Experimental Investigation Of Underwater Impact Resistance Of Carbon Composite Sandwich Structure

With the rapid development of modern science and technology,marine structures are faced with more complicated working conditions which is composed of weapon impact,underwater dynamic loads,high and low temperatures and so on.Under this condition,with the requirements of ship lightweight,the requirements required on the properties of marine materials become high.Compared with conventional metallic materials,carbon fiber composite materials are more corrosion-resistant and have larger stiffness.In addition,carbon fiber composite sandwich panels are used extensively in marine fields due to their superior strength-to-weight ratios and energy absorption capability of soft core.As a result,before such materials can be used extensively and adapt to various working conditions,their underwater impact resistance is worth to be discussed to fully give play to their underwater protective property.In this paper,carbon fiber T700 laminates sprung up recently and were selected as face sheets of sandwich panels while PVC form with different core densities were chosen as cores of sandwich panels.The face sheet and core are bonded together as sandwich panel.First of all,this paper make a briefly introduction of non-explosive underwater shock loading simulator and point out the advantages of the device.On this basis,the experimental investigation was carried out on the underwater shock resistance of carbon composite sandwich panels.Specific contents are listed as follows:(1)Quasi-static compression tests were carried out on cores with different core densities to obtain their quasi-static compression stress-strain curves.(2)Post-mortem analysis was carried on the typical failure modes of sandwich panels subjected to different normalized impulses,and the corresponding failure mechanisms were analyzed from energy point.Additionally,the differences of typical failure modes between sandwich panels of different construction were compared.(3)Normalized deflection was pushed forward due to the deformation characteristic of the fiber composite material in order to assess the influences of loading parameters on underwater shock resistance.On this basis,the influence of underwater shock wave loading parameters,sandwich plate core layer and ply direction on the underwater impact resistance of sandwich panels is quantitatively discussed.(4)The typical failure modes and transverse deflections of waterside and airside face sheets of the carbon fiber composite sandwich plate structure obtained in this paper are compared with typical failure modes and deflections of 5A06 aluminum alloy/PVC sandwich panel of similar areal density of face sheets and total mass under the same loading conditions published in recent years.The results show that carbon fiber composite sandwich panels have superior underwater impact resistance performance.