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Fracture resistance curve for bioinspired multilayered ceramic/polymer composites

Learning lessons from nature is the key element in the design of tough and strong composites. Bone and nacre are prime examples of natural materials with high strength and toughness. Previous studies on mechanical performance of these structural materials show that their outstanding properties are direct results of the nanoscale features and the optimized arrangement of the elements. However, experimental verification of all suggested mechanisms is not fully explored. In this study we investigated the toughening mechanisms of Alumina/PDMS composite samples with lamellar structure. Samples with micron-size layers were made using freeze-casting method which is the best “Top-Down” fabricating method to make ceramic-based materials in large scale of a few inches. There are different parameters such as solution concentration, freezing rate, baking temperature and heating/cooling rates in baking that affect the structure and subsequently mechanical performance of these multilayered materials. Samples with a variety of solution concentration and freezing rates have been made. Single-edge three-point bend test was used to find the R-curve of the samples. The preliminary results show that samples with lower cooling rate (higher lamellae thickness) show higher fracture toughness. The approach is flexible for different material combinations.

Author(s):

Sina Askarinejad    
Worcester Polytechnic Institute
United States

Nima Rahbar    
Worcester Polytechnic Institute
United States