Study On The Impact Energy Threshold And Springback Characteristics Of Composite Materials

Since the advent of composite materials,because of its excellent performance and modular production characteristics,making the composite materials are widely used in aerospace,shipbuilding,construction and other fields.However,As the composite material is very sensitive to the impact,making the impact of material after the impact of serious deterioration of the material,resulting in serious security risks,Therefore,it is very important to study the damage of laminates after the impact of composite laminates.In this paper,the impact energy threshold and damage resilience of composite laminates were studied under the support of National Natural Science Foundation of China(Grant No.51573018).In this paper,three types of glass/epoxy composite one-way plate,glass/epoxy composite multi-purpose plate and carbon fiber/epoxy composite multi-directional plate three types of laminated plates under different impact energy impact test,3D scanning was performed on the surface damage morphology of the three laminated plates after the impact of three depth microscopy.The damage of the laminated plate was analyzed by the self-developed penetration test instrument.The impact energy test threshold of the three types of laminates was obtained by combining the experimental results of impact test and penetration test.Finally,according to the surface damage characteristics of the laminated plate,the relationship k is obtained by introducing the factor k and the relationship between the impact energy and the pit area.Considering the effect of springback on the surface damage,the variation of the pit depth of three different types of laminates was measured with time,and the springback characteristics of the depth of the pits were obtained.With the increase of impact energy and plate thickness,the damage area and pit depth of the laminated plate are also increasing.However,the glass fiber / epoxy composite unidirectional board and the glass fiber / epoxy composite multi-Increase,there is a turning point in the curve,after the turning point changes slowed down,and carbon fiber / epoxy composite multi-board did not find a significant turning point.Comparing the damage to the three types of laminates(including the area of damage and the depth of the pit),it can be found that the carbon fiber / epoxy composite multi-purpose plate> glass fiber / epoxy composite multi-purpose plate> glass / epoxy composite unidirectional board.The impact e nergy of the glass fiber / epoxy composite one-way plate is calculated according to formula(4-3).The calculation formula of the impact energy of the glass fiber / epoxy composite multi-purpose plate is shown in(4-5),The calculation formula of the impact energy of the carbon fiber / epoxy composite multi-purpose plate is shown in(4-7).The calculated error of the glass / epoxy composite one-way plate is less than 15%,and the calculation error of the composite fiber / epoxy composite multi-directional plate and carbon fiber / epoxy composite multi-directional within 10%.The impact energy test threshold of the glass fiber / epoxy composite unidirectional plate is 2 ~ 3 times.The impact energy test threshold of the glass fiber / epoxy composite multi-directional plate is 3 ~ 4 times.The impact energy test threshold of the glass fiber / epoxy composite multi-directional plate is 2 ~ 3 times.Three types of laminates rebound in the law is basically the same,divided into three stages.The first stage is the rapid rebound stage;the second stage is the slow rebound stage;the third stage is the pit stabilization stage.And the rebound occurred mainly within 24 h,more than 24 hours after the rebound can be ignored,that the injury remained stable.The order of the rebound rate is,GS03> GD03> CS03,and the magnitude of the resilience is independent of the magnitude of the impact energy.