Development and characterization of an impact-resilient 3D nano-reinforced fiber metal laminate composite

The global automotive industry has been recently challenged to increase the current fuel efficiency of automobiles by nearly 100% by 2025. One of the most important strategies has been to reduce the weight of vehicles, yet adhering tp the required crashworthiness.

In response to the above challenge, the proposed research aims at developing a hybrid composite material that is (i) relatively light-weight, (ii) provides the required stiffness and strength (iii) offers remarkable crashworthiness and (iv) yet, it is relatively cost-effective. The new material takes advantages of the marriage of a light-weight metallic alloy and a relatively inexpensive FRP to address the challenge. In other words, a recently developed truly novel 3D glass fabric is combined with light-weight magnesium alloy (MgA) sheets (75% lighter than steel) to produce an exemplary fiber-metal laminate composite (FML). To augment the performance of this unique composite panel, the cavities within the 3D-fabric could be filled with a light-weight foam.

However, before this FML can be considered in vehicles, one must gain a thorough understanding of its performance under critical loading conditions. In past three years, we have been investigating the performance of various configurations of the 3D-FML under out-of-plane impact loading. Our investigation on performance of the FML under in-plane impulse loading has begun very recently. Our preliminary investigation has revealed that the quality of the interface bond between MgA and FRP has a significant effect on the buckling and post-buckling response of the FML. Therefore, to maximize the performance of the said FML, optimally functionalized inexpensive nanocarbon particles (namely, graphene platelets), will be used to economically and effectively enhance the resiliency of the interfaces.

Moreover, a key factor in promoting the use of the developed 3D-FML in future applications is the ability to predict the performance of the FML under critical loading conditions (e.g., axial impact), and generation of practical design curves, which will enable practicing engineers to implement differently configured 3D-FMLs for a given application. These tasks would have to be done in two stages. In the first stage, various aspects affecting the response of the FML should be characterized numerically. To optimize the performance of MgA/FRP interface, we will further improve the predictive capability of the numerical framework developed in past three years within our group, which included the effective use of the cohesive zone modeling (CZM). For that we intend to use the relatively recently developed “extended finite element method” (XFEM). Therefore, the basic aim of this part of the proposed research is to gain experience with XFEM, and investigate the effects of GNP inclusion in the resin used to mate FRP to MgA sheets, and to optimize the bond strength.