It is realized that, for many practical problems, the localized vibration pattern usually has a very little contribution to the overall response behavior of the system. From this point, a new dynamic reduction procedure is proposed and applied to the seismic analysis of complex engineering structures. By introducing a set of virtual master degrees of freedom (VMDOF) which represent the mean value of displacements at the substructural interface. The compatibility is conducted to those VMDOF only while all other real nodes at interfaces are considered as secondary slavers and then can be eliminated by the conventional Guyan reduction procedure. Numerical example shows that this method is quite efficient for the seismic analysis of high-rise building structures.

An accurate and efficient boundary element procedure is developed for the analysis of dynamic response of rigid surface footings. The footings are assumed to be resting on an elastic half-space. The problem is formulated in the frequency domain by adopting the half-space Green's function for surface points loads. Therefore, only discretization is required for the soil-footing interface. Two types of element, linear and quadratic isoparametric elements, are employed for the discretization. Examples of the single-footing as well as two-footing system are presented to demonstrate the application of the method. The results are compared with other published results. It is demonstrated that the present results are in good agreement with the approximate solution proposed by Tajimi at low frequency range. However, the approximate solution may lead to an over-estimation of the amplitude and decaying rate as the frequency increases.

A boundary element methodology is developed for studying the response of a system of two rigid, massless or massive, surface foundations of arbitrary planforms to various harmonic waves under three-dimensional conditions. The method employs the frequency domain Green's function for the surface of the elastic half-space, thereby restricting the discretization only to the soil-foundation interfaces, and isoparametric quadratic quadrilateral boundary elements for increased accuracy. Extensive comparison studies with other known numerical solutions confirm the high accuracy of the proposed method. Detailed parametric studies are conducted in order to study the harmonic wave response of two square foundations as a function of the kind of incident wave, the angles of wave incidence, the wave frequency, the separation distance between the foundations and the amount of mass in each foundation and compare it against that of a single foundation for assessing the through the soil coupling effect.

试图对池式快堆结构作较大简化，使计算简图既能反应堆结构的动力特性，又能使计算简便可行。从而把一个复杂的结构用一个简单的弹簧．质量体系来近似地等效代替。引入容器的变形假设和确定的液动压力假设，应用虚位移原理可获得体系在水平地震作用下的运动方程，丽后考察其地震动响应。