Spectroscopy Stress Evaluation of Translucid Polymers Using Laser Photoelasticity

Several studies can be found where the mechanical strength of fiber composites is evaluated, but not much can be found regarding the influence of voids, as a second phase, in the same mechanical behavior of materials. In the present work, the influence of bubble presence into translucid polymeric bars is investigated. For this purpose, cubic probes with an anisotropic distribution of bubbles were casted, and other were casted controlling the manufacture process to avoid the bubble formation. Each probe was placed in a He‐Ne laser‐photoelastic arrangement and subjected to compression by an static load. The transmitted 630 nm, He‐Ne laser beam was captured by a single mode fiber optic sensor and then transmitted to a spectrometer and PC. Analysis of the spectrometer signals showed that the maximum stresses are concentrated on the bubbles reducing the surface stresses and inducing damping on the probe. The amount of damping depends on the size of the bubbles formed within the probe and their arrangement, thu...