Stiffness of variable thickness belleville springs

The present study reports a theiretical analysis on Belleville springs with linearly variable thickness (radially tapered disk springs). The analysis aimed at the solution of two different problems: the realization Of a sprin g with a zone of null slope in the stiffness curve (i,e. with the possibili ty of having different values of the deflection at a constant load, particu lary useful in some regulation processes), and the definition of a disk spr ing with an almost constant stress state (with the stress linearly variable from the neutral axis to the upper and lower surfaces). Based on the hypot hesis of Almen-Laszlo and Curti-Orlando-Podda, the theoretical analysis giv e the values of the stiffness curve and the stresses os a function of the g eometrical parameters and allowed both problems to be resolved clearly with different values of the geometric parameters. In order to compare the stre sses obtained for large deflections, the authors constructed a numerical mo del which validated the theoretical analysis.