Question

Problem 1 Consider two Al aircraft under conditions of high cycle fatigue (HCF). Plate A will be subjected to with ƠmF-100 MPa (compression) and ƠmayR 100 MPa (tensio 0m--50 MPa (compression) and ơma.-150 MPa (tension). (a) Calculate the fatigue lives of the two plates. Based on your results, which plate replaced first? (15 points) (b) Suppose we would like to increase the fatigue life to 25.000.000 cycles, keepin amplitude constant at ơaF 100 MPa. Calculate the new values of Ơminando, mean stress Om (15 points). Data: Basquin's law σα 340 (2M)-0.07 Prosider two Aluminum Alloy plates that are used for the construction of the f n), while Plate B is subjected to should be be g the stress Ơma, as well as the

Answer 1

Cyxle iqul Basu euiin min i50mpa min- -100-(-10D) 2. 2 2 150-650)209 looMP 100-10จ 2 Str«SS 2 150-5010 pa 6n(B) m(8) 2. mean

be less. So ofeent dama 2. 1 95 67033.36 cycles N, 5,000, 000 C1 cus -98.299 MPa SMin