Dynamic Stress Intensity Factors for Unsymmetric Dynamic Isochromatics

摘要

The mixed mode, near-field state of stresses surrounding a crack propagating at constant velocity is used to derive a relation between the dynamic stress intensity factors K sub I, K sub II, the remote stress component sigma sub ox and the dynamic isochromatics. This relation together with an overdeterministic least-square method from the basis of a data reduction procedure for extracting dynamic K sub I, K sub II, and sigma sub ox from the recorded dynamic photoelastic pattern surrounding a running crack. The overdeterministic least-square method is also used to fit static isochromatics to the numerically generated dynamic isochromatics. The resultant static K sub I, K sub II, and sigma sub ox are compared with the corresponding dynamic values and estimates of errors involved in using static analysis to process dynamic isochromatic data are obtained. The data reduction procedure is then used to evaluate the branching stress intensity factor associated with crack branching and the mixed mode stress intensity factors associated with crack curving. (Author)