Transient Response Of Flexible Substrate Laminated Structure By Finite Element Simulation

Flexible electronics has features of portable,transparent,lightweight,stretch/bending,and broad prospects in application.Flexible substrate is an important part of flexible electronic devices,and is also a key material to realize good mechanical properties of functional devices.The material properties of adjacent layers of flexible substrate are very different.It is of great significance to study the transient response characteristics of the flexible substrate laminated structure.This paper is based on the study of the mechanics of flexible electronic multilayer structure.The transient response of flexible substrate structure is calculated by finite element software ABAQUS.Firstly,a study on dynamics performance of laminated column on flexible substrate is carried out by changing the thickness and section size of flexible substrate.Displacement,velocity and acceleration responses of central points on their top surfaces are given.Stress and strain responses of central points on interfaces are also discussed in this paper.Results indicate that structure is in large deformation in the process of impact.The flexible substrate and encapsulation layer play a great role in the buffer protection of the middle layer and reduce the damage to the middle layer.The transient response of laminated column on flexible substrate is much affected by substrate thickness.Under uniform load impact,the transient response of the laminated column with smaller section sizes are smooth and fluctuating in a certain amplitude.Dynamic instability of the laminated column with larger section sizes occurred.Secondly,the transient response process under impact load is studied around flexible substrate/silicon thin-film laminated beam structure.A study on dynamics performance of the flexible substrate/silicon laminated beams is carried out by changing the thickness of silicon layer,elastic modulus of substrate layer,thickness of substrate layer,material combination and so on.Results indicate that the displacement response of the flexible substrate/silicon laminated beams decreases with the increase of thickness of the silicon layer.The peaks of the transient response of velocity and acceleration of laminated beams with the encapsulated layer and substrate layer are SU-8 and PDMS respectively are the lowest.When PDMS as a flexible substrate,the flexible substrate elastic modulus has little influence on the transient response of the flexible substrate/silicon laminated beams,the parameter is not considered in the study on transient response of flexible laminated beams.Increasing the substrate thickness can reduce the transient response amplitude of flexible substrate/silicon laminated beam.Finally,the energy response relation of each parameter and the influence of each parameter on the absorption energy ratio of the silicon layer are calculated based on the above model.The energy relation of each component is that SU-8 strain energy account for most of the whole model,and the strain energy response of Si and PDMS takes up a small part of the whole model.The natural frequencies and modes of such laminated beams are preliminarily analyzed by finite element method.The elastic modulus of flexible substrate has less influence on the frequency of lower order,and has a greater influence on the frequency of higher order frequency.The results of the above studies provide a reference for the dynamic study of flexible electronic structures.