Advances in the embedded-strain-gage technique with an application to contact problems

Improvements in the embedded-strain-gage technique for the measurement of strains at internal points in models of machine components are described. A New measurement module permits an experimental determination of the strain in models of epoxy resin. By its construction, the centers of the rosettes may be accurately located in the model mold, before casting. A large number of gages may be embedded with accuracy in a systematic manner. Application to the study of rolling contact is discussed. The improved technique has permitted an accurate embedment of gages at 0.043 in. below the surface of a flat model of epoxy resin which is then pressed against a spherical model having a radsius of curvature machined to 75 in. A testing machine is described and preliminary test results are presented.