材力试卷07B.doc

2.(10 points) Plane stress state as shown, unit:MPa, determine the principal stresses（主应力） and draw its circles of stress.专业、班级 姓 名 学 号 -密-封- -线-试卷B第1页共 4 页 河南科技大学教务处河 南 科 技 大 学200 6至200 7 学年第 2 学期试卷B课程 MECHANICS OF MATERIALS 年级、专业CIVIL ENGINEERING 2005 题号一二三四五六七八九十总分得分A、Answer these questions briefly(10 points)1. If a rod is subjected to an axial load, there is only strain in the material in the direction of the load. True or false? 2. What conditions should be satisfied（满足）as the torsion formula = Tl/(GIP) is applied ?3. What is the strain in a beam at the neutral axis?4. Write out the impact factor Kd of the structure due to a free falling body. B. Draw diagrams according to demands of problems.1.(15 points)Draw the shear force and bending moment diagrams for the beam shown.C. Calculate below problems1.(15 points) Rods AB and BC each have a diameter of 4mm. If a load of 12kN is applied to the ring at B, determine the smallest angle of rod BC so that the average normal stress in each rod is equivalent. 2.(15 points) The solid rod AB has a diameter dAB = 60mm. The pipe CD has an outer diameter of 90mm and a wall thickness of 6mm. Knowing that both the rod and the pipe are made of a steel for which the allowable shearing stress is 75MPa, determine the largest torque T that may be applied at A. 专业、班级 姓 名 学 号 -密-封-线-试卷B第2页共4页河南科技大学教务处3.(10 points) The beam has a rectangular cross section as shown. Determine the largest load P that can be supported on its overhanging ends so that the bending stress in the beam does not exceed =10MPa.4.(10 points) Determine the maximum force P that can be applied to the handle so that the Q235 steel control rod BC does not buckle. The rod has a diameter of 25mm. Use E=200GPa, P = 200MPa.5.(15 points) Determine the moment M0 in terms of the load P and dimension a so that the deflection at the center of the beam is zer