A novel analytical model for the failure envelope of composite pipes under axisymmetric loading
Haibo Sun, Yingying Wang, Zeqing Lin, Leilei Dong, Gang Liu, Hao Yu
Abstract
Composite pipes are crucial for continuously transporting deep-sea oil, gas, and mineral resources. Composite materials have been applied to the design of flexible pipes to cope with weight and extreme loading challenges. However, under the influence of many nonlinear factors, the failure behaviour of composite flexible pipes is complex. This paper proposes a novel failure envelope analytical and numerical models for composite pipes based on through-thickness failure criteria. The failure characteristics of each layer, the material's nonlinearity, and the fibers' local deformation are fully considered. The numerical model also considers the detailed geometric characteristics of the composite pipe. Select corresponding failure criteria for different material characteristics to construct the failure envelope of composite pipes. An 8-inch composite pipe was used as a case study to verify the accuracy of the analytical model. The failure behaviour of composite pipes under axisymmetric loading is discussed. The composite pipes' stress field and failure envelope under axisymmetric loading are analyzed. In addition, the factors affecting the maximum loading of composite pipes are discussed.