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1.
Peter C. Varadi Gwo-Jeng Lo Oliver M. O'Reilly Panayiotis Papadopoulos 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1999,32(1):85-108
A fully three-dimensional, computationally inexpensive vehicular model is presented. In contrast to traditional rigid body models, the vehicle's sprung mass is modeled as a (nonlinearly) deformable body. The formulation of the equations of motion is based on a continuum theory known as the theory of a Cosserat point. These equations largely preserve the relative simplicity of rigid body dynamics but incorporate deformable features. The ease of computer implementation permits the simultaneous simulation of vehicle and collision dynamics of multiple vehicles and highway objects. In this paper, the theory of a Cosserat point is summarized and its general application to vehicle and collision dynamics is illustrated. A three-dimensional collision algorithm is discussed with emphasis on small closing velocities (negligible residual crush, elastic rebound). The novel model is compared to standard procedures. 相似文献
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Chao Yang Qiang Li Shoune Xiao Xi Wang 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2018,56(4):506-528
A three-dimensional dynamic model of crashed vehicles coupled with moving tracks is developed to research the dynamic behaviour of the train front end collision on tangent tracks. The three-dimensional dynamic model consists of a crashed vehicle model, moving track models, a simple wheel–rail contact model, a velocity-based coupler model and the model of energy absorption and anti-climbing devices. The vector method dealing with the nonlinear wheel–rail geometry is put forward in the paper. The developed model is applicable in the scope that central collisions occur on tangent tracks at low speeds. The examples of the vehicle impacting with a rigid wall and the train front end collision are carried out to obtain the dynamic responses of vehicles. The overriding issue is studied on the basis of the wheel rise in train collisions. The results show that the second bogie of the first colliding vehicle possesses the maximal wheel rise. The wheel rise increases with the increase of vehicles. However, the number of vehicles has tiny influence on the overriding in train collisions at low speeds. On the contrary, the impact speed has significant influence on the overriding in train collisions. The wheel rise increases rapidly if the impact speed is close to the critical speed of overriding. The large wheel rise is principally generated by the great coupler force related to the rigid impact in the axial direction. 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2007,45(10):969-980
A traffic accident is a complex phenomenon with vehicles and human beings involved. During a collision, the vehicle occupant is exposed to substantial loads, which can cause the occupant injuries that depend on the level of passive safety, as well as on the occupant's individual characteristics. Correct estimation of injury severity demands a validated human body model and known impact conditions. A human body modelling procedure for the purpose of accident analysis is introduced. The occupant body has been modelled as a multibody system with rigid body segments connected. Geometrical and inertial properties of individual body segments were estimated using computed tomography. Frontal impact conditions were simulated on a sled test facility, while the human body dynamic response was measured. Comparison of experimental data and computer simulation revealed an influence of joint resistive properties on the occupant motion in collisions. The difference between measured and simulated response was minimised using optimisation method. Individualised human body modelling procedure enabled better prediction of the occupant motion during vehicle collision and thus more precise estimation of possible injuries in real-life traffic accidents. 相似文献
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某货车驾驶室疲劳载荷激励输入位置位于驾驶室与悬置连接处,在进行整车强化道路耐久试验时无法安装设备直接采集。为获取较为准确的驾驶室疲劳寿命分析载荷谱,对强化耐久路面下整车加速度响应信号进行虚拟迭代。虚拟迭代时需调用整车多体动力学模型,为提高整车模型精度,基于Craig-Bampton综合模态理论生成柔性体车架,建立刚柔耦合的整车多体动力学模型。将Femfat-lab与ADAMS/Car进行联合仿真计算,以白噪声为初始输入,求解刚柔耦合整车多体动力学模型的非线性传递函数,基于循环迭代原理,进行各种典型强化路况下驾驶室悬置附近加速度响应信号的虚拟迭代。利用时域信号对比法及损伤阈值法作为迭代收敛判据,获得满足精度需求的位移驱动信号。将位移驱动信号导入到ADAMS/Car中,对整车多体动力学模型进行驱动仿真,提取驾驶室疲劳分析所需激励载荷谱,将虚拟迭代求得的载荷谱用于疲劳寿命分析所得结果与驾驶室疲劳强化台架试验结果进行对比。研究结果表明:出现疲劳破坏的部位相同度达75%,疲劳寿命误差在20%左右,表明虚拟迭代过程中基于柔性体车架建立的刚柔耦合多体动力学模型的仿真计算,可获得较高精度的迭代结果;以位移谱驱动整车多体动力学模型进行仿真能够有效避免六分力直接驱动时模型翻转等不稳定现象,并且整车模型仿真加速度响应结果与实测相应位置加速度响应吻合度较高;相比于传统的疲劳分析载荷获取方法,虚拟迭代技术可以在较低试验成本的情况下获取较高精度的载荷谱,并能够提取由于连接位置导致的无法直接进行载荷测量部位的疲劳分析载荷。 相似文献
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R. Ranganathan Graduate Student S. Rakheja Research Associate Professor S. Sankar Professor Director 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1990,19(4):177-200
The influence of the lateral load shift on the dynamic response characteristics of an articulated tank vehicle is investigated assuming inviscid fluid flow conditions. A quasi-dynamic roll plane model of a partially filled cleanbore tank of circular cross-section is developed and integrated to a three-dimensional model of the articulated vehicle, assuming constant forward speed. The destabilizing effects of liquid load shift are studied by comparing the directional dynamics of the partially filled tank vehicle to that of an equivalent rigid cargo vehicle subject to steady steer input. Dynamic response characteristics demonstrate that the stability of a partially filled tank vehicle is adversely affected by the Liquid load shift The distribution of cornering forces caused by the liquid load shift yield considerable deviation of the path followed by the liquid tank vehicle. The influence of the vehicle speed on the dynamics of the liquid tank vehicle is also investigated for variations in the fill levels and fluid density. 相似文献
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针对现有运动规划算法大多只考虑障碍车当前状态,本文中提出一种基于前车运动轨迹预测的高速车辆运动规划算法。首先,融合考虑驾驶意图与基于车辆运动模型的方法对前车轨迹进行预测;然后,采用贝塞尔曲线(Bezier)规划主车运动轨迹,结合避撞过程中与前车碰撞风险概率,高速避撞车辆速度变化特点以及车辆运动稳定性等因素建立目标函数,并考虑车辆动力学与运动学约束,使用序列二次规划(SQP)方法对Bezier曲线的控制点和主车运动目标点位置进行优化求解,得到最优避撞运动轨迹;最后,以前车直行和换道两种工况为例,对主车的避撞运动轨迹进行规划,分析不同工况下主车避撞过程中的运动状态变化以及与前车碰撞风险概率变化。结果表明,所提出的运动规划算法能够保证车辆的避撞安全性与运动稳定性。 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(4):177-200
SUMMARY The influence of the lateral load shift on the dynamic response characteristics of an articulated tank vehicle is investigated assuming inviscid fluid flow conditions. A quasi-dynamic roll plane model of a partially filled cleanbore tank of circular cross-section is developed and integrated to a three-dimensional model of the articulated vehicle, assuming constant forward speed. The destabilizing effects of liquid load shift are studied by comparing the directional dynamics of the partially filled tank vehicle to that of an equivalent rigid cargo vehicle subject to steady steer input. Dynamic response characteristics demonstrate that the stability of a partially filled tank vehicle is adversely affected by the Liquid load shift The distribution of cornering forces caused by the liquid load shift yield considerable deviation of the path followed by the liquid tank vehicle. The influence of the vehicle speed on the dynamics of the liquid tank vehicle is also investigated for variations in the fill levels and fluid density. 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(11):1695-1721
This paper presents dynamic contact loads at wheel–rail contact point in a three-dimensional railway vehicle–track model as well as dynamic response at vehicle–track component levels in the presence of wheel flats. The 17-degrees of freedom lumped mass vehicle is modelled as a full car body, two bogies and four wheelsets, whereas the railway track is modelled as two parallel Timoshenko beams periodically supported by lumped masses representing the sleepers. The rail beam is also supported by nonlinear spring and damper elements representing the railpad and ballast. In order to ensure the interactions between the railpads, a shear parameter beneath the rail beams has also been considered into the model. The wheel–rail contact is modelled using nonlinear Hertzian contact theory. In order to solve the coupled partial and ordinary differential equations of the vehicle–track system, modal analysis method is employed. Idealised Haversine wheel flats with the rounded corner are included in the wheel–rail contact model. The developed model is validated with the existing measured and analytical data available in the literature. The nonlinear model is then employed to investigate the wheel–rail impact forces that arise in the wheel–rail interface due to the presence of wheel flats. The validated model is further employed to investigate the dynamic responses of vehicle and track components in terms of displacement, velocity, and acceleration in the presence of single wheel flat. 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(1):385-404
SUMMARY A comprehensive directional dynamics model of a tractor-tank trailer is developed by integrating a non-linear dynamic fluid slosh model to the three-dimensional vehicle dynamics model. The nonlinear fluid slosh equations are solved in an Eulerian mesh to determine dynamic fluid slosh loads caused by the dynamic motion of the vehicle. The dynamic fluid slosh forces and moments are coupled with the vehicle dynamics model to study the directional response characteristics of tank vehicles. The directional response characteristics of partially filled tank vehicles employing dynamic slosh model are compared to those employing quasi-dynamic vehicle model, for steady as well as transient directional maneuvers. Simulation results reveal that during a steady steer maneuver, the dynamic fluid slosh loads introduce oscillatory directional response about a steady-state value calculated from the quasi-dynamic vehicle model. The directional response characteristics obtained using the quasi-dynamic and dynamic fluid slosh models during transient steer inputs show good correlation. Based on this study, it can be concluded that the quasi-dynamic model can predict the directional response characteristics of tank vehicles quite close to that evaluated using the comprehensive fluid slosh model. 相似文献
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汽车动力传动系实时动力学仿真模型 总被引:2,自引:0,他引:2
将动力传动系视为刚体系统,建立适用于开发型驾驶模拟器的动力传动系4自由度实时动力学仿真模型,输入驾驶员的点火开关信号、油门踏板信号、离合器踏板信号及挡位信号,在一定的传动系各部件及驱动轮的运动状态下,传动系模型可向整车动力学模型输出驱动轮上的驱动力矩,从而完成车辆的实时动力学仿真,并进一步向驾驶模拟器输送整车的实时运动状态。仿真与动力性试验的对比结果表明,该模型不但具有实时性,而且可通过整车模型使开发型驾驶模拟器为驾驶员提供逼真的整车运动响应。 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(4):229-248
This paper deals with two-dimensional motion analysis of vehicles damaged due to collision. Various parts of vehicles are damaged due to collision in general. The effects of the damage in vehicle body and wheels on the vehicle motions are investigated. The center of gravity of the vehicle and the polar moment of inertia are changed by the deformation of vehicle body. Furthermore, the geometrical relations of wheels like wheelbase, treads and steering angles may be changed by damage of the wheels. Thus the vehicle loses symmetry with respect to the vehicle axis. The four-wheel vehicle model is extended to take into account the vehicle damage due to collision. The motions of damaged vehicles are compared with those of undamaged vehicles. It is found that vehicle damages have a significant influence on vehicle motion after impact. 相似文献
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H. Minamoto S. Takezono 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2000,34(4):229-248
This paper deals with two-dimensional motion analysis of vehicles damaged due to collision. Various parts of vehicles are damaged due to collision in general. The effects of the damage in vehicle body and wheels on the vehicle motions are investigated. The center of gravity of the vehicle and the polar moment of inertia are changed by the deformation of vehicle body. Furthermore, the geometrical relations of wheels like wheelbase, treads and steering angles may be changed by damage of the wheels. Thus the vehicle loses symmetry with respect to the vehicle axis. The four-wheel vehicle model is extended to take into account the vehicle damage due to collision. The motions of damaged vehicles are compared with those of undamaged vehicles. It is found that vehicle damages have a significant influence on vehicle motion after impact. 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(11):1349-1376
This paper presents a framework to investigate the dynamics of overall vehicle–track systems with emphasis on theoretical modelling, numerical simulation and experimental validation. A three-dimensional vehicle–track coupled dynamics model is developed in which a typical railway passenger vehicle is modelled as a 35-degree-of-freedom multi-body system. A traditional ballasted track is modelled as two parallel continuous beams supported by a discrete-elastic foundation of three layers with sleepers and ballasts included. The non-ballasted slab track is modelled as two parallel continuous beams supported by a series of elastic rectangle plates on a viscoelastic foundation. The vehicle subsystem and the track subsystem are coupled through a wheel–rail spatial coupling model that considers rail vibrations in vertical, lateral and torsional directions. Random track irregularities expressed by track spectra are considered as system excitations by means of a time–frequency transformation technique. A fast explicit integration method is applied to solve the large nonlinear equations of motion of the system in the time domain. A computer program named TTISIM is developed to predict the vertical and lateral dynamic responses of the vehicle–track coupled system. The theoretical model is validated by full-scale field experiments, including the speed-up test on the Beijing–Qinhuangdao line and the high-speed running test on the Qinhuangdao–Shenyang line. Differences in the dynamic responses analysed by the vehicle–track coupled dynamics and by the classical vehicle dynamics are ascertained in the case of vehicles passing through curved tracks. 相似文献
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Vehicle safety has become the most important issue in automobile design. However, all efforts to improve safety devices focus
on enhancing safety features for occupants. Notably, pedestrians are the second largest category of motor vehicle deaths,
after occupants, and account for about 13 percent of motor vehicle deaths. It is essential to design pedestrian-friendly vehicles
and pedestrian protection systems to reduce pedestrian fatalities and injuries. To effectively assess pedestrian injuries
resulting from vehicle impact, a deformable pedestrian model must be developed for vehicle-pedestrian collision analysis.
This study constructs a pedestrian-collision numerical model based on LS-DYNA finite element code. To verify the accuracy
of the proposed deformable pedestrian model, experimental data are used in the pedestrian model test. This study applies the
proposed model to analyze the dynamic responses and injuries of pedestrians involved in collisions. The modeled results can
help assess vehicle pedestrian friendliness and assist in the future development of pedestrian-friendly vehicle technologies. 相似文献
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Analysis for response statistics evaluation of a flexible vehicle travelling with variable velocity over nonhomogeneously profiled flexible track is presented with a heave-pitch-roll model. The vehicle body is idealised as a flexible member with variable cross-section, inertia, damping and stiffness distributions. The vehicle may also have variable section slender elastic attachments. Coupled dynamics with rigid body heave-pitch-roll modes and elastic bending-torsion modes of the vehicle body along with coupled bending-torsion modes of the attachments are considered. Equivalent linear suspension system characteristics are employed for developing the analysis. Numerical results are presented for an aircraft with tricycle landing gear arrangements and comparison is made with other models. 相似文献
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D. Yadav S. Kamle S. Talukdar 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2000,33(1):1-28
Analysis for response statistics evaluation of a flexible vehicle travelling with variable velocity over nonhomogeneously profiled flexible track is presented with a heave-pitch-roll model. The vehicle body is idealised as a flexible member with variable cross-section, inertia, damping and stiffness distributions. The vehicle may also have variable section slender elastic attachments. Coupled dynamics with rigid body heave-pitch-roll modes and elastic bending-torsion modes of the vehicle body along with coupled bending-torsion modes of the attachments are considered. Equivalent linear suspension system characteristics are employed for developing the analysis. Numerical results are presented for an aircraft with tricycle landing gear arrangements and comparison is made with other models. 相似文献