Mechanistic investigation of shear load transfer between dissimilar tablets
Rouzbeh Shahsavari (Rice University), Navid Sakhavand (Rice University)
Materials Design and Biomimetic Material Concepts
Tue 10:45 - 12:15
CIT 227
Unlike synthetic composites in which one quality is sacrificed over the other, stiffness, strength and toughness are almost perfectly balanced in biomaterials such as nacre, bone and spider silk. The key to this superior mechanical behavior can be attributed to the unique mechanism of shear load transfer between the thin building blocks. This has imparted an increasing interest for synthesizing “brick-and-mortar” structures with analogous mechanical behavior. Majority of previous studies focus on shear load transfer between tablets with identical properties and dimensions. Herein, we present a analytical model coupled to numerical simulations to study the elastic and plastic shear load transfer between dissimilar tablets with varying dimensions. Our elastic formulations show that how tuning the elastic moduli and the thickness of either of the tablets and the interfacial shear modulus dramatically changes the axial stress distributions in the tablets as wells as the interfacial shear stress distributions. In addition, the efficiency of the shear load transfer is investigated via identifying the maximum strain energy density of the composite, which translates into an overlap length. While for certain ratios of elastic moduli and thicknesses of the tablets, the elastic strain energy can be maximized, we show that for specific combination of tablets there is no optimum strain energy density and overlap length. In such composites, the elastic strain energy density will decrease monotonically with increasing the overlap length. Finally, we extend these analyses to the plastic regime where we explore the interplay between the different tablet strengths and maximum interfacial shear strength. Overall, our analyses provide guiding hypothesis for designing platelet-matrix composite structures with predetermined thicknesses and material properties to achieve stronger and more durable characteristics.