STP1253: Prediction of Matrix Fatigue Crack Initiation from Notches in Titanium Matrix Composites

    Herrmann, DJ
    Graduate student, graduate student, graduate student, and professor, School of Mechanical Engineering, Purdue University, West Lafayette, IN

    Ward, GT
    Graduate student, graduate student, graduate student, and professor, School of Mechanical Engineering, Purdue University, West Lafayette, IN

    Lawson, EJ
    Graduate student, graduate student, graduate student, and professor, School of Mechanical Engineering, Purdue University, West Lafayette, IN

    Hillberry, BM
    Graduate student, graduate student, graduate student, and professor, School of Mechanical Engineering, Purdue University, West Lafayette, IN

    Pages: 18    Published: Jan 1996


    Abstract

    Fatigue crack initiation from notches in titanium matrix composites (TMCs) is of interest in the design of TMC structures. A model is presented for predicting the fatigue crack initiation life of longitudinal, transverse, and symmetric cross-ply laminates using the strain-life behavior of the matrix material. The effective strain parameter, Δεeff, proposed by Hillberry and Johnson is used to account for the residual stress state imposed during composite processing. Since the effective strain parameter requires knowledge of the local residual and applied strain in the matrix, methods for calculating these strains are developed. Model predictions were verified with crack initiation tests of [0]4, [90]4, and [0/90]s SCS-6/TIMETAL 21S center-hole specimens at room temperature and [04/¯90]s SCS-6/Ti-15-3 center-hole specimens at 300 and 550°C.

    Keywords:

    fatigue (materials), titanium matrix composites, silicon-carbide fibers, notches, crack initiation, titanium, life prediction, titanium alloys, modeling


    Paper ID: STP18231S

    Committee/Subcommittee: D30.04

    DOI: 10.1520/STP18231S


    CrossRef ASTM International is a member of CrossRef.