Abstract
This paper is concerned with the photoviscoelastic analysis in the case where the axes of principal stress, principal strain and polarization of light coincide with each other in spite of the existance a large change of temperature in the body. Concretely, this paper intends to obtain the changes of thermal stress and constraint strain with time in the epoxy resin beam having a rectangular section subjected to the quenching from both upper and lower surfaces, in which the time-temperature equivalent law among stress, strain and birefringence holds. That is, the birefringence and temperature which change with time due to the quenching of the beam were measured, from which the changes of thermal stress and constraint strain were obtained with the hereditary integrations. On the other hand, the changes of thermal stress and constraint strain were also calculated from the linear-viscoelastic theory. As a results, the measured value of thermal stress agrees well with the theoretical value. The measured value of constraint strain agrees well, in its tendency, with the theoretical value. And, this measured value of constraint strain after quenching agrees well with the residual strain obtained by measurement from gauge marks on the specimen in the longitudinal direction at room temperature before and after quenching. Consequently, it was found that the photoviscoelastic technique is effective in solving the problem mentioned above.
