課程名稱︰材料力學 課程性質︰必帶 課程教師︰朱錦州 開課學院：工 開課系所︰化工 考試日期（年月日）︰100/12/6 考試時限（分鐘）：120 是否需發放獎勵金：是 （如未明確表示，則不予發放） 試題 : 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 -- 風住塵香花已盡，日晚倦梳頭。 物是人非事事休，欲語淚先流。 聞說雙溪春尚好，也擬泛輕舟。 只恐雙溪舴艋舟，載不動許多愁。 --

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