Study on the Method of Structural Analysis Considering Material Damage and Fracture

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The stress distribution, deformation and the ultimate strength are analyzed in the conventional structural analysis of ship and offshore structures. However, the material damage and fracture such as fatigue and cracking play an important role in actual accidents such as striking, collision and overturning. The consideration of material damage and fracture in the commercial finite element codes is insufficient in comparison with the material and geometrical nonlinearity. The method of limit strength analysis of structures composed of new alloys, plastics, ceramics, concrete and ice as well as steels is required in the field of ship and offshore engineering.The basic study to establish the method of nonlinear structural analysis based on continuum damage mechanics is conducted in the present study. The main results of the present study are (1) the development of the thermal elasto-plastic damage analysis of structural members under thermal loading and its validation, (2) the development … More of the method of computational material testing of pre-damaged steels and its validation. In (1), the cracking behavior due to zinc-embrittlement of bridge girders and pylon members in hot-dip galvanization has been analyzed by the finite element method using damage mechanics models to solve the phenomena from a mechanics point of view. The damage analysis has also been conducted for the functionally graded material disks subjected to thermal shock and cycles in order to point out its validity in material design. In (2), the dynamic tensile behavior of pre-damaged (pre-fatigued or pre-strained) steels has been simulated, using the damage mechanics models identified by the static/dynamic tensile tests and the fatigue SN-curves to show the possibility of computational alternatives for the material testing of pre-damaged steels. Both are the advancement to new fields of computational solid mechanics and can be considered as the first steps for the development of the method of structural analysis considering material damage and fracture. Less