Mechanical Properties Of Inflatable Tube Imitating Clanas Bilineata Larva

Inflatable membrane structure is widely used in the fields of aerospace industry and construction industry with the advantages of small folding volume, light weight and fast shaping. Inflatable membrane tube is a kind of basic inflatable membrane structure which is employed as load-carrying unit to constitute the structure. The researchers has been paying attention on the mechanical properties of inflatable tube.The insect larva is of high load-carrying ability/material consumption ratio in natural world. The advantages of its body contribute to surviving in the progress of biological evolution. The system consists of sealing body wall, internal body fluid with pressure and muscle tissue is useful for reference in application for practical engineering. Therefore, we make a preliminary discussion of the mechanical properties of the membrane structure model inspired by insect larva with the aim of improving the load-carrying ability of conventional inflatable membrane structure. Furthermore, we expect that this new inflatable membrane structure may have better application prospect in the fields of aerospace industry and construction industry.The Clanas bilineata larva was chosed as a typical biological sample and it was used to observe its internal structure with the help of tissue section technique. We noticed that there were large amounts of crisscrossed fibrous muscle tissue inside the body wall of the larva. The muscle tissue was fixed at the depression of the body wall, which made them contact with each other tightly. The muscle tissue performed the role of stiffener to strengthen the body structure of the larva. This provided theoretical foundation to establish the membrane structure imitating insect larva and analyze its mechanical properties.The concrete form of the membrane structure imitating insect larva established preliminarily was stiffened inflatable tube. The research of its mechanical properties consisted of bending, axial compression and vibration based on theoretical analysis, contrast test and simulation by finite element method.The theoretical model fitted the test was chosed to describe the bending property of the inflatable tube in the bending test. The relation between transverse load and displacement under different inflation pressures was obtained. The collapse bending load and the inflation pressure were of linear relation. However, the related theoretical model didn’t fit the test well in the axial compression test and the research should mainly depend on the test. We got the relations between collapse displacement and inflation pressure, collapse load and inflation pressure, collapse work consumption of compression, respectively. Both stiffened and conventional inflatable tube were treated in this way to make a comparison and describe the axial compression property of the inflatable tube in more aspect.The finite element software ANSYS was employed to make a simulation of the stiffened inflatable tube including bending and axial compression properties. The comparison with the test was made to verify the rationalization of the finite element model and the method of simulation. Finally the finite element model of the stiffened inflatable tube was used to make a modal analysis which laid a basis for the dynamic response analysis.Further study on the membrane structure imitating insect larva from the perspective of bionics can be done based on the properties of material, structure and control method of the larva. And the optimized membrane structure imitating insect larva may be designed.