Precision casting of epoxy-resin photoelastic models

Abstract

Photoelastic models may be made by four different methods:

by machining from fully cured blocks;

by machining of oversize simplified castings;

by cementing of machined parts;

by accurate casting to the same shape as the prototype.

A method of casting models to the same proportional accuracy as the prototype and its limitation are described. In this technique a pattern is coated with silicone rubber which is supported by an epoxy-resin casing. Curing shrinkage and differential thermal expansion of the epoxy casing, rubber coating, and Araldite casting are factors which essentially influence the resulting accuracy of the cast models.