THE X-RAY-MEASUREMENT OF AXIAL AND HOOP RESIDUAL-STRESSES IN MICROCOMPOSITE SPECIMENS

Thermal residual stresses were measured ire microcomposites (i.a, the elementary cell of a composite) using the X-ray diffraction method. In order to overcome the geometry problem caused by this type of specime n, three different theoretical methods were applied to analyze the X-r ay results. The first method was used previously for larger microcompo sites (phi = 140 mu m) and cannot be applied successfully here due to the small size of our specimen (phi = 20 mu m). The two other methods (three-dimensional methods) have been used successfully and lead to si milar results. The effects of the interphase type and thickness were s tudied. However the uncertainty on thermal residual stress values are still at about 20%.