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In this paper, we mimic the venous morphology of a typical plant leaf into a fiber composite structure where the veins are replaced by stiff fibers and the rest of the leaf is idealized as an elastic perfectly plastic polymeric matrix. The variegated venations found in nature are idealized into three principal fibers — the central mid-fiber corresponding to the mid-rib, straight parallel secondary fibers attached to the mid-fiber representing the secondary veins and then another set of parallel fibers emanating from the secondary fibers mimicking the tertiary veins of a typical leaf. The tertiary fibers do not interconnect the secondary fibers in our present study. We carry out finite element (FE) based computational investigation of the mechanical properties such as Young’s moduli, Poisson’s ratio and yield stress under uniaxial loading of the resultant composite structures and study the effect of different fiber architectures. To this end, we use two broad types of architectures both having similar central main fiber but differing in either having only secondary fibers or additional tertiary fibers. The fiber and matrix volume fractions are kept constant and a comparative parametric study is carried out by varying the inclination of the secondary fibers. We find significant effect of fiber inclination on the overall mechanical properties of the composites with higher fiber angles transitioning the composite increasingly into a matrix-dominated response. We also find that in general, composites with only secondary fibers are stiffer with closed cell architecture of the secondary fibers. The closed cell architecture also arrested the yield stress decrease and Poisson’s ratio increase at higher fiber angles thereby mitigating the transition into the matrix dominated mode. The addition of tertiary fibers also had a pronounced effect in arresting this transition into the matrix dominated mode. However, it was found that indiscriminate addition of tertiary fibers may not provide desired additional stiffness for fixed volume fraction of constituents. In conclusion, introducing a leaf-mimicking topology in fiber architecture can provide significant additional degrees of tunability in design of these composite structures.

Dr. Olia received his BS, MS and Ph.D. in the field of mechanical engineering from Northeastern University. He Has over thirty years of teaching experience at different universities such as Northeastern, Suffolk and Tufts. He has been teaching as a professor in the department of mechanical engineering at Wentworth Institute of Technology for the last twenty years. Dr. Olia has taught variety of courses such as Statics, Dynamics, Mechanics of Material, Vibrations and System Dynamics. Professor Olia has published more than eighteen technical papers in the areas of stress concentration in the hybrid composites, adhesively bonded composite joints with gaps subjected to bending, biomechanics and dynamic response of adhesively bonded joints. Professor Olia has appeared in a WBZ-TV Channel 4 news interview as an expert on MBTA crash which happened in Newton MA, in May 2008. He has also participated as a science consultant on the WGBH children show called "FETCH" in the summer of 2007. The episode was aired nationally in the fall 2008 season. Dr. Olia appeared in all segments and helped the kids with engineering design process to build, and test a cake protector. Professor Olia has had consulting experience in the area of finite element analysis and has collaborated with the Design Analysis Associates Consulting company which provides CAE consulting services to the utility, industrial and commercial clients. Dr. Olia is a registered professional engineer in the state of Massachusetts and has lectured extensively in FE and PE review courses at different colleges, universities and companies.