Chiral Thermomechanical Metamaterials with Continuous Negative Thermal Expansion
thesisposted on 01.08.2019 by Debajyoti Saha
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Though the negative thermal expansion materials are important and appealing in science and engineering application, the natural materials are very less effective and manifest poor performance than the metamaterials. Here, using chiral design and normal material, metamaterial structure has been achieved. From the derivation, it has been proven that the structure contracted or expanded with an acceleration. It has also been observed that, the contraction or expansion rate depends upon the geometry of the structure (node to length ratio, i.e., size ratio). For the design scenario, node is the metallic structure helps to attach different number of strips. It has also been observed that, the state parameters and the control parameters (i.e. Temperature) share simple relationship between them. The rotation angle is a function of (property of the bimetallic strip), L (length of the strip) and T (temperature). Also, the maximum working temperature depends on the design parameters. So, it would be a metamaterial system. To dimensionalize, all the system equations have been scaled with L. So, length alone will not be a parameter of design, node to length ratio size ratio will be.