| Fiber reinforced polym ers and s andwich structures are more and more popular in ship buildi ng industry and filed of protecti on st ructures because of t heir high stiffness and strength to weight ratio,excell ent corrosion resistance,fire retarda ncy,acoustic damping,impact resistance,easy of manufacture and repa ir.We design a new sandwich panels with UHMW P E(ultra high molecular weight polyethyl ene)fiber reinforced laminates ski n,whi ch is the strongest fiber reinforc e laminate,and aluminum foam core,which is the most wildly used metal foam.Then we study anti-penet ration performance of the new sandwich panels by the numerical simulat ion technology.The calculation results provide a basi s for optim ization design of new sandwich panels and protecti on structures.Specific cont ent as follows:(1)In thi s thesis,we carry out quasi-static compressi on experiments on aluminum foam with different densities,to obtain their quasi-static compression stress-strain curves,which will be used in numeri cal simulation.Then we verify the correctness of the material parameters and calculat ing param eter s,which are used in the anti-penetration num erical simulation.ALE m ethod,one method coupl es fluid and soli d,wil l be verified i f it can corre ctly simulate the anti-penetr ation of underwa ter target.(2)Based on the correct material parameters and the simulation method,t he corre sponding calculation model is established,and the ant i-pene trating performance of the new sandwich panels is studi ed.The energy changes of the projectile and the targe t plate,the fail ure m orphology of the new sandwich panels,the influence between i mpact velocity and resi dual velocity of the project ile are analyzed.The influence of different thickness ratio of core and skin sheet with equal areal densit y,thickness of skin sheet and aluminum foams with diverse densities on the penetration resistance of the new sandwi ch panels are discussed.(3)Based on the validity of material parameters and feasibil ity of ALE method,the anti penetrating perfor mances of the new sandwich panels under different underwa ter condi tions are studied.There are three situations between water and sandwi ch panel,respectively as water back and front,water front and air back,air front and water back.Then t he anti-penetrating perfor mances of the new sandwich panels with different water s ituations and in air are compared to obtain the effects of water on anti-penetrating performance.(4)Based on the correc t m ateri al parameters and the simulation method,the obli quepenetr ation res istance s of the new sandwich pan els unde r differe nt im pact angles are studi ed.Impa ct angle is defined as t he angle between the projectile veloci ty direction and the normal of the target pl ate.The obl ique penetration resistances of the new sandwich panels,with0°,15°,30°,45°,60°im pact angles,are respectively calcul ated.By comparing t he anti penetration perfor mances under different impact angles,we obtain the effect of impact angl e on the penetration resist ance of the new sandwich panels. |
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