Novel conductive-heating system for isothermal tensile testing of sheet metals at variable strain rates

Abstract

Accurate characterization of the temperature- and strain-rate-dependent mechanical behavior of sheet metals is essential for the design and crashworthiness assessment of automotive sheet metals. Conventional high-temperature tensile testing methods, such as thermal chambers, are limited by slow heating rates, restricted temperature ranges, difficult specimen replacement, and limited optical access. This study presents a novel conductive-heating system that enables rapid, uniform, and controlled heating of sheet metal specimens for both quasi-static and dynamic tensile testing. The system is validated by evaluating the deviation between target and actual specimen temperatures, the temperature uniformity across the gauge section, and the heating rate. Its applicability is demonstrated through tensile tests on an advanced high-strength steel DP1000 at temperatures from room temperature to 400 °C and at strain rates of 0.001, 0.1, and 10 s ⁻¹ . The results show that the proposed system provides reliable and repeatable temperature control, allows straightforward integration with optical measurement techniques such as digital image correlation, and captures key thermal effects, including thermal softening and dynamic strain aging. The developed system provides a robust experimental platform for investigating the coupled effects of temperature and strain rate in sheet metals, supporting more accurate constitutive modeling and crashworthiness predictions.