A NEW LOAD DISPLACEMENT FORMULATION USING THE ENERGY METHOD AND DEVELOPMENT OF GEOMETRIC DESIGN ALGORITHM FOR DISC SPRING IN A VECHICLE POWER TRANSMISSION

Abstract

Disc springs have the well-known particularity of being able to show nonlinear stiffness curve, with an initial and a final section of curve which rises in practically linear manner, although with different slopes, and an intermediate section with a null or negative slope. This characteristic makes them particularly suitable for use in design regulation process. Generally, there are two types of disc spring which are referred as a coned disc spring and a slotted disc spring. For prediction, a number of formulae to predict the nonlinear load displacement have been used for a single coned disc spring and a straight slotted disc spring. Yet, there is no formula is proposed for a bended slotted disc spring. To propose a new prediction formula for a bended slotted disc, the available formulae for a coned disc spring which were proposed by Almen is extended in the form of energy method. By extending the formulae to the slots segments and accounting the bended angle, a new prediction formula can be proposed. The nonlinear characteristics shown by a disc spring has gained considerable interest among researchers in analyzing and tuning the nonlinear load-displacement behaviour to meet particular target design. A number of specific criteria have been taken into account to tune the nonlinear load displacement. This study focuses on developing the design framework as guidelines for machine designers. Until now, there is no such design frame work is proposed in any literature review which can assist the design process before manufacturing. The general aim for this study is to improve and finally proposed new theoretical formulae for a coned disc, straight slotted disc, and bended slotted disc spring. As inversed works of prediction, with given nonlinear load displacement function and stress fatigue design criteria, new design frameworks which are referred as inverse design algorithms are proposed. The proposed design algorithms work as a part of machine design process which attempt to satisfy a specific design criterion of a load displacement function.