Two materials A and B of the same density are being considered for the design of a large plate that is 2 m wide and 3 m long. A maximum tensile load of 4.5 MN will act perpendicular to the 2 m dimension and consideration must be given to the possibility of pre-existing cracks. For this problem, failure can be defined as either gross yielding or fracture. In this case, through thickness cracks at the center of the plate and perpendicular to the applied load are of major concern. Because of inspection limitation, the smallest crack that can be detected is 2.54 mm.
Based upon the above consideration, which material would you recommend if the plate is to be of minimum weight?
Given:
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Material A
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Material B
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KIC
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115 MPa.m1/2
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55 MPa.m1/2
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?ys
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910 MPa
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1035 MPa
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