Recent advance on constitutive models of thermal-sensitive shape memory polymers

2011 ◽  
Vol 123 (3) ◽  
pp. 1502-1508 ◽  
Author(s):  
Qiang Zhang ◽  
Qing-Sheng Yang
Keyword(s):  
Shape Memory ◽  
Constitutive Models ◽  
Shape Memory Polymers

A comprehensive review on thermomechanical constitutive models for shape memory polymers

2020 ◽  
Vol 31 (10) ◽  
pp. 1243-1283 ◽  
Author(s):  
Ebrahim Yarali ◽  
Ali Taheri ◽  
Mostafa Baghani
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Constitutive Equations ◽  
Constitutive Relations ◽  
Shape Memory Polymer ◽  
Constitutive Models ◽  
Shape Memory Polymers ◽  
Typical Application ◽  
Comprehensive Review ◽  
Thermally Responsive

Shape memory polymers are a class of smart materials, which are capable of fixing their deformed shapes, and can return to their original shape in reaction to external stimulus such as heat. Also due to their exceptional properties, they are mostly used in four-dimensional printing applications. To model and investigate thermomechanical response of shape memory polymers mathematically, several constitutive equations have been developed over the past two decades. The purpose of this research is to provide an up-to-date review on structures, classifications, applications of shape memory polymers, and constitutive equations of thermally responsive shape memory polymers and their composites. First, a comprehensive review on the properties, structure, and classifications of shape memory polymers is conducted. Then, the proposed models in the literature are presented and discussed, which, particularly, are focused on the phase transition and thermo-viscoelastic approaches for conventional, two-way as well as multi-shape memory polymers. Then, a statistical analysis on constitutive relations of thermally activated shape memory polymers is carried out. Finally, we present a summary and give some concluding remarks, which could be helpful in selection of a suitable shape memory polymer constitutive model under a typical application.

scholarly journals Recent Advances of the Constitutive Models of Smart Materials — Hydrogels and Shape Memory Polymers

2020 ◽  
Vol 12 (02) ◽  
pp. 2050014 ◽  
Author(s):  
Rong Huang ◽  
Shoujing Zheng ◽  
Zishun Liu ◽  
Teng Yong Ng
Keyword(s):  
Phase Transition ◽  
Shape Memory ◽  
Smart Materials ◽  
Constitutive Models ◽  
Shape Memory Polymers ◽  
Soft Materials ◽  
Advantages And Disadvantages ◽  
Recent Advances ◽  
The One ◽  
New Research

Hydrogels and shape memory polymers (SMPs) possess excellent and interesting properties that may be harnessed for future applications. However, this is not achievable if their mechanical behaviors are not well understood. This paper aims to discuss recent advances of the constitutive models of hydrogels and SMPs, in particular the theories associated with their deformations. On the one hand, constitutive models of six main types of hydrogels are introduced, the categorization of which is defined by the type of stimulus. On the other hand, constitutive models of thermal-induced SMPs are discussed and classified into three main categories, namely, rheological models; phase transition models; and models combining viscoelasticity and phase transition, respectively. Another feature in this paper is a summary of the common hyperelastic models, which can be potentially developed into the constitutive models of hydrogels and SMPs. In addition, the main advantages and disadvantages of these constitutive modes are discussed. In order to provide a compass for researchers involved in the study of mechanics of soft materials, some research gaps and new research directions for hydrogels and SMPs constitutive modes are presented. We hope that this paper can serve as a reference for future hydrogel and SMP studies.

scholarly journals Applications of Shape Memory Polymers in Kinetic Buildings

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Jing Li ◽  
Qiuhua Duan ◽  
Enhe Zhang ◽  
Julian Wang
Keyword(s):  
Shape Memory ◽  
Electric Fields ◽  
Constitutive Models ◽  
Shape Memory Polymers ◽  
Building Energy ◽  
Building Structures ◽  
Academic Researchers ◽  
Building Energy Saving ◽  
External Stimuli ◽  
Building Engineering

Shape memory polymers (SMPs) have attracted significant attention from both industrial and academic researchers, due to their useful and fascinating functionality. One of the most common and studied external stimuli for SMPs is temperature; other stimuli include electric fields, light, magnetic fields, water, and irradiation. Solutions for SMPs have also been extensively studied in the past decade. In this research, we review, consolidate, and report the major efforts and findings documented in the SMP literature, according to different external stimuli. The corresponding mechanisms, constitutive models, and properties (i.e., mechanical, electrical, optical, shape, etc.) of the SMPs in response to different stimulus methods are then reviewed. Next, this research presents and categorizes up-to-date studies on the application of SMPs in dynamic building structures and components. Following this, we discuss the need for studying SMPs in terms of kinetic building applications, especially about building energy saving purposes, and review recent two-way SMPs and their potential for use in such applications. This review covers a number of current advances in SMPs, with a view towards applications in kinetic building engineering.

scholarly journals Modeling the response of light-activated shape memory polymers

2016 ◽  
Vol 22 (5) ◽  
pp. 1116-1143 ◽  
Author(s):  
Zhi Yuan ◽  
Anastasia Muliana ◽  
Kumbakonam Ramamani Rajagopal
Keyword(s):  
Shape Memory ◽  
Constitutive Relations ◽  
Constitutive Models ◽  
Shape Memory Polymers ◽  
The Body ◽  
Important Distinction ◽  
Microstructural Changes ◽  
Anisotropic Models ◽  
Loading Modes ◽  
Macroscopic Response

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, cross-linking, 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.

Constitutive Modeling of Shape Memory Effects in Semicrystalline Polymers With Stretch Induced Crystallization

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Kristofer K. Westbrook ◽  
Vikas Parakh ◽  
Taekwoong Chung ◽  
Patrick T. Mather ◽  
Logan C. Wan ◽  
...  
Keyword(s):  
Shape Memory ◽  
Constitutive Modeling ◽  
Three Dimensional ◽  
Constitutive Models ◽  
Shape Memory Polymers ◽  
One Dimensional ◽  
Chain Mobility ◽  
Shape Memory Effects ◽  
External Stimuli ◽  
Induced Crystallization

Polymers can demonstrate shape memory (SM) effects by being temporarily fixed in a nonequilibrium shape and then recover their permanent shape when exposed to heat, light, or other external stimuli. Many previously developed shape memory polymers (SMPs) use the dramatic molecular chain mobility change around the glass transition temperature Tg to realize the SM effect. In these materials, the temporary shape cannot be repeated unless it is reprogramed, and therefore the SM effect is one way. Recently, a semicrystalline SMP, which can demonstrate both one- and two-way SM effects, was developed by one of our groups (Chung, T., Rorno-Uribe, A., and Mather, P. T., 2008, “Two-Way Reversible Shape Memory in a Semicrystalline Network,” Macromolecules, 41(1), pp. 184–192). The main mechanism of the observed SM effects is due to stretch induced crystallization. This paper develops a one-dimensional constitutive model to describe the SM effect due to stretch induced crystallization. The model accurately describes the complex thermomechanical SM effect and can be used for the future development of three-dimensional constitutive models.

Application of Fractional Calculus Methods to Viscoelastic Response of Amorphous Shape Memory Polymers

2015 ◽  
Vol 31 (4) ◽  
pp. 427-432 ◽  
Author(s):  
C-Q. Fang ◽  
H.-Y. Sun ◽  
J.-P. Gu
Keyword(s):  
Fractional Calculus ◽  
Shape Memory ◽  
Constitutive Models ◽  
Shape Memory Polymers ◽  
Viscoelastic Response ◽  
Thermally Activated ◽  
Viscoelastic Models ◽  
Recovery Response ◽  
Viscoelastic Equations ◽  
Rheology Model

AbstractConstitutive models based on fractional calculus are utilized to investigate the viscoelastic response of thermally activated shape memory polymers (SMPs). Fractional calculus-based viscoelastic equations are fitted to experimental data existing in literature compared with traditional viscoelastic models. In addition, a fractional rheology model is applied to simulate the isothermal recovery of an amorphous SMP. The fit results show a significant improvement in the description of the strain recovery response of SMP by the fractional calculus method.

A simplified constitutive model for predicting shape memory polymers deformation behavior

2015 ◽  
Vol 04 (01) ◽  
pp. 1550001 ◽  
Author(s):  
Yunxin Li ◽  
Siu-Siu Guo ◽  
Yuhao He ◽  
Zishun Liu
Keyword(s):  
Shape Memory ◽  
Deformation Behavior ◽  
Constitutive Models ◽  
Shape Memory Polymers ◽  
Element Model ◽  
Small Strain ◽  
Thermomechanical Properties ◽  
Mechanical Coupling ◽  
Functional Textiles ◽  
Complex Forms

Shape memory polymers (SMPs) can keep a temporary shape after pre-deformation at a higher temperature and subsequent cooling. When they are reheated, their original shapes can be recovered. Such special characteristics of SMPs make them widely used in aerospace structures, biomedical devices, functional textiles and other devices. Increasing usefulness of SMPs motivates us to further understand their thermomechanical properties and deformation behavior, of which the development of appropriate constitutive models for SMPs is imperative. There is much work in literatures that address constitutive models of the thermo-mechanical coupling in SMPs. However, due to their complex forms, it is difficult to apply these constitutive models in the real world. In this paper, a three-element model with simple form is proposed to investigate the thermo-mechanical small strain (within 10%) behavior of polyurethane under uniaxial tension. Two different cases of heated recovery are considered: (1) unconstrained free strain recovery and (2) stress recovery under full constraint at a strain level fixed during low temperature unloading. To validate the model, simulated and predicted results are compared with Tobushi's experimental results and good agreement can be observed.

Simulation of shape memory cycle of a polymeric beam undergoing large deflection using a simple incremental approach

2019 ◽  
Vol 31 (4) ◽  
pp. 515-524
Author(s):  
Debojyoti Pandit ◽  
Sivakumar M Srinivasan
Keyword(s):  
Shape Memory ◽  
Large Deflection ◽  
Coefficient Of Thermal Expansion ◽  
Constitutive Models ◽  
Shape Memory Polymers ◽  
Large Matrix ◽  
Multiple Natural Configurations ◽  
Governing Differential Equation ◽  
Memory Cycle ◽  
Scalar Moment

Shape memory polymers are a group of polymers which can store a temporary shape at a relatively cold temperature and recover when heated above its glass transition temperature. Various constitutive models exist in literature to simulate the uniaxial shape memory cycle. One such popular model is based on the concept of multiple natural configurations. In the present work, the stress-strain-based model is adapted for bending application by converting it into a scalar moment-curvature-based relationship. The adapted model is used in a numerical framework for large deflection of beams to simulate the shape memory cycle. The employed numerical framework is based on linearising the non-linear governing differential equation and subsequently solving it in steps by numerical integration. The results are presented in suitable non-dimensional form for generality. Since coefficient of thermal expansion plays a minimal role in bending, it is found that the bending results are considerably different from their uniaxial counterpart. The approach may be claimed to be computationally economic as compared to finite element method because here large matrix inversion is avoided.

scholarly journals A Mechanism-Based Four-Chain Constitutive Model for Enthalpy-Driven Thermoset Shape Memory Polymers With Finite Deformation

2020 ◽  
Vol 87 (6) ◽  
Author(s):  
Cheng Yan ◽  
Guoqiang Li
Keyword(s):  
Constitutive Model ◽  
Shape Memory ◽  
Smart Materials ◽  
Driving Force ◽  
Constitutive Models ◽  
Shape Memory Polymers ◽  
Chain Model ◽  
Cauchy Stress ◽  
Self Healing ◽  
Unit Cells

Abstract Chemically cross-linked thermoset shape memory polymers (TSMPs) are an important branch of smart materials due to their potentially wide applications in deplorable structures, soft robots, damage self-healing, and 4D printing. Further development and design of TSMP structures call for constitutive models. Although the Arruda–Boyce eight-chain model has been very successful and widely used for entropy-driven TSMPs, recent studies found that some new TSMPs, such as those using enthalpy as the primary driving force, show unit cells different from the eight-chain model. Considering that these new epoxy-based TSMP networks consist of a plenty of four-chain features, this study proposes a four-chain tetrahedron structure as the unit cell of the network to construct the constitutive model. In this model, Gibbs free energy is used to formulate the thermodynamic driving force. Then, by introducing a transition of the molecule deformation mechanism from that dominated by bond stretch to that dominated by bond angle opening, the traditional Langevin chain model is modified. It is found that this model can well capture the dramatic modulus change for the new TSMP in the thermomechanical experiments. Moreover, it shows that the original Treloar four-chain model and Arruda–Boyce eight-chain model underestimate the driving force for the enthalpy-driven TSMPs, and thus cannot well capture the thermomechanical behaviors. It is also found that under certain conditions, our four-chain model produces the same Cauchy stress as the eight-chain model does. This study may help researchers understand the thermomechanical response and design a special category of TSMPs with high recovery stress.

Fractional Calculus Approach to Relaxation Behavior of Amorphous Shape Memory Polymers

2016 ◽  
Vol 97 ◽  
pp. 106-111 ◽  
Author(s):  
Chang Qing Fang ◽  
Hui Yu Sun ◽  
Jian Ping Gu
Keyword(s):  
Shape Memory ◽  
Constitutive Models ◽  
Relaxation Modulus ◽  
Shape Memory Polymers ◽  
Relaxation Response ◽  
Relaxation Kernel ◽  
Prony Series ◽  
Material Parameters ◽  
Cole Model ◽  
Comparative Description

To select an appropriate relaxation kernel function is significant for shape memory polymers (SMPs) in their thermomechanical constitutive models. The relaxation modulus of SMPs are described by fractional-order viscoelastic (FOV) kernel and three other kinds of viscoelastic kernel, that is, Prony series, Kohlrausch-Williams-Watts (KWW) kernel and Cole-Cole Model (CCM) kernel. The data fitting result shows FOV kernel is a valuable tool to describe the relaxation response of SMPs. Compared with Prony series, KWW kernel and CCM kernel, the FOV kernel can give a comparative description of relaxation modulus of SMPs with fewer material parameters.

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