双层砼板组合梁下部剪力件对上层砼板应力影响研究

传统组合梁在采用连续梁体系时中间支座附近承受负弯矩会使上层砼板过早开裂,工字钢下翼缘因此承受较大压力易引起局部失稳.弥补此缺陷的措施是在负弯矩区钢梁下翼缘增设砼板,通过剪力件与钢梁连接,其作用是使钢梁下翼缘"固结"于砼板内,增强钢梁的局部抗稳定能力,即双层砼板组合梁.本文将双层砼板组合梁节段假定为Goodman弹性夹层,利用Abaqus6.5建立双层砼板组合梁空间模型,采用滑移单元slide-plane模拟剪力连接件,重点研究下部剪力件的变化对上层砼板应力的影响.得出了下部剪力度的经济值约为1.0.     

MINRES法和有限元法解奇摄动反应扩散方程

讨论奇摄动反应扩散方程 的数值逼近求解问题, 及 均为正实数. 利用有限元方法并结合最小残量法, 给出求解该问题的一个新方 法, 该方法修正了单纯采用有限元方法求解时在边界附近呈现出的非正常扰动的 现象, 避免了因为 过小所引起的解的变异, 从而得到更加精确的数值结果.     

基于ANSYS的卡车燃油箱结构强度分析

卡车燃油箱是燃油供给系统的核心部件,其设计研发主要依靠工程师的经验来完成,产品更新速度慢,成本高.结合现代化设计方法利用三维软件UG设计出卡车油箱的三维结构模型,然后利用有限元方法对卡车燃油箱结构进行应力应变分析,求出卡车油箱的最大应力值σmax为319.237 MPa,最大应变值εmax为13 mm,为卡车油箱的设计修改提供理论参考依据.大大降低了卡车油箱的设计成本,提高了产品研发效率.     

基于ANSYS的细长轴车削加工分析

在对细长轴传统车削(正向)弯曲变形分析的基础上,提出细长轴逆向车削的加工方法,并对细长轴的逆向车削进行弯曲变形分析,再利用有限元法分别对两种车削方案的加工精度进行仿真,最后通过实验验证逆向车削可以在一定程度上提高细长轴类零件的车削加工精度。     

Comparing balance and inverse methods on learning conceptual and procedural knowledge in equation solving: a cognitive load perspective

We examined the use of balance and inverse methods in equation solving. The main difference between the balance and inverse methods lies in the operational line (e.g. +2 on both sides vs ?2 becomes +2). Differential element interactivity favours the inverse method because the interaction between elements occurs on both sides of the equation for the balance method but only on one side of the equation for the inverse method. In an experimental study, 63 students (mean age = 13) were randomly allocated to either balance or inverse group to undertake a pre-test, study an instruction sheet, complete acquisition equations, sit for a post-test and a concept test. Procedural knowledge was assessed on performance on practice equations and post-test, whereas conceptual knowledge was assessed on performance on the concept test. The inverse group outperformed the balance group on practice equations but not the post-test. Both the balance and inverse groups scored higher on the inverse concept test than the balance concept test. Positive association between performance on procedural knowledge and performance on conceptual knowledge was found for the inverse group but not the balance group. Overall, the evidence obtained indicates a number of educational implications for implementation.     

Static and dynamic damage analysis of mass concrete in hydropower house of Three Gorges Project

This paper establishes a 3D numerical model for 15# hydropower house of the Three Gorges Project (TGP) and performs a nonlinear static and dynamic damage analysis. In this numerical model, a coupling model of finite and infinite elements for simulating infinite foundation of hydropower station is adopted. A plastic-damage model based on continuum damage mechanics, which includes the softening and damage behavior under tension is considered for the concrete material. The dynamic equilibrium equations of motion are solved by using the HilberHughes-Taylor (HHT) time integration method. Firstly, the static damage response analysis of the hydropower station is conducted due to high tensile stress resulting from large water head and diameter of an inlet pipe. Then, on the basis of static simulation, the dynamic damage analysis of hydropower house subjected to earthquake motion is simulated. Numerical results show that under large water head and diameter of an inlet pipe of the project, the damages are mainly located near the top of the spiral case from the inlet section to the 0° section; under combined loadings of static loads and earthquake, the damages of the concrete surrounding the spiral case increase insignificantly; however, some damages occur on the side walls of the main powerhouse.     

高速包装机椭圆齿轮的有限元分析

采用有限元分析方法对烟草包装机椭圆齿轮的静力学特性进行理论计算和研究,建立椭圆齿轮的有限元模型,通过有限元分析软件ANSYS Workbench对椭圆齿轮进行分析,得出椭圆齿轮各轮齿的应力分布,并对计算结果进行分析。该方法和所得结果为椭圆齿轮的优化设计提供了参考。     

压型钢板组合梁的有限元模型

利用ANSYS有限元软件对压型钢板组合梁模型进行了有限元数值模拟分析。将有限元分析结果与试验结果进行比较,验证了有限元模型的合理性。     

基于solidworks的车床主轴受力分析

车床主轴的强度、刚度、稳定性对车床加工质量起决定性的作用。利用solidworks simulation软件分析车床主轴,确定应力集中区,从而为维护改造旧车床设备提供理论依据。     

管理理论的困惑与创新

世纪之交，我国的管理正面临着十分严峻的挑战。本文通过分析目前困扰我国管理界的热点问题，指出管理理论创新是走出困境的关键，进而提出了要从动态变化角度建立适应时代要求的管理理论的全新思想，即要在动态变化中认识管理的作用，选择管理模式，度量管理的绩效，测算管理在经济增长中的贡献，并基于此给出了解决问题的具体思路与方法。