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

在船舶和海洋结构物的常规结构分析中，对结构的应力分布、变形和极限强度进行了分析。然而，材料的损伤和断裂，如疲劳和开裂，在实际事故中，如撞击，碰撞和倾覆的重要作用。与材料和几何非线性相比，商业有限元程序中对材料损伤和断裂的考虑是不够的。船舶和海洋工程领域对新型合金、塑料、陶瓷、混凝土、冰和钢等材料组成的结构的极限强度分析方法提出了更高的要求，本文对建立基于连续损伤力学的非线性结构分析方法进行了基础性研究。本研究的主要成果是：（1）发展了热荷载作用下结构构件的热弹塑性损伤分析及其验证;（2）发展了 ...更多信息 预损伤钢的计算材料试验方法及其验证。在（1）中，使用损伤力学模型，从力学观点出发，通过有限元法分析了热浸镀锌中桥梁和桥塔构件的锌脆开裂行为。对功能梯度材料圆盘在热冲击和热循环作用下的损伤进行了分析，指出了其在材料设计中的有效性。在（2）中，利用由静态/动态拉伸试验和疲劳SN曲线确定的损伤力学模型，模拟了预损伤（预疲劳或预应变）钢的动态拉伸行为，以显示预损伤钢材料试验的计算替代方案的可能性。两者都是计算固体力学新领域的进步，可以被认为是考虑材料损伤和断裂的结构分析方法发展的第一步。少

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