平面曲柄摇杆机构的优化设计

本文采用几何解析优化法设计平面曲柄摇杆机构.当给定摇杆摆角(?).和行程速度变化系数K,设计最小传动角有最大值的机构时,把多维优化设计问题转化为一维优化设计.并列出了满足工程设计要求的优化性能曲线.     

基于CDIO的回归工程教育理念的研究与实践

对内燃机曲柄连杆机构的工作性能进行仿真分析是该产品设计过程中的重要组成部分。运用机械系统仿真软件ADAMS,建立了曲轴、飞轮、连杆、活塞在内的虚拟样机模型,之后将曲轴视为柔性体,利用PRO/E建立曲轴的三维实体模型,导入ANSYS进行模态分析,生成中性文件,再导入ADAMS中生成曲轴的柔性体模型来替换刚体模型,构造刚柔混合体模型,通过对模型的多体动力学仿真,得到曲轴连杆和活塞的运动特性曲线,为以后内燃机的优化设计及疲劳分析提供参考。     

用相对极点法设计曲柄摇杆机构

针对曲柄摇杆机构中按行程速度变化系数设计,又有极限位置传动角要求的问题,提出了用相对极点法来设计的方法.     

Sliders,visual analogue scales,or buttons: Influence of formats and scales in mobile and desktop surveys

ABSTRACT

In an experiment dealing with the use of personal computer, tablet, or mobile, scale points (up to 5, 7, or 11) and response formats (bars or buttons) are varied to examine differences in mean scores and nonresponse. The total number of “not applicable” answers does not vary significantly. Personal computer has the lowest item nonresponse, followed by mobile and tablet, and a lower mean score than for mobile. Slider bars showed lower mean scores and more nonresponses than buttons, indicating that they are more prone to bias and difficult in use. Sider bars, which work with a drag-and-drop principle, perform worse than visual analogue scales working with a point-and-click principle and buttons. Five-point scales have more nonresponses than eleven-point scales. Respondents evaluate 11-point scales more positively than shorter scales.