Fracture mechanism and failure criterion of S-07 steel for liquid rocket engine

Abstract

Purpose

The fracture mechanism of S-07 steel was investigated by observing the fracture surface of the specimens with scanning electron microscope (SEM). Furthermore, the overall elastic–plastic behaviors and the stress state evolution during the loading procedure of all specimens were simulated by FE analysis to obtain the local strain at crack nucleated location and the average triaxiality of each type of specimen.

Design/methodology/approach

Three types of tests under various stress states were performed to study the ductile fracture characteristics of S-07 high strength steel in quasi-static condition.

Findings

Under tensile and torsion loading conditions, S-07 steel exhibits two distinctive rupture mechanisms: the growth and internal necking of voids governs the rupture mechanism in tension dominated loading mode, while the change of void shape and internal shearing in the ligaments between voids dominants for shear conditions.

Originality/value

The failure criterion for S-07 steel considering the influence of the triaxial stress state was established.

Citation

Gao, Y., Jiang, W. and Huo, S. (2023), "Fracture mechanism and failure criterion of S-07 steel for liquid rocket engine", Multidiscipline Modeling in Materials and Structures, Vol. 19 No. 3, pp. 389-404. https://doi.org/10.1108/MMMS-11-2022-0257