Effects of anisotropy and pre-strain on the shear fatigue behaviour of DP600 steel

Abstract

The effects of anisotropy and pre-strain on the low-cycle-fatigue properties of DP600 steel sheet under shear path were investigated. Fully reversed strain-controlled fatigue tests were performed along the 0° and 90° directions with the initial strain direction. The cyclic-loading amplitude determined whether the pre-strained material had a hardening process. The high dislocation density in the crystals of pre-strained material can promote the formation of low-energy substructures, obviously accelerating the cyclic-softening rate and reducing the fatigue life. Average plastic strain energy density was affected by the pre-straining state and loading direction and had a linear relationship with the strain amplitude. Overall, these results can be used to verify the calculation model of structural parts.

KEYWORDS:

• Dual-phase steel
• pre-straining
• shear path
• low cycle fatigue
• nonproportional loading

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant numbers 51975327 and 51605257]; and the Future Plan Project for Young Scholars of Shandong University [grant number 2017WHWLJH06].