课程名称︰材料力学 课程性质︰必修 课程教师︰王安邦 开课学院：工学院 开课系所︰化工系 考试日期（年月日）︰2012/10/23 考试时限（分钟）：70分钟 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : problem 1(20%) a teddy bear is standing on a chair in the figure P1.the force exerted by the teddy bear on the frame at one side of the chair is equivalent to horizontal and vertical forces of 48N and 168N,respectively, at E and a force of 56N perpendicular to member BH at G (a)show the free-body diagram(10%) (b)determine the intermal forces on a sectin perpendicular to and midway between pins D and F(10%) 图 http://ppt.cc/230E problem 2(30%) at a point in a structural member subjected to plane stress there are normal and shear stresses on horizontal and vertical planes through the point, as shown in the figure P2 (Using Mohr's circle) a.determine the principal stresses and the maximum shear stress at the point. show these stresses on a triangular stress element(15%) b.determine the normal and shear stresses on the inclined plane a-b shown in the figure. show these stresses on a sketch of the plane on which they act. (15%) 图 http://ppt.cc/3c8E problem 3(25%) at rigid bar FEBC is supported by two steel deformable bars AB and DE, as shown in figure3. there is no strain in vertical bars before the load P is applied. after the load is applied,the strain in bar DE is 0.0006in/in determine a.the axial strain in bar AB(8%) b.the axial strain in bar AB if there is a 0.001-in. clearance in the connection at B before the load is applied(10%) c.the axial strain in bar AB if the clearance becomes 0.06in(7%) 图 http://ppt.cc/rAIL problem 4(25%) the strain rosette on the free surface of an impression cylinder of a precision coating machine for OLED electronics devices(v=0.33,shown in the figure below)was used to obtain the following normal strain data:εa=+800μin/in εb=+950μin/in,εc=+600μin/in a.determine the principal strains and the maximum shearing strain at the point .prepare a sketch showing all of these strains.(15%) b.determine the normal strain in the n-direction at the point.(10%) 图 http://ppt.cc/EcD~ --

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