以螺旋晶體設計負波松比材料

Abstract

在這篇論文中，我們設計了一種能展現出負波松比的結構，並且詳述設計的規則與方法；之後此結構的實體也由3D列印技術製作出來，並進行壓縮試驗，由於結構的非對稱性，我們進行了不同方向的壓縮試驗，且觀察到了非等向性；除了壓縮的荷重與位移之外，結構的變形也由攝影機錄製，而錄製的影像則使用影像量測軟體ImageJ進行分析；另外我們也以軟體Abaqus 6.12製作了有限元素模型與實驗比較，再以模型研究實驗難以觀察的結構內部的變形，然後藉由調整模型材料與幾何參數進行參數研究，探討波松比、等效應力、孔隙比與幾何間的關係，最後再討論此結構的可能應用與未來研究方向。

In this thesis, we designed a structure that can achieve negative Poisson’s ratio (auxeticity). The design rules and procedures were developed. The structure is studied experimentally by compressing a 3D printed specimen. Due to the complex geometry of the structure, compression test of different load direction were performed and anisotropic behavior is observed. Besides compression force and displacement, deformed shape is recorded by camera and the video was analyzed by image measurement software ImageJ. Also, a model was built by finite element software Abaqus 6.12 to compare with experiment. Then we studied the deformation inside the structure by finite element (FE) model because it’s hard to observe the internal deformation in experiment. Next, parametric study was performed by changing material setting and structure geometry in FEM model. The relation between Poisson’s ratio, effective stress, porosity and geometry is investigated. Finally, the possible application and future research are discussed.