STP1559

    Fatigue Crack Initiation in Superelastic Nitinol

    Published: Sep 2013


      Format Pages Price  
    PDF Version (8.0M) 18 $25   ADD TO CART
    Complete Source PDF (45M) 18 $60   ADD TO CART


    Abstract

    Phase shifted moiré interferometry is used to study fatigue initiation in superelastic Nitinol. Notched four-point bend coupon samples were fatigue tested according to a multi-level amplitude test protocol tailored for medical implant applications. Fringe patterns of local strain measurements are presented for three loading sequences based on the type of loading and range of anticipated strains in service. The effect of an initial series of pre-load cycles is examined and resulting life data is accompanied by local strain results highlighting the unique mechanisms associated with the initiation of fatigue cracks and the development of effective test methods and protocols.

    Keywords:

    nitinol, fatigue, crack, initiation, local, strain, gradient, phase transformation, multiaxial, constraint, plasticity, mean stress, dynamic, moiré interferometry


    Author Information:

    Perry, Kenneth E.
    ECHOBIO LLC, Bainbridge Island, WA

    Teiche, Alex
    ECHOBIO LLC, Bainbridge Island, WA

    Perry, Kenneth E.
    ECHOBIO LLC, Bainbridge Island, WA

    Teiche, Alex
    ECHOBIO LLC, Bainbridge Island, WA


    Paper ID: STP155920130030

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP155920130030


    CrossRef ASTM International is a member of CrossRef.