Flexural and torsional behaviour of biaxial and triaxial braided composite structures

This paper presents a systematic investigation of flexural and torsional properties of biaxial and triaxial braided composites, with one or more layers, at different braid angles. Braided tubes were impregnated with vacuum infusion process to produce void free samples. Flexural and torsional tests were conducted using special attachments to an Instron test machine. Assuming a lenticular geometry for the tow cross-section, a modified laminate analysis was performed by computing reduced tow properties due to the presence of tow waviness (crimp). The results obtained from the laminate analysis were used in the macro-analysis of the braided tube in order to compute the flexural and torsional properties. The experimental results were in good agreement with the computed values.