Toward the design of bio-inspired composites
Natural materials exhibit outstanding mechanical properties that are superior of their constituents. These remarkable properties are the results of evolutionary developments and architecture optimization that lead to high-performance lightweight materials, made of relatively weak and mundane constituents, with complex hierarchical structure topology. Classical examples of natural materials with exceptional performance of mechanical properties of limited constituents include nacre, wood, coconut endocarp, antler bone and armadillo armor. Through integrated multiscale simulations we aim at achieving deep understandings of structure-property relationships at different scales, unveiling the underlying governing mechanisms and design principles of biological materials, which will bring the possibility of developing new multifunctional materials with diverse technological applications.
Toward the design of strong, tough, light-weight advanced medium/high entropy alloys
CrCoNi-based medium- and high-entropy alloys display enhanced strength, ductility, and toughness at cryogenic temperature. However, as the temperature increases to 293 K, the yield and ultimate strength, ductility, fracture energy are lowered by ~50%, ~25% and ~80%, respectively, which significantly hinder its practical structural applications. To strengthen the FCC MEAs at room temperature, various strategies are developed. Among them precipitation strengthening has been proved to be a very effective method to improve the strength, especially the yield stress of alloys. Our goal is to to understand and predict how the nanoscale precipitates affects the microstructural evolution and consequently enhances the yield and ultimate strengths of CoCrNi-based MEA by utilizing multiscale computational simulations.
Funding source: ORAU Ralph E. Powe Junior Faculty Enhancement Awards.
Toward the design of “green” polymer composites
The covalently curing process for rubbers is indispensable in the rubber industry; however, there have been several inherent issues caused by traditional curing methods, such as the utilization of toxic curing additives, release of volatile organic compounds (VOCs), and difficulties in the recycling of end-of-life rubbers. To address these inherent issues, the concept and design strategy of green-curing system have been put forward. For example, a simple and effective curing strategy for epoxy-functionalized rubbers was provided to obtain a green curing process, excellent mechanical properties, and good recyclability. The epoxy-functionalized styrene-butadiene rubbers (SBR-GMA) with different epoxy group contents were synthesized by introducing glycidyl methacrylate (GMA) during emulsion polymerization. Through multiscale simulations we will provide essential information of interfacial interaction between SBR and fillers, failure mechanisms.
Funding source: NSF CAREER Award #2145086: “Multiscale Mechanics of Bio-based, Reprocessable, Recyclable and Mechanically Robust Polymer Composites.”