Damage to rigid-particle-filled polymer under cyclic tension

The effect of particle volume fraction, strain rate and interfacial bonding strength on the damage to a glass bead-filled high density polyethylene composite was studied experimentally by means of cyclic tension tests. Although the volume fraction of the glass beads varies from 5% to 25%, the materials studied are always sensitive to the strain rate, reflected by an increase of the modulus with strain rates changing from 10(-3)S (1) to 10(-5) s-(1). The damage evolution is a function of the applied far-field strain, but is also strongly influenced by the particle volume fraction, strain rate and interfacial bonding strength. Strong interfacial adhesion can postpone the initiation of damage and cause a lower level of damage than that occuring with weak adhesion under a given strain. For the studied materials with interfacial debonding taking place, the higher the volume fraction of the glass beads, the greater the number of microcracks formed at the interface. The effect of strain rate on the damage may be related to the effect of loading time, ie low strain rate favours damage development. The residual strain is a function of far-field strain and also depends on the strain rate and residual deformation of microvoids formed at two poles of the particle. (C) 2001 Society of Chemical Industry