An Evaluation of a Load-Line Extensometer for Elastic-Plastic Fracture Toughness Testing

Abstract

A load-line extensometer using linear variable differential transformer (LVDT) displacement transducers was developed and evaluated for use in multispecimen and single specimen J value versus crack growth (J-R) curve testing. The LVDT extensometer accuracy and repeatability was compared with that of clip gage extensometers commonly used in fracture toughness evaluatons. Data on load versus displacement and J value versus crack growth for ASTM A533, Grade B, Class 1 (Unified Numbering System [UNS] K12539) steel obtained by using both extensometers were also compared.