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懂得断裂力学的哥哥姐姐，叔叔阿姨快来帮忙 国庆前，老师留的作业，明天要交。 我这几天都在看，可是还是不会做。哪位这行高手帮忙指点一下吧！ 会者不难啊。我想不会太费事的。多谢啊！ 老师留的作业还是英文的，有难度才需要高人出手呢！！ 共5个题，用中文答就行了，高手能答几个算几个吧，不要把自己搞得faint。 1. Calculate the maximum permissible crack size in a center cracked panel subjected to a uniform stress of 20 ksi. The toughness is 50 ksi(in)1/2; the yield stress is 60 ksi; W=12 inches. 2. A large sheet containing a 50 mm long crack fractures when loaded to 500 MPa. Determine the fracture load of a similar sheet with a 100 mm crack. 3.The tensile strength of brittle solids are usually controlled by the size of defects such as microporesor microcracks. The typical tensile strength of cement is 3 MPa. After careful pressure processing and other treatments, the strength may go up to as 50 MPa. Assume that the fracture toughness of the cement remains the same before and after going through the special processing, and is equal to 0.2 MPam1/2, determine the maximum flaw size in these materials. (Assume that the flaws are widely separated apart so that they do not interact with each other.) 4.Calculate and plot the maximum external load P for three point bending specimen with crack length up to 70% beam height. B=100mm, W=100mm, S=4W. KIC=0.2 MPam1/2. 5. Rocket motor casings may be fabricated from either of two steels : (a) low alloy steel, yield 1.2 GPa, toughness 70 MPa√m, (b) maragingsteel,yield 1.8 GPa, toughness 50 MPa√m. The relevant Code specifies a design stress of yield 1.5GPa. Calculate the minimum defect size which will lead to brittle fracture in service for each material, and comment on the result. 休 闲居 编 辑 >>>>>>>>休闲养生网回答： 没有人知道 |