Study of unidirectional fiber reinforced epoxy composites in short-beam bending test

The present paper deals with the computational study of unidirectional glass fiber reinforced epoxy composites in short-beam bending test and the comparison of the induced results with experimental and analytical results. The measurement of the interlaminar shear strength of composite beams, an important design variable in many applications, may be performed by short-beam three-point bending test. A two-dimensional finite element analysis is adopted throughout the composite beams in order to, on the one hand, correlate with the experimental results and, on the other hand, to obtain the stress distributions at the supports and at the loading points where usually there is an abrupt variation due to the indentation existing because of the noses. Thus, the linear variation of the normal stress according to bending theory is not valid near the supports and characteristics of curves. Similarly, the shear stress which shows, normally, a parabolic variation becomes a curve with a different shape near the point where the load is applied. The discrepancies among theoretical, experimental and Finite Element Method (FEM) results support the qualitative conclusions of the study concerning the significance of non-isotropy and point effects for the correct interpretation of the three-point bending tests-results.