A photoviscoplastic model for photoactivated covalent adaptive networks

doi:10.1016/j.jmps.2014.05.008

CORC > 北京大学 > 工学院

	A photoviscoplastic model for photoactivated covalent adaptive networks
	Ma, Jing ; Mu, Xiaoming ; Bowman, Christopher N. ; Sun, Youyi ; Dunn, Martin L. ; Qi, H. Jerry ; Fang, Daining
刊名	固体力学与固体物理学杂志
	2014
关键词	Light activated polymers Photo-induced viscoplasticity Finite deformation constitutive model Photoforming Covalent adaptive network TIME-INTEGRATION PROCEDURE SHAPE-MEMORY CONSTITUTIVE-EQUATIONS MODERATE DEFORMATIONS MECHANICAL-PROPERTIES GLASSY-POLYMERS BULGE TEST LIGHT DIFFUSION FILMS
DOI	10.1016/j.jmps.2014.05.008
英文摘要	Light activated polymers (LAPs) are a class of contemporary materials that when irradiated with light respond with mechanical deformation. Among the different molecular mechanisms of photoactuation, here we study radical induced bond exchange reactions (BERs) that alter macromolecular chains through an addition-fragmentation process where a free chain whose active end group attaches then breaks a network chain. Thus the BER yields a polymer with a covalently adaptable network. When a LAP sample is loaded, the macroscopic consequence of BERs is stress relaxation and plastic deformation. Furthermore, if light penetration through the sample is nonuniform, resulting in nonuniform stress relaxation, the sample will deform after unloading in order to achieve equilibrium. In the past, this light activation mechanism was modeled as a phase evolution process where chain addition-fragmentation process was considered as a phase transformation between stressed phases and newly-born phases that are undeformed and stress free at birth. Such a modeling scheme describes the underlying physics with reasonable fidelity but is computationally expensive. In this paper, we propose a new approach where the BER induced macromolecular network alteration is modeled as a viscoplastic deformation process, based on the observation that stress relaxation due to light irradiation is a time-dependent process similar to that in viscoelastic solids with an irrecoverable deformation after light irradiation. This modeling concept is further translated into a finite deformation photomechanical constitutive model. The theological representation of this model is a photoviscoplastic element placed in series with a standard linear solid model in viscoelasticity. A two-step iterative implicit scheme is developed for time integration of the two time-dependent elements. We carry out a series of experiments to determine material parameters in our model as well as to validate the performance of the model in complex geometrical and loading configurations. The comparison between the finite element simulations and experiments shows that the model can accurately capture the response of the LAP under a wide range of coupled photo-mechanical loading conditions, such as light induced stress relaxation, creep in tension, and bending. Furthermore, we demonstrate the versatility of the model by simulating a series of examples that exhibit complex three-dimensional, time-dependent photodeformation, including photoorigami, photoforming, and photobulge tests. (C) 2014 Elsevier Ltd. All rights reserved.; http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000341466200006&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701 ; Materials Science, Multidisciplinary; Mechanics; Physics, Condensed Matter; SCI(E); EI; 6; ARTICLE; qih@me.gatech.edu; fangdn@pku.edu.cn; 1; 84-103; 70
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/154188]
专题	工学院
推荐引用方式 GB/T 7714	Ma, Jing,Mu, Xiaoming,Bowman, Christopher N.,et al. A photoviscoplastic model for photoactivated covalent adaptive networks[J]. 固体力学与固体物理学杂志,2014.
APA	Ma, Jing.,Mu, Xiaoming.,Bowman, Christopher N..,Sun, Youyi.,Dunn, Martin L..,...&Fang, Daining.(2014).A photoviscoplastic model for photoactivated covalent adaptive networks.固体力学与固体物理学杂志.
MLA	Ma, Jing,et al."A photoviscoplastic model for photoactivated covalent adaptive networks".固体力学与固体物理学杂志 (2014).