Research On Low-velocity Impact Properties And Damage Mechanism Of Woven Fabric Composite

Inflatable space structures get more and more attention because of its superiority in the side of communications and military affairs. The woven fabric composites on the inflatable space structures are one of the most important materials. In this paper, low velocity impact failure modes and damage mechanism of cured woven fabric composites were studied. These woven fabric composites contain carbon woven fabric composites and aramid woven fabric composites. We focused on the failure modes and impact response characteristics of woven fabric composites as a function of impact velocity, material parameters (thickness and layer). To analyze the response of composite laminated plate under low-velocity impact, a finite element analysis model is established.Investigations show that the failure modes after low velocity impact are related to the nature of fiber. The failure modes of carbon woven fabric composites are brittle fracture which is dominated by fiber fracture following matrix cracking along the direction of fiber and interfacial debonding. The positive damage area is round. Aramid woven fabric composites obviously show a cross damage area which makes stress concentration as a center. This damage area has matrix cracking along the direction of fiber, fiber fracture and, aplit and fiber fibrillation. Faliure progress is divided into four stages. Two types of materials are different with each other. Carbon woven fabric composites experience overall bending, a large number of fiber fracture, penetrating and reaming. But aramid woven fabric composites contain overall bending, fiber fracture and aplit, penetrating and crack extension along the direction of fiber. The process of energy absorption contains three stages which are initial stage, linear stage and stable atege. The means of energy absorption contains overall bending, fiber fracture and aplit, matrix cracking and interfacial debonding, and they are dominated by fiber fracture.The failue modes and impact response are related to velocity, thickness and layer. The response of carbon fiber fabric reinforced epoxy resin composites is related to impact velocity. They have shown the strain rate sensitivity. The anti-penetrate capability of composites increases when the impact speed increases. The ability of energy absorption and impact resistance is increasing with the thickness, so thickness effect is significant. Layer is also one of the most important factors affecting the impact response characteristics. When designing the composite laminates, we should avoid having the same direction of the layer, and the surface must be (±45) layer. Also the proportion of (0,90) layer structure should be increased. The result also showed that internal damage area is larger than the surface after impacting.We establish the finite element model based on explicit finite element software ABAQUS/Explicit and the mechanical model of laminated structure. The material model parameters of carbon fiber fabric and aramid fabric composites are determined. The Hashin failure criteria and stiffness degradation are used to model the failure and response of composite material by comparing the computed results with the test data at the velocity of 2.5m/s, 3.0m/s and 3.9m/s. we can confirm that finite element analysis model is effective to analyze composite laminated plate under low velocity impact.