A finite element model for asymmetric creep behavior of ceramics

Asymmetric creep responses of ceramics between tension and compression under high temperature were investigated. Multiaxial creep equations were proposed for ceramic materials under general loading conditions. The proposed constitutive equations were implemented into a finite element program (ABAQUS) to simulate asymmetric creep responses of ceramics under complex loading conditions. Finite element calculations were compared with experimental data in the literature for siliconized silicon carbide (Si-SiC) C-rings under compression and alumina and Si-SiC bending specimens under bending creep. Finite element calculations agreed well with experimental data when the principal stresses are smaller than the threshold stress for creep damage. A good agreement was also obtained for damage zone in a Si-SiC bending specimen compared with experimental data.