Assessment of Cyclic Load Induced Energy Dissipation and Damping on GFRP Composite Laminate

Abstract

Polymeric composites exhibit load sensitive stiffness unlike the case of homogeneous metallic material. Composites are widely used in dynamic loading environment and hence it is necessary to study their response in terms of structural properties. Behavioural changes of glass epoxy composite laminate on exposure to cyclic loading has been assessed in terms of energy dissipation (Ed) and Damping factor (DF) by hysteresis loop. GFRP composite specimens (UD-0, 0/30/60/0, 0/45/0/-45, 0/90/90/0, and 0/90/0/90) are exposed to low velocity constant amplitude cyclic loading using a laboratory arrangement (by an eccentric disc) at 4.6 Hz and 8.6 Hz frequencies. In fibre-reinforced composites apart from the fibre volume fraction, the fibre interaction angle significantly influences their dynamic properties on loading. Unidirectional (UD-0) laminate exhibits low damping/energy dissipation, while 0/90/0/90 laminate with large fibre interaction angle shows highest damping/energy dissipation. Whereas, symmetric cross ply (0/90/90/0) laminate acts as a performance demarcation among the chosen laminates. Thus, optimum Ed/DF properties of GFRP laminate in dynamic environment is attributed to symmetric lay-up, smaller fibre orientation interaction angle in the lay-up sequence and 0 fibre layer at the boundary.