-18-03-00259/4/2025
This article presents a novel mechanical model for simulating the behavior of pavement deflection measuring systems (PDMS). The accuracy of the model was validated by comparing the acceleration of the new model with the data achieved through experimental tests fusing a deflection measurement system mounted on a Ford F-150 truck. The experimental test for the PDMS is carried out on a random road profile, generated by an inertial profiler, over a 7.4-mile (12 km) loop around a lake near Austin, Texas. Integrating a reliability-based optimization (RBO) algorithm in a PDMS aims to optimize system parameters and reduce vibrations effectively. The PDMS noises and uncertainties make it crucial to use a robust system to ensure the stability of the system. This article presents a robust algorithm for considering the uncertainties of PDMS parameters, including the damping coefficients and spring stiffness of the supporting brackets. Moreover, it considers the variation of system parameters, such as stiffness of the vehicle’s tire and changing in the weight of the vehicle based on the number of passengers sitting in the cars. This approach ensures the system’s high accuracy and reliability, despite uncertainties and variations. Moreover, the presented algorithm calculates the optimum parameters of the PDMS model by minimizing the acceleration of the front and rear lasers and the rotation of the beam about the y-axis at the center of the beam. The accuracy of the RBO is being evaluated by comparing RBO with deterministic optimization methods. This comparison illustrates the accuracy of the RBO method for obtaining a more precise and reliable PDMS system. It also indicates the effectiveness of the RBO method in obtaining a more accurate and robust system, which can be utilized in real-world applications. RBO significantly minimizes the mean angular displacement of the beam (from 8.68° to 2.18°), as well as the RMS of front and rear accelerations (from 5.0 m/s2 to as low as 0.66 m/s2), based on variance reductions.
Yarmohammadisatri, Sadegh, Sandu, Corina, Claudel, Christian
Leaf Springs in Focus: Integrated Validation of Material, Process, and Performance in Mechanical Suspensions2025-36-03128/1/2025
The continuous improvement of validation methodologies for mobility industry components is essential to ensure vehicle quality, safety, and performance. In the context of mechanical suspensions, leaf springs play a crucial role in vehicle dynamics, comfort, and durability. Material validation is based on steel production data, complemented by laboratory analyses such as tensile testing, hardness measurements, metallography, and residual stress analysis, ensuring that mechanical properties meet fatigue resistance requirements and expected durability. For performance evaluation, fatigue tests are conducted under vertical loads, with the possibility of including "windup" simulations when necessary. To enhance correlation accuracy, original suspension components are used during testing, allowing for a more precise validation of the entire system. Additionally, dynamic stiffness measurements provide valuable input for vehicle dynamics and suspension geometry analysis software, aiding in predictive modeling and optimization of suspension behavior. The implementation of this structured and comprehensive validation methodology, already adopted by companies in the mobility industry, ensures the development of reliable and high-performance products. This approach is particularly beneficial for commercial suspensions used in road transport of cargo and passengers, addressing industry challenges related to safety, durability, and efficiency. By improving validation techniques, the mobility industry strengthens its ability to innovate, comply with regulatory standards, and meet the growing demand for more robust and efficient vehicle suspension systems.
Zahn, André N., Graebin, Matheus, Malacarne, Rodrigo, Toniolo, Juliano C.
Virtual Validation of a Light Duty Leaf Spring Using Road Load Data2025-36-03078/1/2025
It is widely common for commercial vehicles to use Hotchkiss suspension with leaf springs attached to the solid axles. This configuration is cost effective and robust enough for the required application. The leaf springs evolved in the past decades in terms of new materials and construction, and the validation methods also changes. Since the application can be aggressive in some markets, physical tests are done to validate their durability and performance. Looking for a way to reduce development time and costs, high confidence level virtual validations are targeted by the whole industry. Using FEA fed by road load data as inputs for the loads applied to the leaf springs is an evolving methodology that can be considered as a high confidence level validation method, achieving very representative results, allowing engineering team to dismiss physical tests and release the item for production. The stages of spring development will be described in this paper, focusing on the virtual simulations and comparison to real data.
Belli, Milton Monteverde, da Costa, Mateus Cesário
Advanced Motion Control Components for Critical Aerospace ApplicationsTBMG-535418/1/2025
Advanced motion control technologies are essential to modern aerospace design, supporting a wide range of safety-critical and comfort-driven applications. In aerospace, motion control components such as gas springs, actuators, and dampers are integral to nearly every commercial aircraft, rocket, satellite, and space vehicle. These critical elements support flight safety and transport functions, from the dependable deployment of landing gear and cargo doors to the smooth, ergonomic operation of seating for pilots and passengers.
Developing Military Light Utility Vehicle Performance Based on Air Semi-Active Suspension System Using Recurrent Neural Network–Based Controller10-09-04-00306/19/2025
This research presents a semi-active suspension system that combines an air spring and a magneto-rheological (MR) fluid damper to produce both active force and variable damping rates based on the road conditions. The suspension system used for the military light utility vehicle (MLUV) has seven degrees of freedom. A nonlinear model predictive control system generates the desired active force for the air spring control signal, while the linear quadratic regulator (LQR) estimates the target tracking of the intended damping force. The recurrent neural network is designed to develop a controller for an identification system. To achieve the optimal voltage for the MR damper without log time, it is used to simultaneously determine the active control force of the air spring by modifying the necessary damping force tracking. The MLUV suspension system is integrated with the traction control system to improve overall vehicle stability. A fuzzy traction controller adjusts the throttle angle based on the driver’s throttle input and the slip ratio of the driving wheels. Constant speed, passing maneuvers, increasing acceleration, and forceful braking are the four scenarios the driver uses to assess the traction control capability. Investigations are conducted to examine the interaction between the suspension and traction systems and how this interaction influences the integrated model that represents the vehicle’s behavior and performance. The effectiveness of the suspension is assessed under bump and random road excitations, based on the presentation of vehicle performance criteria in both the time and frequency domains. The results of the simulation show that in terms of ride comfort and vehicle stability, the air–MR suspension system performs significantly better than the passive suspension system. A fuzzy traction controller can smooth out the torque applied to the vehicle’s wheels by adjusting the engine’s speed and torque.
Shehata Gad, Ahmed
Development of the Central Coordinated Motion Control System for Pure Electric Vehicles2025-01-01886/16/2025
The article introduces the air springs, CDC, rear-wheel steering system, braking system, front-wheel steering system, and electric drive system in the vehicle’s central coordinated motion control system. It explores achieving more comfortable shock absorption by adjusting the CDC (Continuously Variable Damping system) damping and other means. By combining open-loop and closed-loop rear-wheel steering control, the turning radius in small-radius steering mode is reduced by up to 10%, enabling crab-walking, optimizing the moose test entering speed up to 90.9 kph, and improving vehicle behavior on split-friction surfaces. Through the cooperation of IBS (Intelligent Brake System) and VMC, an extremely comfortable braking process is achieved.
Zhou, Yuxing, Li, Wen
Application of Blocked Force Methodology to an Electrified Beam Axle from a Medium-Duty Truck in Vehicle and in a Dynamometer Test Cell2025-01-00545/5/2025
The recent addition of fully electric powertrains to propulsion system options has increased the relevance of sound and vibration from electric motors and gearboxes. Electrified beam axles require different metrics from conventional beam axles for noise and vibration because they have multiple sources of vibration energy, including an electric motor and a reduction gearbox. Improved metrics are also driven by the stiff suspension connections and lack of significant isolation compared to electric drive units. Blocked force is a good candidate because it can completely characterize the vibration energy transmitted into a receiver and is especially useful because it is theoretically independent of the vehicle-side structure. While the blocked force methodology is not new, its application to beam axles is relatively unexplored in the literature. This paper demonstrates a case study of blocked force measurement of an electrified beam axle with a leaf spring suspension. The axle was tested both in vehicle and in a hemianechoic axle test cell. Measurement setup, including the selection of interface, instrumentation, and impact locations, is discussed. Comparisons between the blocked forces measured in vehicle and in dyno are made. Several key learnings, opportunities for measurement improvement, and ideas for future work are also addressed.
Shaw, Matthew D, Grimmer, Michael J
Analysis of Subharmonic Torsional Resonance in Powertrains with Two-Stage Spring Isolators2025-01-00965/5/2025
A vehicle powertrain system with a two-stage spring isolator separating a combustion engine from a transmission can exhibit significant nonlinear dynamics if the input torques cause the spring to continuously alternate between its first-stage and second-stage stiffnesses. In particular, this nonlinearity can result in subharmonic resonance of the system’s natural frequencies at half the frequency of the engine’s primary excitation order. A 1D torsional vibration model was prepared using Siemens’s Simcenter Amesim software to study these nonlinear vibrations. First, a correlated vehicle-level model was developed to replicate a half-order torsional resonance that was measured in a test of a research vehicle. Then, simplified theoretical models were used to study and demonstrate the sensitivity of this kind of subharmonic resonant response to changes in mean input torque level, amplitude of input torque oscillation, first-stage capacity of the spring isolator, and other factors.
Villiger, Jacob
Road Noise Analysis using Component TPA and FBS with Vehicle Component Modifications2025-01-00555/5/2025
Road noise caused by road excitation is a critical factor for vehicle NVH (Noise, Vibration, and Harshness) performance. However, assessing the individual contribution of components, particularly bushings, to NVH performance is generally challenging, as automobiles are composed of numerous interconnected parts. This study describes the application of Component Transfer Path Analysis (CTPA) on a full vehicle to provide insights into improving NVH performance. With the aid of Virtual Point Transformation (VPT), blocked forces are determined at the wheel hubs; afterward, a TPA is carried out. As blocked forces at the wheel hub are independent of the vehicle dynamics, these forces can be used in simulations of modified vehicle components. These results allow for the estimation of vehicle road noise. To simulate changes in vehicle components, including wheel/tire and rubber bushings, Frequency-Based Substructuring (FBS) is used to modify the vehicle setup in a simulation model. In this process, analytic springs were added in parallel to the actual rubber mounts, which were also measured using VPT on the actual vehicle. These springs simulate positive or negative changes in stiffness, allowing the study of how changes in the rubber mounts affect the vehicle's NVH performance. In this study, a sensitivity analysis was conducted using the FBS model to observe changes in road noise resulting from variations in bushing stiffness and blocked force. Based on the results of this analysis, the optimal combination of components was proposed for reducing the road noise. This approach provides an efficient and accurate method for analyzing the effects of rubber mount modifications on NVH performance.
Kim, Jungu, Reichart, Ron, de Klerk, Dennis, Schütler, Willem, Malic, Mario, Kim, Hyeongjun, Kim, Uije
A Study on Luxury Captain Seat Vibration in MPV Vehicles with Semi-Active Suspension2025-01-01075/5/2025
More and more captain-seat-like, luxury individual seats have been appeared inside MPV vehicles in order to meet various customer needs and improve market competitiveness. In the same time, customer complaints about seat vibration also increase significantly. Thus, luxury captain seat vibration is becoming MPV issues facing the vehicle development engineers. Typically, luxury captain seats are much heavier due to the added mechanisms to provide functions like massage or temperature controls, etc., and it is not feasible to structurally improve the seat modal frequencies to meet the need for NVH issue resolution. This paper presents a systematical study on the second-row luxury captain seat vibration issue between 10-25Hz with MPV vehicles. An axle contribution is analyzed with a 4-poster shaker test, and the test data show that the seat vibration is more sensitive to rear axle excitation than that of front axle, and to the out-of-phase excitation than the in-phase one. The similar results are displayed by a coherence analysis of on-road test data. It also discusses the effects of a continuous damping control (CDC) shock absorber and air spring tuning on the seat vibration, and the engineering resolutions for the development of the suspension, body and seat. The CDC current effect on seat vibration is interpreted through a quarter-car suspension model in theory.
Zhou, Changshui, Yu Sr, Jing, Gu, Perry, Zhang, Fan, Bu, Kunquan, Liu, Xinhua
Experimental Characterization of a Steel Spring Mount Using Virtual Point Transformation2025-01-00465/5/2025
The application of virtual point transformation for determining the transfer dynamic stiffness of a helical coil spring is demonstrated in this experimental study. Rigid fixtures are attached to both ends of the spring, and frequency response functions are measured using impact hammer excitations. These frequency response functions are transformed into virtual points, analogous to a node in finite element analysis, with six degrees of freedom. The six degrees of freedom transfer dynamic stiffness is then extracted using the inverse substructuring method, which eliminates the need to account for fixture dynamics. The results are validated by a direct measurement approach. Additionally, the study investigates the effect of liquid applied sprayed damping coatings on the spring's transfer dynamic stiffness, revealing that the coating significantly reduces vibration amplitudes at the surge frequencies. This suggest that the springs effective damping properties are enhanced.
Neihguk, David, Herrin, D. W., de Klerk, Dennis
On-the-Market Air Suspension Systems for Passenger Cars10-09-02-00164/28/2025
This article conducts a thorough review of contemporary air suspension systems on the market for passenger cars. The evolution of suspension structures and control methodologies are briefly discussed. The layout of air suspension systems is introduced in detail, with each component receiving a comprehensive description and analysis. The open-loop and closed-loop arrangements are explained. Various types of air springs are discussed and compared. The sensory system, special working conditions, and failure analysis are also elaborated. In the case studies, some example models are listed to show a complete guide of how air suspension is implemented on passenger cars, which includes functionalities, air spring configurations, control methods, signal flow, service modes, and diagnostic messages. The major sources are OEMs’ official websites and previously released documents, such as user manuals and maintenance manuals, which are valid up to April 2023. Finally, the article concludes with a forward-looking discussion on the future application of air suspension.
Ma, Changye, Lu, Yukun, Zhen, Ran, Liu, Yegang, Pan, Bingwei, Khajepour, Amir
Development and Validation of Hands-off Detection Function for Steering Wheel for the CEPS System with a Torque Sensor2025-01-80474/1/2025
Traditional Hands-Off Detection (HOD) is realized by analyzing the torque applied to the steering wheel by the driver (driver torque), which is less accurate. In order to solve this problem, this paper takes the Column Electric Power Steering (CEPS) system as an object, analyzes the influence of the inertia effect and damping effect of the steering wheel and steering column on the HOD, establishes two kinds of state observers to obtain the accurate driver torque, proposes the estimation method of the road condition level, and can determine the torque threshold according to the information of the road condition level and the vehicle speed, and finally compares the driver torque and the torque threshold to obtain the HOD results. Experimentally, it is proved that this method can effectively reduce the interference of road surface interference on HOD. In addition, a fault-tolerant detection mechanism is proposed and validated to calculate the HOD result based on the frequency-domain characteristics of the torque sensor's signal only when the observer cannot work properly due to the failure of the EPS motor position sensor.
Huang, ZhaoLin, Li, Min, Shangguan, Wenbin, Duan, XiaoCheng, Xia, ZhiJun
Simulation and Parameter Optimization of Commercial Vehicle Cab Suspension System2025-01-82684/1/2025
Taking a commercial vehicle cab suspension system as the research focus, a rigid-flexible coupled dynamics model was established based on the nonlinear characteristics of the integrated damper air spring and bushings. Time-domain vibration acceleration signals were acquired at the connection points between the frame, cab, and suspension. The vibration signals at the frame and suspension connection points were input into the simulation model, where the vibration responses at the cab and suspension connection points were calculated and analyzed using the established cab suspension system model. The accuracy of the model was verified by comparing the simulation results with experimental data. The established cab suspension system model was further used to evaluate human vibration comfort within the cab, following national standards for subjective human perception. A piecewise polynomial function was employed to fit the stiffness-damping characteristics of the integrated damper air spring, resulting in the determination of the coefficients for each segment and the coordinates of the transition points in the fitting function. The total weighted root mean square (RMS) value of the cab floor acceleration was used as the optimization objective, while the coefficients and the coordinates of the breakpoints in the fitting function were employed as optimization variables. A multi-island genetic algorithm was applied to optimize the cab suspension's stiffness and damping properties. The optimization results indicate that the enhanced suspension system contributes to an improvement in cab ride comfort.
Hao, Qi, Zhu, Yuntao, Sun, Wen, Sun, Kai, Sun, Zhiyong, Huang, Yu, Zhen, Ran, Shangguan, Wen-Bin
Computational Method of Static and Dynamic Mechanical Properties of a Rolling Lobe Air Spring2025-01-82614/1/2025
To investigate the static and dynamic mechanical properties of air springs and their influencing factors, two models were established in this paper to calculate the static and dynamic mechanical properties of air springs, including a simulation model based on the finite element method and a mathematical calculation model based on thermodynamic theory. First, a performance calculation model for rolling lobe air springs with aluminum tubes was established, which considered the thickness of the bellow and the impact of the inflation and assembly process on the state of the bellow. The static and dynamic mechanical properties of air springs were calculated using this model, including static load-bearing capacity and static/dynamic stiffness. The calculation results showed that both the static characteristics of the air spring under isothermal conditions and the dynamic characteristics under adiabatic conditions were able to be calculated accurately. However, the changes in dynamic stiffness and the hysteresis phenomena caused by heat exchange during the polytropic process of the air spring are unable to be simulated by the finite element model. A mathematical calculation model was then established to analyze the mechanical properties of air spring during polytropic process. Some factors, such as heat transfer, external work and mass exchange, which cause changes in energy and temperature, were considered in the model. The dynamic characteristics of the air spring under different excited amplitudes and excited frequency were calculated using this model. The comparison of the calculation and experimental results showed that the dynamic stiffness and hysteresis characteristics of air springs across various frequencies were able to be calculated effectively by the proposed model, and the maximum relative error of dynamic stiffness and hysteresis force were less than 5%.The influence of volume, pressure, and heat exchange performance on the dynamic characteristics of the air spring were analyzed using the model. The modeling and analysis methods in this article can predict the static and dynamic mechanical properties of air springs and analyze the influence of relevant structural parameters, providing guidance and reference for designing the rolling lobe air springs.
Wang, Sirui, Kang, Yingzi, Xia, Zhao, Yu, Chao, Li, Jianxiang, Shangguan, Wen-Bin
The Model Predictive Control of Dual-Chamber Active Air Suspension Based on Road Preview2025-01-87894/1/2025
Adverse weather conditions such as rain and snow, as well as heavy load transportation, can cause varying degrees of damage to road surfaces, and untimely road maintenance often results in potholes. Perception sensors equipped on intelligent vehicles can identify road surface conditions in advance, allowing each wheel’s suspension to actively adjust based on the road information. This paper presents an active suspension control strategy based on road preview information, utilizing a newly designed dual-chamber active air suspension system. It addresses the issue of point cloud stratification caused by vehicle body vibrations in onboard LiDAR data. The point cloud is processed through segmentation, filtering, and registration to extract real-time road roughness information, which serves as preview information for the suspension control system. The MPC algorithm is applied to actively adjust the nonlinear stiffness and damping of the suspension’s dual-chamber air springs, enhancing suspension response speed and accuracy. The effectiveness of the active air suspension MPC method under real-time road sensing is validated through co-simulation using Matlab/Simulink and CarSim. Vehicle ride comfort is used as the evaluation criterion, demonstrating that the integrated sensing and control approach can effectively reduce vehicle.
Dong, Fuxin, Shen, Yanhua, Wang, Kaidi, Liu, Zuyang, Qian, Shuo
A Control Strategy for Height Adjustment in Closed-Loop Air Spring Suspension System2025-01-87984/1/2025
This study examines a closed air spring suspension system. To address issues such as over-inflation, over-deflation, and excessive overshoot during vehicle height adjustment, a threshold control method is implemented. This method controls the triggering conditions for height adjustment and effectively reduces overshoot while enhancing precision. Experimental results indicate that this control strategy decreases overshoot and improves accuracy. However, risks are associated with varying threshold settings across different control modules, which can lead to over-control. A fuzzy PID controller is developed to resolve this issue. This controller adjusts PID parameters in real time based on fuzzy rules, thereby refining height adjustments. During testing, it was found that the degree of electromagnetic valve opening could not be controlled by the fuzzy PID controller. Therefore, a control strategy to adjust the compressor speed is designed. Experiments show that the fuzzy PID controller, capable of regulating compressor speed, effectively addresses the problems associated with threshold control. Additionally, this approach increases the rate of height adjustment. Real vehicle tests confirm the feasibility of the proposed control strategy. The results demonstrate that the closed air spring suspension system achieves smoother and more efficient height adjustments with improved accuracy.
Zheng, Guoqing, Yin, Zhihong, Chen, Shiwen, Shangguan, Wen-Bin
A Distributed Control Strategy for Highway Merge Zone Based on Virtual Rotation2025-01-72002/21/2025
The merging problem in the highway merge zone has been a research focus in the field of transportation for a long time. The rise of Connected and Automated Vehicles (CAVs) provides the potential to improve traffic flow efficiency, alleviate congestion and handle safety issues. However, existing two-dimensional merging strategies are facing challenges such as high computational complexity and the inevitable traffic oscillations during merging, which hinder the stability of traffic flow and fail to meet the dynamic requirements of merging control. To address these issues, this study proposes a distributed control strategy for CAVs in highway merge scenarios. Firstly, a virtual rotation method is designed to transform the merging problem of two different lanes into a car-following problem of a virtual platoon, and a virtual leader vehicle is introduced, to reduce computational complexity and determine vehicle sequencing. Based on this method, a Spring Cooperative Merging System (SCMS) is developed. It uses spring characteristics to regulate the longitudinal motion states of vehicles. Virtual spring forces are employed to adjust the vehicle distance and speed instantaneously, aiming to achieve an ideal traffic flow. To further enhance the study’s authenticity, the impact of input saturation constraints is also considered. Finally, simulations are conducted via SUMO. The results show that the proposed control strategy exhibits convergence, as the total elastic energy approaches zero over time. This can demonstrate the effectiveness of the method, so that it is possible to improve the stability and efficiency of merging in the highway merge zone and provide theoretical insights for future practical applications.
Liu, Yandan, Qu, Xu
“Smart Testing Methodology for Air Suspension System of Buses”2024-28-020112/5/2024
In the fast growing automotive sector, reliability & durability are two terms of utmost importance along with weight and cost optimization. Therefore it is important to explore new technology which has less weight, low manufacturing cost and better strength. It also seek for a quick, cost effective and reliable methodology for its design validation so that any modification can be made by identifying the failures. This paper presents the rig level real world usage pattern simulation methodology to validate and correlate the vehicle level targets for micro strain, wheel forces and displacement on suspension components like optimized Z spring, torque rods, pan hard rod & mounting brackets of newly developed air suspension for buses.
Tangade, Atul Bandu, Babar, Sunil, Bankar, Milind Achyutrao, Mehendale, Ravindra, Dhumal, Kailas, Bhusari, Deepak, Sonawane, Ravindra, Shinde, Saurabh
EDITORIAL: Bauma the big one in 202524TOFHP12_0412/1/2024
December is a good time to reflect on the past year - to celebrate successes and consider opportunities for improvement - but it is also an opportune time to look to the future. As I think about the year ahead and appraise the tradeshow landscape that'll provide significant content for this magazine, mobilityengineeringtech.com, our e-newsletters and other multimedia products, none is bigger than Bauma in Munich, Germany, particularly in terms of the global construction and mining vehicle industries. The triennial event will cover an area that's equivalent to 86 soccer fields, according to Stefan Rummel, CEO of Messe München GmbH. Speaking to the press during an October virtual preview of Bauma 2025, which takes place from April 7-13, Rummel said that the number of exhibitors - expected to be about 3,600 - will be closer to the 2019 event versus the post-COVID-19 edition that was pushed back from its usual spring timeslot to the fall of 2022.
Gehm, Ryan
Semi-Active Suspension Design for Truck Using Pneumatic Spring Joining MR Fluid Damper Based on Neural Networks Controller10-09-01-000110/21/2024
In order to modify both stiffness and damping rates according to various road conditions, this research introduces a pneumatic spring in conjunction with a magnetorheological (MR) fluid damper as a single suspension unit for each wheel in the truck. Preventing weight transfer and improving riding comfort during braking, acceleration, and trajectory prediction are the main objectives. A two-axle truck has been used, consisting of three degrees of freedom for the sprung mass, including vertical, pitch, and roll motions, and four degrees of freedom for the unsprung masses, which have been redesigned according to the different types of springs and dampers. Pneumatic-controlled springs, often referred to as dynamic or classic models, replace laminated leaf springs commonly found in vehicles. Additionally, an MR damper replaces a hydraulic double-acting telescopic shock absorber. These models are studied to evaluate the effect of pneumatic spring parameters on truck dynamics. Pneumatic stiffness and the intended damping force are monitored by a recurrent neural network in conjunction with leveling control. This process provides the recommended voltage for the MR damper based on the Signum function damper controller. The performance of the suspension is assessed in the time and frequency domains for both step and random road excitations using vehicle dynamic parameters. Six suspension system configurations are compared with the air spring dynamic model integrated with the MR damper (Model 6), which is recommended as a suspension system for trucks. According to simulation data, when compared to alternative suspension systems, Model 6 significantly enhances both ride comfort and vehicle stability. Model 6 offers improvements in tire workload, truck path, tire–ground contact point during acceleration, braking efficiency, and stopping distance. Compared to previous controlled models, Model 6 also demonstrates zero steady-state offset and zero steady-state error.
Shehata Gad, Ahmed, El-Zomor, Haytham M.
Synergistic 1-D and 3-D Analysis to Optimize the Performance and Reliability of the Reed Valve Used in Reciprocating E-Compressor2024-28-001310/17/2024
With the advent of electric and hybrid drivetrain in the commercial vehicle industry, electrically driven reciprocating compressors have gained widespread prominence. This compressor provides compressed air for key vehicle systems such as brakes, suspension systems and other auxiliary applications. To be a market leader, such an E-compressor needs to meet a myriad of design requirements. This includes meeting the performance by supplying air at required pressure and flow rate, durability requirements and having a compact design while maintaining cost competitiveness. The reed valve in such a compressor is a vital component, whose design is critical to meet the aforementioned requirements. The reed valves design has several key parameters such as the stiffness, natural frequency, equivalent mass, and lift distance which must be optimized. This reed valve also needs to open and close rapidly in response to the compressor operating speed. Since it is the order of milliseconds, the valve is subjected to high velocity and impact force during this short time. A 1-D AMESim representation of the compressor has the reed valve modeled as an equivalent spring mass system. 3-D static structural analysis is performed using FEA tool to predict the stiffness, natural frequency and equivalent mass which acts as the input to the 1-D model. The overall performance of the compressor is then predicted through the 1-D Model simulation. The pressure data from this 1-D model is fed back to FEA to perform a 3-D transient dynamic analysis. The impact velocity and dynamic stresses induced during valve operation is studied to ensure reed valve durability. Optimization of the design parameters of reed valve is performed by synergistically combining the key insights from the AMESim performance outputs as well as the stiffness and dynamic stress prediction from FEA.
J, Bharadwaj, T, Sukumar, Pendyala, Vamsi Krishna, Paul Pandian, Adheenthran
Liftgate Slam by Bilinear Quasistatic Approach Using Modal Transient Method under Equivalent Static Loads2024-01-50778/5/2024
Automotive closure slam is the most crucial attribute affecting the closure structure and its mountings on BIW due to its high occurrence in real-world usage. Thus, virtual simulation of closure slam becomes necessary and is generally carried out using explicit codes with associated technical hitches like all-requisite inputs availability, FE modeling and analysis techniques, substantial human effort, high solution time, human and computational resource competence, or even access to suitable expensive explicit FE solver. Hence it becomes challenging to virtually analyze the design at every design phase of product development cycle under strict timelines leading to possibilities of both over- and under-designed parts, sometimes resulting in physical testing or even field failures. So, the need for an alternative simplified representation of closure slam, addressing the typical issues faced during explicit dynamic simulation and producing acceptable analysis outputs, gains significance. In this article the rotation of the liftgate about its hinge axis during slam is first segregated into two successive rotation phases based on the geometric configuration of its latch/locking components in terms of initial state to half-latched and half-latched to full-latched condition. Linear springs are introduced at critical locations in the FE model and the two rotation phases are initially represented by two linear static analysis, under equivalent static loads, determined using kinematic and inertia properties relationships at a particular operating velocity. This is followed by modal transient analysis on the linear static analysis setups in successive time domains in accordance to the rotation phase. Kinematic and inertia properties compliance are ensured during each phase. The combined modal transient analysis results, representing the entire event, shows outputs consistent with explicit dynamics simulation and stress history in tandem with the loading dynamics, thus resulting in a reasonable estimate of fatigue life of the structure.
Chatterjee, Suprakash
Carbon Steel, Wire Spring Quality Music Wire 0.70 - 1.00C Cold DrawnAMS5112N (Current)6/24/2024
This specification covers a carbon steel in the form of wire supplied as coils, spools, or cut lengths (see 8.2).
AMS E Carbon and Low Alloy Steels Committee
Development and Analysis of a Multibody Dynamics Suspension Air Spring Model as a Function of Sprung Mass, Un-Sprung Mass, and Design Height10-08-03-00206/13/2024
Air spring systems are challenging to mathematically model due to the complexity of their nonlinear dynamic characteristics. Numerous air spring mechanical and thermodynamic models have been proposed, but this study focused on the development and analysis of a new thermodynamic air spring model under a polytropic thermodynamic process that could accurately represent the force output in a multibody dynamics (MBD) virtual suspension subsystem. This model considered function inputs of sprung mass, un-sprung mass, and design height to efficiently generate updated air spring properties for new vehicle configurations, specifically for a self-propelled sprayer application. After this model was validated against physical ground-truth sensor data, it was utilized in a sensitivity study to experimentally test an alternative air spring component and to understand the resulting performance effect on an operator comfort key performance indicator.
Adams, Bailey
Analysis of Low-Frequency Brake Noise for Drum Brakes on Semi-Trailers2024-01-28954/9/2024
A road test on semi-trailers is carried out, and accelerations of some characteristic points on the braking system,axles,and truck body is measured,also brake pressure and noise around the support frame is acquired.The measured data was analyzed to determine the causes of the brake noise, and the mechanism of the noise of the drum brake of semi-trailers during low-speed braking was investigated. The following conclusions are obtained: (1) Brake noise of the drum brake of the semi-trailer at low-frequency is generated from vibrations of the brake shoes, axle, and body, and the vibration frequency is close to 2nd natural frequency of the axle. (2) Brake noise is generated from stick-slip motion between the brake shoes and the brake drum, where the relative motion between the brake drum and the brake shoes is changed alternately with sliding and sticking, resulting in sudden changes in acceleration and shock vibration. A multi-body dynamic model of the semi-trailer is established for analyzing vibrations causing noise and the influencing parameters. In the model, the elastic deformation of components, such as brake drums, brake shoes, axles, and leaf springs during the braking process, is considered. The model is validated by comparing calculated data with experiment data.The simulation shows that there is a heavy stick-slip vibration between the brake drum and brake shoes, which is transmitted to the axle through the brake shoes, and then to the body through the leaf spring. As the speed of the semi-trailer increases, the stick-slip frequency between the frictional pairs increases. When the stick-slip frequency is close to the natural frequency of the axle, it resonance.
Tang, Hao, Shangguan, Wen-Bin, Kang, Yingzi, Zheng, Jing-Yuan, Lan, Wen-Biao
Development of simulation methodology to evaluate Leaf Spring strength and predict the Leaf Interface stresses and correlating with test2024-01-27354/9/2024
Leaf Springs are commonly used as a suspension in heavy commercial vehicles for higher load carrying capacity. The leaf springs connect the vehicle body with road profile through the axle & tire assembly. It provides the relative motion between the vehicle body and road profile to improve the ride & handling performance. The leaf springs are designed to provide linear stiffness and uniform strength characteristics throughout its travel. Leaf springs are generally subjected to dynamic loads which are induced due to different road profiles & driving patterns. Leaf spring design should be robust as any failure in leaf springs will put vehicle safety at risk and cost the vehicle manufacturer their reputation. The design of a leaf spring based on conventional methods predicts the higher stress levels at the leaf spring center clamp location and stress levels gradually reduce from the center to free ends of the leaf spring. In RWUP conditions, the failures of leaf spring can occur at the leaf interfaces (i.e. where the succeeding leaf ends) in addition to center clamp locations. The aim of this paper is to capture and demonstrate the potential failure at leaf interfaces which is not predicted through conventional methodology, in addition to leaf center. The experimental strains measured on leaf spring using strain gauges in vehicle level testing are correlating with the strains predicted by the proposed simulation methodology. The correlation is demonstrated on the front leaf spring of pickup vehicle. An investigation into new simulation methodology is incorporated to study the base design and further the influence of design parameters, nipping, leaf travel, shot peening and stress peening processes were explored to improve the design. Based on these studies the new design is proposed that incorporates stepping, stress peening and diamond cut design which improves the life considerably.
Balasubramani, Sritharkumar, S Kangde, Suhas, Mohapatra, Durga Prasad, M, Ayyappadas
An Active Suspension Control Strategy for Planet Rover on Rough Terrain2024-01-23004/9/2024
The soft and rough terrain on the planet's surface significantly affects the ride and safety of rovers during high-speed driving, which imposes high requirements for the control of the suspension system of planet rovers. To ensure good ride comfort of the planet rover during operation in the low-gravity environment of the planet's surface, this study develops an active suspension control strategy for torsion spring and torsional damper suspension systems for planet rovers. Firstly, an equivalent dynamic model of the suspension system is derived. Based on fractal principles, a road model of planetary surface is established. Then, a fuzzy-PID based control strategy aimed at improving ride comfort for the planet rover suspension is established and validated on both flat and rough terrains. This study provides an advanced suspension system control strategy for planet rovers' ride comfort and safety during high-speed driving, ensuring the smooth operation of vehicles on the rough extraterrestrial terrain.
Liu, Jun, Zhang, Kaidi, Shi, Junwei, Wu, Jinglai, Zhang, Yunqing
Fatigue Life Analysis Methods for Rolling Lobe Air Spring2024-01-22594/9/2024
The fatigue prediction model of an air spring based on the crack initiation method is established in this study. Taking a rolling lobe air spring with an aluminum casing as the studying example, a finite element model for analyzing force versus displacement is developed. The static stiffness and dimensional parameters of limit positions are calculated and analyzed. The influence of different modeling methods of air springs bellow are compared and analyzed. Static stiffness measurement of an air spring is conducted, and the calculation results and the measured results of the static stiffness are compared. It is shown that the relative error of the measured stiffness and calculated stiffness is within 1%. The Abaqus post-processing stage is redeveloped in Python language. The damage parameters including the maximum principal nominal strain, maximum Green-Lagrange strain, and effective stress of air spring bellows are extracted and calculated to find out the critical points, where the maximum amplitude of damage parameters appear. Finally, according to the Miner damage accumulation rule, the fatigue life of an air spring under variable amplitude loads is estimated. The durability of the air spring is carried out. The fatigue life of the air spring predicted by the three models is given and compared with the measured fatigue life. It is concluded that the three proposed models in this paper for fatigue life prediction can be used to estimate the fatigue life for an air spring.
Yu, Yingjin, Yin, Zhihong, Li, Jianxiang, Shangguan, Wen-Bin
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