利用动力有限元程序LS-DYNA，对纽约世界贸易中心受飞机撞击后的倒塌，进行了力学分析和仿真，并根据计算结果进行了参数讨论。仿真计算的结果与真实倒塌过程非常接近，说明通过适当的选取计算参数和计算模型，可以对这种特殊的复杂破坏过程进行模拟分析和仿真。计算结果说明，世界贸易中心倒塌的直接原因，是火灾导致的钢材软化和楼板塌落冲击荷载引起的连锁反应。如果能够提高结构的抗火能力或者提高结构的延性，将有可能避免结构倒塌，避免惨剧再次发生。

利用非线性有限元方法，对预应力钢混凝土组合单向楼板和双向楼板进行了空间受力全过程分析，并通过改变预应力筋配置进行了参数讨论。分析结果说明，相对于钢混凝土组合单向楼板，组合双向楼板的承载力可以提高133%，刚度可以提高66%。而施加预应力后,承载力还可以继续提高。钢混凝土组合双向楼板是一种非常有前途的结构形式。

从传统的混凝土分离裂缝模型和弥散裂缝模型出发，使用不同的模型模拟不同发展阶段的混凝土裂缝，并利用无网格方法可以灵活布置节点和边界的优点，使分离裂缝模型的使用得到很大的简化。通过在宏观裂缝表面布置基于试验结果的混凝土与混凝土界面单元，正确地模拟了裂缝表面抗剪能力的变化。算例表明，使用本文方法可以准确模拟斜拉破坏混凝土梁的破坏过程，且精度和数值稳定性要高于传统的有限元弥散裂缝方法。

With the development of mechanics and computer technology, computer simulation has become an important tool in the structure analysis and design. Especially when the structures are under disaster load such as blast, penetration, impact of collapse or typhoon, it is difficult to analyze with test method, while the advantages of computer simulation method such as safe, efficient and cheap, are shown obviously in these problems. Various simulation systems are classified and discussed in this paper generally. And four practical examples are presented to demonstrate the function of simulation system. The first one is the analysis for the safety of blast-resist-doors under blast load. The second one is the study on new earth-penetration-weapons. The third one is the simulation on the collapse ofWorld Trade Center (WTC) in New York. And the forth one is the real-time display system for bridge under typhoon. These examples are used to illuminate the advantage of computer simulation technology on disaster load conditions and emphasis some problems in the simulation.

External bonding of fiber-reinforced polymer (FRP) plates or sheets has recently emerged as a popular method for the strengthening of reinforced concrete (RC) structures. The behavior of such FRP-strengthened RC structures is often controlled by the behavior of the interface between FRP and concrete, and this interfacial behavior is commonly studied through a pull test in which an FRP sheet or plate is bonded to a concrete prism and is subject to tension. In this paper, a meso-scale finite element (FE) model implemented with the MSC.MARC program is presented for the simulation of interfacial debonding failures in a pull test. In this model, very small nearly square elements (0.25-0.5mm in size) are used with the fixed angle crack model (FACM) to capture the development and propagation of cracks in the concrete layer adjacent to the adhesive layer. The effect of element size is taken into account in modeling both the tensile and shear behavior of cracked concrete. Comparisons between the predictions of this model and test results are presented to demonstrate the capability and accuracy of this FE model. The debonding mechanism is also examined using results obtained with the FE model. Finally, a method for the determination of the local bond-slip curve of the FRP-to-concrete interface from the FE results is described.