Development and validation of a pedestrian deformable finite element model

Pedestrian protection has become an increasingly important consideration in vehicle crash safety. Pedestrian-vehicle crashes cause a significant number of pedestrian fatalities and injuries globally. Computer models are powerful tools for understanding how to reduce the severity of injuries in such crashes. Real-world studies of pedestrians provide an important source of information for evaluating pedestrian model dynamic performance and ability to reconstruct injury-causing events. This study describes the validation process of deformable pedestrian model using published postmortem human subject (PMHS) trajectory and head resultant velocity corridors, and demonstrates its applicability to pedestrian — vehicle impact research. We implemented the deformable pedestrian model using LS-DYNA finite element code. Based on PMHS data, the pedestrian model is used to validate the displacement trajectories of the head, pelvis, knee and foot. The finite element pedestrian model thus obtained can help assess the friendliness of vehicles with pedestrians in traffic crashes and assist in the future development of pedestrian safety technologies. This paper was recommended for publication in revised form by Associate Editor Young Eun Kim Tso-Liang Teng is a Professo r in the Department of mechanical and automation engi-neer ing and the Dean of engineeri ng college at the Da-Yeh Uni versity, Taiwan. He received a BS (1981), MS (1986) and PhD (1994) from the Chung Cheng Institute of Technology. His research intere sts include design of passive safety systems in ve hicles, crash tests simulation, passenger and pedest rian injuries analysis, design of pedestrian protecti on systems.     

一种新型篮球轮椅的结构设计与有限元分析

基于人机工程学的理论对篮球轮椅进行了结构设计,采用了PRO/E软件对篮球轮椅进行三维实体造型,并利用I-DEAS软件对篮球轮椅进行了有限元计算分析,计算结果验证了所设计的篮球轮椅的安全性.     

含油轴承动态负载摩擦学性能测试装置

介绍了动态负载条件下含油轴承摩擦学性能测试台的工作原理及其组成。试验台由试验台机械结构和试验信号采集控制两部份组成,试验台可在动态加载条件下,对含油轴承PV值、滑动摩擦系数、温升进行实时测试。     

高速动车空心车轴超声波探伤工艺及探伤机的研究

介绍了高速动车空心车轴的结构及其疲劳缺陷的产生机理,并针对该缺陷研究相应的探伤工艺及探伤机,介绍了探伤机的原理和结构及缺陷信号的采集和处理.     

Establishment of a 3D FE model for the bending of a titanium alloy tube

Establishing and developing a finite element (FE) model is key to the effective study of the complex bending of a titanium alloy tube. This paper focuses on the establishment of a three-dimensional (3D) FE model for the numerically controlled (NC) bending of a titanium alloy tube that considers both bending and springback. The key procedures for establishment of the model are described in detail, including the choice of elements, mesh density control, the choice of single- or double-precision computation, and the choice of the mass scaling factor. Combining explicit and implicit FE methods, a significant amount of springback can be modeled for the bending, which is in good agreement with what is observed in practice. Single-precision computation tends to provide increasingly inadequate results as the mass scaling factor decreases. Analyses performed using double-precision computation can improve the accuracy of the results. A decrease in the mass scaling factor when double-precision computation is used leads to improved results to some degree, but also to an increase in computation time. Taking accuracy and efficiency into consideration, a mass scaling factor of 1600 is considered reasonable. Using our 3D FE model, results for the distributions and variations of the tangential stress, tangential strain, wall thickness, and springback angle for the bending of a TA18 M tube were obtained.     

低架桥固有特性模态综合分析法及其模型试验验证

利用Guyan静力变换推导了一种含超单元连接子结构的双协调自由界面模态综合法,该法计算精度高,缩减了系统自由度,可对含铅芯橡胶支座、非线性弹簧等非线性连接元件的结构进行动力分析.基于该法和自由界面模态综合法比较分析了自动化码头低架桥铅芯橡胶支座全柔性、全刚性支撑下结构的固有特性,结果表明,铅芯橡胶支座对低架桥的调频效果明显.用量纲分析法推导了结构固有特性动力模型相似条件,通过锤击法测试了低架桥模型的固有特性.模型试验与原型仿真结果相互验证,说明仿真结果可靠,试验设计合理,同时验证了超单元间接法以及铅芯橡胶支座的调频作用.     

发动机连杆精细有限元分析模型和算法的研究

在总结大量连杆计算经验的基础上,分析了影响计算精度的各种因素,提出了一个精细有限元组合计算模型：摒弃了各种近似处理方法,计算模型完全根据连杆实际结构确定,计入了连杆组装的全部零件以及活塞销、活塞和曲轴,其间所有配合关系用有摩擦的3维弹性多体接触模型模拟。采用有限元参数二次规划算法,并结合多重多支的子结构技术求解。同时指出了这套理论和方法对于解决这类机械工程问题所具有的优点和广泛的适用性。     

机械式汽车变速箱同步器试验系统研制

针对汽车变速箱同步器的试验要求,阐述了同步器试验台的系统结构和测控系统设计,采用矢量变频控制技术实现同步过程中的电机稳速控制,各路传感器信号高速并行采集,最后给出同步器的试验结果并对结果进行分析.     

Development of a novel SCADA system for laboratory testing

This document summarizes the supervisory control and data acquisition (SCADA) system that allows communication with, and controlling the output of, various I/O devices in the renewable energy systems and components test facility RESLab. This SCADA system differs from traditional SCADA systems in that it supports a continuously changing operating environment depending on the test to be performed. The SCADA System is based on the concept of having one Master I/O Server and multiple client computer systems. This paper describes the main features and advantages of this dynamic SCADA system, the connections of various field devices to the master I/O server, the device servers, and numerous software features used in the system. The system is based on the graphical programming language "LabVIEW" and its "Datalogging and Supervisory Control" (DSC) module. The DSC module supports a real-time database called the "tag engine," which performs the I/O operations with all field devices attached to the master I/O server and communications with the other tag engines running on the client computers connected via a local area network. Generic and detailed communication block diagrams illustrating the hierarchical structure of this SCADA system are presented. The flow diagram outlining a complete test performed using this system in one of its standard configurations is described.     

阀门启闭扭矩连续测试装置的试验与研究

介绍了阀门启闭扭矩连续测试装置的性能特点、技术参数基及其控制方式。给出了装置通过扭矩传感器测试阀门的力矩变化并将模拟数据转换成数字信号由计算机控制输出的工作过程（该装置专利申请号：200620149672X）。     

建立斜拉桥基准有限元模型的新方法与实现

在进行斜拉桥监测与检测研究时,为了建立准确而可靠的基准有限元模型,使其索力、位移等趋于监测或检测结果,需进行模型修正工作,但各种模型修正方法多数需要进行迭代运算,不仅计算工作量巨大,而且有时难以实现预期目标。针对这一问题,提出了一种使用Ansys与Matlab软件,利用影响矩阵和优化算法相结合进行模型修正的新方法。该方法不需要迭代,可获得索力、位移等参数,且与实测值相吻合。通过实例对该方法进行了验证,证明了该方法可行并易于实现。     

带接管组合法兰的强度和密封有限元分析

螺栓法兰连接是石化设备和管道中应用最广泛的密封形式,对其完整性和紧密性分析仍是工程中亟待解决的问题。综合考虑垫片的非线性压缩回弹本构关系、螺栓预紧和法兰垫片接触作用,将带接管的组合法兰、垫片、螺栓作为一个系统进行三维非线性有限元模拟。基于强度和密封要求,借助Waters公式和有限元试算,选定合适的螺栓预紧载荷。计算获得组合法兰在预紧、操作、设计和水压试验4种工况下的应力与变形分布规律。依据JB 4732对法兰应力进行分类强度评定,依据ASMEⅧ-1从垫片应力和法兰转角两个方面进行密封评定。可为实际应用提供参考。     

RADIOSS整车碰撞模型转换方法及其应用

整车被动安全性研究是汽车研发领域中的重点,工程实际中经常遇到不同软件有限元模型之间的转化问题。根据实际工程的应用情况,详细的介绍了上海汽车某轿车整车碰撞模型从LS-DYNA格式转化为RADIOSS格式的具体应用方法,并最终将使用RADIOSS显式求解器对整车碰撞各工况的仿真分析计算结果与整车试验测试数据进行比较分析。从对比结果可以看出,采用RADIOSS显式求解器得到的整车碰撞仿真结果与试验结果吻合较好,计算精度较高,从而验证了新转化的RADIOSS模型的有效性,并进一步验证了模型的转化方法的可行性和合理性。同时,文中所介绍的模型转换方法和流程,可为各领域类似的模型转换工作提供一定的指导作用,具有重要的工程应用价值。     

振动环境试验设备与技术的现状及进展

综述了国内外振动环境试验设备及技术的现状,简要分析了我国振动试验水平与国外产生较大差距的原因,指出了振动环境试验存在的问题,说明了振动环境试验设备及技术发展方向。     

汽车仪表耐久测试系统研制

针对某型号汽车仪表,基于工控机上USB和RS232通信端口等设备构成的硬件平台,与LabVIEW平台开发的软件构成一套完整的耐久测试系统。实践证明,系统具有操作简单、开发成本低、测试效率高和抗干扰能力强等优点。     

汽车空调用热力膨胀阀性能测试系统的研制

热力膨胀阀是汽车空调的重要部件,其性能对汽车空调的制冷效果、运行寿命有着重要影响。针对汽车空调用热力膨胀阀的关键性能现有测试方法的不足以及性能测试系统的缺失,对过热度、阀口泄漏和耐久性能的测试方法进行了研究,提出了过热度流量测试法和阀口泄漏差压测试法,并对耐久性能测试的时间参数进行了优化。在此基础上采用PLC控制技术研制了一套热力膨胀阀性能测试系统,并利用图形化编程语言VB开发了测试系统控制软件。研究结果表明,该系统能按照标准要求自动完成热力膨胀阀过热度、阀口泄漏和耐久性能的测试。所研究的热力膨胀阀关键性能检测方法能够满足热力膨胀阀主要性能指标的测试要求,所设计的测试系统提高了热力膨胀阀性能测试的精度,提升了检测效率及自动化水平。     

Development of an anisotropic constitutive model for single-crystal superalloy for combined fatigue and creep loading

A unified anisotropic viscoplastic constitutive model for single-crystal superalloys is developed based on a modification of a phenomenological isotropic model. Orientation-dependent viscoplastic behaviour was observed in experiments. The model is used to simulate the orientation and cyclic mechanical response of single-crystal SRR99 under combined fatigue and creep conditions at 950°C. The results from the simulations are then used to estimate the fatigue-creep lives of the single-crystal nickel-base superalloy SRR99 using a new life prediction methodology. The predicted fatigue-creep lives are in good agreement with the experimental results.     

A new algorithm for reduction of number of press-forming stages in forging processes using numerical optimization and FE simulation

This study presents a new simulation-based technique for the optimum design of a multi-stage forging process aiming at reduction of the number of press-forming stages. This iterative design technique involves response-surface-based numerical optimization and a finite element analysis of the process. The design procedure starts with an initial process design that is deemed too conservative, i.e. allows to arrive at the desired product but involves an excessive number of stages. To obtain a better process design, one stage of the existing multi-stage process is eliminated using numerical optimization in conjunction with an FE simulation. This is repeated by reducing the number of stages one by one until the minimum possible number of stages is reached. This design technique is applied to stage reduction of a three-stage forging process of an axisymmetric aluminum billet. It is confirmed that a new two-stage process design is obtained successfully and the developed design optimization technique showed its effectiveness in reduction of the number of press-forming stages in a multi-stage forming process.     

小模数齿轮单面啮合测量机的研制

小模数齿轮因几何与机械性能的限制,传统的单向驱动式单面啮合测量技术一直未能在其测量中得到应用.针对此问题,提出了"双向驱动"式单面啮合测量新原理,基于该原理研制了小模数齿轮单面啮合测量机.重点介绍齿轮单面啮合测量新原理、测量机的组成及关键技术.在结构设计方面,采用两轴系平行但不在同一端的结构布局,利用两伺服电机同步驱动实现两轴系的主动回转,通过微角度测量装置获取测量齿轮相对其轴系的微转角差,开发无线传输技术进行信号采集.在软件设计方面,基于Microsoft Visual C++6.0开发了小模数齿轮单面啮合测控软件.实际测试表明,该测量机能实现小模数齿轮的快速测量.