Published online by Cambridge University Press: 06 March 2019
The method presented In 1976 for measuring stresses in polymeric materials including fiber-reinforced composites (1,2) yielded directly only one or two of the principal stresses and (elastic) strains in the embedded crystalline particles. The method is now extended so as to yield determinations of all three principal stresses σ1, σ2, σ3 and strains, ε1, ε2, ε3, The method applies to both residual and applied stresses and strains.
High angle diffractometry such as is used in ordinary X-ray stress determinations in metal objects is used, with suitable particles being embedded in a homogeneous plastic or reinforced composite before curing.