Photoelastic-fringe multiplication—For tenfold increase in sensitivity

Slices from three-dimensional frozen-stress models were collected from numerous photoelastic laboratories and these diverse samples were used to demonstrate fringe multiplication. Multiplied isochromatic patterns of excellent clarity and fidelity are presented. Maximum multiplication factors of 9 or 11 are exhibited for most demonstrations, but multiplications by 17 and 25 are exhibited for special cases. Speed, accuracy and simplicity of the method are discussed, and benefits of full-field data retrieval are emphasized.