Instability under compression of wire/strip embedded in silicone

• Main Author: Kiong, Michael Jienyi
• Other Authors: Huang Weimin
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Mechanical engineering; Engineering::Materials
• Online Access: https://hdl.handle.net/10356/150445
• Institution: Nanyang Technological University

Instability mechanisms such as buckling and wrinkling happens frequently for thin film material, which might lead to debonding and fracture failure. Characteristics of buckling and wrinkling can be visibly seen most of the time where formal exhibit a localized patterns and homogenous pattern for latter. Part of the project focus on the controlled buckling of sheet material laminated in PDMS as well as shape memory polymer such as Vitrimers, to understand how different material and shape would buckle in reaction to stress loading. Structural coloration, different from pigmentation colours, can be achieve through diffraction of light in microscopically structured material. The other objective of this project is to produce structural colour in specimens by achieving submicron sized wavelength of wrinkles-atop a polymer without any additional coating layer such as paint. There is a total of 2 types of substrates being used in this experiment, which are Polyvinyl Acetate (PVA), also known as the Art & Craft glue as well as Poly(dimethylsiloxane) (PDMS), as well as the SiO2 Nano Particles (NP) to be mixed or embedded in between substrate to test for visible structural coloration. Both substrate material can be easily attained and are transparent after curing, having a similar refractive index as SiO2 NP. Additional possible parameters, which includes but not limited to, material selection, solvent selection, various thermomechanical methods can be further studied, could obtain and improve quality submicron wavelength. This would in turn produce visible structural coloration under white light.