Reliability-based failure analysis of brittle materials

The reliability of brittle materials under a generalized state of stress is analyzed using the Batdorf model. The model is modified to include the reduction in shear due to the effect of the compressive stress on the microscopic crack faces. The combined effect of both surface and volume flaws is included. Due to the nature of fracture of brittle materials under compressive loading, the component is modeled as a series system in order to establish bounds on the probability of failure. A computer program was written to determine the probability of failure employing data from a finite element analysis. The analysis showed that for tensile loading a single crack will be the cause of total failure but under compressive loading a series of microscopic cracks must join together to form a dominant crack

Reliability based analysis of contact problems

The Batdorf model is modified to include the reduction in shear due to the effect of compressive stresses on the crack face. This new formulation was used to obtain the probability of failure of ceramic components under contact stress conditions. The combined effect of the surface and volume flaws are included in the analysis. Due to the nature of the fracture of brittle materials under compressive loading, the component is modeled as a series system in order to establish bounds on the probability of failure

Reliability analysis of structural ceramic components using a three-parameter Weibull distribution

Described here are nonlinear regression estimators for the three-Weibull distribution. Issues relating to the bias and invariance associated with these estimators are examined numerically using Monte Carlo simulation methods. The estimators were used to extract parameters from sintered silicon nitride failure data. A reliability analysis was performed on a turbopump blade utilizing the three-parameter Weibull distribution and the estimates from the sintered silicon nitride data

Repeated Reading to Improve Oral Reading Fluency

The focus of this project was to review the available research on repeated reading as a method of improving a student\u27s oral reading fluency (ORF), to determine its contribution to the reading process, and to create an implementation guide for middle school teachers to use in their language arts classroom. The results of the research show that there is a need for effective repeated reading instruction. Including this instruction at the middle school level will provide tremendous benefits for students. Repeated reading is an effective way to expose students to short, interesting, fictional and non-fictional texts. The project includes a teacher\u27s guide with directions for effective repeated reading instruction and a step-by-step process to implement the format

Ceramic component reliability with the restructured NASA/CARES computer program

The Ceramics Analysis and Reliability Evaluation of Structures (CARES) integrated design program on statistical fast fracture reliability and monolithic ceramic components is enhanced to include the use of a neutral data base, two-dimensional modeling, and variable problem size. The data base allows for the efficient transfer of element stresses, temperatures, and volumes/areas from the finite element output to the reliability analysis program. Elements are divided to insure a direct correspondence between the subelements and the Gaussian integration points. Two-dimensional modeling is accomplished by assessing the volume flaw reliability with shell elements. To demonstrate the improvements in the algorithm, example problems are selected from a round-robin conducted by WELFEP (WEakest Link failure probability prediction by Finite Element Postprocessors)

Phillip Dean Powers and Gary Lynn Corker in a Joint Senior Recital

This is the program for the joint senior recital of tenor Phillip Dean Powers and baritone Gary Lynn Corker. Pianist Mary Worthen accompanied Powers; pianist and harpsichord player Brad Hunnicutt and celloist Alex Nisbet accompanied Corker. The recital took place on April 1, 1982, in the Mabee Fine Arts Center Recital Hall

Reliability Analysis of Structural Ceramic Components Using a Three-parameter Weibull Distribution

This paper describes nonlinear regression estimators for the three-parameter Weibull distribution. Issues relating to the bias and invariance associated with these estimators are examined numerically using Monte Carlo simulation methods. The estimators were used to extract parameters from sintered silicon nitride failure data. A reliability analysis was performed on a turbopump blade utilizing the three-parameter Weibull distribution and the estimates from the sintered silicon nitride data