Affiliation of Author(s):民航学院

Journal:JOURNAL OF AEROSPACE ENGINEERING

Key Words:Ceramic-matrix composites (CMCs) Airworthiness Fatigue Damage evolution Life prediction Hysteresis loops Fiber fracture

Abstract:In this paper, damage monitoring and fatigue-life prediction of cross-ply silicon carbide fiber-reinforced calcium aluminosilicate (SiC/CAS) ceramic-matrix composites (CMCs) at room temperature and elevated temperatures of 700 and 850 degrees C in an air atmosphere have been investigated. Considering the fatigue-damage mechanisms of interface wear, interface oxidation, and fiber oxidation, the relationships among fatigue hysteresis-loop evolution, interface shear-stress degradation, broken fibers, and fatigue lifetime have been established. The evolution of damage parameters, i.e., fatigue hysteresis dissipated-energy changing rate, interface shear-stress degradation rate, broken-fiber fraction, and fatigue-life stress-cycle (S-N) curves have been analyzed. The interface shear-stress degradation rate is affected by the maximum stress level and testing environment; the fatigue hysteresis dissipated energy decreases with the applied increment cycles and experimental temperatures. The fatigue limit stresses are 50, 36, and 30% of tensile strength at room temperature and 700 and 850 degrees C, respectively. (C) 2017 American Society of Civil Engineers.

ISSN No.:0893-1321

Translation or Not:no

Date of Publication:2018-01-01

Correspondence Author:llb