Accession Number : ADA194875

Title :   An Investigation of Constitutive Models for Predicting Viscoplastic Response during Cyclic Loading.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s) : Shaffer, David A

PDF Url : ADA194875

Report Date : Jun 1988

Pagination or Media Count : 95

Abstract : The Air Force's Engine Structural Integrity Program (ENSIP) (Ref 1) requires determination of damage tolerance for jet engine components in order to allow more economical rejection criteria to be adopted. To this end, means have been developed for predicting fatigue crack growth in jet engine components such as turbine disks made of nickel-based superalloys and operating at elevated temperatures. The presence of time-dependent plastic deformation greatly affects crack propagation rates, particularly at elevated temperatures and thus must be accounted for when modelling crack growth in turbine materials. The purpose of this thesis was to investigate the frequency response aspects of the Bodner-Partom constitutive law's behavior and to compare its results with those of other models and to cyclic and non-cyclic uniaxial tensile test data.

Descriptors :   *CRACK PROPAGATION, *ENGINE COMPONENTS, *FATIGUE(MECHANICS), *JET ENGINES, BASE METAL, CYCLES, DAMAGE, DETERMINATION, FREQUENCY RESPONSE, HIGH TEMPERATURE, LOADS(FORCES), MATERIALS, NICKEL ALLOYS, PLASTIC DEFORMATION, RATES, SUPERALLOYS, TIME DEPENDENCE, TOLERANCE, TURBINE COMPONENTS, TURBINES, THESES

Subject Categories : Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE