基于Abaqus的轻型汽车牵引装置强度分析

为保证汽车牵引装置强度满足最新的国标要求,运用Abaqus中的非线性有限元方法对某轻型汽车的后部牵引装置进行强度分析.通过试验与仿真结果的对比找出牵引装置的薄弱区域和失效原因,并提出避免地板屈曲失稳的优化方案.仿真和试验结果表明优化方案满足设计要求.     

电动汽车线控转向系统性能分析与参数优化

研究电动汽车操纵稳定性优化问题,电动汽车采用线控转向系统,可靠性差,成本高.为提高操纵稳定性和主动安全性,提出对设计的线控转向系统的实体结构进行适当简化,建立了电动汽车线控转向系统的动力学模型.然后,研究了电机及减速器等的结构参数对系统频率响应特性和时域响应特性的影响,进行了电动汽车线控转向系统性能分析.最后,对系统的稳定性条件,采用非线性带约束优化算法进行了电动汽车线控转向系统的参数优化仿真.结果表明,经过参数优化后,电动汽车的操纵稳定性大大提高,可用于指导转向系统的参数设计与匹配.     

永磁驱动器的多目标参数优化设计

为了满足永磁驱动器在实际运行中具有较大的输出转矩和较小的涡流损耗的目的,建立了永磁驱动器的3维有限元模型,分析了永磁驱动器的主要结构参数对输出转矩和涡流损耗的影响。采用正交实验设计方法,获得了用于非线性永磁驱动器建模的样本空间。采用支持向量机建立永磁驱动器的非线性回归模型,并用多目标微粒群算法进行永磁驱动器的结构参数多目标优化,得到了最优结构参数解。有限元仿真实验对比优化前后永磁驱动器的涡流密度和受力分布的结果,验证了该优化方法用于永磁驱动器结构参数优化是可行的。优化结果使永磁驱动器可在涡流损耗较小的情况下获得较大的输出转矩,从而进一步提高系统的工作效率。     

基于MWOA-ELM代理模型的有限元模型修正

为得到待修正参数与结构响应之间的关系,提高模型修正效率,将极限学习机(ELM)和鲸鱼优化算法(WOA)引入有限元模型修正(FEMU).通过高斯(Gauss)混沌初始化、非线性调整策略、自适权重系数等改进鲸鱼优化算法,利用其优化极限学习机,建立待修正参数与加速度频响函数之间的非线性映射关系.以试验与优化极限学习机模型输出...     

高速铁道车辆悬挂系统参数化建模、优化与仿真分析

为了协调高速铁道车辆的运动稳定性与曲线通过性能之间的矛盾,本文采用多目标优化方法对一种高速铁道车辆的关键悬挂参数进行了优化处理.采用多体动力学技术建立了某型高速铁道车辆62个自由度的动力学模型,模型考虑了轮轨接触几何非线性、轮轨蠕滑非线性和阻尼非线性等.采用ADAMS-Matlab联合仿真对车辆悬挂系统进行参数化改造,使弹簧刚度和阻尼系数均可调.采用基于遗传算法的多目标优化方法对悬挂参数进行优化,使车辆模型能同时满足3种动力学指标.对比优化前后模型的动力学性能可以发现:模型的运动稳定性和曲线通过性能得到显著提高,虽然运行平稳性有小幅降低,但仍能保持在优良的工作状态.     

未知参数非线性系统的自适应广义预测控制

研究非线性系统的稳定性和跟踪优化问题,针对未知参数非线性系统的参数辨识和输出跟踪问题,给出参数自适应广义预测控制方法,为使辨识模型能实时反映被控对象特性以及输出对设定值的跟踪有较高精度.提出将非线性系统转化为受控自回归滑动平均模型,根据输入输出数据辨识模型参数.采用广义预测控制滚动优化的策略得出最优控制律,将最优控制律作用于对象实现非线性系统的优化控制以及系统输出对设定值的跟踪控制.明显克服了自适应控制对模型精度要求高的缺陷且具有在线辨识,滚动优化的特点.最后,通过仿真实例验证了方法的有效性.     

融合稳定性与炮口扰动的车载火炮参数优化

射击稳定性与射击密集度是体现车载火炮综合作战性能的关键指标,也是进行车炮匹配问题研究与优化的重要内容。针对稳定性参数与炮口扰动参数时空属性不同,在ADAMS中无法进行综合优化的难题,结合多体动力学仿真软件ADAMS、Box-Behnken试验设计方法及Matlab遗传算法工具箱等技术提出了融合射击稳定性与炮口扰动的组合优化方案,并基于某车载火炮虚拟样机对上述方法进行了验证。根据优化结果,某车载火炮车尾跳高、车尾侧移、炮口位移均获得较为明显的优化效果,为车载火炮车炮总体参数优化匹配研究奠定了基础。     

应用于纳米测量机的MEMS微接触式测头的结构设计和优化

为了提高MEMS微接触式测头的性能,系统开展了测头的结构设计和参数优化.根据测头结构各个部分的设计目标,提出了测头悬挂系统拓扑结构的设计方案.基于测头结构的力学模型,提出了结构参数对测头性能的影响机理,并采用有限元方法对测头的测杆、中心连接体、梁等结构参数进行了仿真优化,获得了符合测头整体性能设计要求的参数及应力分布曲线.     

船舶航向非线性H∞逆优化输出反馈控制

为抑制船舶航向非线性优化控制中模型参数摄动和由状态观测器引入的不确定观测误差,提出了一种非线性H∞逆优化控制算法.首先,基于无源理论设计观测器以实现海浪滤波,该观测器无需海浪扰动的方差信息从而减少了观测器参数数量.然后,考虑模型参数摄动对观测误差的影响,给出了描述系统局部(全局)性态的局部(全局)H∞优化性能指标.在以广义黎卡提方程(GARE)对局部优化问题的求解的基础上,应用逆优化方法将全局H∞优化问题转化为构造闭环系统的Lyapunov函数问题,得到同时满足两种指标的优化控制器,并证明了稳定性.仿真结果证明了该算法的有效性.     

基于Adams的某机枪射击密集度仿真

为研究武器结构对射击密集度的影响,提出一种低伸弹道武器射击密集度的分析方法.采用刚柔耦合分析方法和Adams软件建立某机枪的动力学仿真模型,计算两种枪管设计方案的射击密集度.仿真结果为设计人员进行结构设计及优化提供参考依据.     

水面舰艇编队拖曳声纳舰阵位配置及行动方法

研究水面舰艇编队优化问题,由于潜艇对水面舰艇编队构成严重威胁,为有效保护舰艇安全,选择声纳舰的位置十分重要.拖曳声纳舰作为水面舰艇编队主要对潜警戒信号,对阵位配置及行动方法对编队的反潜效能影响巨大.针对水面舰艇编队航渡中近程拖曳声纳舰的阵位配置问题,提出了一种方法.通过对舰艇编队反潜警戒区的划分,总结了拖曳声纳舰阵位配置原则,建立了关于拖曳声纳舰阵位的模型,仿真计算了各种参数对拖曳声纳舰阵位的影响,并提出了拖曳声纳舰“蛙跳”行动的方法,并进行仿真.结果表明,方法有效,为指挥员编队决策提供了参考依据.     

Comparison of numerical techniques for 3D flutter analysis of cable-stayed bridges

This paper presents the results of a comparison study of the numerical techniques of structural and aerodynamic force models developed based on the spline finite strip method with the conventional finite element approach in three-dimensional flutter analysis of cable-stayed bridges. In the new formulation, the bridge girder is modelled by spline finite strips. The mass and stiffness properties of the torsional behaviour of complex bridge girder, which have a significant influence on the wind stability of long-span bridges, are modelled accurately in the formulation. The effects of the spatial variation of the aerodynamic forces can be taken into account in the proposed numerical model by distributing the loads to the finite strips modelling the bridge deck. The numerical example of a 423 m long-span cable-stayed bridge is presented in the comparison study. The accuracy and effectiveness of the proposed finite strip model are compared to the results obtained from the equivalent beam finite element models. The advantages and disadvantages of these different modelling schemes are discussed.     

参数化有限元分析的液压机机身轻量化设计

建立了液压机机身的参数化有限元模型。通过正交试验模拟实际工况进行了应力和角变形的分析计算。从试验样本出发,采用基于最小二乘法的回归模型构建了机身最大应力及角变形与结构主参数间的映射关系。在库恩-塔克条件下构造了优化的数学模型,并通过仿真运算提出了合理的机身轻量化设计方案。结果表明,轻量化效果明显,改进后的方案能完全符合实际工况的要求。     

Shape sensitivities in the reliability analysis of nonlinear frame structures

A unified and comprehensive treatment of shape sensitivity that includes variations in the nodal coordinates, member cross-section properties, and global shape parameters of inelastic frame structures is presented. A novelty is the consideration of geometric uncertainty in both the displacement- and force-based finite element formulations of nonlinear beam-column behavior. The shape sensitivity equations enable a comprehensive investigation of the relative influence of uncertain geometrical imperfections on structural reliability assessments. For this purpose, finite element reliability analyses are employed with sophisticated structural models, from which importance measures are available. The unified approach presented herein is based on the direct differentiation method and includes variations in the equilibrium and compatibility relationships of frame finite elements, as well as the member cross-section geometry, in order to obtain complete shape sensitivity equations. The analytical shape sensitivity equations are implemented in the OpenSees software framework. Numerical examples involving a steel structure and a reinforced concrete structure confirm that geometrical imperfections may have a significant impact on structural reliability assessments.     

基于ANSYS Workbench的低温储罐多目标优化设计

为更加高效合理地设计质量更小的低温储罐,应用ANSYS Workbench中的Design Modeler模块建立某低温储罐外容器的有限元参数化模型,并对该设备进行特征值屈曲分析,得到其临界外压载荷。考察相关结构参数的影响,在此基础上利用多目标驱动优化分析得出在满足临界屈曲压力要求下的最优加强结构,实现设备的轻量化设计。     

单管计算电容式液位传感器的仿真与特性研究

计算电容式液位传感器采用计算电容原理,经过单管式轻量化的结构改良设计.为探究改良结构对传感器特性的影响,针对单管计算电容式液位传感器建立有限元模型,利用分析软件ANSYS仿真分析几个重要结构参数对传感器灵敏度的影响.特性试验表明:传感器输入输出曲线与仿真结果具有良好的一致性;在0~200 mm量程内传感器线性度为±0.8%,回程误差为±0.03 pF,液位测量的最大引用误差为-1.0%FS.该研究为计算电容式液位传感器的结构优化提供了理论基础,有利于该新型传感器在航空、航天燃料液位测量领域的应用推广.     

The application of cap-plasticity-model to embankment problems

Several typical embankment problems are analyzed using the proposed procedure for determining the cap-plasticity-model parameters and the general-purpose finite element program in this paper. Several important practical features of embankment design are described and illustrated with numerical examples. These include undrained condition, embankment widening and raising, multiple-layer foundation soils, and measures for improving embankment stability. Emphasis of the analyses was placed on the engineering interpretation of the finite element results, including evaluation of the effects of construction processes, characteristics of deformation, and evaluation of stability and performance of embankment with some measures for improving stability. It is concluded that the drainage of foundation soil can improve the stability of the embankment fill, construction of berms can effectively improve embankment stability, and geotextile will develop considerable resistance in the occurrence of large deformation.     

基于单元生死功能的转向架构架拓扑优化设计

为了更好地实现转向架构架的轻量化设计,根据设计经验,采用渐进结构优化法(ESO)的基本思想,通过对ANSYS单元生死功能的二次开发,应用APDL(ANSYS Parametric Design Language)编制拓扑优化程序,以直观的有限元模型代替复杂的拓扑优化的数学模型,提出了一种构架拓扑优化设计的工程方法。通过方法优化,使某高速动力车转向架构架在疲劳强度符合要求的前提下,结构应力趋于均匀分布,质量减少了143.92kg。结果表明,提出的方法是有效的和可行的,具有一定的工程实用价值,为设计提供依据。     

Structural optimization methods of nonlinear static analysis with contact and its application to design lightweight gear box of automatic transmission of vehicles

In this paper, we consider lightweight design methods for gear box of automatic transmission of vehicles with contact constraints. Lightweight design is a fundamental requirement for protecting the environment and improving fuel economy. In addition, durability is another important requirement for safe driving. However, in the design of automatic transmissions, these two requirements are usually in a trade-off relationship and engineers spend a long design study time. This paper deals with design approaches using structural optimization method to design lightweight structures and to minimize stress with contact constraints. Stress with contact constraints is solved using the finite element method. Three different structural optimization methods, topometry, topography and freeform optimization, are applied for the design of a lightweight gear box of an automatic transmission. The optimization results show that the optimization methods successfully found the lightweight gear box design and can be used at the early stage of the design process of automatic transmissions.