Thesis (M. App. Sc.)--University of Adelaide, Dept. of Mechanical Engineering, 1990. / Some mounted ill. Includes bibliographical references (leaves 48-50).

Thesis (M.Eng.Sc.) -- University of Adelaide, Dept. of Mechanical Engineering, 1983. / Typescript (photocopy).

The results of this work will be useful to those interested in predicting or improving the cutting accuracy of guided circular saws. In this thesis an experimentally verified numerical model of the guided fixed collar circular saw is presented. Features of the model include the ability to represent the blade and collar geometry, blade runout, rotational stresses, guide dynamics, guide pad shape, guide lubricant, and guide or blade misalignment. The blade is assumed to be governed by thin plate theory and the guide arms are modelled as a lumped parameter system. The lubricating fluid is modelled as a number of massless spring-dampers. Numerical solutions are given for the natural frequency response, the forced response due to static or harmonic lateral loading, and for the self-excited response caused by the interaction of the blade runout with the guides. The behaviour of the runout as a function of blade rotation speed and the conditions for which a resonant condition is produced in the guides are also determined. Experimental results obtained for the natural response, the deflection caused by a static load, the effect of speed on the blade runout, and the self-excited response correlate well with the numerical results. Numerical results are presented to show the effects of guide position, guide shape and the use of multiple guides on the natural and forced response. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

This study investigates the dynamics of circular saws at supercritical speeds. A classical governing equation of a circular saw subjected to transverse and membrane forces is derived in both body-fixed and space-fixed coordinate systems. The transverse loads are generalized as spring, damping and out of plane cutting forces, and the membrane loads include rotational, thermal and in-plane cutting forces. Galerkin's Method is used to study the natural and forced response of a saw blade, and the effects of spring and damping on the stability at supercritical speed are discussed. An idling experiment is conducted to comprehend the fundamental behavior of circular saws at supercritical speed. The natural frequency, the steady state response, the flexibility and the runout variation of the circular saws are measured. The nonlinear vibration of the thin blade is observed. The effects of a spring-damper system and heating on the stability of a circular saw are investigated. A cutting test is conducted to find out the dominant parameters of supercritical speed cutting. At first, the prehminary experiments of the standard blade are conducted. Then, tip side cutting marks are discussed, and finally, the phenomenon of unstable cuttings are presented. The general solution of a rotating string subject to an elastic constraint is developed. Based on this, the discrepancy between theoretical and experimental stability results is analysed for a guided rotating disk. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate