曲げ荷重を受ける段付き平板・丸棒のすみクラックに対する応力拡大係数

抄録

The mixed mode stress intensity factors for the corner cracks of stepped plate and round bar subjected to bending load are evaluated by means of photoelastic experiment. The stepped plate models are made by machining the epoxy resin plate. The stepped round bar models are completed by machining the epoxy resin round bar without step using a turning machine. The cracks with systematically varied form factors are machined with the diamond disk saw at the corner of steps. The plate models are loaded by pure in-plane bending, and the round bar models are loaded by means of the apparatus made to give pure bending in electric furnace.
The isochromatic fringe patterns are taken by a CCD camera, and recorded in the magneto optical disk. From the thinning images of them obtained by utilizing the image processing analyzer, the required data are collected for the following analysis, and the mixed mode stress intensity factors are estimated by personal computer using the program based on the over-deterministic methodh.
The obtained mixed mode stress intensity factors and the effective stress intensity factors are summarized in lots of diagrams shown as the behavior depending on the form factors of models.