Study On The Debonding Mechanism And The Protection Capability Of Ceramic Composite Armors Against Multi-hit

The light armoured vehicles have to meet to the demands against multi-hit byarmour-piercing projectiles (APP) and high speed fragments in the battle. Based on theballistic experiments, the protection capability of ceramic/ aluminium composite armorsagainst 7.62mm APP single and multi-hit were investigated by numerical simulation.The main contents and innovative work include:(1)The ballistic experiments of ceramic/ aluminium composite armors againstsingle hit were simulated by the method, without setting an adhesive layer and withsetting adhesive layers, the related theory was expounded and a method of reasonabledereferencing for failure strain of the metal materials hardening model was set up. Bycomparing the numerical results with the experiments, the results show that thenumerical results by using the two methods were well agreement with experiments onthe limit velocity, the deformation of the aluminium back layers and etc. However, inthe number of debonding ceramics, the methods without setting an adhesive layer wasextremely different with experiments, and the methods with setting adhesive layers werecomplete agreement with experiment. The method without setting an adhesive layermay be employed to study single hit but the method with setting adhesive layers shouldbe adpoted to simulate multi-hit.(2)The ceramic/ aluminium debonding contact stress failure criterion and theadhesive layer stain failure criterion were analyzed, the debonding mechnism ofceramic/ aluminium composite armors were deeply studied by numerical simulation.The results indicate that the debonding failure should adopt the stain failure criterion ofadhesive layer and the tension failure of the adhesive layers is brought by thedeformation of the aluminium back layers under shock action and the ceramic plates aredebonding in the end.(3)The analogy method named"Geometry Space Method"was set up to simulatemulti-hit. The algorithmic example of ceramic/ aluminium composite armors againstthree APP strikes show that the method is not only effectively reflect multi bullets atregular intervals, but aslo ensure that the process of the target response to the continuityof the board and damage, fully demonstrated the damage to an attack against theperformance impact.(4)The adhesive layer thickness effect of ceramic/ aluminium composite targetswas studied by numerical simulation. The results indicate that the better thickness of polyurethane adhesive layer is 0.4 mm against not more than three APP hits, whenagainst more than three APP hits, the better thickness of polyurethane adhesive layer is0.6 mm.