| The work presented in this thesis is structured into three parts,i.e.origami geometrical design,origami-inspired mechanical metamaterials and thermoplastic foldcores.Firstly,the geometrical configurations of two origami tessellations,namely piecewise tapered Miura and Resch’s patterns,are analyzed.The influences of geometric parameters on the folded shapes of these patterns are studied.The results show that folding parameters such as side lengths of the fold pattern and folding angles have a strong influence on the in-and out-profiles of folded piecewise tapered Miura structuresand with certain parameters,the folded structure manifest a doubly curved profile.Moreover,the relationship between the fold angle and the shape and height of Resch’s pattern folded structure is established.Secondly,origami-inspired mechanical metamaterials based on Miura-derivative fold patterns and with curved creases are studied.Analytical models for the prediction of their Poisson’s ratios and moduli are developed.The relationship between geometric parameters and mechanical properties is investigated.It is found that the curved-crease metamaterials provide negative in-plane and out-of-plane Poisson’s ratios and interestion stiffness properties,which are infinity in most conditions.Thirdly,an experimental and numerical study on thermoplastic foldcores is presented.A manufacturing process for the production of thermoplastic foldcores is established.A parametric study on the mechanical properties of thermoplastic foldcores with different geometric parameters is performed by means of a validated virtual testing protocol.Finally,the mechanical properties of a PEEK model and its aramid counterpart with the same geometry are compared.It is shown that although the aramid foldcore model has higher compressive and shear stiffnesses and strengths than the PEEK model does,the PEEK foldcore exhibits comparable or even better energy absorption performance than the aramid foldcore. |
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