13th International Conference on Fracture June 16–21, 2013, Beijing, China -6- 1 F n c m B t (21) To validate the efficiency and effectiveness of the numerical scheme, the proposed method was applied to benchmark examples of Bree problem and a holed plate [6]. In the next session of this paper, two types of weldments subjected to different reverse bending moments with various creep dwell periods are evaluated by the proposed method. 3. Numerical application: welded joints under high temperature–creep fatigue conditions 3.1. Problem Description In this paper, the proposed LMM is applied to evaluate the creep fatigue lifetime of both Type 1 and Type 2 weldments [13] subjected to cyclic bending moment under creep condition. Fig. 2 shows the dimensions and configurations of the considered Type 1 and 2 welded joints, and the applied 2D symmetric FE model of the specimen assuming a plane strain condition with designation of different materials (parent, weld materials and heat-affected zone), boundary conditions and loading. A cyclic linear distribution of normal pressure P is applied to the end face of the parent material (Fig. 2) to simulate the reverse pure bending moment M, and a schematic bending moment loading history with a dwell period t considered for the creep-fatigue analysis is given in Fig.3. In addition to the pure fatigue case, one hour and 5 hours dwell periods are considered to investigate the effect of dwell period on the creep fatigue behavior. Five variants of reverse bending moment are analyzed, which correspond to 1.0%, 0.6%, 0.4%, 0.3% and 0.25% of total strain range at remote parent material. Figure 2. Dimensions and Finite Element models for Type 1 and Type 2 weldments, according to [13] Figure 3. Schematic bending moment loading history for creep-fatigue analysis using the LMM
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