Sectional Area for Calculation of Deformation in Screw Thread

Abstract

The elastic behavior of screw thread has been studied by tensile test on the screw thread of M6-M20×1.5, and by Finite Element Method. Elastically equivalent cylinder's cross sectional areas of threaded bar approximately coincide with experimental and calculated values. Both values are small compared to the usual value called stress area, which is used to estimate the tensile strength of the screw thread. Then a new equivalent cross sectional area is proposed expressing the relation between load and elongation in the screw thread, and an empirical equation is obtained that the equivalent area of the screw thread is considered to be a function of the ratio of pitch to major diameter on the external thread.