Numerical and experimental research on the fracture damage mechanism of composite clamps for aircraft engine pipeline system

In this paper, the failure load, damage behavior, and damage mechanism of composite clamps under tensile loading were investigated by experiments and numerical simulations. Firstly, tensile tests of clamp rubber mat specimens at different strain rates revealed that their mechanical properties were insensitive at low strain rates. Secondly, composite clamps were subjected to tensile tests to obtain failure loads and failure modes. The results showed that the composite clamp was 2.08 times stronger in the radial (P1) direction than in the axial (P2) direction, and it had greater tensile capacity in the radial direction. Then, the failure mechanism of the clamps was analyzed by scanning electron microscopy (SEM) as fiber fracture caused by matrix cracking and interlayer delamination. Finally, the progressive failure model of composite clamps was established by considering matrix, fiber, and delamination damages in combination with the rubber intrinsic model obtained from the tests. The results showed that the damage of the composite clamp first occurs in the transition region of the flat and arc segments, and as the load increases, the damage extends outward until the destruction occurs. This paper's composite clamp damage failure model can provide reference for engine hydraulic pipeline-clamp system design.