The role of stress analysis in the design of force-standard transducers

The thesis proposed in this lecture is that solutions given by design equations representing the behavior of a structure or body will give the best approximation if an integral use is made of theoretical and experimental stress-analysis methods. To demonstrate the validity of the thesis, an investigation is described concerning a ring-shaped elastic element used to measure a force by relating it to diameter variations or to inner and outer surface strains.To attain this goal, analytical, experimental (strain gages and photoelasticity) and numerical (finite-element) methods were used. The results obtained were investigated through an analysis of the acting nominal force and the influence quantities, namely, force components, parasitic components and interactions of the transducer, testing machine and measurement instrumentation.Other experimental results based on a statistical analysis were found to make the actual behavior of the elastic element clearer, also they approximate closely the solutions given by design equations.