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.

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.

Three-dimensional Graphene Coated Shape Memory Polyurethane Foam with Fast Responsive Performance

2021 ◽  
Author(s):  
Tianjiao Wang ◽  
Jun Zhao ◽  
Chuanxin Weng ◽  
Tong Wang ◽  
Yayun Liu ◽  
...  
Keyword(s):  
Shape Memory ◽  
Polyurethane Foam ◽  
Three Dimensional ◽  
Shape Memory Polymers ◽  
Practical Applications ◽  
External Stimuli ◽  
Shape Memory Polyurethane

Shape memory polymers (SMPs) that change shapes as designed by external stimuli have become one of the most promising materials as actuators, sensors, and deployable devices. However, their practical applications...

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 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.

Time and Temperature Dependent Recovery of Epoxy-Based Shape Memory Polymers

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Francisco Castro ◽  
Kristofer K. Westbrook ◽  
Jason Hermiller ◽  
Dae Up Ahn ◽  
Yifu Ding ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Shape Memory ◽  
Recovery Rate ◽  
Thermal Conditions ◽  
Shape Memory Polymers ◽  
Time Frame ◽  
Scanning Calorimetry ◽  
Recoverable Strain ◽  
External Stimuli

Shape memory polymers (SMPs) are a group of adaptive polymers that can recover the permanent shape from a temporary shape by external stimuli on demand. Among a variety of external stimuli for polymer actuation, temperature is the most extensively used. In SMP applications, one of the major design considerations is the time necessary to recover the shape without external deformation constraints, or free recovery, and the amount of the recoverable strain. This paper investigates the amount of the recoverable strain and the recovery rate of an epoxy-based SMP (Veriflex® E, VFE1-62 (CRG, Dayton, OH)) under different thermal conditions. In particular, the free recovery behaviors of the SMPs under two experimental protocols, isothermal and shape memory (SM) cycle, are studied. It is found that free recovery in isothermal experiments is much faster than that in a SM cycle at the same recovering temperature and the material is fully recoverable at the temperature above differential scanning calorimetry Tg. Furthermore, for the recovery in SM cycle experiments, reshaping the sample at a low temperature and recovering from the deformation at a high temperature yield the fastest recovery rate, while reshaping at a high temperature and recovering at a low temperature cannot recover the original shape within this work’s experimental time frame. The possible mechanism for these observations is discussed.

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.

Modeling the Mechanics of Crystallizable Shape Memory Polymers With Two Crystallizing Phases for Crystallization Under Constant Strain

2012 ◽  
Author(s):  
Swapnil Moon ◽  
I. Joga Rao
Keyword(s):  
Shape Memory ◽  
Crystalline Phase ◽  
Smart Materials ◽  
Phase 1 ◽  
Polymer Networks ◽  
Shape Memory Polymers ◽  
Original Shape ◽  
Aerospace Technology ◽  
Multiple Natural Configurations ◽  
External Stimuli

Shape Memory Polymers are a promising class of smart materials with applications ranging from biomedical devices to aerospace technology. SMPs have a capacity to retain complex temporary shapes involving large deformations and revert back to their original shape when triggered by external stimuli such as heat. Crystallizable SMPs are a subclass of SMPs where the transient shape is retained by formation of a crystalline phase and return to the original shape is due to melting of this crystalline phase [1]. Recently CSMPs with multiphase polymer networks containing two different crystallizable segments have been reported which have the capability to switch between three shapes when stimulated by changes in temperature [2,4]. These properties open up many new possibilities for applications. Our research is focused upon modeling the mechanics associated with these CSMPs. The model is developed using a framework based upon theory of multiple natural configurations [3]. The developed model is then used to simulate results for typical boundary value problems.

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.

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