课程名称︰材料力学 课程性质︰必带 课程教师︰朱锦州 开课学院：工 开课系所︰化工 考试日期（年月日）︰100/12/6 考试时限（分钟）：120 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : 1. The cinical gas tank is shown in Fig.1 was babricated from 1/8-in thick stell plate. Determine the axial and hoop stresses at a point in the wall 8-ft below the apex of the cone due to an interal gas pressure of 250psi Hint:volume of the conical tank is (1/3)pir^2h (20) 2. Determine the change in length of the homogeneous bar in Fig.2 due to its own weight. Express the results in terms of L,E, and the specific weight gama(r) ofthe material. The taper of the bar is slightly enough for the assumption of a uniform axial stress distribution over a cross section to be valid. (25) 3. Explain: (35) (a) modulus of elasticity and rigidity (b) yeild point and ultimate strength of a material (c) Poisson's ratio (d) Saint-Venant's principle (e) Stress concentration (f) Elastic and plastic 4. Nice 0.75 in diameter stell (E=30,000 ksi) reinforcing bars were used when the short concrete (E=4,500 ksi) pier shown in Fig.4 was constructed. When a load P of 150 kip was applied to the pier. (a) Determine the normal stress in the concrete and the stell bars after load P is applied.(15) (b) The cjamge in length of the pier resulting from the effect of P(5) (c) After P was applied, the temperature increased 100 degree F. The coefficients of thermal expansion for steel and concrete are 6.66E-6 and 6.0E-6/ degree F respectively. Determine the normal stress in the concrete and in the steel bars after the temperature is increased.(15) (d) The change in length of the pier resulting from the combined effects of temperature and load P.(5) 5. At a point on the free surface of a stell (E=200 GPa and v=0.3) machine partm the strain rosette shown in Fig.5 was used to obtain the following normal strain data: epison a=-555,epsion b = 925, epison c = 740 E-6 m/m (a) Determine the strain components x y z and shear strain xy (15) (b) Determine the stress components x, y, z and shear stress at the point(10) (c) Determine the princial stress sigma P1,P2, P3 and the maximum shearing stress at the opint (10) Extra credit: In Question 1, if the tank is full of water, Determine sigma h and a. (15) (specific weight of water = 62.4 lb/in^3) total: 165 points -- 风住尘香花已尽，日晚倦梳头。 物是人非事事休，欲语泪先流。 闻说双溪春尚好，也拟泛轻舟。 只恐双溪舴艋舟，载不动许多愁。 --

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