Finite element analysis of fracture statistics of ceramics: Effects of grain size and pore size distributions

Abstract

A novel numerical simulation method based on finite element analysis (FEA), which can evaluate the fracture probability caused by the characteristics of flaw distribution, is considered an effective tool to facilitate and increase the use of ceramics in components and members. In this study, we propose an FEA methodology to predict the scatter of ceramic strength. Specifically, the data on the microstructure distribution (i.e., relative density, size and aspect ratio of pore, and grain size) are taken as the input values and reflected onto the parameters of a continuum damage model via a fracture mechanical model based on the circumferential circular crack emanating from an oval spherical pore. In addition, we numerically create a Weibull distribution based on multiple FEA results of a three‐point bending test. Its validity is confirmed by a quantitative comparison with the actual test results. The results suggest that the proposed FEA methodology can be applied to the analysis of the fracture probability of ceramics.

Self-healing by design: universal kinetic model of strength recovery in self-healing ceramics

“…Using Equations (11) and (12), the total V h under both isothermal and nonisothermal oxidations can be estimated, as implemented in our calculations. Equation (11) will be useful in future computational simulations for describing damage and healing behaviors, e.g., using the finite element method [51][52][53][54].…”

“…Further, the σ o U and σ o L values for specimens without surface flaws were defined for use in our calculations and are listed in Table 2. These values can be estimated using recent FEA based on the distributions of the pore size and grain size under various stress conditions [52].…”

“…To model the crack-gap filling behavior, the crack geometry, notably, V g (Equation 3) and the area of one side of the fracture surface A (Equation 7), must be evaluated. In general, both values are estimated using FEA based on the material properties and various damage conditions [51][52][53][54]. Many studies have experimentally evaluated the self-healing behavior of a Vickers crack [17,56].…”

Finite element analysis of the fracture statistics of self-healing ceramics

“…In this study, we propose a finite element analysis (FEA) method for fracture statistics of self-healing ceramics by combining a numerical simulation of the damage-healing process with the prediction method of scatter of ceramic strength proposed by the authors [36,37]. Concretely, we conducted the following investigation:…”

“…In addition to this examination, a qualitative comparison of the experimental results [15] was performed to demonstrate the effectiveness of the method used for the analyses of fracture statistics of self-healing ceramics. It should be noted that the ceramics we examined were Al 2 O 3 /15 vol% SiC, which were also used in previous studies [15,36,37]. The processing defects on their surfaces were repaired in advance through heat treatment.…”