SCARE: A Postprocessor Program to MSC/NASTRAN for Reliability Analysis of Structural Ceramic Components

Abstract

A computer program is developed for calculating the statistical fast fracture reliability and failure probability of ceramic components. The program includes the two-parameter Weibull material fracture strength distribution model, using the principle of independent action for polyaxial stress states and Batdorf’s shear-sensitive as well as shear-insensitive crack theories, all for volume distributed flaws in macroscopically isotropic solids. Both penny-shaped cracks and Griffith cracks are included in the Batdorf shear-sensitive crack response calculations, using Griffith’s maximum tensile stress or critical coplanar strain energy release rate criteria to predict mixed mode fracture. Weibull material parameters can also be calculated from modulus of rupture bar tests, using the least-squares method with known specimen geometry and fracture data. The reliability prediction analysis uses MSC/NASTRAN stress, temperature, and volume output, obtained from the use of three-dimensional, quadratic, isoparametric, or axisymmetric finite elements. The statistical fast fracture theories employed, along with selected input and output formats and options, are summarized. A sample problem to demonstrate various features of the program is included.

Computer simulation of electro‐thermomechanical interactions of an oxygen sensor during warm‐up

“…Gyekenyesi and Wang (1985) developed the SCARE program to post-process the NASTRAN output to perform statistical reliability analysis for ceramic materials. It would be meaningful to do statistical reliability analysis for the ceramic materials used in fabricating the sensor body, if SCARE is now able to post-process ABAQUS output.…”

Modeling Stress Strain Relationships and Predicting Failure Probabilities For Graphite Core Components

“…The work by Batdorf and Crose (1974) represented the first attempt at extending fracture mechanics to reliability analysis in a consistent and rational manner. Work by Gyekenyesi (1986), Cooper, et al (1986, 1988 and Lamon (1990) are representative of the reliability design philosophy used in analyzing structural components fabricated from monolithic ceramic. Duffy et al (1990aDuffy et al ( , 1990bDuffy et al ( , 1991Duffy et al ( , 1993Duffy et al ( , 1994 presented an array of failure models to predict reliability of ceramic components that have isotropic, transversely isotropic, or orthotropic material symmetry.…”

Design of Ceramic Gas Turbine Components

“…Consequently, the numerical code CERITS was developed to predict the failure probability of ceramics. The code follows a similar strategy to that suggested by Gyekenyesi (1986). With the aid of CERITS the critical areas within a ceramic component can be identified.…”

“…In the case of inhomogeneous stress distribution, the probability of survival for the entire component can be calculated from (Rufin et al, 1984;Gyekenyesi, 1986) Ps=exp { V fv [(vo ) (2) where Qo represents the Weibull scale parameter of the unit volume V. in dimensions of stress, m the Weibull modulus, and V the stressed volume. Eq.…”