Inhomogeneous deformations of Light Activated Shape Memory Polymers

Sodhi, Jaskirat; Cruz, P.R.; Rao, I. J.

doi:10.1016/j.ijengsci.2014.11.010

Cited by 35 publications

(12 citation statements)

References 43 publications

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“…Substituting Equation (37) into Equation (33) and by prescribing the stretch rate K we can facilitate ordinary differential equations (ODEs) for different viscoelastic deformations. To solve these ODEs, we require material parameters (µ i and η i ) and proper initial conditions.…”

Section: Numerical Proceduresmentioning

confidence: 99%

“…We use a Neo-Hookean model for the hyperelastic equilibrium branch, and the model of the viscoelastic non-equilibrium branch is developed using the theory of multiple natural configurations [21]. The material response of materials belonging to many different classes have been modeled using this framework, some of them are: multi-network polymers [22], metal plasticity [23], viscoelastic liquids [24,25], crystallization in polymers [26][27][28], crystallizable SMPs [29][30][31], and light-activated SMPs [32,33]. Classical elasticity and linear viscous fluids arise as simple cases within this theory.…”

Section: Introductionmentioning

confidence: 99%

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Modeling the Viscoelastic Behavior of Amorphous Shape Memory Polymers at an Elevated Temperature

Cui

Moon

Rao

2016

Fluids

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Shape memory polymers (SMPs) are soft active materials, their special property is the ability to hold a temporary shape and when exposed to a suitable trigger, they come back to their original shape. These external stimuli can be temperature, light or electromagnetic fields. Amorphous SMPs are a class of thermally-activated SMPs that rely on glass transition to retain their temporary shape. Above the glass transition temperature (T > T g), (amorphous SMPs exhibit finite deformation and viscoelastic behavior. In this work we develop a model to capture the viscoelastic behavior of the amorphous SMPs at elevated temperatures. The model uses an approach that was initially developed to study non-Newtonian viscoelastic fluids. We accomplish this by developing a multi-branch model based on the theory of multiple natural configurations using the maximization of the rate dissipation to determine the evolution of the natural configurations. We apply our model to study several different deformations at an elevated temperature T = 130˝C and show that this approach is able to capture the viscoelastic behavior of these polymers. The predictions of the theory are then compared with experimental results.

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Section: Numerical Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling the Viscoelastic Behavior of Amorphous Shape Memory Polymers at an Elevated Temperature

Cui

Moon

Rao

2016

Fluids

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“…They are capable of changing its size and shape when activated through a suitable stimuli like heat [22][23], light [24][25], electricity [26][27], solution [28], and so on [29][30][31]. SMPs are particularly promising in aerospace [20][21][22][23][24][25][26][27][28][29][30][31][32], biomedical [33][34], additive manufacturing [35][36], and other engineering fields [37][38][39] owing to their characteristic of high deformability, high shape recoverability and easy processing [40][41]. Thermal-responsive SMPs are the most prospective SMPs because of their simple stimulus form and fast response [42]; thus, they are investigated in the present work.…”

Section: Introductionmentioning

confidence: 99%

Finite element analysis of shape-memory polymer mast

Liu

Yang

2019

International Journal of Smart and Nano Materials

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Space masts are widely used in the aerospace engineering as one type of deployable space structures. In this paper, based on the stimuli-responsive effects of shape-memory polymers (SMPs), an intelligent mast with shape-memory function is studied. The thermos-mechanical constitutive model of SMPs is associated with the finite element (FE) software, and then the deployable deformation and shape-memory effect of the intelligent mast are investigated by the FE method. It is demonstrated that the mast can automatically deploy due to the shape recovery characteristics of SMPs. Furthermore, the effects of structure parametric of the mast and temperature are also investigated. The results can contribute to the design and application of novel SMP masts.

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“…Also, in this study, Sodhi and Rao [18] assumed that the intensity of light was homogeneous and they also considered homogeneous deformations. In a recent paper, Sodhi et al [19] considered inhomogeneous light intensity and also inhomogeneous deformations. Another study, from a very different point of view, that warrants mention, is that of Beblo and Weiland [20] who proposed a multiscale model to describe the soft and hard state moduli of the polymer based on a molecular argument and used statistical mechanical techniques to predict the mechanical response of LASMPs.…”

Section: Introductionmentioning

confidence: 99%

Modeling the response of light-activated shape memory polymers

Yong

Muliana

Rajagopal

2016

Mathematics and Mechanics of Solids

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The aim of this paper is to model the macroscopic response of light-activated shape memory polymers (LASMPs) subject to mechanical loadings and exposure to light at certain wavelengths and frequencies. When exposed to external stimuli of mechanical, thermal, photochemical and other origins, polymers undergo microstructural changes, e.g., scission, crosslinking, crystallization, etc. These microstructural changes affect the macroscopic performance of the polymers. In this study, in order to incorporate the effect of microstructural changes on the macroscopic response of light-activated shape memory polymers, we formulate constitutive models based on the notion that the natural configuration of the body under consideration evolves during its response. The theoretical framework appeals to a multinetwork approach consisting of two microstructural networks, which are the original network and the new network formed owing to a light activation. An important distinction between the approach considered here and the usual multinetwork approaches is that there is no conversion of one network to another; instead, what we have is the formation of a second network owing to the linking of photosensitive particles that get linked due to light irradiation. Furthermore, two different constitutive models are considered. The first model assumes the two networks are isotropic. The second model takes into account the directional preference of the second network that is formed. Both these models build on the work of Sodhi and Rao, which is based on the framework developed by Rajagopal and Srinivasa. Several classical boundary value problems involving homogeneous and inhomogeneous deformations are studied. We also investigate two nonlinear constitutive relations and different loading modes. The results highlight the differences in the responses when isotropic and anisotropic models are considered.

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Inhomogeneous deformations of Light Activated Shape Memory Polymers

Cited by 35 publications

References 43 publications

Modeling the Viscoelastic Behavior of Amorphous Shape Memory Polymers at an Elevated Temperature

Modeling the Viscoelastic Behavior of Amorphous Shape Memory Polymers at an Elevated Temperature

Finite element analysis of shape-memory polymer mast

Modeling the response of light-activated shape memory polymers

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