Numerical calculation of the end-effect of cylinders, used as measuring element in load-cells

Summary

The present paper deals with load-cells essentially consisting of a circular cylindrical shell provided with wire-electrical strain gauges whose electrical output should be in proportion to the magnitude of the forces to be measured. However, the output of the strain gauges very often appears to depend upon the way in which the measuring device is loaded. In order to estimate the effect of the eccentricity of loading, a factorε has been calculated,ε being a measure for the decay of the strain in the middle cross section of a thin-walled cylinder with constant wall-thickness, due to an external axial load varying with cospϕ in circumferential direction, applied symmetrically to the two end-rims of the cylinder. Numerical values ofε have been computed as a function of a number of nondimensional parameters related to the radius, wall-thickness and length of the cylinder, the orderp of the harmonic loads, and the length and number of the strain gauges used.