Effect of Increments Quantity on Determination of Residual Stresses inIncremental Hole Drilling Technique

Experimental determination of residual stresses in thin sheets has been implemented by hole drilling method. The incremental hole drilling technique is suggested as an acceptable technique for determination of residual stress variation in thickness. In the present research, basic formulations of converting experimentally measured strains into residual stress profiles have been studied. The number of increments in drilling process affects the results. Two different set of tests have been used for investigating this effect. A unidirectional tension test and a four point bending test are simulated by FEM and the four point bending test (with same condition) is done experimentally. The drilling test has been applied in 10, 20 and 40 increments. Comparison of the experimental and numerical results with analytical result shows that by increasing the increment numbers, higher precision can be obtained and stress profile results will be improved.

Keywords:

Incremental Hole Drilling , Residual Stress , Number of Increments , Non-Uniform Stress Profile