Report on objective ride quality evaluation

The correlation of absorbed power as an objective ride measure to the subjective evaluation for the bus data was investigated. For some individual bus rides the correlations were poor, but when a sufficient number of rides was used to give reasonable sample base, an excellent correlation was obtained. The following logarithmical function was derived: S = 1.7245 1n (39.6849 AP), where S = one subjective rating of the ride; and AP = the absorbed power in watts. A six-degree-of-freedom method developed for aircraft data was completed. Preliminary correlation of absorbed power with ISO standards further enhances the bus ride and absorbed power correlation numbers since the AP's obtained are of the same order of magnitude for both correlations. While it would then appear that one could just use ISO standards, there is no way to add the effect of three degrees of freedom. The absorbed power provides a method of adding the effects due to the three major directions plus the pitch and roll

Stress Analysis of Mechanical Sheaves and Pulleys

Sheaves and pulleys of various shapes and sizes are frequently employed in the mechanical transmission of power. The conventional design of sheaves is based on either empirical formulae or very elementary stress analysis. This paper presents a three-dimensional finite element stress analysis of a sheave and describes a preprocessor developed here, capable of generating data for sheaves of various configurations. Due to pecularities of their geometry and loading, the models are built using eight-node and twelve-node isoparametric brick elements. The preprocessor requires as few as twenty cards for generating data for any of the seven sheave models incorporated in the model library. Excellent correlation of results is obtained, when strains thus generated are compared with those experimentally available for a specific sheave type under loading

Automated Stress Analysis of Mechanical Sheaves and Pulleys

The conventional design of sheaves is based on either empirical formulae or very elementary stress analysis. A finite element stress analysis is presented for the full hub and the spoked sheaves with elliptical spoke cross sections. For performing the analysis, a general-purpose finite element analysis computer program, SAPIV is provided. The program can perform static and dynamic analyses of large 3-D problems and show the effects of varying design parameters