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 Fractional Calculus Approach to the Prediction of Free Recovery Behaviors of Amorphous Shape Memory Polymers

2015 ◽  
Vol 32 (1) ◽  
pp. 11-17 ◽  
Author(s):  
C.-Q. Fang ◽  
H.-Y. Sun ◽  
J.-P. Gu
Keyword(s):  
Differential Equations ◽  
Fractional Calculus ◽  
Shape Memory ◽  
Nonlinear Differential Equations ◽  
Shape Memory Polymers ◽  
Temperature Dependent ◽  
Zener Model ◽  
Fractional Model ◽  
Recovery Response ◽  
The One

AbstractA fractional model generalized from the Zener model is proposed for the prediction of temperature-dependent free recovery behaviors of amorphous shape memory polymers (SMPs). This model differs from the Zener model in that it involves nonlinear differential equations of fractional, not integer, order. The theoretical solution based on this fractional model is utilized to simulate the isothermal and nonisothermal free recovery of an amorphous SMP compared with the one based on the Zener model. The results show a reasonable improvement in the prediction of the strain recovery response of SMP by the fractional calculus method.

Deployable Process Analysis of Packaged SMP Sandwich Beam

2010 ◽  
Vol 123-125 ◽  
pp. 943-946 ◽  
Author(s):  
Zheng Fa Li ◽  
Zheng Dao Wang
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Sandwich Structure ◽  
Shape Recovery ◽  
Process Analysis ◽  
Sandwich Beam ◽  
Shape Memory Polymers ◽  
Recovery Stress ◽  
Recovery Response

Shape memory polymers own many advantages compared with traditional shape memory alloys or ceramics. In order to improve their shape recovery stress and realize a stable recovery response during the deployable process, the structure of SMP sandwich beam composed of two metallic skin and one SMP core is considered. The recovery behaviors of pure SMP and SMP beams reinforced by one-layer metallic skin are also discussed for comparison. The results confirm that the deployable properties of SMP matrix can be significantly improved by using sandwich structure.

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.

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