Natural Loofah Based Bio-inspired Structural Material And Its Thermal And Mechanical Properties

Natural structural materials such as bone,wood and shells are built and evolved through various ambient environments and they usually have complex hierarchical architectures with characteristic dimensions spanning from the nanoscale to the macroscale,and display lightweight feature and unique combinations of strength and toughness.In this thesis,natural loofah based Bio-inspired structural material is designed and its effective thermal and mechanical properties are experimentally measured and numerically simulated.The main research includes the following three parts:·Microstructure of loofah material.The comprehensive study of loofah's microstructure is the foundation of the bio-inspired design.Therefore,this thesis firstly describes the geometrical morphology of loofah and loofah fiber's microstructure by scanning electron microscope and laser cutting technique at Australian National University.Then compressive experiment is carried out for some loofah samples and the approximated formulation of equivalent elastic modulus and density of the loofah material is presented by curve fitting method.·Based on loofah structure characteristics,the new bio-inspired lightweight structure material with regular hexagonal pores is geometrically designed by using the commercial software Pro/E,and then such structure is produced with ABS-M30 by using 3-D printing machine.Compressive test reveals its equivalent modulus of elasticity(about 166.9 ~ 180.59MPa).·The quasi-static compression process and bucking of the present bio-inspired structure material with ABS-M30 solid phase are respectively simulated by the commercial finite element software ABAQUS.For the sake of convenience,the present bio-inspired structure material is modeled as a sandwich structure by adding upper and bottom plates.The equivalent elastic modulus and the first-order critical buckling load are respectively evaluated to be 133.21 MPa and 1064.8N.In addition,the heat transfer simulation of the present structure is performed to calculate the equivalent heat transfer coefficient 6.35W/(m·K).