An investigation on the bending straightening process of D-type cross section shaft

Abstract

D-type cross section shaft is widely used in many industrial fields. As a crucial factor, the shaft straightness has potential significant impact on its working performance, thus the bending straightening process becomes an essential correction step in shaft manufacturing. With a piecewise linearized elastic-plastic stress-strain relation, the bending straightening process of both side-cut and flat-cut D-type cross section shaft is modeled and deduced as a straightening prediction model. The prediction model can provide an accurate and practical relation between the straightening press curvature and the initial bending curvature. For the straightening process simulation, systematic D-type shaft stress and deformation models are built by using classic principle of material mechanics. Three-point parabola method and parabolic fitting method are both proposed for the curvature conversion in the straightening process. To verify the theoretical straightening prediction model, some specialized D-type shaft specimens are designed and manufactured, and a parameter calibration method of straightening prediction model is proposed. Finally, experimental research and comparison analysis are carried out to verify the correctness and feasibility of the straightening prediction model, and a straightening process flowchart is presented as an application guideline of current models and methods.