汽车钢圈疲劳强度的有限元分析与寿命预测

针对汽车钢圈动态弯曲疲劳问题,以某型号汽车钢圈为例,运用ANSYS软件建立了该钢圈的有限元模型,模仿其动态弯曲疲劳测试试验,对钢圈的疲劳强度进行了仿真分析。通过钢圈应力分布情况的仿真试验,确定了钢圈上最易导致疲劳裂纹产生的危险点,然后用ANSYS FE-safe对钢圈寿命进行预测,并与试验数据进行对比。分析计算结果表明,汽车钢圈疲劳强度的有限元仿真分析是有效可行的,是钢圈前期设计开发的重要手段。     

钢制车轮弯曲疲劳寿命的影响因素

弯曲疲劳寿命是钢制车轮的一项重要性能指标,但制造过程中的过盈配合和轮辐板厚变化对车轮疲劳寿命的影响规律尚不清楚。本文通过测定轮辐板厚变化规律,并建立考虑过盈配合和轮辐板厚变化的钢制车轮弯曲疲劳有限元模型,比较了是否考虑这两种因素对车轮疲劳热点位置应力水平的影响,最后采用比例双轴疲劳方法预测车轮疲劳寿命。结果表明,过盈配合及轮辐板厚变化均会带来车轮弯曲疲劳寿命的下降,在有限元分析中不可忽略。     

轿车车轮钢圈疲劳寿命的有限元分析

运用ANSYS软件对柳州钢圈厂某型号轿车钢圈进行有限元分析,模仿其动态弯曲疲劳测试试验并计算其疲劳寿命.计算结果与试验结果相一致.分析计算结果表明,轿车钢圈强度的有限元仿真分析是实现轿车结构部件强度的有效手段.     

汽车钢圈疲劳寿命研究

汽车车轮是介于轮胎和车桥之间承受整车负荷的旋转件,是汽车行驶系统中重要的安全部件。钢圈的主要破坏形式是循环载荷产生的疲劳破坏,它是导致钢圈破坏的主要原因。文中研究了轮辐与轮辋的装配过盈量、接触量长度及轮辐外圆的加工状态对钢圈径向疲劳寿命的影响。结果表明,当接触量长度一定时,钢圈的疲劳寿命随着过盈量的增加而增大;当过盈量一定时,随着接触量长度的增加,钢圈的疲劳寿命逐渐增大,钢圈的最大疲劳寿命大于100万次。轮辐外圆未车削时,在较大的过盈量下,钢圈可达到较高的疲劳寿命。     

接触分析在车轮弯曲疲劳有限元分析中的应用

利用有限元接触分析方法,建立车轮、试验轴、螺栓连接件的有限元模型,施加合理的载荷与边界条件,模拟车轮弯曲疲劳试验。通过有限元分析软件ANSYS,建立模型、设置接触对与相关参数,得出车轮高应力区域与各应力值。运用疲劳寿命计算理论中的名义应力法及ANSYS软件估算车轮疲劳寿命,且两数据基本一致。与车轮弯曲疲劳试验结果比较表明:在疲劳寿命计算理论与ANSYS软件估算的疲劳寿命内车轮均没有破坏。从而验证了运用接触分析有限元法预估车轮寿命的有效性,为以后的结构改进起到了指导作用。     

膜片联轴器膜片应力计算及疲劳寿命分析

对六孔圆环形和束腰形膜片 ,利用有限元方法和薄板弯曲理论建立膜片应力计算模型。引入改进的局部应力 -应变法 ,建立计算膜片联轴器膜片疲劳裂纹形成寿命的模型和方法。定量分析两种形式膜片的应力、附加载荷的疲劳寿命 ,最后 ,得出对膜片组设计有参考价值的结论     

汽车钢圈疲劳寿命的有限元分析

钢圈是位于轮胎和车轿之间承受负荷的旋转部件,其作用是安装轮胎,承受轮胎与车轿之间各种作用力和力矩,对汽车行驶的安全性、稳定性、平顺性和牵引性均起着重要的作用。基于名义应力法的分析过程及有限元分析软件,探讨了钢圈弯曲工况下结构强度及疲劳寿命预估的方法。通过理论计算、实际使用情况及弯曲疲劳试验的结果验证了所提方法的正确性,所提方法可在产品设计阶段就预测设计产品的使用寿命及结构特点,为钢圈的设计及优化提供依据。     

基于弯曲疲劳试验的铝合金车轮有限元分析

基于某型车轮弯曲疲劳试验建立了铝合金车轮有限元模型,使用NX有限元分析软件进行静力分析,采用名义应力法和局部应力应变法预测了铝合金车轮弯曲试验的疲劳寿命。通过与弯曲疲劳试验对比,车轮弯曲疲劳试验结果与有限元计算结果相吻合,验证了有限元方法预测疲劳失效部位、降低研发成本和缩短研发周期的有效性。     

载重车车轮的强度分析与优化设计

通常超载情形下,某载重车车轮常因强度无法满足要求而产生破坏。针对上述问题,利用APDL语言编写建模程序,以弯曲疲劳试验的力学模型为基础,快速有效建立车轮等效力学模型来进行强度分析。在弯曲疲劳试验机上对车轮进行应力应变电测试验,将有限元结果与试验结果进行比较验证前者的正确性。以车轮危险点的最大应力为目标函数,在轮辋厚度基本不变的情况下,优化轮辐形状和通风孔的位置,使危险点的最大应力降低了11.52%,从而提高了车轮的承载重量和寿命。     

温度对动车组车轮钢服役次生疲劳裂纹起裂扩展特性影响

高速动车组车轮材料在严酷服役温度条件下的抗疲劳裂纹起裂与扩展能力是制定车轮合理维修周期和进行服役寿命评估的基础。选用高速动车组用ER8C车轮钢作为研究对象，对其在-60~60 ℃服役温度范围内进行了应力疲劳试验及疲劳失效机制探讨。结果表明：随着测试温度的升高，轮辋、轮辐材料疲劳寿命均呈现出显著缩短趋势；在较高的服役温度条件下，试样出现了半椭圆形的次生疲劳裂纹起裂扩展形貌特征，且由于轮辋与轮辐不同位置材料强度韧性的差异，使得产生次生疲劳裂纹起裂扩展形貌特征所对应的温度条件不同，对于轮辋材料，当试验温度升高到50 ℃时，试样开始产生次生疲劳裂纹，而对于轮辐材料，当试验温度升高到30 ℃时，试样便开始产生次生疲劳裂纹；通过对主次生疲劳裂纹的扩展特性比较分析可知，随着应力强度因子幅值的增大，材料微观薄弱区域由珠光体片层层间转变为珠光体团晶粒边界。     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

基于多目标非支配解提取法的电力系统无功优化

针对传统的电力系统多目标粒子群优化算法采用权重系数法将多目标转化为单目标,从而忽视了各目标函数间的竞争关系这一问题,提出将非支配解提取法运用到电力系统多目标无功优化中,并设定了一套提取规则,以电力系统中的有功网损、电压偏差和电压稳定裕度为目标,使目标在充分竞争的情况下得出Pareto最优解,利用IEEE-14节点系统对多目标非支配解提取法的电力系统无功优化进行了仿真测试。研究结果表明,该算法一次运行可以得出多组非支配解,既有偏向单个目标的解也有兼顾所有目标的解,克服了权重系数法的盲目性和单一性,可使电力决策者根据实际问题选择最优解,具有较好的灵活性与多样性。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.