Application of metal laminates to aircraft structures: Prediction of penetration performance

A major thrust of the transportation industries in the US is the incorporation of advanced structural materials in airplanes and automobiles. These advanced materials include metal matrix composites, where particulate or whisker reinforcements stiffen and strengthen a ductile phase matrix. In aerospace structures, specific stiffness, improved strength, and weight reduction are key factors. Both in the certain parts of the airframe structure and in the engine fan containment area, increased emphasis is being given to the ability of the material to resist penetration from engine debris and other projectiles which might impact the aircraft structures. Experimental measurements of the ballistic limit velocity of a material versus material thickness gives a method to rank the relative penetration performance of aircraft structural materials. Dynamic finite element analysis aids in understanding the experimental results and in predicting the aircraft debris containment response. For certain aluminum alloys and metal laminates, the relationship between the ballistic limit velocity and plate thickness is linear, while for an aerospace titanium alloy, the ballistic penetration response is more complex.