STP1508

    In-situ Fatigue Damage Investigations in Welded Metallic Components by Infrared Techniques

    Published: Jan 2009


      Format Pages Price  
    PDF Version (5.4M) 24 $25   ADD TO CART
    Complete Source PDF (236M) 24 $139   ADD TO CART


    Abstract

    The paper reviews the state of the art of thermal damage assessment in metals and proposes a specialized form of lock-in thermography as an efficient tool for the quantification of early fatigue damage phenomena in welded steel structures in the regime of mid- to high-cycle fatigue. It can be proved that advanced thermographic techniques are sensitive to early damage phenomena in the weld toe. They provide a new experimental mean for in-situ investigation of early inhomogeneous fatigue damage phenomena as mesoplasticity and fatigue cracks. The results demonstrate that noncontacting full field temperature measurements using highly sensitive infrared technology can be applied successfully to detect localized fatigue damage at around 10 % to 20 % of the total fatigue lifetime of the tested specimens. The applied method is based on the separation of thermoelastic and thermoplastic temperature effects which cause characteristic local temperature signatures. In contrast to other well-known approaches—as, e.g., measuring the rise of mean temperature during fatigue loading—the applied method offers a very high spatial resolution and resolves extremely localized phenomena. The methodology can be applied to monitor the fatigue process during conventional fatigue testing. The additional effort for the specimen preparation and the installation of the testing setup is minimal.

    Keywords:

    Fatigue damage, fatigue crack, crack initiation, thermography


    Author Information:

    Medgenberg, Justus
    Technische Universitaet Carolo-Wilhelmina, Braunschweig,

    Ummenhofer, Thomas
    Technische Universitaet Carolo-Wilhelmina, Braunschweig,


    Paper ID: STP48793S

    Committee/Subcommittee: E08.03

    DOI: 10.1520/STP48793S


    CrossRef ASTM International is a member of CrossRef.