Method for calculating power hardening elastic-plastic bending crack opening displacement under the action of dynamic load

Abstract

The invention discloses a method for calculating power hardening elastic-plastic bending crack opening displacement under the action of dynamic load. According to the calculation method, the dynamic action stress, the normal stress and the shear stress on the boundary of a plastic region are comprehensively considered, and the opening displacement of a tip point of an elastic-plastic bending crackof a hardened material is calculated by using the Castigliano's theorem. The variation relationship between the maximum value of the dynamic opening displacement of the elastic-plastic bending crackand a material hardening exponent is analyzed by drawing. In a power hardening material, the maximum value of the dynamic opening displacement of the tip point of the elastic-plastic bending crack decreases with the increase of the material hardening exponent n, when the n increases uniformly at a constant velocity, the maximum value of the dynamic opening displacement of the tip point of the elastic-plastic bending crack decreases in an acceleration manner, and the reduction amplitude becomes bigger and bigger. When the hardening index of the material is the same, the maximum value of the dynamic opening displacement of the tip point of the elastic-plastic bending crack gradually decreases with the continuous decrease of the external load.

Description

technical field [0001] The invention relates to a calculation method for the opening displacement of a bending crack, in particular to a calculation method for the opening displacement of a power-hardened elastic-plastic bending crack under the action of a dynamic load. Background technique [0002] The perturbation analysis of quasi-static slight bending cracks was first done by Banichuk, Goldstein and Salganik. Cotterell and Rice used the same method to obtain a simple expression of the stress intensity factor, and studied the path prediction of semi-infinite cracks in infinite planes. Karihaloo et al. and Sumi et al. used the second-order and first-order perturbation methods to study the propagation of slight bending cracks in an infinite plane subject to multidirectional tensile stress at infinity. Yoichi Sumi et al. have calculated the approximate value of the stress intensity factor of the linear elastic bending crack tip for arbitrary far-field boundary conditions. ...

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Problems solved by technology

[0003] However, the predecessors' studies on the bending crack propagation path are all aimed at the problems of linear elastic fracture and elastic-plastic fracture of ideal plastic materials.

However, the calculation of the opening displacement of the elastic-plastic bending crack tip of power-hardened materials under dynamic load has not yet been studied by scientific and technological workers.

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