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Showing papers in "Journal of Engineering for Industry in 1977"





Journal ArticleDOI
TL;DR: In this article, the authors present an approach to solve the problem of the problem with the use of a set of techniques from Mechanical Engineering. Dept. of Mechanical Engineering, Massachusetts Institute of Technology.
Abstract: Thesis. 1977. Mech.E.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

105 citations


Journal ArticleDOI
TL;DR: In this paper, an impact in the classical impact pair configuration is investigated considering the impact pulse level and its frequency composition as possible sources of high-frequency energy in articulated systems, and the analog representation of the impact pair uses a nonlinear surface stiffness together with a non-linear surface damping.
Abstract: With the need to improve the reliability and noise emissions from real mechanisms, an impact in the classical impact pair configuration is investigated considering the impact pulse level and its frequency composition as possible sources of high-frequency energy in articulated systems. The analog representation of the impact pair uses a nonlinear surface stiffness together with a nonlinear surface damping. Developments of the Dubowsky model carried out by Crossley are further extended to allow the surface damping coefficient, as a function of the coefficient of restitution, to be calculated assuming energy is dissipated throughout the impact for any series power law representation of the surface stiffness. The practical system used by Veluswami is simulated, and the results for Dubowsky, Crossley, and the direct solution are compared to Veluswami’s practical data.

105 citations















Journal ArticleDOI
TL;DR: In this article, the authors considered the problem of minimizing the number of passes required to remove a given total depth of cut from a workpiece, considering both the probabilistic nature of the objective function and the constraints in the machining processes.
Abstract: This paper deals with the problem of optimizing the number of passes required together with the cutting speed, the feed, and the depth of cut at each pass for a given total depth of cut to be removed from a workpiece, considering both the probabilistic nature of the objective function and the constraints in the machining processes. Applying the concept of dynamic programming and stochastic programming, the problem is formulated in an analytically tractable form and a new algorithm is developed for determining the optimum value of the cutting speed, feed, depth of cut, and number of passes, simultaneously. For illustration, a typical example is solved to obtain the cost-minimizing cutting conditions in a turning operation, and the effect on the optimum cutting conditions of the various factors such as total depth of cut, uncertainty of the tool life, and constraints are discussed.







Journal ArticleDOI
TL;DR: Fracture-induced failure rate is admittedly not independent from speed, but current models built around the assumption that X = 0 often do not make sense at all.
Abstract: as shown in Fig. 1. Fracture-induced failure rate is admittedly not independent from speed (and a host of other factors, too, unfortunately). Much research work is being carried on currently in universities and industries in order to clarify the mechanism of brittle failure of cutting tools. Reliable experimental data concerning the effect of speed on failure rate for a reasonably broad range of cutting conditions are not generally available. However, tools keep breaking in production at rates high enough to affect markedly machining economics. Current models built around the assumption that X = 0 often do not make sense at all. Thus for the time being one must put up either with the X = const, assumption, or with more elaborate, untested X V equations. The first choice suggests itself as a first approximation for theoretical work, especially since the upperand lower-bound curves in Figs. 5-7 remain unchanged no matter what X — V equation is adopted. Speed figures are given in diagrams as examples only, as the paper deals with theoretical considerations. Upper speed limits in Figs. 2-4, and in Figs. 5-7 are spaced one order of magnitude apart as a matter of convenience only, without reference to actual production machining data. Mechanisms as Components of Dynamic Systems: A Bond Graph Approach