13th International Conference on Fracture June 16–21, 2013, Beijing, China -5- -40 -20 0 20 40 601000000 601500000 602000000 602500000 603000000 603500000 604000000 F(cycle) T (℃) -40 -20 0 20 40 0.0030 0.0031 0.0032 0.0033 0.0034 0.0035 D(%) T (℃) Fig 6 Fatigue life under different temperature Fig 7 Fatigue damage under different temperature -40 -20 0 20 40 1.2050 1.2052 1.2054 1.2056 1.2058 1.2060 1.2062 1.2064 1.2066 1.2068 1.2070 S(%) T (℃) Fig 8 Safe factor with different temperature 5 Conclusion By the theoretical analysis and finite element analysis, we can get about fatigue life and fatigue damage as well as the structure of the safety factor, the following conclusions: (1) the effective life of the cycle the same number of times of fatigue due to the approach, in the contact surface between the structure of the different working environment varies, the contact surface more rough lower fatigue life, the lower the higher the fatigue life of the temperature of the working environment. (2) of the contact surface of the node using a different approach and structure in a different working environment showed a different degree of damage. Contact surface more rough structure of fatigue damage is more severe, and the greater the higher the temperature of the work environment the structure of the fatigue damage. (3) The different treatment of the contact surface causes the contact surface of the geometric discontinuity degree is increased, resulting in crack growth rate is accelerated to the structure of the lower safety coefficient; increase the safety of the structure with the elevated temperature of the fatigue crack growth rate coefficient is reduced. 6 References [1] Wang Tianliang, the overall steel truss node test study [J] bridge construction, 1999, 4: 32 to 40. [2] the Fu Xiangjiong, structural fatigue and fracture [M], Northwest Industrial Press, Xi'an, 1995:114 ~
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