Full-field strain and temperature evolution of electroactive three-dimensional braided thermoplastic shape memory composites

2021 ◽  
pp. 109250
Author(s):  
Yingying Qi ◽  
Bohong Gu ◽  
Baozhong Sun ◽  
Wei Zhang
Keyword(s):  
Shape Memory ◽  
Three Dimensional ◽  
Temperature Evolution ◽  
Field Strain ◽  
Full Field ◽  
Shape Memory Composites

Three-Dimensional Printing of Shape Memory Composites with Epoxy-Acrylate Hybrid Photopolymer

2017 ◽  
Vol 9 (2) ◽  
pp. 1820-1829 ◽  
Author(s):  
Ran Yu ◽  
Xin Yang ◽  
Ying Zhang ◽  
Xiaojuan Zhao ◽  
Xiao Wu ◽  
...  
Keyword(s):  
Shape Memory ◽  
Three Dimensional ◽  
Epoxy Acrylate ◽  
Three Dimensional Printing ◽  
Shape Memory Composites ◽  
Dimensional Printing

scholarly journals Mechanical, Thermal, and Shape Memory Properties of Three-Dimensional Printing Biomass Composites

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1234 ◽  
Author(s):  
Hongjie Bi ◽  
Min Xu ◽  
Gaoyuan Ye ◽  
Rui Guo ◽  
Liping Cai ◽  
...  
Keyword(s):  
Shape Memory ◽  
Wood Flour ◽  
Memory Performance ◽  
Thermoplastic Polyurethane ◽  
Tensile Elongation ◽  
Three Dimensional ◽  
Mechanical Analysis ◽  
Shape Memory Properties ◽  
Shape Memory Composites ◽  
Recovery Angle

In this study, a series of heat-induced shape memory composites was prepared by the hot-melt extrusion and three-dimensional (3D) printing of thermoplastic polyurethane (TPU) using wood flour (WF) with different contents of EPDM-g-MAH. The mechanical properties, microtopography, thermal property analysis, and heat-induced shape memory properties of the composites were examined. The results showed that, when the EPDM-g-MAH content was 4%, the tensile elongation and tensile strength of the composites reached the maximum value. The scanning electron microscopy and dynamic mechanical analysis results revealed a good interface bonding between TPU and WF when the EPDM-g-MAH content was 4%. The thermogravimetric analysis indicated that the thermal stability of TPU/WF composites was enhanced by the addition of 4% EPDM-g-MAH. Heat-induced shape memory test results showed that the shape memory performance of composites with 4% EPDM-g-MAH was better than that of unmodified-composites. The composites’ shape recovery performance at a temperature of 60 °C was higher than that of the composites at ambient temperature. It was also found that, when the filling angle of the specimen was 45°, the recovery angle of the composites was larger.

scholarly journals Testing System for the Mechanical Properties of Small-Scale Specimens Based on 3D Microscopic Digital Image Correlation

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3530
Author(s):  
Xu Liu ◽  
Rongsheng Lu
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Three Dimensional ◽  
Image Correlation ◽  
Field Strain ◽  
Small Scale ◽  
Testing System ◽  
Shape Functions ◽  
Full Field

The testing of the mechanical properties of materials on a small scale is difficult because of the small specimen size and the difficulty of measuring the full-field strain. To tackle this problem, a testing system for investigating the mechanical properties of small-scale specimens based on the three-dimensional (3D) microscopic digital image correlation (DIC) combined with a micro tensile machine is proposed. Firstly, the testing system is described in detail, including the design of the micro tensile machine and the 3D microscopic DIC method. Then, the effects of different shape functions on the matching accuracy obtained by the inverse compositional Gauss–Newton (IC-GN) algorithm are investigated and the numerical experiment results verify that the error due to under matched shape functions is far larger than that of overmatched shape functions. The reprojection error is shown to be smaller than before when employing the modified iteratively weighted radial alignment constraint method. Both displacement and uniaxial measurements were performed to demonstrate the 3D microscopic DIC method and the testing system built. The experimental results confirm that the testing system built can accurately measure the full-field strain and mechanical properties of small-scale specimens.

A Noncontacting Approach for Full-Field Strain Monitoring of Rotating Structures

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Javad Baqersad ◽  
Peyman Poozesh ◽  
Christopher Niezrecki ◽  
Peter Avitabile
Keyword(s):  
Three Dimensional ◽  
Turbine Rotor ◽  
Field Strain ◽  
Dynamic Strain ◽  
Fe Model ◽  
Fe Method ◽  
Full Field ◽  
Modal Expansion ◽  
Point Tracking ◽  
Measurement Approach

The three-dimensional point-tracking (3DPT) measurement approach is used in conjunction with finite element (FE) method and modal expansion technique to predict full-field dynamic response on a rotating structure. A rotating three-bladed wind turbine rotor was subjected to different loading scenarios, and the displacement of optical targets located on the blades was measured using 3DPT. The out-of-plane measured displacement of the targets was expanded and applied to the FE model of the turbine to extract full-field strain on the turbine. The sensitivity of the proposed approach to the number of optical targets was also studied in this paper. The results show that the dynamic strain on a structure can be extracted with a very limited set of measurement points (optical targets) placed on appropriate locations on the blades. It was shown that the proposed technique is able to extract dynamic strain all over the entire structure, even inside the structure beyond the line of sight of the measurement system. Because the method is based on a noncontacting measurement approach, it can be readily applied to a variety of structures having different boundary conditions.

Full-Field Strain Monitoring of a Wind Turbine Using Very Limited Set of Displacements Measured With Three-Dimensional Point Tracking

2015 ◽  
Author(s):  
Javad Baqersad ◽  
Peyman Poozesh ◽  
Christopher Niezrecki ◽  
Peter Avitabile
Keyword(s):  
Wind Turbine ◽  
Three Dimensional ◽  
Element Model ◽  
Turbine Rotor ◽  
Field Strain ◽  
Full Field ◽  
Modal Expansion ◽  
Point Tracking ◽  
Expansion Technique ◽  
Measured Displacement

In the current work, the optical three-dimensional point-tracking (3DPT) measurement approach is used in conjunction with a recently developed modal expansion technique. These two approaches (empirical and analytical) complement each other and enable the prediction of the full-field dynamic response on the surface of the structure as well as within the interior points. The practical merit of the approach was verified using a non-spinning and spinning wind turbine rotor. The three-bladed wind turbine rotator was subjected to different loading scenarios and the displacement of optical targets located on the blades was measured using 3DPT. The measured displacement was expanded and applied to the finite element model of the turbine to extract full-field strain on the turbine. The sensitivity of the proposed approach to the number of optical targets was studied in this paper. It is shown the approach can accurately predict the strain even with very few set of measurement points.

A method for building self-folding machines

Science ◽  
2014 ◽  
Vol 345 (6197) ◽  
pp. 644-646 ◽  
Author(s):  
S. Felton ◽  
M. Tolley ◽  
E. Demaine ◽  
D. Rus ◽  
R. Wood
Keyword(s):  
Shape Memory ◽  
Three Dimensional ◽  
Human Intervention ◽  
Walk Away ◽  
Controlled Assembly ◽  
Flat Sheet ◽  
Wide Range ◽  
Shape Memory Composites ◽  
Embedded Electronics

Origami can turn a sheet of paper into complex three-dimensional shapes, and similar folding techniques can produce structures and mechanisms. To demonstrate the application of these techniques to the fabrication of machines, we developed a crawling robot that folds itself. The robot starts as a flat sheet with embedded electronics, and transforms autonomously into a functional machine. To accomplish this, we developed shape-memory composites that fold themselves along embedded hinges. We used these composites to recreate fundamental folded patterns, derived from computational origami, that can be extrapolated to a wide range of geometries and mechanisms. This origami-inspired robot can fold itself in 4 minutes and walk away without human intervention, demonstrating the potential both for complex self-folding machines and autonomous, self-controlled assembly.

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...

NIR-II light-responsive biodegradable shape memory composites based on cuprorivaite nanosheets for enhanced tissue reconstruction

2021 ◽  
Vol 419 ◽  
pp. 129437
Author(s):  
Chen Yang ◽  
Rui Zheng ◽  
Muhammad Rizwan Younis ◽  
Jundong Shao ◽  
Lian-Hua Fu ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Composites ◽  
Tissue Reconstruction
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