Failure analysis of a frangible cover made of short‐cut basalt fiber reinforced epoxy composites

The frangible cover made of continuous fiber reinforced composites has become widely used structure for the new generation launch canisters. However, destroying the continuity of fibers is needed during the hand lay‐up process to make the frangible cover fail in predetermined patterns. In this article, composite frangible covers were fabricated with short‐cut basalt fiber reinforced epoxy(BF/Epoxy) composites instead of continuous fiber‐reinforced composite materials, reducing the strength redundancy in the local structure of the frangible covers. Tensile tests were firstly conducted on material samples to obtain the stress–strain characteristics of the short‐cut BF/Epoxy composites. The constitutive model and failure criterion of the short‐cut BF/Epoxy composites material were established. Then failure pressure and failure mode of the frangible covers were predicted by finite element method. Two frangible covers with different geometric parameter were fabricated and subjected to static bursting strength tests. The influence of structure parameter on the bursting pressure of the frangible cover was investigated in detail. it was found that the bursting pressure of the BF/Epoxy composite fragile cover can be tailored by adjusting the geometry size of the weak zones on surface of the cover. Meanwhile, Failure modes and the bursting pressure of the BF/Epoxy composite fragile covers are highly consistent with the predictions.Highlights A frangible cover made of the short‐cut basalt fiber reinforced epoxy(BF/Epoxy) composites was fabricated. The constitutive model and failure criterion were established based on the mechanical properties of the short‐cut BF/Epoxy composites. The static burst strength of the short‐cut BF/Epoxy composite frangible cover subjected to uniform pressure was investigated via both theoretical and experimental approaches. The short‐cut BF/Epoxy composite frangible cover eventually failed in accordance with the predetermined pattern. The simulation error of the failure pressure of the short‐cut BF/Epoxy composite frangible cover was less than 20%.