Affiliation of Author(s):民航学院

Journal:JOURNAL OF AEROSPACE ENGINEERING

Key Words:Ceramic-matrix composites (CMCs) Damage evolution Multiple loading stress levels Hysteresis loops Matrix cracking Interface shear stress

Abstract:In this paper, the multiple-step loading damage evolution in two-dimensional (2D) SiC/SiC ceramic-matrix composites (CMCs) at room and elevated temperatures and subjected to different applied cycle numbers was investigated. The unloading/reloading fiber axial stress distributions were analyzed, considering different fiber-matrix interface damage regions. The interface debonding and slip lengths upon unloading/reloading were obtained, considering the coupling effects of multiple loading stress levels and interface damage. The relationships between the hysteresis loops, interface debonding and sliding, and different loading sequences were established. Comparisons of damage evolution between constant and variable fiber-matrix interface shear stress, constant peak stress with cycle loading and multiple loading, and low-high multiple loading and high-low multiple loading sequences were conducted. The experimental cyclic multiple loading/unloading stress-strain hysteresis loops and fiber-matrix interface slip lengths of 2D SiC/SiC composites were predicted for different testing temperatures and applied cycles. The effects of temperature on the fiber-matrix interactions and the evolution of interfacial shear stress and the effect of cyclic loading number on the multiple-step loading damage evolution of two different SiC/SiC composites are discussed. With increasing temperature and applied cycle number, the area of the hysteresis loops and the interface debonding/sliding lengths subjected to multiple loading stress levels increase. (C) 2018 American Society of Civil Engineers.

ISSN No.:0893-1321

Translation or Not:no

Date of Publication:2019-01-01

Correspondence Author:llb