FRP/AC sandwich panel with a core of lightweight high performance Aerated Concrete (AC) (e.g., Autoclave Aerated Concrete, Cellular Concrete etc.) and face sheets of Fiber Reinforced Plastics (FRP) composites has the potential to be an excellent energy absorbing construction material plus it is relatively inexpensive and available over much of the globe. Consistent with the recent interests in high performance, zero maintenance civil infrastructures, the proposed project will investigate the potential of FRP/AC sandwich panels (that are cost effective, long lived, and lightweight), and concepts will be developed and feasibility demonstrated for construction of low cost building structures using the panel. FRP/AAC sandwich components will also be durable in severe environments including corrosion and against ballistic impact. The results of the program has the potential to provide commercial and residential building that is more energy efficient and cheaper than traditional construction. It also has some properties, in addition to those mentioned above, that may be of interest to the military and others responsible for protecting lives. The unique contribution of the effort will be the application of cost-effective VARTM (Vacuum Assisted Resin Infusion Molding process) processing using innovative FRP hardening schemes with recently developed glass-and carbon fiber architectures and vinyl ester as well as epoxy resin types. The proposed effort will also eliminate traditional hand lay-up processing techniques which prove to be expensive and time-wise inefficient, and simultaneously advanced the state of the art of usage of advanced composites in civil infrastructure.
This project, a first step towards the long-term goal, will address five fundamental queries: 1) Investigate cost-effective manufacturing of FRP/AC sandwich panels with damage tolerant architectures and new resin systems. 2) Perform material characterization and structural testing of FRP/AC sandwich panels through a comprehensive experimental program. The experimental studies are expected to provide an understanding of the (a) failure mechanisms of the proposed sandwich panels, (b) the strength, energy absorption, strain and modulus characteristics, (c) the role of the fiber-to-AC concrete interface, and (d) failure of the composite layers in the sandwich structure. 3) Develop concept and demonstrate the ballistic response of affordably produced sandwich panels that have promise to harden/strengthen without adding weigh penalty, and are cost-effective. 4) Understand the structural response of such structures through analytical simulations. 5) Develop modular systems to show how the FRP/AC panels can be used for a variety of types of building construction. Erection, assembly, and connections will be provided to clearly show how the construction can handle the material in the field. The proposed effort will explore the tangible benefits for wider application in structural engineering application areas. Finally, it was demonstrated in our previous study that the impact response of two proven materials- i.e., carbon fiber reinforced composite (CFRC) and glass fiber reinforced composite (GFRC), in conjunction with engineered Polycarbonate (PC) thermoplastic exhibits desirable failure mechanisms through indention of the Polycarbonate accompanied by delaminating at Polycarbonate-laminate interface rendering minimal damage to the laminate. The dynamic tests included ballistic impact loading conditions using a 30-cal sabot assisted projectile and high strain rate loading using compression Split Hopkinson Pressure Bar (SHPB). The rationale was that by providing a PC facing, the damage resistance of the composite structure could be enhanced, as the PC can absorb energy, with minimal weight penalty, and can serve the purpose of a sacrificial layer, that is easily repairable or replaceable.
Two graduate students and three undergraduate students will be involved in the project. They will be exposed to a wide range of technological issues crossing the boundaries of different engineering disciplines such as materials science, structural design, computer simulations, infrastructure analysis, hazard mitigation, and a variety of fabrication techniques at the University of Alabama (Birmingham) campus. The REUs will also organize demonstration for the high school students at the university high school on the UAB campus. The PI has had prior rewarding experiences working with REUs from diverse groups.
