9531719 Lin Engineering structures are often exposed to dynamic random excitations which can only be described in terms of probability and statistics. Examples of such excitations include seismic ground accelerations, turbulent winds, ocean waves, and traffic loads. It has also been well recognized that most structures need not be or should not be designed for eternal life; otherwise, the required size may be too large to be practical, or the cost too high. Thus the possibility of large deformation and failure must be considered in the design. The choice must then be made for the optimal total cost within a desired minimum service life of a structural system, including the costs of initial construction, maintenance and repair, costs associated with interruption of service, etc. The problem of a randomly excited structures undergoing large deformation is a difficult one, since nonlinear behaviors of the structure must be taken into account. For nonlinear structures, known exact analytical solutions are, by an large restricted to the case of single degree of freedom under white noise excitations. Extension to the case of multiple degrees of freedom is successful only under additional severe restrictions. The PI plans to develop new advanced analytical techniques to obtain the response statistics and probability of failure for multi-degree-of-freedom nonlinear structural systems under random dynamical excitations. Both geometrical and material nonlinearities will be considered.
