3D Stress Distribution Analysis around Blind-holes in Thin Plates Under Non-uniform Tension Loads

A three-dimensional photo elasticity analysis and an interactive finite-element package were used in parallel to analyze the stress distribution on the root of blind-holes in thin plates. Experimental analysis was conducted via stress freezing method. The FEM analysis was performed with the ABAQUS commercial code using material properties obtained experimentally as input. The results showed that the maximum stress distribution occurred in three zones: the first one at the beginning of the blind-hole; the second one at the transition zone where the root begins his shape; and at the center of the root.These results are expected to improve blind-hole design according to its function. The combined use of experimental and numerical methods provides more information than each method taken alone. This information is essential when the relation between depth and thickness has to be taken into account. As shown here, the stresses near the free boundary are relevant for failure considerations, for example due to the presence of debris in thin plates or sheets. An analog statement can be made for blind-holes made to fasten metal sheets with bolts or hollows for human prosthesis. KEY WORDSBlind-hole, stress-freezing method, FEM, photoelasticity, stress concentration.