1已知铸铁的拉伸许用应力[]=30MPa,压缩许用应力[o]=90MPa,μ=0.30,试对铸 铁零件进行强度校核,危险点的主应力为: (1)=30MPa,=20MPa,=15MPa; (2)o1=-20Ma,o2=-30pa,3=-40Ma (3)o1=10mpa,o2=-20mpa,3=-30a

1T形截面铸铁梁受力如图,许用拉应力[o=40Ma,许用压应力o=60mpa,已知 F1=12kN,F2=4.5k,=76510-8m4,y152mm,y2=88mm。不考虑弯曲切 应力,试校核梁的强度

1试用积分法写出图示梁的挠曲轴方程,说明用什么条件决定方程中积分常数,画出挠曲 轴大致形状。图中C为中间铰。EI为已知。 解题分析:梁上中间铰处,左、右挠度相等,转角 不相等

典型习题解析 1作图示简支梁的剪力图和弯矩图,并求出Fm和Mm

1已知矩形截面梁,某截面上的剪力Fs=120kN及弯矩M=10kNm绘出表示1

1图示№20a工字钢,在温度20℃时安装,这时杆不受力,试问:当温度升高多少度时,工 字钢将丧失稳定?钢的线膨胀系数a=12.5×10-61/℃ 解题分析:计算时,取i的最小值。此题是 一度静不定问题,利用变形协调方程求解

1一圆杆横截面面积为A,弹性模量为E杆下端带一法兰盘,杆上部套一圆形重物,如 图所示。设重物P离法兰盘高为h,当重物自由落下时,形成冲击载荷作用在杆上。试计算 杆中动应力

3.064 Quiz 3- Sample Questions 1. Consider a unidirectionally reinforced fiber-matrix composite a)What elastic constants(relative to the fiber and transverse directions )are needed to describe this material?

uiz2(11/7/03)-sar esti。ns rse and fiber-directi moduli for a transversely isotropic composite lamina 2. Plot and explain the variation of fiber-direction strength of a unidirectionally-reinforced lamina as a function of fib fraction

3.064Quiz10/10/03 Sample questions 1. What is the glass transition temperature of a polymer How can it be measured? What molecular characteristics determine its value Illustrate by giving the chemical structure and Tg for polyethylene polyvinyl chloride and polystyrene