Experimental verification of optimal strain gage locations for the accurate determination of stress intensity factors

摘要

In the present investigation experimental verification of optimal strain gage locations and their importance in accurate determination of mode I stress intensity factors (SIFs) using Dally and Sanford's single strain gage technique (DS technique) has been carried out.The results of the present experimental study are also used to substantiate the efficacy of the methodology for determination of maximum permissible strain gage radial location proposed earlier by the same authors for locating the optimal strain gage locations.Experiments have been conducted using an edge cracked plate made of Polymethylmethacrylate.Results clearly demonstrate that very accurate values of mode I SIFs can be determined if the strain gages are placed at the optimal locations.On the other hand,the experimental results also show that the mode I SIFs obtained using strain gages placed at non-optimal locations contain significant and unacceptable errors.The results of the present investigation clearly confirm the importance of knowing the maximum permissible strain gage radial location corresponding to an experimental specimen before conducting experiment for determination of mode I SIF using the DS strain gage technique.