Active Rigidity Smart Joint for a Bat-Wing Micro Air Vehicle

2007 ◽  
Author(s):  
Justin E. Manzo ◽  
Ephrahim Garcia
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Shape Change ◽  
Shape Memory Polymer ◽  
Aircraft Design ◽  
Passive State ◽  
External Loading ◽  
Arbitrary Length ◽  
Bat Wing ◽  
Biological Shape

In order to maximize lift for use in turning and landing maneuvers, bats make use of continuous camber change along their fifth metacarpal more effectively than all modern-day aircraft flaps. This biological shape change produces lower drag than modern aircraft, allowing for greater flight efficiency and lower noise signatures. A mechanism to replicate this demands a seamless actuator to avoid gaps and discontinuities, and requires the use of morphing structures. However, a recurring problem in morphing aircraft design is inefficiency of both space and power consumption. Problems often stem from the replacement of rigid structural elements with actuator elements that must be powered in order to carry static loads. To resolve this issue, a ‘smart joint’ concept is proposed which allows rigidity in its passive state, and becomes compliant while serving as an actuator by way of a composite of smart materials. Using a network of shape memory alloy and shape memory polymer, the joint is capable of rotations on the order of 5 percent camber over an arbitrary length when placed along a skeletal element of a bat-like wing structure. An analytical model is used to predict the behavior of the joint as a function of resistive heating and external loading, and is used to examine the layer thicknesses and locations (i.e. bimorph vs. unimorph) and placement of rigid elastic members in order to maximize deflection under a given load. Validation of the joint using is conducted via finite element modeling, and expected airfoil data for a generic shape maneuver to be accomplished by this joint is shown.

scholarly journals Shape memory polymer network with thermally distinct elasticity and plasticity

2016 ◽  
Vol 2 (1) ◽  
pp. e1501297 ◽  
Author(s):  
Qian Zhao ◽  
Weike Zou ◽  
Yingwu Luo ◽  
Tao Xie
Keyword(s):  
Shape Memory ◽  
Molecular Design ◽  
Shape Change ◽  
Shape Memory Polymer ◽  
Polymer Network ◽  
Stimuli Responsive ◽  
Responsive Materials ◽  
Device Applications ◽  
Temperature Ranges ◽  
Rational Molecular Design

Stimuli-responsive materials with sophisticated yet controllable shape-changing behaviors are highly desirable for real-world device applications. Among various shape-changing materials, the elastic nature of shape memory polymers allows fixation of temporary shapes that can recover on demand, whereas polymers with exchangeable bonds can undergo permanent shape change via plasticity. We integrate the elasticity and plasticity into a single polymer network. Rational molecular design allows these two opposite behaviors to be realized at different temperature ranges without any overlap. By exploring the cumulative nature of the plasticity, we demonstrate easy manipulation of highly complex shapes that is otherwise extremely challenging. The dynamic shape-changing behavior paves a new way for fabricating geometrically complex multifunctional devices.

Blocking force measurement of shape memory polymer composite hinges for space deployable structures

2018 ◽  
Vol 29 (18) ◽  
pp. 3667-3678 ◽  
Author(s):  
Thanh Duc Dao ◽  
Nam Seo Goo ◽  
Woong Ryeol Yu
Keyword(s):  
Shape Memory ◽  
Polymer Composite ◽  
Mechanical Performance ◽  
Force Measurement ◽  
Shape Change ◽  
Shape Memory Polymer ◽  
Mass System ◽  
Manufacturing Method ◽  
Moment Arms ◽  
Repeated Test

This study introduces a method for measuring the blocking force of a shape memory polymer composite hinge to quantify the performance of a shape memory polymer composite hinge for space deployable structure applications. A detailed design of how to select heating elements for a self-deployable configuration is also suggested. The shape memory polymer composite hinge consists of two reverse carpenter shape memory polymer composite tapes that were made from carbon-epoxy fabric, shape memory polymer resin, and two heating elements. The heating elements were attached to the shape memory polymer composite tape using the composite manufacturing method, and they were used as the heating source in the deployment test. The blocking force and moment of the hinge were measured using a pulley–mass system setup to examine the mechanical performance of the hinge. During the test, the shape change was recorded with a camera to calculate the moment arms. While the blocking force was 7.21 N in the initial test, it decreased slightly with the working cycle and was 6.27 N in the repeated test. The maximum hinge moment was 0.47 N m in the repeated test. In addition, the results revealed that a pop-up phenomenon occurred at the middle period of deployment. These results confirm that the shape memory polymer composite hinge works well with heating elements and provide a guideline for performance evaluation of the shape memory polymer composite hinge.

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.

scholarly journals Shape-Memory Polymeric Artificial Muscles: Mechanisms, Applications and Challenges

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4246 ◽  
Author(s):  
Yujie Chen ◽  
Chi Chen ◽  
Hafeez Ur Rehman ◽  
Xu Zheng ◽  
Hua Li ◽  
...  
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Recent Progress ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Artificial Muscles ◽  
Linkage Design ◽  
Wide Range ◽  
Liquid Crystal Elastomers ◽  
Made In

Shape-memory materials are smart materials that can remember an original shape and return to their unique state from a deformed secondary shape in the presence of an appropriate stimulus. This property allows these materials to be used as shape-memory artificial muscles, which form a subclass of artificial muscles. The shape-memory artificial muscles are fabricated from shape-memory polymers (SMPs) by twist insertion, shape fixation via Tm or Tg, or by liquid crystal elastomers (LCEs). The prepared SMP artificial muscles can be used in a wide range of applications, from biomimetic and soft robotics to actuators, because they can be operated without sophisticated linkage design and can achieve complex final shapes. Recently, significant achievements have been made in fabrication, modelling, and manipulation of SMP-based artificial muscles. This paper presents a review of the recent progress in shape-memory polymer-based artificial muscles. Here we focus on the mechanisms of SMPs, applications of SMPs as artificial muscles, and the challenges they face concerning actuation. While shape-memory behavior has been demonstrated in several stimulated environments, our focus is on thermal-, photo-, and electrical-actuated SMP artificial muscles.

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.

Carbon Fiber Reinforced Shape Memory Nanocomposites Incorporated With Highly Conductive Carbon Nanopaper for Electro Actuation

2013 ◽  
Author(s):  
Fei Liang ◽  
Jihua Gou ◽  
He Shen ◽  
Yunjun Xu ◽  
Bob Mabbott
Keyword(s):  
Carbon Fiber ◽  
Shape Memory ◽  
Smart Materials ◽  
Shape Memory Polymer ◽  
Flexural Modulus ◽  
Fiber Reinforcement ◽  
High Strength ◽  
Mechanical Analysis ◽  
Carbon Fiber Reinforcement ◽  
Continuous Carbon Fiber

Shape memory polymers (SMPs) are one of the most popular smart materials due to light weight and high elastic deformation capability. In this study, highly conductive carbon nanofibers paper (CNFP) was coated on the surface of SMP as a conductive layer for electro actuation of SMP. To overcome the drawback of low modulus and low strength of shape memory polymer (SMP), continuous carbon fiber reinforcement was also incorporated with SMP by autoclave processing. The dynamic mechanical analysis (DMA) result showed over 600% increase of storage modulus of SMP by introducing carbon fiber reinforcement. Also, the shape recovery time of SMP has been reduced over 150%, while the recovery ratio of SMP has been improved to 99% by incorporating with carbon fiber reinforcement. Additionally, the mechanical property degradation of SMP composites has been investigated after different electro actuation cycles. After 50 actuation cycles, the decrease of flexural modulus of SMP composites is negligible (< 2%), and the ultimate flexural strength of SMP composites only decreased 25%. The SMP composite shows high strength and modulus, and good durability.

Thermo-Mechanical Behavior of Epoxy Shape Memory Polymer

2013 ◽  
Vol 721 ◽  
pp. 169-172 ◽  
Author(s):  
Yu Gu ◽  
Shao Xiong Li
Keyword(s):  
Mechanical Behavior ◽  
Shape Memory ◽  
Significant Influence ◽  
Smart Materials ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Testing Temperature ◽  
Curing Agent ◽  
Different Temperatures ◽  
Viscoelastic Behaviors

The viscoelastic behaviors of shape memory polymers have a significant influence on the function realization of this kind of smart materials. In this study, stress-strain hysteresis under uniaxial tension of epoxy shape memory polymers with varied curing agent contents and types were tested at different temperatures. The effects of the testing temperature, curing-agent type and content on the viscoelastic behaviors of the materials were discussed.

The Application of Shape Memory Polymer Composite in Space Deployable Truss Structure

2011 ◽  
Vol 287-290 ◽  
pp. 2756-2759 ◽  
Author(s):  
Yi Jun Zhou ◽  
Fu Ling Guan ◽  
Li Feng Qian
Keyword(s):  
Shape Memory ◽  
Polymer Composite ◽  
Smart Materials ◽  
Shape Memory Polymer ◽  
Truss Structure ◽  
Large Ring ◽  
Smart Materials And Structures ◽  
Recovery Strain

In this paper, the advantages of smart materials and structures are introduced. Because of the influence of friction, it’s difficult to deploy the large ring truss antenna driving by cable. The SPMC hinge is added in the deployable joint, the deployable antenna is deployed by heating the material to cause recovery strain, which substitutes for the driving by cable. Describe the behavior of SPMC material, and do the simulation, from the analysis results, we can aim that the stress of SPMC satisfies the yielding stress when the node is furled. At the same time, the force to expand the antenna caused by heating SPMC is also obtained. Compared the different size of width, the variation of recovery force can be got.

Design and characterization of 3D multilayer woven reinforcements shape memory polymer composites

2020 ◽  
pp. 002199832095817
Author(s):  
Ibrahim Goda ◽  
Zakariya Zubair ◽  
Gildas L’Hostis ◽  
Jean-Yves Drean
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Shape Recovery ◽  
Mechanical Performance ◽  
Shape Memory Polymer ◽  
Woven Fabric ◽  
Deformation Analysis ◽  
Shape Memory Behavior ◽  
Functional Composites ◽  
Memory Cycle

Shape memory polymer (SMP) composites are attractive and excellent smart materials due to their outstanding properties and rich functionality as they combine typical mechanical and functional properties of composites with shape memory properties. In particular, 3D reinforced preforms have tremendous potential for the development of functional composites by using the capabilities of 3D woven fabric preform design, and polymer shape memory behavior. Within that scope, this work aims to investigate the shape memory behavior and shape recovery properties of a specific type of 3D multilayer woven SMP composite in response to external stimuli. For this purpose, nine different multilayer stitched fabrics are produced with different weave structures, and different fabric thread densities using polyimide filaments. Then, a series of tests is carried out on these fabrics to evaluate their mechanical and physical properties. The layered fabric design that delivers high mechanical performance is next involved to manufacture the SMP composite samples, for which shape recovery capability is investigated. Fold-deploy and other shape memory cycle tests are performed to evaluate the shape memory characteristics. An optical 3D scanner based on fringe projection is further proposed to precisely acquire the geometry data and perform deformation analysis to quantitatively evaluate the shape fixity and shape recovery behaviors. The results from this study are very promising, demonstrating that these multilayer SMP structures can successfully be recovered following the desired design constraints without noticeable damage.

RECENT PROGRESSES IN POLYMERIC SMART MATERIALS

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2351-2356 ◽  
Author(s):  
YAN-JU LIU ◽  
XIN LAN ◽  
HAI-BAO LU ◽  
JIN-SONG LENG
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Shape Recovery ◽  
Shape Memory Polymer ◽  
Strain Energy Function ◽  
Electroactive Polymer ◽  
Electrically Conductive ◽  
Wide Range ◽  
Polymer Actuator ◽  
Analysis Of Stability

Smart materials can be defined as materials that sense and react to environmental conditions or stimuli. In recent years, a wide range of novel smart materials have been developed in biomaterials, sensors, actuators, etc. Their applications cover aerospace, automobile, telecommunications, etc. This paper presents some recent progresses in polymeric smart materials. Special emphasis is laid upon electroactive polymer (EAP), shape memory polymer (SMP) and their composites. For the electroactive polymer, an analysis of stability of dielectric elastomer using strain energy function is derived, and one type of electroactive polymer actuator is presented. For the shape memory polymer, a new method is developed to use infrared laser to actuate the SMP through the optical fiber embedded within the SMP. Electrically conductive nanocarbon powders are utilized as the fillers to improve the electrical conductivity of polymer. A series of fundamental investigations of electroactive SMP are performed and the shape recovery is demonstrated.

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