Browse Topic: Finite element analysis

Items (3,403)
Researchers at the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) previously conducted a full-scale crash test of a Fokker F28 MK1000 aircraft to study occupant injury risks. The goal of the current study was to investigate the injury predictions of the Global Human Body Models Consortium (GHBMC) and Total Human Model for Safety (THUMS) occupant models in the tested aircraft crash condition and explore possible utilization of both human body models (HBMs) in this context. Eight crash conditions were simulated utilizing each of the models. The HBMs were positioned in two postures, a neutral upright posture with hands resting on the legs and feet contacting the floor and a braced posture with head and hand contact with the forward seat back. Head and neck injury metrics and lumbar vertebra axial force were calculated and compared for all simulations. Both HBMs reported similar kinematic responses in the simulated impact conditions. However, the GHBMC
Jones, NathanielPutnam, JacobUntaroiu, Costin Daniel
Recent studies have found that Brain Injury Criteria (BrIC) grossly overpredicts instances of real-world, severe traumatic brain injury (TBI). However, as it stands, BrIC is the leading candidate for a rotational head kinematics-based brain injury criteria for use in automotive regulation and general safety standards. This study attempts to understand why BrIC overpredicts the likelihood of brain injury by presenting a comprehensive analysis of live primate head impact experiments conducted by Stalnaker et al. (1977) and the University of Pennsylvania before applying these injurious conditions to a finite element (FE) monkey model. Data collection included a thorough analysis and digitization of the head impact dynamics and resulting pathology reports from Stalnaker et al. (1977) as well as a representative reconstruction of the Penn II baboon diffuse axonal injury (DAI) model. Computational modeling techniques were employed on a FE Rhesus monkey model, first introduced by Arora et al
Demma, Dominic R.Tao, YingZhang, LiyingPrasad, Priya
Current voluntary standards for wheelchair crashworthiness only test under frontal and rear impact conditions. To help provide an equitable level of safety for occupants seated in wheelchairs under side impact, we developed a sled test procedure simulating nearside impact loading using a fixed staggered loading wall. Publicly available side impact crash data from vehicles that could be modified for wheelchair use were analyzed to specify a relevant crash pulse. Finite element modeling was used to approximate the side impact loading of a wheelchair during an FMVSS No. 214 due to vehicle intrusion. Validation sled tests were conducted using commercial manual and power wheelchairs and a surrogate wheelchair base fixture. Test procedures include methods to position the wheelchair to provide consistent loading for wheelchairs of different dimensions. The fixture and procedures can be used to evaluate the integrity of wheelchairs under side impact loading conditions.
Boyle, KyleHu, JingwenManary, MiriamOrton, Nichole R.Klinich, Kathleen D.
This study aims to develop a lightweight bus passenger seat frame by conducting structural nonlinear finite element analysis (FEA) on various thickness combinations of seat frame components to identify the optimal configuration. The thicknesses of critical structural members that primarily bear the load when force is applied to the seat frame were selected as independent variables, while stress on each component and compliance with ECE R14 seatbelt anchorage displacement regulations were set as dependent variables. A regression analysis was performed to calculate the importance of each component and analyze the influence of each design variable on the dependent variables. Strain gauges were attached to critical areas of the actual seat frame to conduct a seatbelt anchorage test, and simulations under identical conditions were performed using the nonlinear FEA software (LS-DYNA) to validate the reliability of the analysis results. The optimized seat frame exhibited a maximum stress of
Ko, Yeong GookCho, Kyu ChunLee, Ji SunKang, Ki Weon
Composite materials are increasingly utilized in industries such as automotive and aerospace due to their lightweight nature and high strength-to-weight ratio. Understanding how strain rate affects the mechanical and crashworthiness properties of CFRP composites is essential for accurate impact simulations and improved safety performance. This study examines the strain rate sensitivity of CFRP composites through mechanical testing and finite element analysis (FEA). Experimental results confirm that compressive strength increases by 100%–200% under dynamic loading, while stiffness decreases by up to 22% at a strain rate of 50 s−1, consistent with trends observed in previous studies. A sled test simulation using LS-Dyna demonstrated that the CFRP crash box sustained an average strain rate of 46.5 s−1, aligning with realistic impact conditions. Incorporating strain rate–dependent material properties into the FEA model significantly improved correlation with experimental crashworthiness
Badri, HesamJayasree, Nithin AmirthLoukodimou, VasilikiOmairey, SadikBradbury, AidanLidgett, MarkPage, ChrisKazilas, Mihalis
To enhance the power density of the system and reduce production costs, the high-speed electric drive system featuring integrated design and control is poised to be the future development trend. However, the high speeds of motors and gear reducers can lead to challenges such as system reliability and issues related to NVH. This paper specifically addresses the NVH concerns associated with the in-wheel reducer and motor drive system (IWRMDS). First, a bench test scheme is established, and vibration and noise tests are conducted under a range of conventional operating conditions. The results indicate that at a torque of 200 Nm and a speed of 5500 rpm, the noise sound pressure level reaches 86.2 dB, highlighting significant vibration and noise issues within the system. Subsequently, Operational Deflection Shape (ODS) testing and analysis are performed on the system. It was discovered that the IWRMDS exhibits a relatively rich modal frequency spectrum, with the breathing mode being the
Huang, ChaoXiong, LuMeng, DejianGong, YuGuo, HanZhang, Mengyuan
Thermal Management Integration Module (TMIM), which comprises components such as water pumps, runner boards, brackets, sensors, etc., is a multifunctional integrated component for electric vehicles. However, the water pump generates an excitation over a wide range of frequencies due to a wide range of speed variations. This excitation causes the TMIM to vibrate and generate noise. In this study, a TMIM that generates noise is studied and analyzed. Using the TMIM of an electric vehicle as a case study, a full-vehicle experimental test was conducted, revealing that the noise originates from the integration module. The finite element method is used to analyze the cause of noise generation. Given the characteristics of the TMIM, which comprise many components, high integration, and a complex structure, this paper simplifies the bracket, heat exchanger, sensor, and other components using the centralized mass point method. The modal state of the TMIM is obtained by impact hammer testing the
Xu, Shenao
The proposed work performs the detailed investigation of material damping ratio for different Electronic Ignition Switch Module (EISM) used in two-wheeler automobiles. A Finite Element Method (FEM) based simulation model has been developed. The simulation is performed by matching the failure areas of critical components in the assembly with physical sinusoidal vibration based shaker table test. The results (particularly breakage) have been reproduced by utilizing different damping ratios for the assembly. The damping ratio parameter is further utilized to perform FEM based harmonic response analysis for different EISM and evaluate critical structural breakage zones. The breakage zones predicted by simulation are found to be aligned with breakage zones depicted by shaker table sinusoidal test results. The simulation outcomes are validated, specifically considering the damping ratio parameter. The FEM based harmonic response analysis has been performed for a particular acceleration
Shah, VirenKalurkar, ShantanuKumar, RahulKushari, SubrataMiraje, JitendraD, SureshParandkar, Parag
Electric motor whine is a significant source of noise in electric vehicles (EVs). To improve the noise, vibration, and harshness (NVH) performance of electric propulsion systems, it is essential to develop a physics-based, high-fidelity stator model. In this study, a machine learning (ML) model is developed using an artificial neural network (ANN) method to accurately characterize the material properties of the copper winding, varnish, and orthotropic stator laminate structure. A design of experiments (DOE) approach using Latin hypercube sampling of parameters is implemented after evaluating alternative surrogate models. A finite element (FE) model is constructed using the nominal stator design parameters to train the ANN model using 121 DOE variables and 72,000 data points. The ML-trained ANN model is then verified to predict the driving point frequency response function (FRF) spectrum with reasonable accuracy. Subsequently, modal tests are conducted on the electric stator, and the
Rao, Bhyri RajeswaraGSJ, GautamHe, Song
Pulse width modulation (PWM) and the corresponding modulation index (MI) value are of critical importance to the performance of electric drive systems for electric vehicle applications. For interior permanent magnet (IPM) machines, operating in overmodulation (OVM) and six-step modes increases the voltage output beyond the linear region, allowing the motor to achieve higher torque and power with reduced inverter loss. However, the resulting distorted current waveforms and higher current ripple harmonics lead to a notable increase in the motor noise. A multi-disciplinary approach has been developed to analyze the NVH performance of a three-phase 8-pole IPM motor when it operates in the OVM and six-step regions at high speed. The PWM current ripple harmonics induced by voltage-source inverters are predicted using different MIs and subsequently validated through experiments. The current ripple data are used for the prediction of dynamic electromagnetic (EM) forces in the OVM and six-step
He, SongChang, LeGong, ChengZhang, PengGSJ, Gautam
During cylinder deactivation events, high amplitude torque pulsations are generated at the crankshaft of the engine over a wide frequency range creating a potential risk for noise, vibration and harshness (NVH) performance of the vehicle. As passive tuned mass dampers are effective only in a narrow frequency range, active tuned mass dampers (ATMD) have become a popular choice to mitigate the risk. Often, engineers rely on finite element (FE) models of vehicle structures to make design decisions during the early stages of vehicle development. However, there is limited literature on the simulation of ATMD using FE techniques. Consequently, several details related to the ATMD design are decided through physical testing at the latter stages of vehicle development which is not ideal. To address these issues, a novel methodology to simulate an ATMD during cylinder deactivation events using FE technique is presented here. In this study, an ATMD based on force feedback control method was
Maddali, RamakanthMogal, Akbar BaigHaider, SyedJahangir, Yawar
The multifaceted, fast-paced evolution in the automotive industry includes noise and vibration (NVH) behavior of products for regulatory requirements and ever-increasing customer preferences and expectations for comfort. There is pressing need for automotive engineers to explore new and advanced technologies to achieve a ‘First Time Right’ product development approach for NVH design and deliver high-quality products in shorter timeframes. Artificial Intelligence (AI) and Machine Learning (ML) are trending transformative technologies reshaping numerous industries. AI enables machines to replicate human cognitive functions, such as reasoning and decision-making, while ML, a branch of AI, employs algorithms that allow systems to learn and improve from data over time. The purpose of the paper is to show an approach of using machine learning techniques to analyze the impact of variations in structural design parameters on vehicle NVH responses. The study begins by executing the Design of
Miskin, Atul R.Parmar, AzanRaj, SoniaHimakuntla, Uma Maheswar
Every vehicle has to be certified by the concerned governing authority that it matches certain specified criteria laid out by the government for all vehicles made or imported into that country. Horn is one of the components that is tested for its function and sound level before a vehicle is approved for production and sale. Horn, which is an audible warning device, is used to warn others about the vehicle’s approach or presence or to call attention to some hazard. The vehicle horn must comply with the ECE-R28 regulation [1] in the European market. Digital simulation of the horn is performed to validate the ECE-R28 regulation. In order to perform this, a finite element model of a cut model of a vehicle, which includes the horns and other components, is created. Fluid-structure coupled numerical estimation of the sound pressure level of the horn, with the appropriate boundary conditions, is performed at the desired location as per the ECE-R28 regulation. The simulation results thus
Ramachandran, BalachandarRaveendran, RoshinMondal, Arghya
When a vehicle is driven at high speed, there exists intricate flow pattern and vortex shedding at the side window area with intense pressure fluctuation. A significant dynamic pressure difference between the vehicle's exterior and interior can render the side window sealing system vulnerable to aspiration. This susceptibility can lead to the generation of leakage noise, adversely affecting acoustic comfort in the vehicle's cabin. This paper delves into the aspiration properties of glassrun seal system under time-varying pressure difference. A nonlinear finite element model of the glassrun seal was established to simulate the quasi-static deformation of the sealing strip during installation process, which aims to obtain the deformed geometric shape and residual stress after this process. Then, the exterior flow field of the glassrun sealing area of a simplified vehicle model was calculated with CFD simulation to obtain the hydrodynamic pressure excitation acting on the outer surface of
Li, HanqiHe, YinzhiZhang, LijunZhang, YongfengYu, WuzhouJiang, ZaixiuBlumrich, ReinhardWiedemann, Jochen
Squeak and Rattle (S&R) issues present significant challenges in the automotive industry, negatively affecting the perceived quality of vehicles. Early identification of these issues through rigorous testing protocols—such as auditory assessments and dynamic simulations—enables the development of more robust systems while optimizing resource use. Finite Element Method (FEM) simulations are crucial for identifying S&R issues during the design phase, allowing engineers to address potential problems before the creation of physical prototypes. By developing high-fidelity virtual models and accurately simulating flexible connections, these simulations effectively capture rattle effects, enhancing prediction reliability. Traditional snap stiffness calculations typically employ a cantilever-based formulation, which is suitable for simple snap-fit designs but insufficient for more complex geometries that require enhanced stiffness. To address this limitation, the proposed methodology utilizes
Rao, SohanElangovan, PraneshReddy, Hari
Based on the objective and subjective experiment and finite element analysis, the influencing factors on the door closing sound quality of a heavy truck is analyzed and optimized. Results show that the loudness and sharpness can be reduced by increasing stiffness and damping of the door. The sound quality can be enhanced by increasing the pressure release area, which can decrease the air pressure resistance of dooring closing. By adding holes on the inner liner and changing the pressure release location, the dooring closing air pressure resistance is reduced from 289 Pa to 181 Pa. In terms of the rebound sound, the sound level is positively related to the door closing force. Increasing the protrusion height and decreasing the stiffness of the vibration absorber of the handle can improve the rebound sound quality. Optimizing the absorbers on both ends of the handle and adding damping material can decrease the loudness by 47.8%, reduce the cavity sound, reduce the rattle and improve the
Wang, JianZhang, YongshenFeng, LeiXie, ChenhaoLin, JieweiSun, Changchun
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, DavidHerrin, D. W.de Klerk, Dennis
This study focuses on the numerical analysis of weather-strip contact sealing performance with a variable cross-sectional design, addressing both static and dynamic behaviors, including the critical issue of stick-slip phenomena. By employing finite element modeling (FEM), the research simulates contact pressures and deformations under varying compression loads, DCE (Door Closing Efforts) requirements, typical in automotive applications. The analysis evaluates how changes in the cross-sectional shape of the weather-strip affect its ability to maintain a consistent sealing performance, especially under dynamic vehicle operations. The study also delves into stick-slip behavior, a known cause of noise and vibration issues, particularly improper/ loosened door-seal contact during dynamic driving condition. This study identifies key parameters influencing stick-slip events, such as friction coefficients, material stiffness, surface interactions, sliding velocity, wet/dry condition
Ganesan, KarthikeyanSeok, Sang HoSun, Hyang Sun
This research optimizes sheet metal gusset geometry to support a suspension pickup point in a Formula SAE racecar. The sheet metal gusset design incorporates an external radial cut-out and an internal triangular cut-out, each of which can be adjusted in size to optimize the stiffness to mass ratio. A finite element analysis was set up using a heavy braking load case, which applied 3900 N to the suspension point being supported by the gusset. A parametric optimization (finite element analysis) was run in SolidWorks to gather mass and stiffness data for each of the 143 designs under the prescribed load case. The parametric optimization was run on both a simulated front hoop and a test fixture, which showed a similar trend in their results. Experimental testing was performed on three designs. The gusset profiles were waterjet and TIG welded to the test fixture tube frames. The results of the test agreed with the simulation results with a discrepancy of less than 10% in all cases. The
Burggraf, JacobWillerth, Stephanie MichelleYu, Bosco
Composite sandwich beams are widely favored for their high strength-to-weight ratio, so understanding their vibration characteristics is important for optimizing designs in critical industries. This study investigates, through experimental and statistical analyses, the impact of core geometry on the vibration characteristics of epoxy/carbon fiber composite sandwich beams featuring sinusoidal and trapezoidal cores. Modal tests were conducted to determine natural frequencies, damping ratios, and mode shapes. The height and angle of the cores were treated as key independent factors influencing the beams’ vibration characteristics. In both of the cores the damping ratio values increased about 25% and 35% with increasing the height and angle of the sinusoidal and trapezoidal cores, respectively. Additionally, response surface methodology (RSM) was used for statistical analysis of these input parameters’ effects on damping properties, and the optimal values of core’s geometries were
Alwan, Majeed A.Abbood, Ahmed Sh.Farhan, Arkan J.Azadi, Reza
The escalating weight of main battle tanks (MBTs) has compelled designers to innovate with Ultra-high hard armor (UHA) steel against the current generation rolled homogenous armor (RHA). This study delves into investigating the experimental and numerical ballistic performance of 15 mm–thick UHA steel and 15 mm–thick RHA steel against a 7.62 mm armor-piercing (AP) small-arm projectile. Finite element (FE) simulations were executed using ANSYS software, incorporating the Johnsons Cook model and shock Rankine–Hugoniot equations. The outcomes highlight that the UHA steel arrests the projectile’s advancement at a depth of penetration (DoP) of 3 mm, where the mode of failure is projectile break-up with cleavage failure. Conversely, the RHA base metal demonstrates perforation accompanied by ductile hole growth as the mode of failure. This perforation is attributed to plastic deformation and material extrusion, aligning well with the FE model. In the second scenario, the ballistic limit of a
Naveen Kumar, SubramaniBalasubramanian, V.Malarvizhi, S.Sonar, TusharHafeezur Rahman, A.Balaguru, V.
Modern aircraft, ships, and offshore structures are increasingly constructed using fiber-reinforced composite materials. However, when subjected to lightning strikes, these materials can suffer significant structural and functional damage due to their electrical and thermal properties. This study aims to develop a novel finite element (FE) model to minimize the error in estimating the thermal damage caused during lightning strikes. This will aid in design and optimization of lightning protection systems. The developed model introduces a simplified numerical approach to model the lightning arc interaction with CFRP laminate. The existing FE model includes idealized loading conditions, leading to high error in estimation of severe damage area and in-depth damage. The proposed methodology incorporates a more realistic lightning-induced loading pattern to improve accuracy. Several cases are analyzed using available FE methods and compared to the proposed model (case 6) to evaluate the
Sontakkey, AkshayKotambkar, MangeshKaware, Kiran
The arc welding process is essential for motorcycle frames, which are difficult to form in one piece because of their complex shapes, because a single frame has dozens of joints. Many of the damaged parts of the frames under development are from welds. Predicting the strength of welds with high reliability is important to ensure that development proceeds without any rework. In developing frames, CAE is utilized to build up strength before prototyping. Detailed weld shapes are not applicable to FE models of frames because weld shapes vary widely depending on welding conditions. Even if CAE is performed on such an FE model and the evaluation criteria are satisfied, the model may fail in the actual vehicle, possibly due to the difference between CAE and actual weld bead geometry. Therefore, we decided to study the extent to which the stresses in the joint vary with the variation of the weld bead geometry. Morphing, a FE modeling method and design of experiment method, was utilized to
Hada, YusukeSugita, Hisayuki
This article analyses the fundamental curving mechanics in the context of conditions of perfect steering off-flanging and on-flanging. Then conventional, radial, and asymmetric suspension bogie frame models are presented, and expressions of overall bending stiffness kb and overall shear stiffness ks of each model are derived to formulate the uniform equations of motion on a tangent and circular track. A 4 degree of freedom steady-state curving model is formulated, and performance indices such as stability, curving, and several parameters including angle of attack, tread wear index, and off-flanging performance are investigated for different bogie frame configurations. The compatibility between stability and curving is analyzed concerning those configurations and compared. The critical parameters influencing hunting stability and curving ability are evaluated, and a trade-off between them is analyzed. For the verification, the damped natural frequencies and mean square acceleration
Sharma, Rakesh ChandmalSharma, Sunil KumarPalli, SrihariRallabandi, Sivasankara RajuSharma, Neeraj
This study aims to predict the impact of porosities on the variability of elongation in the casting Al-10Si-0.3Mg alloy using machine learning methods. Based on the dataset provided by finite element method (FEM) modeling, two machine learning algorithms including artificial neural network (ANN) and 3D convolutional neural network (3D CNN) were trained and compared to determine the optimal model. The results showed that the mean squared error (MSE) and determination coefficient (R2) of 3D CNN on the validation set were 0.01258/0.80, while those of ANN model were 0.28951/0.46. After obtaining the optimal prediction model, 3D CNN model was used to predict the elongation of experimental specimens. The elongation values obtained by experiments and FEM simulation were compared with that of 3D CNN model. The results showed that for samples with elongation smaller than 9.5%, both the prediction accuracy and efficiency of 3D CNN model surpassed those of FEM simulation.
Zhang, Jin-shengZheng, ZhenZhao, Xing-zhiGong, Fu-jianHuang, Guang-shengXu, Xiao-minWang, Zhi-baiYang, Yutong
In this work, design optimization for the lightweight of the body frame of a commercial electric bus with the requirements of stiffness, strength and crashworthiness is presented. The technique for order preference by similarity to ideal solution (TOPSIS) is applied to calculate the components that have a great impact on the output response of the static modal model and the rear-end collision model. The thickness of the five components with the highest contribution in the two models is determined as the final design variable. Design of experiment (DOE) is carried out based on the Latin Hypercube sampling method, and then the surrogate models are fitted by the least squares regression (LSR) method based on the DOE sampling data. The error analysis of the surrogate model is carried out to determine whether it can replace the finite element (FE) model for optimization, then the optimization scheme for lightweight optimization of electric bus frame is implemented based on the algorithm of
Yang, XiujianTian, DekuanLiu, JiaqiCui, YanLin, Qiang
Automotive audio components must meet high quality expectations with ever-decreasing development costs. Predictive methods for the performance of sound systems in view of the optimal locations of loudspeakers in a car can help to overcome this challenge. Use of simulation methods would enable this process to be brought up front and get integrated in the vehicle design process. The main objective of this work is to develop a virtual auralization model of a vehicle interior with audio system. The application of inverse numerical acoustics [INA] to source detection in a speaker is discussed. The method is based on truncated singular value decomposition and acoustic transfer vectors The arrays of transfer functions between the acoustic pressure and surface normal velocity at response sites are known as acoustic transfer vectors. In addition to traditional nearfield pressure measurements, the approach can also include velocity data on the boundary surface to improve the confidence of the
Baladhandapani, DhanasekarThaduturu, Sai RavikiranDu, Isaac
The integrated vehicle crash safety design provides longer pre-crash preparation time and design space for the in-crash occupant protection. However, the occupant’s out-of-position displacement caused by vehicle’s pre-crash emergency braking also poses challenges to the conventional restraint system. Despite the long-term promotion of integrated restraint patterns by the vehicle manufacturers, safety regulations and assessment protocols still basically focus on traditional standard crash scenarios. More integrated crash safety test scenarios and testing methods need to be developed. In this study, a sled test scenario representing a moderate rear-end collision in subsequence of emergency braking was designed and conducted. The bio-fidelity of the BioRID II ATD during the emergency braking phase is preliminarily discussed and validated through comparison with a volunteer test. The final forward out-of-position displacement of the BioRID II ATD falls within the range of volunteer
Fei, JingWang, PeifengQiu, HangLiu, YuShen, JiajieCheng, James ChihZhou, QingTan, Puyuan
Electric vehicles (EVs) have experienced significant growth, and the battery safety of EVs has drawn increased attention. However, the mechanical responses of battery during crashes have rarely been studied. Hence, the objective of this study was to understand EV battery package mechanics during side-pole crashes at different impact locations and speeds beyond regulated side-pole test with one specific speed and one location. An EV finite element (FE) model with a battery package was used. Side-pole impact simulations were conducted at four impact locations, including the baseline impact location according to side-pole impact regulation, plus three positions by moving the rigid pole 400 mm toward the back of the EV and moving the pole 400 and 800 mm toward the front of the EV. In addition, the impact velocities at 32, 50, and 80 km/h were simulated. Based on simulations, the peak relative displacement, the maximum change in gap between batteries, the maximum change in gap between the
Chen, JianBian, KeweiMao, Haojie
Based on the harmonic current injection method used to suppress the torsional vibration of the electric drive system, the selection of the phase and amplitude of the harmonic current based on vibration and noise has been explored in this paper. Through the adoption of the active harmonic current injection method, additional torque fluctuations are generated by actively injecting harmonic currents of specific amplitudes and phases, and closed-loop control is carried out to counteract the torque fluctuations of the motor body. The selection of the magnitude of the injected harmonic current is crucial and plays a vital role in the reduction of torque ripple. Incorrect harmonic currents may not achieve the optimal torque ripple suppression effect or even increase the motor torque ripple. Since the actively injected harmonic current is used to counteract the torque ripple caused by the magnetic flux linkage harmonics of the motor body, the target harmonic current command is very important
Jing, JunchaoZhang, JunzhiLiu, YiqiangHuang, WeishanDai, Zhengxing
The electric motor is a significant source of noise in electric vehicles (EVs). Traditional hardware-based NVH optimization techniques can prove insufficient, often resulting in trade-offs between motor torque or efficiency performance. The implementation of motor control-based torque ripple cancellation (TRC) technology provides an effective and flexible solution to reduce the targeted orders. This paper presents an explanation of the mathematical theory underlying the TRC method, with a particular focus on the various current injection methods, including those that allow up to 4DOFs (degrees-of-freedom). In the case study, the injection of controlled fifth or seventh order current harmonics into a three-phase AC motor is shown to be an effective method for cancelling the most dominant sixth order torque ripple. A dedicated feedforward harmonic current generation module is developed the allows the application of harmonic current commands to a motor control system with adjustable
He, SongGong, ChengChang, LePeddi, VinodZhang, PengGSJ, Gautam
Vehicle restraint systems, such as seat belts and airbags, play a crucial role in managing crash energy and protecting occupants during vehicle crashes. Designing an effective restraint system for a diverse population is a complex task. This study demonstrates the practical implementation of state-of-the-art Machine Learning (ML) techniques to optimize vehicle restraint systems and improve occupant safety. An ML-based surrogate model was developed using a small Design of Experiments (DOE) dataset from finite element human body model simulations and was employed to optimize a vehicle restraint system. The performance of the ML-optimized restraint system was compared to the baseline design in a real-world crash scenario. The ML-based optimization showed potential for further enhancement in occupant safety over the baseline design, specifically for small-female occupant. The optimized design reduced the joint injury probability for small female passenger from 0.274 to 0.224 in the US NCAP
Lalwala, MiteshLin, Chin-HsuDesai, MeghaRao, Shishir
Neck injury is one of the most common injuries in traffic accidents, and its severity is closely related to the posture of the occupant at the time of impact. In the current era of smart vehicle, the triggered AEB and the occupant's active muscle force will cause the head and neck to be out of position which has significant affections on the occurrence and severity of neck injury responses. Therefore, it is very important to study the influences of active muscle force on neck injury responses in in frontal impact with Automatic Emergency Braking conditions. Based on the geometric characteristics of human neck muscles in the Zygote Body database, the reasonable neck muscle physical parameters were obtained firstly. Then a neck finite element model (FEM) with active muscles was developed and verified its biofidelity under various impact conditions, such as frontal, side and rear-end impacts. Finally, using the neck FEM with or without active muscle force, a comparative study was
Junpeng, XuGan, QiuyuJiang, BinhuiZhu, Feng
This study investigates the impact of various notch geometries on the outer surface of the rotor of an interior permanent magnet synchronous motor intended for traction applications, focusing on improving both its thermal and electromagnetic performances. Traditional motor cooling methods, such as water jackets or oil spray/impingement, typically target the stator and/or end windings, neglecting rotor cooling. As a result, the dissipation of the heat from the rotor is dependent on the heat transfer across the air gap surrounding the rotor, despite air’s poor thermal conductivity, which causes it to act as an insulator. Rotor notches are used to limit the higher order harmonics from air gap flux density which results in decreased torque ripple, cogging torque, noise, and vibration of the machine. While the effect of rotor notches on electromagnetic performance is analyzed, their impact on the thermal management of the motor, particularly the heat transfer coefficient in the air gap
Zajac, ArthurDe Silva, BuddhikaLee, SunMistry, JigarNasirizarandi, RezaJianu, OfeliaKar, Narayan
In the field of automotive engineering, the performance and longevity of suspension bushings and powertrain mounts are critical. These components must endure fatigue loads characterized by their variable amplitude, multi-axial nature, and out-of-phase oscillations. The challenge lies in comprehensively characterizing these service loads during the early stages of vehicle production to foresee potential issues that may arise during later stages. Additional complexity in this analysis is introduced by the nonlinear hyperelastic deformation exhibited by natural rubber, a common material used in these components. To address these challenges, original equipment manufacturers (OEMs) and suppliers employ Computer-Aided Engineering (CAE) techniques for fatigue life predictions. These predictions are complemented by physical testing involving what are known as block cycles. However, the results obtained from these approaches often fail to fully represent the real loading conditions that a
Zarrin-Ghalami, TouhidDatta, Sandip
Triply Periodic Minimal Surface (TPMS) structures have gained significant attention in recent years due to their excellent mechanical properties, lightweight characteristics, and potential for energy absorption in various engineering applications, particularly in automotive safety. This study explores the design, manufacturing, and mechanical performance of both general and hybrid TPMS structures for energy absorption. Three types of fundamental TPMS unit cells—Primitive, Gyroid, and IWP—were modeled using implicit functions and combined to form hybrid structures. The hybrid designs were optimized by employing Sigmoid functions to achieve smooth transitions between different unit cells. The TPMS structures were fabricated using Selective Laser Melting (SLM) technology with 316L stainless steel and subjected to quasi-static compression tests. Numerical simulations were conducted using finite element methods to verify the experimental results. The findings indicate that hybrid TPMS
Liu, ZheWang, MingJieGuo, PengboLi, YouguangLian, YuehuiZhong, Gaoshuo
As the utilization of lithium-ion batteries in electric vehicles becomes increasingly prevalent, there has been a growing focus on the mechanical properties of lithium-ion battery cores. The current collector significantly impacts the tensile properties of the electrode and the internal fracture of the battery cell. The stripping process tends to cause additional damage to the current collector, so tensile testing is not able to obtain in-situ mechanical properties of the current collector. Therefore, nanoindentation tests are required to acquire the in situ mechanical properties of the current collector. Nanoindentation testing represents the primary methodology for the determination of the mechanical properties of thin films. The Oliver-Pharr method is the standard approach used by commercial indentation instruments for the evaluation of mechanical properties in materials. Nevertheless, this approach is constrained by the limitations imposed by the sample boundary conditions. To
Dai, RuiSun, ZhiweiPark, JeongjinXia, YongZhou, Qing
In recent years, energy scarcity and environmental pollution have intensified globally, prompting increased research and development in new energy vehicles as countries prioritize environmental protection and energy conservation. Compared to fuel-powered vehicles, new energy vehicles have relatively larger battery volumes and weights, which can increase damage and the risk of fires and explosions in collisions. To analyze and optimize the safety performance of a specific vehicle model's battery pack, we constructed a finite element model using existing software and performed pre-processing, simulation, and analysis of modal, random vibration, and extrusion characteristics. This revealed specific damage scenarios and enabled reliability analysis under working conditions. To enhance safety and reduce mass, we parametrically modeled power pack components and optimized parameters via multi-objective genetic algorithms under three road conditions. Results indicate reduced mass and improved
Wang, Zhi
In-Mold Graining (IMG) is an innovative production technology applied to the skin wrapping of automotive interior components. In the design of automotive interior components of door panels and instrument clusters, to overcome process-related problems, such as the thinning of grain patterns and excessive reduction in thickness, simulation of the skin vacuum forming process is required. The Thermoplastic Olefin (TPO) skin material is investigated in this paper, and a viscoelastic mechanical model for this material is established. Dynamic Mechanical Analyzer (DMA) is utilized to perform scan for frequency and temperature, and the tested data is used to obtain key model parameters of the viscoelastic constitutive model. Based on the experimental data, the study explores how to calculate the relaxation time spectrum to describe the viscoelastic properties of TPO material during the vacuum forming process. Numerical simulation of the vacuum forming process of TPO material is conducted using
Chai, BingjiGuo, YimingXie, XinxingZhang, Qu
Virtual prototyping enables tires to be involved in automotive research and development (R&D) at an early stage, eliminating the trial-and-error process of physical tire samples and effectively reducing time and costs. Semi-empirical/empirical tire models are commonly used to evaluate vehicle-tire virtual mating. To parameterize these models, finite element (FE) simulations are necessary, involving combinations of sideslip, camber, and longitudinal slip under various loads. This paper identifies that when multiple inputs are combined, the FE simulation conditions become complex and numerous, presenting a significant challenge in virtual prototyping applications. Through an extensive analysis of more than ten tire prediction modeling methods and models in detail, this paper demonstrates the significant potential of tire prediction modeling in addressing this challenge. We begin with an overview of the current state of research in tire virtual prototyping, reviewing its application
Yin, HengfengSuo, YanruLu, DangXia, DanhuaMin, Haitao
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
Wang, SiruiKang, YingziXia, ZhaoYu, ChaoLi, JianxiangShangguan, Wen-Bin
Automotive chassis components are considered as safety critical components and must meet the durability and strength requirements of customer usage. The cases such as the vehicle driving through a pothole or sliding into a curb make the design (mass efficient chassis components) challenging in terms of the physical testing and virtual simulation. Due to the cost and short vehicle development time requirement, it is impractical to conduct physical tests during the early stages of development. Therefore, virtual simulation plays the critical role in the vehicle development process. This paper focuses on virtual co-simulation of vehicle chassis components. Traditional virtual simulation of the chassis components is performed by applying the loads that are recovered from multi-body simulation (MBD) to the Finite Element (FE) models at some of the attachment locations and then apply constraints at other selected attachment locations. In this approach, the chassis components are assessed
Behera, DhirenLi, FanTasci, MineSeo, Young-JinSchulze, MartinKochucheruvil, Binu JoseYanni, TamerBhosale, KiranAluru, Phani
An approach for the precise analysis of residual stress in arc welded lap joints of high strength steel sheets is proposed. This approach involves the development of a method for measuring material properties during both the heating and cooling processes. The measured material properties are then utilized in a thermal elastic-plastic finite element method (FEM) analysis of the welding residual stresses in the lap joints. Analysis accuracy is investigated by comparing the results using material properties measured during heating, cooling, or both. The maximum temperature distribution on the surface of the heat affected zone (HAZ) is measured and accurately predicted by a welding thermal conduction analysis. When the material properties measured only during heating, only during cooling, or during both heating and cooling were used in the thermal elastic-plastic FEM analysis, the results showed that the stress histories in arc welded joints of 780 MPa high strength steel sheets are
Ohnishi, YoichiroSato, KentaroMa, NinshuNarasaki, KunioWeihao, LiYasuda, Koichi
This paper presents a new regression model-based method for accurate predictions of stiffness of different glass laminate constructions with a point-load bending test setup. Numerical FEA models have been developed and validated with experimental data, then used to provide training data required for the statistical model. The multi-variable regression method considered six input variables of total glass thickness, thickness ratio of glass plies as well as high-order terms. Highly asymmetrical, hybrid laminates combining a relatively thick soda-lime glass (SLG) ply joined with a relatively thin Corning® Gorilla® Glass (GG) ply were analyzed and compared to standard symmetrical SLG-SLG constructions or a monolithic SLG with the same total glass thickness. Both stiffness of the asymmetrical laminates and the improvement percentage over the standard symmetrical design can be predicted through the model with high precision.
Yu, ChaoCleary, ThomasJoubaud, Laurentkister, EvanFisher, W Keith
As electric vehicles (EVs) become increasingly prevalent, ensuring the safety of their battery systems is paramount. Lithium-ion batteries, present unique safety challenges due to their high energy density and the potential for failure under certain conditions. There is an extensive amount of research on pouch and cylindrical cells, however, prismatic cells have not received similar attention. This study presents an extensive series of experimental tests conducted on prismatic cells from two different manufacturers. These tests include flat punch, hemispherical punch, axial compression and three-point bending tests, all designed to assess the cells’ mechanical properties and failure behavior. A model was developed simulating the behavior of the cell under local loading scenarios. While this paper focuses primarily on testing methodologies, initial findings and an introductory FEA model, future work will incorporate these experimental results into detailed FEA models across all loading
Patanwala, HuzefaSong, YihanSahraei, Elham
The primary functions of mounts include providing structural support, sound insulation, and vibration damping. Dynamic stiffness and loss angle are critical metrics for evaluating their NVH (Noise, Vibration, and Harshness) performance. This paper examines a floating decoupler hydraulic mount featuring a long decoupler membrane track. A nonlinear lumped parameter model is developed to calculate the dynamic stiffness and loss angle. The model incorporates fluid flow in the lower chamber and variations in the support reaction force of the decoupler membrane under switching conditions. Parameters of the nonlinear lumped parameter model, including rubber stiffness, equivalent piston area, and volumetric compliance of the fluid chamber, were analyzed and calculated using the finite element method. The influence of different decoupler membrane track structures on the frequency corresponding to the minimum high-frequency dynamic stiffness was investigated based on the established model. The
Li, ShenghaoZhang, ShenglanYu, ChaoTu, XiaofengShangguan, Wenbin
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