Stress Concentration Factors For Intersecting Arrays of Notches In Beams Under Pure Bending

Abstract

Three-dimensional frozen-stress photoelasticity was used to study two rectangular beams under pure bending loading. Regular, orthogonal arrays of different shallow notches were cut in the top and bottom surfaces, aligned at 0°/90° and also at ± 45° to the applied stress direction. The s.c.f. K_n defined as the maximum stress/nominal stress at the roots of the notches, was measured and compared with previous 2D results for multiple notches. The results for the V-notch profile Type A showed that K_n = 2.4 when the array was orientated at 90° to the applied stress, but the s.c.f. reduced to K_n = 1.6 when at ± 45° (as it was on the implanted hip stems and bone plate orthopaedic devices). Prototype profiles Types B and C at ± 45° had only slightly lower K_n = 1.4.