MODIFICATION OF LEAK BEFORE BREAK CRITERION WITH FOCUS ON THE RESIDUAL STRESS

摘要

The article deals with the study of the conditions of breach of pressure vessels and determination of the safety of use of the modified criteria of Leak Before Break when a residual stress is found in the material of a vessel. Design criterion is based on a critical crack length, which must be less than the thickness of the vessel wall. In this case it is guaranteed that there will not be an uncontrolled breach of the vessel. Superposition of residual stress, which occurs in the production of a vessel by impact extrusion, and the hoop stress caused by the internal pressure significantly affects the life and conditions of technical use. Size and character of the distribution of residual stresses were determined experimentally by use of the hole-drilling method. The numerical simulation and mathematical calculations used ANSYS and MATLAB software. The main attention was focused on the application of residual stress in the numerical analysis, based on values obtained by the experimental measurements hole-drilling method.