Subjects: Mechanics >> Applied Mechanics submitted time 2023-03-20 Cooperative journals: 《应用力学学报》
Abstract： Surface instability of hard films adhered on soft substrate has always been a difficult problem forflexible electronic devices. Considering the shear stress between the bi-layer film and the elastic gradedsubstrate , an analytical model of bi-layer film/ elastic graded substrate is established.By using the dis-placement continuity of the interface , the analytical expressions of the critical strain and wavelength of thebi-layer film/elastic graded substrate are obtained. Then , through several examples , the validities of theproposed expressions are verified which are compared with those results obtained by the finite element analysis.At the same time, the influences of the geometric parameters of the bi-layer film and physical pa-rameters of the elastic graded substrate on the buckling behavior are analyzed. 'The results in this papershow that decreasing the thickness of device layer or increasing the thickness of encapsulation layer canimprove the stability of bilayer film/elastic graded substrate structure; if the substrate is relatively“soft”orthe device layer is “hard”,the shear force of the interface between the device layer and the substrate willbe taken into account , which can prevent the resistance of the three-layer film/ substrate structure from un-dergoing interface failure.Above all, the research will provide theoretical support for the fabrication of flex-ible electronic devices with hard film/elastic graded substrate structure.
Subjects: Mechanics >> Basic Mechanics submitted time 2022-12-21 Cooperative journals: 《应用力学学报》
Abstract：
Polydimethylsiloxane(PDMS)is widely used in flexible devices such as electronics,solar cells,and microfluidic chips,due to its distinguished ductility and mechanical properties.PDMS also has exploited its applications in space composite materials and flexible deployable mechanisms,where it is necessary to consider the long-term effects of the space irradiation environment on the materials.In this study,the mechanical properties of PDMS exposed to electron irradiation were studied:①First,the resin and curing agent were mixed in designed proportions and dumbbell-shaped tensile specimens of PDMS were produced according to the national standard.Then,a uniaxial tensile test was carried out.②Tensile testing was carried out on the specimens exposed to different doses of high-energy electron irradiation.Scanning electron microscope(SEM)was used to observe the fracture morphology of the tensile specimens both with or without irradiation and analyze the elemental composition.③Based on the Neo-Hookean model,the stress-strain relationship of uniaxial tension was derived from the energy density function by fitting it from the experimental data.The results demonstrate that electron irradiation has a significant effect on the mechanical properties and surface morphology of PDMS.The irradiated PDMS specimen appears to be hardened,and its elastic modulus increases with the increase of radiation,while an opposite trend is found at the elongation at break.
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