Multi-axial fatigue life prediction method based on weighted average maximum shear strain amplitude plane

Abstract

The present invention discloses a multi-axial fatigue life prediction method based on the weighted average maximum shear strain amplitude plane, and relates to the field of the multi-axial fatigue strength theory. The method comprises: synthesizing the multi-axis amplitude-varying load history into a von Mises equivalent strain history by using the equivalent von Mises strain formula, and carrying out Wang- Brown cycle counting on the von Mises equivalent strain history; determining the critical plane under the multi-axial amplitude-varying load by using the proposed weight average maximum shear strain amplitude plane; calculating fatigue damage parameters on the critical surface in each half-cycle obtained by counting; carrying out damage calculation by using the Wang and Brown damage models or the Fatemi and Socie damage models; and accumulating the calculated damage in each half-cycle by using the Miner's linear cumulative law, and calculating the fatigue life. The proposed life prediction method is validated by four kinds of materials, and the results show that the proposed method can predict the failure plane and fatigue life under the multi-axial amplitude-varying load.

Description

technical field [0001] The invention relates to the technical field of multiaxial fatigue strength theory, in particular to a multiaxial fatigue life prediction method based on a weighted average maximum shear strain amplitude plane. Background technique [0002] Fatigue fracture is the main cause of failure of many mechanical structures and engineering components, and many mechanical components such as crankshafts, engines, pressure vessels and turbine rotors are subjected to complex multi-axis variable amplitude loads, or complex single-axis, multi-axis ratio, Multi-axis non-proportional interactive cyclic load action. The classic uniaxial fatigue strength theory is far from meeting the design requirements of strength and life of actual engineering components. Therefore, in recent years, the fatigue field has generally paid more attention to the more realistic multiaxial fatigue research. [0003] Compared with uniaxial fatigue, multiaxial fatigue is more complex in terms...

AI Technical Summary

Problems solved by technology

Although some progress has been made in the research of multiaxial constant amplitude fatigue life prediction methods, there is still no suitable method for dealing with multiaxial complex loads, so that the existing research results cannot be applied to actual engineering.

Images