| In the 21 st century,advanced structural composites,such as carbon fiber composites,have begun to appear more and more in the design and use of the new generation of aerospace vehicles.The composite materials used have also begun to develop from small parts to large areas of skin,from minor parts to main structure,from local use to overall design,from simple structural role to functional application.At the same time,with the increase of the proportion of composite materials used in the main structure,the damage mechanism of composite materials and the selection of design safety factor begin to restrict the further use of composite materials.Among many problems,the most prominent one is the in-layer damage of composite materials.Because the use environment of aerospace vehicles,especially commercial airliners,is often accompanied by the impact of runway debris such as rubber particles,sand and gravel during takeoff and landing,as well as extreme weather such as hail impact.These high frequency shocks will cause "barely detectable visual damage" in composite structures,which will affect the flight safety of aircraft.For this reason,this paper chooses the explicit solver calculation method of ABAQUS software.Based on Hashin damage criterion,an impact model of composite laminates coupled with shell element and cohesion element is established in the software.At the same time,the damage evolution process related to fracture energy is introduced to simulate the material response of composite laminates under impact.At the same time,due to the spontaneous interlaminar delamination of composite laminates in the process of preparation and use,this paper also improves the demonstration model by presupposing interlaminar defects between shell elements to simulate the effect of invisible interlaminar defects on the impact response of composite laminates.The following research steps have been carried out:(1)、validation of the low velocity impact model.Comparing with experimental data to demonstrate the rationality of the model;(2)、Influence of interlayer defect location on impact response.Setting interlayer defects in different layers.The established model is used to predict the interlayer delamination after impact.(3)、Influence of interlayer defect size on impact response.Set different area of interlayer defect in the same layer to predict interlaminar delamination after impact. |
