Lee Yonghee, Moon Junghwan, Choi Joonmyung, Cho Maenghyo
Division of Multiscale Mechanical Design, School of Mechanical and Aerospace Engineering, Seoul National University, San 56-1, Shillim-Dong, Kwanak-Ku, Seoul, 151-744, South Korea.
Sci Rep. 2017 Oct 27;7(1):14277. doi: 10.1038/s41598-017-14599-z.
Concentrated light-absorption on specific areas of polystyrene (PS) sheet induces self-folding behaviour. Such localized light-absorption control is easily realized by black-coloured line pattern printing. As the temperature in the line patterns of PS sheet increases differently due to the transparencies in each line pattern, localized thermal contraction generates folding deformation of the PS sheet. The light-activated folding technique is caused by the shape memory effect of PS sheet. The shape memory creation procedure (SMCP) is described by using molecular dynamic (MD) simulation, and the constitutive model of PS sheet is identified. This study employs the shell/cohesive line element for the folding deformation of PS sheet, and utilizes the constitutive model obtained from the MD simulation. Based on the continuum-model analysis of the PS sheet folding deformation activated by light, various self-folding structures are designed and manufactured.
聚苯乙烯（PS）片材特定区域的集中光吸收会引发自折叠行为。通过黑色线条图案印刷可轻松实现这种局部光吸收控制。由于PS片材各线条图案的透明度不同，线条图案中的温度会以不同方式升高，局部热收缩会使PS片材产生折叠变形。光激活折叠技术是由PS片材的形状记忆效应引起的。通过分子动力学（MD）模拟描述了形状记忆创建过程（SMCP），并确定了PS片材的本构模型。本研究采用壳/粘结线单元来模拟PS片材的折叠变形，并利用从MD模拟中获得的本构模型。基于光激活的PS片材折叠变形的连续介质模型分析，设计并制造了各种自折叠结构。
