A method for designing multiload component dynamometers incorporating octagonal strain rings

To optimize the design of force dynamometers incorporating octagonal ring elements it is important to be able to predict the dynamometer sensitivities. Previous methods relying on thin ring theory have been inadequate because octagonal rings often have a thickness which cannot be considered thin and, further, the thickness is not uniform. In this paper, empirical equations that describe the deflections, strains and von Mises stresses of individual octagonal rings due to radial, tangential and axial forces are developed using finite-element models. These models are loaded and constrained to simulate the most common uses of octagonal rings in force dynamometers. A nonlinear regression routine is used to develop the above equations from the data given by the finite-element analysis. The performance of these equations is evaluated and presented in tabular form. A procedure is also outlined to describe the use of these equations in the design of six-load-component dynamometers.