Effect of non-uniform stress characteristics on stress measurement in specimen

• Published in: Transactions of Nonferrous Metals Society of China Vol. 20; no. 5; pp. 789 - 794
• Main Author: 廖凯 吴运新 龚海 闫鹏飞 郭俊康
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2010; School of Mechanical and Electronic Engineering, Central South University, Changsha 410083, China; Practice and Experiment Station, Guilin University of Electrical Technology, Guilin 541004, China%School of Mechanical and Electronic Engineering, Central South University, Changsha 410083, China
• Subjects: aluminum alloy plate; Deviation; Electric discharge machining; layer removal method (LRM); non-uniform characteristic; Parallelograms; Simulation; specimen; Stress concentration; Stress distribution; Stress measurement; X-rays; 不规则形状; 实验分析; 平行四边形; 应力分布; 应力测量; 应力特征; 非均匀; aluminum alloy plate; non-uniform characteristic; stress distribution; layer removal method (LRM); specimen
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(09)60215-6

There is a remarkable difference in stress distribution between a specimen and a plate removed from the specimen.The plate presents a uniform stress distribution whereas the specimen presents a non-uniform stress distribution.Firstly,the real stress distributions in plates with thickness of 30,40 and 50 mm and then in the specimens were obtained through simulation and X-ray surface stress measurement.Secondly,in order to study the impact of specimens shapes and processing ways on the results accuracy,two irregular shapes （parallelogram and trapezoid） and two processing ways （saw and electron discharge machining （EDM）） were compared and analyzed by simulation and experiment using layer removal method,then the specimen effects on measurement results were evaluated.The results show that：1） the non-uniform stress distribution characteristics of the specimen near the surface of the cut is significant,the range of non-uniform stress distribution is approximately one-thickness distance away from the cut,and it decreases gradually along the depth;2） In order to ensure the stability in the results,it is suitable to take the specimen plane size 2-3 times of its thickness;3） Conventional processing methods have little effect on experimental results and the average deviation is less than 5%.