Study on Feasibility and Accuracy of Stress Test

Abstract

In practice, surface residual stress test methods mainly contain the traditional semi-destructive central blind-hole method and the emerging non-destructive X-ray diffraction technology. The two methods process different measuring principle, which indirectly reflect material elastic deformation in macroscopic and microscopic fields respectively. Generally, comparative study of the feasibility of stress test scheme and accuracy of the measurements should be implemented experimentally. Surface residual stress levels and distributions of quenched high-strength aluminum alloy plate, shot-peened specimens and welded steel plate were tested by contrast using the two methods in this paper. The results show that both of the two surface stress measurement methods are effective and correct in most cases. But center blind-hole method is not suitable in measuring the gradient distribution with large stress gradient while X-ray method would be much affected by surface treatments and material microscopic inhomogeneity despite its capable of reflecting local details of the stress distribution. In engineering applications, proper test methods should be chosen according to the level and distribution of initial stresses. In addition, several methods are suggested to apply comparatively if conditions permitted.