Investigation of Optimum Stress Concentration Factor for Shoulder Fillet in Round Bar under Different Loading Conditions

Abstract

The focus of this study is to investigate the optimal fillet radius of shoulder fillet in round bar which gives minimum stress concentration factor under different loading conditions i.e. torsional, bending and axial. Peterson’s curves were developed based on experimental work and analytical work carried out by number of researchers in the past. In that curves it is stated that the r/d ratios in the curves were taken from the specimens used by researchers in the past to do experimental work and but no clear guidelines stated about this r/d ratio. In this present work, effort is made to obtain a relation between fillet radius (r) and stress concentration factor ( ) by varying the values of stress concentration factor. In this reverse method the D/d ratio is known and value of stress concentration factor is varied as per Peterson’s curve. By these known values of D/d ratios and stress concentration factor various fillet radius is find out. New equations of fillet radius were developed which gives a relationship between fillet radius (r) and stress concentration factor ( ). The outcome of the present study shows that the minimum stress concentration factor found where the fillet radius (r) is equal to fillet height (h). At last the stress concentration factors for various D/d ratios are provided in a graphical way so the design process becomes easy.