Fault Elements Research Articles

A qualitive fault tree analysis for the tensile failure of fibrous laminated composites

The use of fault tree analysis for the identification of failure modes and mechanisms for laminated composite materials is discussed. The fault tree technique is first defined and a synopsis of the technique as well as a synopsis of the failure of composites is given. The two, fault tree analysis and elements of composite failure, are then combined to identify a fault tree for composite failure. The elements of fault tree are discussed qualitatively in relation to the likely failure modes for composites such as delamination, fibre breakage, matrix cracking, etc. Further, the necessity for quantitizing the fault tree described is outlined.

The Discriminative Logic of Fault Elements for a Centralized Backup Protection in Power Circuits

In this paper author describes a new concept of computer control protective relaying system of electric power network and an algorithm of centralized back up protection.

Spectral response of an elastic sphere to dipolar point-sources

Abstract A stratified elastic sphere is excited by an harmonic dipolar source of arbitrary orientation and depth. The total field is expanded in series of vector spherical harmonics and then condensed into a convenient form of a displacement dyadic. The Haskell-Gilbert matrix method is employed to obtain the radial factor of the displacements for a multilayered sphere. The dependence of the field on the azimuth angle and the fault elements is obtained for the case of a double-couple at depth. Expressions are also developed for the radiation pattern of surface waves over a spherical stratified earth.

The geometrical representation of fault-plane solutions of earthquakes

Abstract Investigations into the mechanism at the focus of an earthquake have been in progress for a long time. In the course of these investigations it has been demonstrated that the mathematical model of a simple fault is a plausible assumption, at least so far as the explanation of the direction of first motion at distant seismic observatories is concerned. Various methods have been devised for representing and determining the elements of the focal fault of an earthquake, by investigators in Japan, Holland, North America, Italy, and Russia. It is often very difficult to see the connection between the various representations, and the present paper has been undertaken to demonstrate the relationships between them and to devise corresponding “translation schemes.” It is shown that there exists an infinite number of representations of fault-plane solutions all of which satisfy certain basic requirements. However, only four thereof have reached any popularity. It is shown that three of these four representations are entirely equivalent. In each, one uses a sphere; in each, one uses some stereographic projection of this sphere; and in each, one substitutes the tangent to the seismic ray at the focus for the ray itself. Whether one tabulates the angle i which that tangent makes with the vertical and plots tan i/2, as Ritsema and most Russians do, or whether one tabulates and plots tan i, as some of the Russians do, or tabulates and plots cot i, as Hodgson and his various co-workers do, one obtains identical results with equivalent amounts of work. What particular representation anyone will choose for studying an earthquake will therefore depend largely on his taste and previous custom.