Simplifications in the Behavior of Viscoelastic Composites with Growing Damage
Some analytical results for the mechanical behavior of elastic composite materials and structures with growing damage are summarized and then extended to viscoelastic media. The effect of strain rate only at crack tips is considered first; it is shown that if the crack speed is a strong function of energy release rate, the overall mechanical response is like that for an aging elastic material. Both stable crack growth and unstable crack growth followed by arrest produce this aging-like behavior. Viscoelastic behavior throughout one or more of the phases is then introduced. A simplification is used in which only one relaxation modulus characterizes the viscoelasticity, apart from that at crack tips. Upon replacing the physical displacements in the response for an elastic material by quantities called pseudo displacements, a simple model for viscoelastic composites with growing damage is obtained.
KeywordsEnergy Release Rate Relaxation Modulus Viscoelastic Medium Stable Crack Growth Crack Speed
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