Volume 32, Issue 3 (May 2004)
Stress Concentration Factor Formulas Useful for Any Dimensions of Shoulder Fillet in a Flat Test Specimen Under Tension and Bending
In this work stress concentration factors Kt for a flat bar with fillets are considered on the basis of exact solutions now available for special cases and accurate numerical results. Then, a convenient Kt formula useful for any dimensions of the fillet is proposed. The conclusions can be summarized as follows.
1. For the limiting cases of deep (d) and shallow (s) fillets, the body force method is used to calculate the Kt values. Then, the formulas are obtained as Ktd and Kts.
2. On the one hand, upon comparison of Kt and Ktd, it is found that Kt is nearly equal to Ktd if the fillet is deep or blunt.
3. On the other hand, if the fillet is sharp or shallow, Kt is controlled mainly by Kts and the fillet depth.
4. The fillet shape is classified into several groups according to the fillet radius and fillet depth. Then, the least-squares method is applied for calculation of Kt/Ktd and Kt/Kts.
5. Finally, convenient formulas are proposed that are useful for any dimensions of fillet in a flat bar. The formulas give SCFs with less than about 1 % error in most cases for any dimensions of fillet under tension and bending.