Determining the fatigue life of parts under periodic, sinusoidal vibration is a fairly straightforward process in which damage content is calculated by multiplying the stress amplitude of each cycle from harmonic analysis with the number of cycles that the parts experience in the field. The computation is relatively simple because the absolute value of the vibration is highly predictable at any...

The recent development of wavelet analysis techniques has made it possible to represent the temporal variations of frequency content in an earthquake accelerogram elegantly. These techniques are more versatile than the other time-frequency localizing techniques due to their flexible time-frequency windowing feature. This development has led to the timeand frequency-based characterizations of gr...

Normal modes of one-dimensional disordered chains with two couplings, one of them assigned at random to pairs in an otherwise perfect chain, are investigated. We diagonalize the dynamical matrix to And the normal modes and to study their spatial extent. Multifractal analysis is used to discern clearly the localized or delocalized character of vibrations. In constrast to the general viewpoint th...

This paper presents an important outcome of a research programme which focuses on the development of a method for synthesizing, under controlled conditions in the laboratory, the non-stationary random vibrations generated by road transport vehicles. It addresses an important limitation of current methods used for synthesising random vehicle vibrations which assume that vibrations produced by wh...

where the qk represent charges, Lik inductances, Rik resistances, Gik reciprocals of capacitance, the Ejk are random e.m.f's**, and primes denote differentiations with respect to time. The theory of such systems of equations, quite carefully examined during the war years in applications to noise in electrical networks, turns out also to be applicable to the various mechanical systems—in particu...

Formal extensions of the response spectrum method to include spatial seismic effects are reviewed. Two approaches are described in detail: the first based on random vibrations of a simple oscillator under two-component excitations, and the second analyzing multi-column building seismic response. The subjective choice of these two complementing approaches aims at analyzing the phenomenon of spat...