An Enhanced Method to Evaluate Tensile Yield Stress by Small Punch Tests Using Deflection Curves

Betül Gülçimen Çakan; Peter Hähner; Celal Soyarslan; Swantje Bargmann

doi:10.3390/ma13122840

An Enhanced Method to Evaluate Tensile Yield Stress by Small Punch Tests Using Deflection Curves

Materials (Basel). 2020 Jun 24;13(12):2840. doi: 10.3390/ma13122840.

Authors

Betül Gülçimen Çakan¹, Peter Hähner², Celal Soyarslan³, Swantje Bargmann³

Affiliations

¹ Department of Mechanical Engineering, Bursa Uludağ University, Görükle, 16059 Bursa, Turkey.
² Nuclear Safety and Security Directorate, Joint Research Centre, European Commission, NL-1755 LE Petten, The Netherlands.
³ School of Mechanical Engineering and Safety Engineering, University of Wuppertal, 42119 Wuppertal, Germany.

Abstract

While force-displacement curves are often preferred in Small Punch (SP) tests due to the ease of the experimental set-up, they encompass significant uncertainties arising from frame compliance. In this work, a methodology is presented to predict yield stresses from the force vs. deflection curves. The present method relies on determining different force levels from the initial part of the force-deflection curve to reflect both the slope and the curvature instead of using a single force level only. The predicted yield stresses for different types of materials, that is, low- and high-strength alloys, are found to be in good agreement with the actual proof stresses with a maximum error of 16%.

Keywords: deflection; finite element method; small punch test; yield stress.