Novel material model to predict the residual strength of a composite overwrapped pressure vessel after impact

Abstract Composite overwrapped pressure vessels are typically used to store gases such as hydrogen under high pressure. Internal damage due to an impact may reduce the strength of the vessel, through which the internal pressure at failure, the so-called burst pressure, may drop significantly. Advanced material models can be used to predict to what extend the burst pressure of a vessel decreases. However, current studies do not consider the complex mechanisms that cause a reduction of the burst pressure for vessels with a wall thickness over 20 mm (common in the automotive industry), nor do they correctly take into account the reduced stiffness during reloading. The failure mechanisms in these thick-walled vessels under impact loading localizes in shear bands that consist of fiber kinking and matrix damage. Fiber fracture due to fiber kinking is identified as the most important mechanism that reduces the burst pressure. In this paper, a new material model is proposed that adequately captures these mechanisms. The model is validated using impact loads and subsequent burst tests on pressure vessels. It is shown that the model is able to predict the burst pressure after impact well.