Critical hydrogen pressure at crack initiation of silica-filled EDPM composite in high pressure hydrogen gas

Junichiro Yamabe, Shin Nishimura

    Research output: Contribution to journalArticlepeer-review

    5 Citations (Scopus)

    Abstract

    A silica-filled EPDM composite (SCT) was exposed to hydrogen gas at P H ≤ 10 MPa, and the critical hydrogen pressure at crack initiation PH,cr was evaluated. From observations of cracks by an optical microscope, PH.cr ranged from 4 to 5 MPa. It was inferred that these cracks initiated due to the stress concentration of the micrometer-sized bubbles caused by supersaturated hydrogen molecules after decompression. Furthermore, tearing energy of these bubbles, T, was calculated by FEM and theoretically. In this calculation, the SCT was regarded as a hyperelastic material, and so its strain energy density was approximated by a polynominal Mooney-Rivlin model which can express the strain energy density of practical sealing materials more exactly than the Neo-Hookean model. Parallel to the calculation, static crack growth tests were conducted using single edge crack specimens in air and in 0.7 MPa hydrogen gas at room temperature. Since the hydrogen gas did not influence the Ts,th value, an inner pressure at T ≥ T s,thΠF, was estimated using the Ts,th value in air. As a result, the critical hydrogen pressure at crack initiation of the SCT was successfully estimated, i.e., PH,crΦF as well as that of an unfilled composite.

    Original languageEnglish
    Pages (from-to)1726-1737
    Number of pages12
    JournalNihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A
    Volume75
    Issue number760
    DOIs
    Publication statusPublished - Dec 2009

    All Science Journal Classification (ASJC) codes

    • Materials Science(all)
    • Mechanics of Materials
    • Mechanical Engineering

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