Nonequilibrium statistical theory of damage and fracture for glassy polymers, 1. The statistical distribution and evolution of microcracks in glassy polymers

✍ Scribed by Qiang Li; Ziru He; Mingshi Song; Aoqing Tang

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 557 KB
• Volume: 5
• Category: Article
• ISSN: 1022-1344
• DOI: 10.1002/mats.1996.040050202

✦ Synopsis

The purpose of this paper is to construct a unified theoretical framework to link microto macro-mechanical properties of glassy polymers. Starting from a model of microcrack propagation in craze on a mesoscale, the kinetic process of microcrack propagation resulting from fibril breakdown in the crack tip zone is mathematically formulated by a combination of fracture mechanics and fracture kinetics. A microcrack evolution equation involving both the geometric structure parameters of craze and the meso-mechanical quantities is obtained. After solving this evolution equation, a statistical distribution function of microcrack size which evolves with time and the moment generating function of microcrack size are derived. Any-order averaged damage functions can be therefore deduced. Specifically, the analytical expressions of the first-order averaged damage function and its damage rate are presented, which correspond to a similar definition of damage mechanics.