Evaluation of Fracture Toughness Test Data for Multilayer Dissimilar Joint Welds Using a Weibull Stress Model

    Volume 9, Issue 3 (March 2012)

    ISSN: 1546-962X

    CODEN: JAIOAD

    Published Online: 1 March 2012

    Page Count: 15


    Takashima, Yasuhito
    Graduate School of Engineering, Osaka Univ., Osaka,

    Ohata, Mitsuru
    Graduate School of Engineering, Osaka Univ., Osaka,

    Seto, Masaru
    Kawasaki Heavy Industries, Ltd., Kobe,

    Okazaki, Yoshitomi
    Kobe Steel, Ltd., Kobe,

    Minami, Fumiyoshi
    Graduate School of Engineering, Osaka Univ., Osaka,

    (Received 13 May 2011; accepted 6 December 2011)

    Abstract

    Fracture behaviour of welded joints with dissimilar weld metals (WMs) has been investigated in this paper. A low-toughness WM and a high-strength WM with a moderate toughness were layered alternately in the thickness direction. Fracture tests were conducted with 3-point bend (3PB) specimen and tension plate with a through-thickness crack. The 3PB specimen showed a multistage fracture. The first fracture was originated from the low-toughness WM. On the other hand, no multistage fracture occurred in the tension plate, although the low-toughness WM was responsible for brittle fracture initiation in the same manner as in the 3PB specimen. The fracture toughness of the multilayer dissimilar joint was apparently larger than the welded joint made with the low toughness WM only. The weakest-link model has been applied for analyzing those toughness properties of the multilayer dissimilar joint. The estimated fracture toughness by the weakest-link model was not necessarily consistent with the toughness data, which was because of the local stress elevation in the low-toughness WM area close to the high-strength WM. Because of this, a modified Weibull stress model was used to estimate fracture toughness values for the multilayer dissimilar joint WM and to account for an active fracture zone length scale in the multilayer weld joint materials.


    Paper ID: JAI103979

    DOI: 10.1520/JAI103979

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    Title Evaluation of Fracture Toughness Test Data for Multilayer Dissimilar Joint Welds Using a Weibull Stress Model
    Symposium , 0000-00-00
    Committee E08