The Significance of Stretch Bending Combination Four-Point Bending Test in Composite Pipe Laying

Through force analysis on pipe body during ocean laying, this paper first puts forward the possible failure modes (e.g. wall thickness reduction exceeds the standard, ellipticity exceeds the standard, liner tube wrinkles, etc.) of mechanical bi-metal composite pipe during the process, then points out that stretch bending combination four-point bending test is the unique reliable detection method of maintaining integrity of composite pipe during laying by estimating the occurrence of failure mode in mechanical composite pipe laying through comparison of analytical method, finite element simulation method and bending combination bending test, and finally verifies the uniqueness of stretch bending combination test through the result of stretch bending combination four-point bending test on mechanical composite pipe of PY Project.