Constitutive modeling of shape memory polymer based self-healing syntactic foam

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:47

Article

Xu, We¹  Li, Guoqiang^1,2 

[1] Louisiana State Univ, Dept Mech Engn, Baton Rouge, LA 70803 USA

[2] Southern Univ, Dept Mech Engn, Baton Rouge, LA 70813 USA

关键词: SMP;    Syntactic foam;    Self-healing;    Thermomechanics;    Constitutive model;    Stress strain recovery;   

DOI  :  10.1016/j.ijsolstr.2010.01.015

来源: Elsevier

【 摘 要 】

In a previous study, it was found that the shape memory functionality of a shape memory polymer based syntactic foam can be utilized to self-seal impact damage repeatedly, efficiently, and almost autonomously [Li G., John M., 2008. A self-healing smart syntactic foam under multiple impacts. Comp. Sci. Technol. 68(15-16), 3337-3343]. The purpose of this study is to develop a thermodynamics based constitutive model to predict the thermomechanical behavior of the smart foam. First, based on DMA tests and FTIR tests, the foam is perceived as a three-phase composite with interfacial transition zone (interphase) coated microballoons dispersed in the shape memory polymer (SMP) matrix; for simplicity, it is assumed to be an equivalent two-phase composite by dispersing elastic microballoons into an equivalent SMP matrix. Second, the equivalent SMP matrix is phenomenologically assumed to consist of an active (rubbery) phase and a frozen (glassy) phase following Liu et al. [Liu, Y., Gall, K., Dunn, M.L., Greenberg, A.R., Diani J., 2006. Thermomechanics of shape memory polymers: uniaxial experiments and constitutive modeling. Int. J. Plasticity 22,279-313]. The phase transition between these two phases is through the change of the volume fraction of each phase and it captures the thermomechanical behavior of the foam. The time rate effect is also considered by using rheological models. With some parameters determined by additional experimental testing, the prediction by this model is in good agreement with the 1D test result found in the literature. Parametric studies are also conducted using the constitutive model, which provide guidance for future design of this novel self-healing syntactic foam and a class of light-weight composite sandwich structures. (C) 2010 Elsevier Ltd. All rights reserved.

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