Time Domain Dynamic Analysis Research Articles

Application of frequency domain analysis to transient response of nuclear containment structures

A combination of frequency domain and time domain analyses is proposed to obtain the dynamic responses of nuclear power plant containment structures. A soil-structure model of a boiling water reactor containment subjected to an assumed safety relief valve blowdown load is used as illustration. Linear time-invariant systems are analyzed using input forcing functions with varying frequency contents. Time domain analysis is performed using a synthesized input forcing function. The system characteristic function is generated in the frequency domain through Fourier transforms of the response time history and the synthesized input time history. The frequency response due to any other forcing function is obtained in frequency domain by using the system characteristic function, and the response time history is obtained by inverse Fourier transforms of the frequency response. The results obtained by the proposed method are in close agreement with the conventional time domain dynamic finite element analysis.

Application of Symbolic Manipulation to Time Domain Analysis of Nonlinear Dynamic Systems

The digital computer is often used to perform time domain dynamic analyses of non-linear systems. Such analyses are notoriously expensive. In many cases this expense is due to algebraic computation with the solution process. Presented is a solution approach, using modern automatic symbolic manipulation techniques, which will result in substantial computational savings for a wide class of problems. Included are guidelines based on fundamental mathematical analysis, to predict which problems will benefit from this simulation approach.

A New Technique for Dynamic Analysis of Acoustical Noise

This communication discusses some preliminary work on a new acoustical analysis technique and its application to the detection of noise sources in paper document handling machines. The technique, a time-domain dynamic-analysis method, used in conjunction with the conventional analysis techniques based on frequency and spatial analysis, has permitted the development of design principles for minimizing the output of “paper noise”* from document handling systems. The analyses show that, in general, paper noise can be minimized by maintaining maximum control of all document surfaces throughout the document path. The dynamic analysis system described here is the first part of an effort to develop a method for instantaneous recording of noise levels. When fully developed, the system will permit rapid analysis of many noise problems.