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.

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.

Modeling the Behavior of Crystallizable Shape Memory Polymers Subject to Inhomogeneous Deformations

2010 ◽  
Author(s):  
Mahesh Khanolkar ◽  
Jaskirat Sodhi ◽  
I. Joga Rao
Keyword(s):  
Constitutive Model ◽  
Shape Memory ◽  
Research Work ◽  
Shape Memory Polymers ◽  
Inhomogeneous Deformation ◽  
The Past ◽  
Constant Shear ◽  
Multiple Natural Configurations ◽  
Constant Moment

The constitutive model for the mechanics of crystallizable shape memory polymers (CSMP) has been developed in the past [1, 2]. The model was developed using the theory of multiple natural configurations and has been successful in addressing a diverse class of problems. In this research work, the efficacy of the developed CSMP model is tested by applying it to the torsion of a cylinder, which is an inhomogeneous deformation. The crystallization of the cylinder is studied under two different conditions i.e. crystallization under constant shear and crystallization under constant moment.

Novel Behavior in Smart Polymeric Materials: Stress Memory and its Potential Applications

2016 ◽  
Vol 97 ◽  
pp. 93-99
Author(s):  
Jin Lian Hu ◽  
Harishkumar Narayana
Keyword(s):  
Magnetic Field ◽  
Shape Memory ◽  
Smart Materials ◽  
Shape Memory Polymers ◽  
Polymeric Materials ◽  
External Stimulus ◽  
Artificial Muscles ◽  
Recovery Stress ◽  
Stress Memory ◽  
Potential Applications

Materials, structures and systems, responsive to an external stimulus are smart and adaptive to our human demands. Among smart materials, polymers with shape memory effect are at the forefront of research leading to comprehensive publications and wide applications. In this paper, we extend the concept of shape memory polymers to stress memory ones, which have been discovered recently. Like shape memory, stress memory represents a phenomenon where the stress in a polymer can be programmed, stored and retrieved reversibly with an external stimulus such as temperature and magnetic field. Stress memory may be mistaken as the recovery stress which was studied quite broadly. Our further investigation also reveals that stress memory is quite different from recovery stress containing multi-components including elastic and viscoelastic forces in addition to possible memory stress. Stress memory could be used into applications such as sensors, pressure garments, massage devices, electronic skins and artificial muscles. The current revelation of stress memory potentials is emanated from an authentic application of memory fibres, films, and foams in the smart compression devices for the management of chronic and therapeutic disorders.

Three-dimensional constitutive model for shape-memory polymers considering temperature-rate dependent behavior

2021 ◽  
Vol 30 (3) ◽  
pp. 035030
Author(s):  
Jinsu Kim ◽  
Seung-Yeol Jeon ◽  
Seokbin Hong ◽  
Yongsan An ◽  
Haedong Park ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Shape Memory ◽  
Three Dimensional ◽  
Shape Memory Polymers ◽  
Rate Dependent ◽  
Dependent Behavior ◽  
Temperature Rate

Inhomogeneous Deformation Examples and Applications of Light Activated Shape Memory Polymers

2012 ◽  
Author(s):  
Jaskirat S. Sodhi ◽  
Swapnil Moon ◽  
I. Joga Rao
Keyword(s):  
Constitutive Model ◽  
Shape Memory ◽  
Boundary Value Problems ◽  
Boundary Value ◽  
Aerospace Industry ◽  
Shape Memory Polymers ◽  
Inhomogeneous Deformation ◽  
The Past ◽  
Innovative Materials ◽  
Biomedical Industry

Light Activated Shape Memory Polymers (LASMP) are recently developed innovative materials defined by their capacity to store a deformed (temporary) shape and recover an original (parent) shape. This change in shape and the return to original shape is achieved by exposing the polymer to light at different wavelengths. These unique properties have led to the use of LASMP’s in a wide variety of applications. These SMP’s have a great potential in the biomedical industry as well as the aerospace industry. In the past, the authors have introduced a constitutive model to model the mechanics of these LASMP [1] and used it to solve a few cases of boundary value problems of interest. In this paper, the developed model is used to solve some other inhomogeneous deformation boundary value problems.

Shape Memory Behavior of Carbon Composites With Functional Interlayer

2018 ◽  
Author(s):  
L. Santo ◽  
L. Iorio ◽  
G. M. Tedde ◽  
F. Quadrini
Keyword(s):  
Carbon Fiber ◽  
Shape Memory ◽  
Polymer Composites ◽  
Polymer Matrix ◽  
Smart Materials ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Carbon Composites ◽  
Three Point Bending ◽  
Functional Behavior

Shape Memory Polymer Composites (SMPCs) are smart materials showing the structural properties of long-fiber polymer-matrix together with the functional behavior of shape memory polymers. In this study, SM carbon fiber reinforced (CFR) composites have been produced by using a SM interlayer between two CFR prepregs. Their SM properties have been evaluated in comparison with traditional structural CFR composites without the SM interlayer by using an especially designed test. Active and frozen forces are measured during a thermo-mechanical cycle in the three-point bending configuration. Experimental results show that SMPCs are able to fix a temporary deformed shape by freezing high stresses.

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