Damage, Fracture, and Fatigue of Ceramic-Matrix Composites

The effect of matrix cracking on hysteresis behavior of cross-ply ceramic matrix composites is investigated in the present analysis. The cracking of cross-ply ceramic composites was classified into five modes, where cracking mode 3 and mode 5 involve matrix cracking and fiber/matrix interface debonding in 0° ply. The matrix crack space and interface debonded length are obtained by matrix statistical cracking model and fracture mechanics interface debonding criterion. Based on the damage mechanisms of fiber sliding relative to matrix in the interface debonded region, the unloading interface reverse slip length and reloading interface new slip length of cracking mode 3 and mode 5 are determined by the fracture mechanics approach. The hysteresis loops of four different cases for cracking mode 3 and mode 5 are derived respectively. The hysteresis loss energy as a function of interface shear stress of mode 3 and mode 5 are analyzed. The theoretical results have been compared with experimental data of two diffe...

Effect of matrix cracking on hysteresis behavior of cross-ply ceramic matrix composites

This study concerns the development of a combined experimental and analytical technique to determine the critical values of fracture parameters for interfaces between dissimilar materials in electronic packages. This technique utilizes specimens from post-production electronic packages. The mechanical testing is performed inside a scanning electron microscope while the measurements are achieved by means of digital image correlation. The measured displacements around the crack tip are used as the boundary conditions for the analytical model to compute the energy release rate. The critical energy release rate values obtained from post-production package specimens are obtained to be lower than those laboratory specimens.

A combined experimental and analytical approach for interface fracture parameters of dissimilar materials in electronic packages

When fiber-reinforced ceramic-matrix composites (CMCs) are first loading to fatigue peak stress, matrix multicracking and fiber/matrix interface debonding occur. Under fatigue loading, the stress–s...

http://journals.sagepub.com/doi/pdf/10.1177/0021998314566055

Micromechanics modeling of fatigue hysteresis loops in carbon fiber-reinforced ceramic-matrix composites

Under fatigue loading of fiber-reinforced ceramic–matrix composites (CMCs), fiber slipping relative to matrix in the interface debonded region upon unloading/reloading is the mainly fatigue damage mechanism. The shape, location and area of fatigue hysteresis loops would change with degradation of the interface shear stress for interface wear or interface oxidation. Based on the fatigue damage mechanism of interface frictional slip between fiber and matrix, the micromechanics fatigue hysteresis loops models corresponding to four different interface slip cases have been developed, in which the unloading interface counter-slip length and reloading interface new-slip length were determined by fracture mechanics approach. The fatigue hysteresis loss energy, fatigue hysteresis loops and interface slip of unidirectional, cross-ply and woven CMCs are formulated in terms of the interface shear stress. With decrease of the interface shear stress, the fatigue hysteresis loss energy increases to the maximum value first, and then decreases to 0; the fatigue hysteresis loops correspond to different interface slip cases. The effects of the fiber volume fraction, fatigue peak stress, fatigue stress amplitude, matrix crack spacing and matrix cracking mode on the fatigue hysteresis loss energy evolution with decrease of the interface shear stress have been analyzed. The range and extent of the interface frictional slip between fiber and matrix during fatigue loading would be decreased with increase of the fiber volume fraction and matrix crack spacing, increased with increase of the fatigue peak stress and fatigue stress amplitude, and greatly affected by matrix cracking mode in cross-ply CMCs.

Micromechanical modeling of fatigue hysteresis behavior in carbon fiber-reinforced ceramic–matrix composites. Part I: Theoretical analysis

Matrix crack evolution was studied for SiC fiber-reinforced glass-matrix cross-ply laminates. A novel in situ SEM (scanning electron microscope) observation was conducted to measure the fiber/matrix debonding and sliding in 0° plies using specimens with parallel micro-lines printed on the surfaces. Interfacial debondings were found to grow intermittently as the applied stress increased. The debonding length distribution depends on the number of 90° plies as well as the type of damage modes. An analytical model for the matrix crack evolution was proposed using the energy balance calculation based on Kuo and Chou (Kuo WS, Chou TW. Multiple cracking of unidirectinal and cross-ply ceramic matrix composites. J Am Ceram Soc 1995;78(3):745–755), with the modification of including the effects of damage mode interaction as well as Poisson contraction in the debonded regions. The predicted evolution agrees well with the experimental one.

Manami Kiriyama

Papers

Matrix crack evolution in SiC fiber/glass matrix cross-ply laminates