Transparent EPDM composite crosslinked by peroxide with no fillers was exposed to hydrogen gas at a maximum pressure of 10 MPa, and then the behavior of blister initiation and growth in the composite after decompression was observed by an optical microscope. The critical pressure where no blisters initiated PH.cr was 1-2 MPa, while micrometer-sized blisters initiated in the composite at PH > 1-2 MPa. It is considered that these blisters initiated due to stress concentration of micrometer-sized bubbles under an inner pressure Π formed by supersaturated hydrogen molecules after decompression ; then the energy release rate-tearing energy, T-of these bubbles was calculated theoretically or by FEM. Parallel to the calculation, static crack growth tests were conducted, and the threshold tearing energy for the static crack Ts.th was experimentally obtained. From the criterion expressed by T> Ts.th, the inner pressure at blister initiation πF was estimated and then was compared with PH.cr. Consequently, πF≈PH.CT, i.e., the critical pressure where no blisters initiated was successfully estimated in terms of fracture mechanics.
|Number of pages||11|
|Journal||Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A|
|Publication status||Published - May 2009|
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering