Trans-scale analysis of composite overwrapped pressure vessel at cryogenic temperature

Abstract

Composite over-wrapped pressure vessels (COPVs) are ideal structures for the gaseous helium vessels that is located within the liquid hydrogen (LH2) fuel tank. Their thermo-mechanical properties at cryogenic temperatures are critical to ensure the safety and reliability requirements. Most of the current analyses of thermal deformation only focus on the mismatch of thermal expansion coefficients between metal liner and composite winding layer, as the winding layers were usually assumed to be homogeneous material. However, the mismatch deformation between the reinforcing phase and the matrix phase is also significant to the micro-crack incubation, which is critical to the failure of structure. In this paper, a computational model of COPVs is developed based on the micro-structure of COPV. Finite element analysis is performed on a representative volume element based on the detailed structure of fiber/matrix to determine the effective elastic constants and thermal expansion coefficients at micro-scale. This micromechanical model gives higher prediction quality and more details about the thermo-mechanical deformation of COPV at cryogenic temperature. These microscopic details are critical to the future design of COPV structure with consideration of crack incubation.