ADHESIVELY BONDED COMPOSITE IOSIPESCU SPECIMENS WITHOUT SINGULAR STRESS-FIELDS

The asymptotic singular stress fields at bi-material wedge corners in adhesively bonded composite losipescu specimens have been studied usin g two-dimensional finite-element techniques. In particular, the singul ar powers of the fields have been analyzed using the finite element it erative method. Different combinations of the elastic properties of th e composite adherends have been considered, taking into account variou s volume fractions of fibers as well as different fiber orientations w ith respect to the adherend/adhesive interface. It has been shown that there are critical angles of the interfaces that separate the regions with positive and negative singular powers. This creates stress field s that are not singular in nature. It appears that the critical angles are dependent on the elastic properties of the composite adherends. I n the second part of this work, the critical angle approach has been a pplied to the design of adhesively bonded composite losipescu specimen s free from singular stress fields at their bi-material wedge corners. The samples will not develop singular stress fields either in shear o r under Biaxial shear-dominated loading conditions.