The prediction technology study of fatigue life for key parts of a tracked vehicle’s suspension system

In allusion to fatigue life of a tracked vehicle torsion bar, a virtual prototype model of the tracked vehicle suspension system including a flexible torsion bar was built based on dynamic simulation software ADAMS. Node force and stress results of the torsion bar from last step simulation were acquired; taking into account the material characteristics and influential factors, fatigue life of the flexible body of the torsion bar was predicted. Engineering results can be acquired through the contrast of the result of virtual test and statistical fatigue.     

转炉倾动柔性支承系统的疲劳分析

本文应用大型有限元分析软件ANSYS,对某30 t转炉倾动装置的扭力杆柔性支承系统进行疲劳寿命分析,得出了当柔性支承系统的关键零件扭力杆采用不同材料时的系统的疲劳寿命,为同类柔性支承系统的设计与优化提供理论依据。     

Fuel optimal control of parallel hybrid electric vehicles

A mathematical model for fuel optimal control and its corresponding dynamic programming (DP) recursive equation were established for an existing parallel hybrid electric vehicle (HEV). Two augmented cost functions for gear shifting and engine stop-starting were designed to limit their frequency. To overcome the problem of numerical DP dimensionality, an algorithm to restrict the exploring region was proposed. The algorithm significantly reduced the computational complexity. The system model was converted into real-time simulation code by using MATLAB/RTW to improve computation efficiency. Comparison between the results of a chassis dynamometer test, simulation, and DP proves that the proposed method can compute the performance limitation of the HEV within an acceptable time period and can be used to evaluate and optimize the control strategy. __________ Translated from Journal of Shanghai Jiaotong University, 2006, 40(6): 947–951, 957 [译自: 上海交通大学学报]     

减振器阻尼对扭力梁疲劳寿命的影响

为了研究减振器阻尼对扭力梁疲劳寿命的影响,建立了扭力梁有限元模型以及刚柔耦合整车模型。通过试验采集强化路面道路载荷谱作为整车模型的输入激励,仿真得到疲劳寿命分析所需文件,利用模态应力恢复法对扭力梁进行疲劳寿命分析,并通过扭力梁耐久性台架试验证明了仿真模型与疲劳寿命分析方法的准确性。仿真得到了不同阻尼系数下的扭力梁疲劳寿命分布云图以及最小疲劳寿命循环数,分析结果总结出了减振器阻尼大小对扭力梁本体疲劳寿命的影响规律。     

Multi-axle dynamic steering system of truck-howitzer

A two-degree-of-freedom (2-DOF) steering model of multi-axle vehicle was established. The steering center position, the relationship between the steering angle and the vehicle velocity, and the minimum turn radius were deduced on the basis of the proportional control with a zero sideslip angle. Results indicate that the system stability is decided by the vehicle barycenter position and the lateral stiffness of a tire. Under this control, the steady value of the lateral acceleration is obviously diminished and the yaw angular velocity changes little under any vehicle velocity. The system rapidly responds, the vehicle smoothly steers, and its handling stability is prominently improved. __________ Translated from Journal of Jilin University, 2006, 36(3): 321–326 [译自: 吉林大学学报]     

月球车用扭杆弹簧疲劳寿命功率谱预测法

研制的行星轮式月球车的安全行驶寿命主要取决于扭杆弹簧悬架中扭杆弹簧的扭转疲劳寿命。模拟月球表面的温度环境进行了扭杆弹簧的扭转疲劳试验，确定了扭杆弹簧的扭转疲劳次数。在此基础上，建立了扭杆弹簧悬架的动力学模型，通过此动力学模型及功率谱寿命预测法推导出了扭杆弹簧疲劳寿命与悬架参数之间的关系式，并估算了月球车的安全行驶里程。     

Research and implementation of flexible coding system oriented multi-view

On the basis of the requirements of a product data management system (PDM) for the flexible coding system, the principle of the flexible coding system oriented multi-view is analyzed. Generation and utilization of coding should be associated with the context of the object. The architecture of the flexible coding system oriented multi-view is studied and the implementation class diagram of the system is designed. The system can support the establishment of five types of code segments, provide the tools of flexible defining coding rules and drive the automatic generation of object coding in different views (contexts). On the foundation of the characteristics of the system, coding for parts is taken as a sample to validate and elaborate the flexible coding process of the system. __________ Translated from Transactions of Beijing Institute of Technology, 2006, 26(1): 14–18 [译自: 北京理工大学学报]     

Bandwidth-limited active suspension controller for an off-road vehicle based on co-simulation technology

This paper presents the design process of a controller for bandwidth-limited active hydro-pneumatic suspension employed by an off-road vehicle based on co-simulation technology. First, a detailed multi-body dynamic model of the vehicle is established by using the ADAMS/View software package, which is followed by validation using a vehicle field test. Second, a combined PID and fuzzy controller is designed for the bandwidth-limited active suspension system and then programmed by means of S-functions in Matlab/Simulink, to which a data exchange interface with ADAMS/View is also defined. Third, the proposed control algorithm is implemented on the multi-body dynamic vehicle model to enable the co-simulation to run repeatedly until a more practical controller is achieved. In the end, the proposed active suspension system is compared with a conventional passive system. Simulation results show that the proposed active suspension system considerably improves both the ride and handling performance of the vehicle and therefore increases the maximum traveling speeds even on rough roads. __________ Translated from Journal of Shanghai Jiao Tong University, 2006, 40(6): 952–957 [译自: 上海交通大学学报]     

Influence of temperature on cam-tappet lubrication in an internal combustion engine

The transient thermo-elastohydrodynamic (TEHL) lubrication simulation and isothermal elastohydrodynamic (EHL) simulation were performed on the exhausting camtappet friction pair of an internal combustion engine. Although by employing the two models the center pressure, the thickness of the lubricant film and friction coefficient obtained were similar in the changing trend during a rotating cycle, the parameters make a great difference, especially for the thickness of the lubricant film; the TEHL was four times thicker than the EHL. These results show that the temperature should not be neglected in the study of the lubrication of cam-tappet pairs. __________ Translated from Tribology, 2006, 26(4): 362–366 [译自: 摩擦学学报]     

悬架扭杆和稳定杆刚度对车辆转向灵敏度的影响分析

为研究悬架和横向稳定杆的刚度对车辆操纵性能的影响,进而为悬架设计和调整提供参考,以某轻型客车为原型,在ADAMS/Car中构建了无横向稳定杆和前悬架装配横向稳定杆的两辆虚拟样车及其变型车,通过转向盘转角阶跃输入仿真试验,得到了前悬架扭杆和横向稳定杆角刚度对车辆转向灵敏度的影响曲线。研究结果表明,对于无、有稳定杆两种车型,扭杆角刚度自0.5倍增大至2.0倍基准刚度,转向灵敏度分别产生相对于经验值域约20%和1%的下降量;横向稳定杆角刚度自基准角刚度减小至0或增大至2.0倍基准刚度,转向灵敏度分别产生相对于经验值域约10%的增长量或1%的下降量。     

基于LMS的舱门机构中曲杆的疲劳寿命仿真分析

应用虚拟样机疲劳寿命预测方法,对飞机内埋弹舱舱门机构中的曲杆进行了疲劳寿命分析.利用LMS.Virtual.Lab多体动力学系统仿真软件,建立起舱门简化机构的多体仿真模型,结合有限元方法和多体动力学分析,获得曲杆上的载荷时间历程,再根据材料的疲劳性能对曲杆进行疲劳寿命预测.结果表明,曲杆的疲劳寿命符合舱门机构的设计要求.     

Output tracking control of mobile manipulators based on dynamical sliding-mode control

A dynamical sliding-mode controller is devised to track the output of mobile manipulators. During the investigation, firstly a reduced dynamic model considering the dynamics of the driving motor is developed for mobile manipulators. Then, the system is decomposed into four lower-dimensional subsystems by means of diffeomorphism and nonlinear input transformation. Moreover, a design method of the dynamical sliding-mode controller that is applied to the output tracking of mobile manipulators is proposed. The simulation results indicate that the dynamical sliding-mode controller can not only track the given trajectory correctly but also reduce the chattering of sliding-mode control system considerably. __________ Translated from Journal of South China University of Technology (Natural Science Edition), 2006, 34(6): 29–33 [译自: 华南理工大学学报 (自然科学版)]     

基于DFSS的扭杆弹簧分析及优化设计

针对某车型扭杆弹簧的原设计方案,运用DFSS流程,在建立CAE有限元模型的基础上,综合分析影响扭杆性能的多种因素,提出了18种备选的改善方案并从中找出最优的设计方案。仿真和实验结果都表明:优化后的设计方案不仅消除了原设计方案的断裂风险,还提高了扭杆5%以上的使用寿命,减少了10%的质量;同时也证明了DFSS在汽车零部件质量改善领域的实用性。     

转向节疲劳性能与减振器阻尼关系研究

为探明减振器阻尼系数对转向节疲劳寿命的影响规律,以某紧凑型SUV为研究对象,通过对转向节模态分析与测试,建立其柔性体模型与疲劳仿真分析模型;以实车参数建立了整车刚柔耦合多体动力学模型,并以试验场强化路实车采集的轮心六分力和转向节监测点应变信号为基础,应用虚拟迭代法仿真获取了转向节载荷时间历程(模态位移);应用模态应力恢复法运算分析了减振器在不同阻尼系数条件下转向节的疲劳寿命,探讨了二者的相互关系。研究表明,在兼顾整车舒适性与安全性的阻尼系数范围内,随减振器阻尼系数增大,转向节疲劳寿命先增后减,即影响其疲劳寿命的主要区域损伤面积先减后增,而影响转向节疲劳寿命的次要区域损伤面积始终随着减振器阻尼系数的增大而增大。     

HJL1020汽车扭杆弹簧的设计与实验

对HJL1 0 2 0汽车的扭杆弹簧进行了设计 ,所采用的方法是一种以扭杆弹簧的最大变形能为优化目标的优化设计方法 ,可计算获得主要几何参数的最优值。使用设计计算所得的参数进行扭杆弹簧样品试制 ,并进行了疲劳实验 ,实验证明样品均合格 ,也证实了设计方法和计算结果的实用性和可靠性。同时 ,对计算结果进行了分析 ,提出了改进设计的参考意见     

The role delegation authorization model of a computer-supported cooperative design system

According to the specific characteristics of a computer-supported cooperative design (CSCD) system, the characteristics of role delegation authorization (RDA) are analyzed and deduced, and a set of fitful status is arrived at. Because of the diversified characteristics of RDA features in different systems, the RDA model has multi-varying status. On the basis of the basic model of role-based access control (RBAC), some basic characteristics of RDA are summed up. Then, according to the specific characteristics of CSCD system, the characteristics of RDA are recombined to develop a RDA model that is suitable for the CSCD system. It is different from the conventional role authorization models of RBAC, that is, it adopts the decentralized authorization management instead of the centralized one in CSCD system, which makes the management more flexible. This model is verified through a specific case of CSCD system. Translated from Journal of Northeastern University (Natural Science), 2006, 27(5): 548–551 [译自: 东北大学学报 (自然科学版)]     

Finite element simulations of sheet metal forming under complex strain paths

Fracture is a common defect in sheet metal forming and it is essentially caused by tensile instability. This paper analyzes some experiments and theories for building forming limit diagrams of sheet metal and points out the advantages and disadvantages of current experiments and theories. According to this, a method that integrates the finite element simulation and experiment was used to research the forming limit diagrams of the sheet metal under complex strain paths. Taking the rear hanger that undergoes twice stamping as an example, the strain paths of the dangerous point of the rear hanger is investigated. Finally, the forming method of the rear hanger is confirmed. Results indicate that finite element method (FEM) can achieve the complex strain paths and different strain paths will have great impacts on the result of the sheet metal forming. __________ Translated from Journal of Jiangsu University (Natural Science Edition), 2005, 26(4): 289–293 [译自: 江苏大学学报 (自然科学版)]     

Fatigue analysis of the main frame of over head transportation vehicles using flexible multibody dynamics

The industrial over head transportation vehicle is a guided railway vehicle that is attached overhead and transports cargo, hoisting it up and down from the factory ceiling. The vehicle is widely used in many industries, such as automobile and liquid crystal display (LCD), because it can carry freight very safely and quickly to destinations. This kind of freight transportation usually operates for several months to a few years, carrying large amounts of products. Accidently, the vehicle often fails during operation because of a part’s plastic deformation from large loads. Furthermore, periodic dynamic loads cause fatigue accumulation, which leads to OHT failure. This failure is directly connected to significant economic loss during mass production processes. Therefore, the prediction of fatigue life for the important parts becomes an important task. In this study, the fatigue life of an OHT main frame was calculated and predicted by using a flexible multibody dynamic model. The development of a flexible multibody dynamic model and the procedure of fatigue life prediction were presented. To predict the fatigue lives of parts of interest, the prediction procedure required three kinds of data: Dynamic stress time history from a dynamic analysis, material properties of the parts, and stress-life curves of the parts. Using a finite element model and a multibody model, a flexible multibody model was developed. To ensure the reliability of the model, displacement and strain measurement tests were conducted. After verification of the reliability, the fatigue life of the main frame was predicted.     

Design of a piezoelectric transducer cylindrical phase modulator for simulating acoustic emission signals

To conveniently carry out the pipeline leak experiment in a laboratory, leak acoustic signals are simulated by using the converse piezoelectric effect of a piezoelectric transducer (PZT) cylindrical phase modulator. On the basis of the piezoelectric equations and electromechanical equivalence principle, the transfer function of a PZT cylindrical phase modulator is delivered. A PZT cylindrical phase modulator is designed, and the numerical simulation is conducted. Results prove that the PZT cylindrical phase modulator can effectively simulate leak acoustic emission signals when the frequency is lower than 25 KHz. __________ Translated from Journal of Beijing University of Technology, 2006, 32(8): 683–687 [译自: 北京工业大学学报]