ANALYSIS OF CONTACT OF A RIGID SPHERE AGAINST A DEFORMABLE FLAT

Abstract

In the paper the strain hardening effect on the contact of a rigid ball and elastic-plastic flat is considered using experiments and finite element method. The experiments were carried out for DC04 steel sheet metal. The flat samples of 20 mm width and 200 mm length were straightened using uniaxial tensile test to receive different strain values: 5, 10, 15, 20, 25 and 30%. The indentation tests were performed using a modified Zwick Roell Z030 operated in the compression mode. The diameter of bearing steel indenter was 6 mm. It was found that the strain hardening phenomenon and anisotropy of material have a great influence on the ball indentation value and the maximal indentation force. The linear dependence between the normal load and penetration depth was observed. Furthermore, it was found that the value of penetration depth for specific force value decreases non-linearly with the increase of sample strain. Pre-strained samples cut transverse to the rolling direction exhibit higher deformation resistance than samples cut along the rolling direction. The springback analysis in ABAQUS was executed for studying the actual indentation depth after the indenter is unloaded.