Impact Properties Of Bio-Inspired Helicoidal Composite Laminates

Carbon fiber reinforced epoxy resin composites have excellent properties of high specific strength and high specific modulus,and are widely used in aerospace,shipbuilding,rail transportation and other fields.However,the impact resistance of traditional composite materials is poor,and it is easy to produce delamination damage under impact load,which seriously affects its bearing capacity and structural safety.However,there are many bio-composite materials with excellent impact resistance in nature,such as mantis shrimp’s claw rod,whose microstructure is formed by spiral arrangement of mineralized fibers.Inspired by this,this paper designed and prepared spiral laminated carbon fiber/epoxy composite laminates,and systematically studied the effects of rotation Angle,layer thickness and fiber mixture on the impact resistance of spiral laminated composites under 10 J and 100 J different impact energy.The effect of rotation Angle on impact resistance of spiral laminated composite was studied.The results showed that 10 j impact energy,relative to the quasi isotropic laminates,spiral laminates raised the thickness of composite laminated plate to absorb energy,when the rotation Angle is 5 °,the biggest increase by about 10%,the main reason is the spiral laminates changed the internal stress distribution of laminated plates,leading to more crack to consume more energy.Under the impact of 100 J energy,the absorption energy per thickness of spiral laminated composite increases first and then decreases with the increase of rotation Angle.When the rotation Angle is 10°,the spiral laminated composite has the highest absorption energy per unit thickness,which is23.2% higher than that of QI laminated composite.After impact of 10 J or 100 J,the residual compressive strength of the spiral laminated composite decreases,and when the rotation Angle is 5°,the decline is the largest,which is 37.3% and 23.2%,respectively.The main reason is that the overall stiffness of the sample decreases,which leads to the decline of the anti-compression instability ability.The effect of ply thickness on impact resistance of spiral laminated composite was studied.The results show that the absorption energy per unit thickness of the thin laminated spiral composite is twice that of the thick laminated spiral composite under10 J energy impact,while the absorption energy per unit thickness of the thin laminated spiral composite under 100 J energy impact is less than that of the corresponding thick laminated spiral composite.The main reason for this difference is the change of failure mechanism under low energy impact and high energy impact.After impact,the residual compressive strength of thin laminated spiral composites is smaller than that of thick laminated spiral composites,with a maximum difference of 40.4% after 10 J impact and15.2% after 100 J impact.The main reason for the reduction of residual compressive strength is that the overall thickness of thin laminated spiral composite is smaller,which is more prone to compression buckling failure.The effect of fiber mixture on impact resistance of spiral laminated composites was studied.The results show that the absorption energy per unit thickness increases linearly with the increase of the volume fraction of glass fiber under 10 J energy impact,while the absorption energy per unit thickness increases linearly with the increase of the volume fraction of glass fiber under 100 J energy impact,with obvious confounding effect.One of the main reasons for the hybrid effect is that the failure mechanism of carbon fiber layer is changed by the existence of glass fiber layer,which leads to more matrix cracks.The second is that the high ductility of glass fiber can produce larger deformation,which can absorb more energy.After 10 J impact,the residual compressive strength of spiral laminated composites decreases linearly with the increase of glass fiber volume fraction.Compared with pure carbon fiber spiral laminated composites,the residual compressive strength of hybrid fiber spiral laminated composites decreases by 11.2% 12.0% 21.6% 27.6% 48.3%,respectively.The main reason for the decline of residual compressive strength of hybrid fiber spiral laminated composites is that the instability of glass fiber is much less than that of carbon fiber.However,after 100 J impact,the residual compressive strength of spiral laminated composites does not decrease significantly.The main reason is that after high energy impact,the opening damage is the decisive factor leading to the compression instability of composites,thus reducing the difference in compressive properties caused by the performance difference between carbon fiber and glass fiber.