ABSTRACT:

This study is concerned with reliability index computation using the PHIMECA Software for the case of a high density polyethylene (HDPE) pipe subjected to internal pressure. The critical stress intensity factor (KIC) is adopted as a criterion to the maximum limit of a numerically calculated KI. The reliability index β is obtained using a mechanical model based on fracture mechanics. It is found that at lower KIC values, no safe domain existed for actual service pressures while for moderate and higher values of KIC (above 3.5 MPa.√m), the β design index is reached. In terms of increasing crack length, β decreased systematically for all considered toughness cases supporting the idea that reliability and fracture toughness designate similar properties for service life estimation or material resistance to cracking. At KIC=5 MPa.√m, the pipe is in secured zone when crack length is below 370 μm. Finally, it is shown that specific dimension ratio (SDR) is a reasonable and conservative design approach for plastic pipes.