Showing papers by "Defence Research and Development Laboratory published in 1994"
TL;DR: In this paper, an experimental investigation of EDM of titanium alloy with a copper-tungsten electrode in respect of metal removal rate, electrode wear, surface roughness by varying currents and electrode rotations is presented.
104 citations
TL;DR: In this paper, the formation of spheroidal particles (globules) during rotary electrodischarge machining of titanium alloy and high carbon high chromium die steel was investigated using scanning electron microscopy.
77 citations
TL;DR: By linking data about scientific quantities with one or more appropriate formulae, it is shown that the knowledge base can be used for simple problem solving.
Abstract: An object-oriented knowledge based system has been developed to store and manipulate scientific knowledge in the form of data and formulae encountered in conventional textbooks on science and engineering. The formulae are input in the same form as they are written in, in terms of the well known symbols used by engineers and scientists. The system interprets the symbols as representing scientific quantities and links them with the underlying data and methods in the knowledge base. By linking data about scientific quantities with one or more appropriate formulae, it is shown that the knowledge base can be used for simple problem solving. The development of the system on a Sun Sparcstation was facilitated by the use of an object-oriented environment, Objectworks C++.
10 citations
TL;DR: In this paper, a carbon-epoxy shaft is fabricated by a filament winding technique, and the composite shaft is subjected to cyclic loadings because of unbalance excitation, and a plot is generated for crack length versus the number of rotational cycles.
4 citations
TL;DR: In this article, the effect of electron beam surface treatment (EBST) on fatigue crack growth (FCG) resistance of an austenitic steel has been investigated, and the EBST results in significant improvement in the FCG resistance.
2 citations
TL;DR: An error model of the strapped down inertial navigation system in the state space format is provided and a method to estimate the circular error probability is presented using time propagation of error covariance matrix.
Abstract: This paper provides an error model of the strapped down inertial navigation system in the state space format. A method to estimate the circular error probability is presented using time propagation of error covariance matrix. Numerical results have been obtained for a typical flight trajectory. Sensitivity studies have also been conducted for variation of sensor noise covariances and initial state uncertainty. This methodology seems to work in all the practical cases considered so far. Software has been tested for both the local vertical frame and the inertial frame. The covariance propagation technique provides accurate estimation of dispersions of position at impact. This in turn enables to estimate the circular error probability (CEP) very accurately.
1 citations
TL;DR: The methodology for the CAD of MIC layouts is presented and the algorithm for filling of a general polygon with curved edges, and which lies in the real domain is discussed, is used in the postprocessor for a photoplotter.
Abstract: A PC-based computer-aided design (CAD) package for designing microwave integrated circuit (MIC) printed circuit board (PCB) layout, called microwave artwork postprocessor for photoplotter (MAPP), is developed. The small size of MIC PCBs makes them suitable for defence applications. MAPP has a postprocessor which converts the MIC layout data to a format acceptable as input to a Gerber photoplotter. Photomask of the PCB is obtained from the photoplotter. This paper presents the methodology for the CAD of MIC layouts and also discusses the algorithm for filling of a general polygon with curved edges, and which lies in the real domain. This algorithm is used in the postprocessor for a photoplotter.