scholarly journals Actuating Shape Memory Polymer for Thermoresponsive Soft Robotic Gripper and Programmable Materials

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 522
Author(s):  
Dennis Schönfeld ◽  
Dilip Chalissery ◽  
Franziska Wenz ◽  
Marius Specht ◽  
Chris Eberl ◽  
...  
Keyword(s):  
Shape Memory Polymer ◽  
Average Molecular Weight ◽  
Soft Robotics ◽  
Fused Filament Fabrication ◽  
Polyester Urethane ◽  
Shape Morphing ◽  
System A ◽  
Dependent Behavior ◽  
Unit Cells ◽  
Programmable Materials

For soft robotics and programmable metamaterials, novel approaches are required enabling the design of highly integrated thermoresponsive actuating systems. In the concept presented here, the necessary functional component was obtained by polymer syntheses. First, poly(1,10-decylene adipate) diol (PDA) with a number average molecular weight Mn of 3290 g·mol−1 was synthesized from 1,10-decanediol and adipic acid. Afterward, the PDA was brought to reaction with 4,4′-diphenylmethane diisocyanate and 1,4-butanediol. The resulting polyester urethane (PEU) was processed to the filament, and samples were additively manufactured by fused-filament fabrication. After thermomechanical treatment, the PEU reliably actuated under stress-free conditions by expanding on cooling and shrinking on heating with a maximum thermoreversible strain of 16.1%. Actuation stabilized at 12.2%, as verified in a measurement comprising 100 heating-cooling cycles. By adding an actuator element to a gripper system, a hen’s egg could be picked up, safely transported and deposited. Finally, one actuator element each was built into two types of unit cells for programmable materials, thus enabling the design of temperature-dependent behavior. The approaches are expected to open up new opportunities, e.g., in the fields of soft robotics and shape morphing.

scholarly journals Design of Shape Memory Thermoplastic Material Systems for FDM-Type Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4254
Author(s):  
Paulina A. Quiñonez ◽  
Leticia Ugarte-Sanchez ◽  
Diego Bermudez ◽  
Paulina Chinolla ◽  
Rhyan Dueck ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Shape Memory ◽  
Thermomechanical Processing ◽  
Material Selection ◽  
Shape Memory Polymer ◽  
Fused Filament Fabrication ◽  
Materials Development ◽  
Thermoplastic Material ◽  
Polymer Systems ◽  
Injection Molded

The work presented here describes a paradigm for the design of materials for additive manufacturing platforms based on taking advantage of unique physical properties imparted upon the material by the fabrication process. We sought to further investigate past work with binary shape memory polymer blends, which indicated that phase texturization caused by the fused filament fabrication (FFF) process enhanced shape memory properties. In this work, two multi-constituent shape memory polymer systems were developed where the miscibility parameter was the guide in material selection. A comparison with injection molded specimens was also carried out to further investigate the ability of the FFF process to enable enhanced shape memory characteristics as compared to other manufacturing methods. It was found that blend combinations with more closely matching miscibility parameters were more apt at yielding reliable shape memory polymer systems. However, when miscibility parameters differed, a pathway towards the creation of shape memory polymer systems capable of maintaining more than one temporary shape at a time was potentially realized. Additional aspects related to impact modifying of rigid thermoplastics as well as thermomechanical processing on induced crystallinity are also explored. Overall, this work serves as another example in the advancement of additive manufacturing via materials development.

Design of Three-Dimensional, Triply Periodic Unit Cell Scaffold Structures for Additive Manufacturing

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Mazher Iqbal Mohammed ◽  
Ian Gibson
Keyword(s):  
Additive Manufacturing ◽  
Periodic Structures ◽  
Three Dimensional ◽  
Unit Cell ◽  
Final Size ◽  
Fused Filament Fabrication ◽  
Cell Structures ◽  
Triply Periodic ◽  
Unit Cells ◽  
Scaffold Structure

Highly organized, porous architectures leverage the true potential of additive manufacturing (AM) as they can simply not be manufactured by any other means. However, their mainstream usage is being hindered by the traditional methodologies of design which are heavily mathematically orientated and do not allow ease of controlling geometrical attributes. In this study, we aim to address these limitations through a more design-driven approach and demonstrate how complex mathematical surfaces, such as triply periodic structures, can be used to generate unit cells and be applied to design scaffold structures in both regular and irregular volumes in addition to hybrid formats. We examine the conversion of several triply periodic mathematical surfaces into unit cell structures and use these to design scaffolds, which are subsequently manufactured using fused filament fabrication (FFF) additive manufacturing. We present techniques to convert these functions from a two-dimensional surface to three-dimensional (3D) unit cell, fine tune the porosity and surface area, and examine the nuances behind conversion into a scaffold structure suitable for 3D printing. It was found that there are constraints in the final size of unit cell that can be suitably translated through a wider structure while still allowing for repeatable printing, which ultimately restricts the attainable porosities and smallest printed feature size. We found this limit to be approximately three times the stated precision of the 3D printer used this study. Ultimately, this work provides guidance to designers/engineers creating porous structures, and findings could be useful in applications such as tissue engineering and product light-weighting.

scholarly journals Divergent Design of Mechanical Metamaterials Clan Deducted from Arc-serpentine Curve

2021 ◽  
Author(s):  
Shengli Mi ◽  
Hongyi Yao ◽  
Xiaoyu Zhao ◽  
Wei Sun
Keyword(s):  
Thick Plate ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Design Strategies ◽  
Shape Morphing ◽  
Mechanical Metamaterials ◽  
Unit Cells ◽  
Combinatorial Principles ◽  
Composite Curve ◽  
Typical Design

Abstract The exotic properties of mechanical metamaterials are determined by their unit-cells' structure and spatial arrangement, in analogy with the atoms of conventional materials. Companioned with the mechanism of structural or cellular materials1–5, the ancient wisdom of origami6–11 and kirigami12–16 and the involvement of multiphysics interaction2,17,18 enrich the programable mechanical behaviors of metamaterials, including shape-morphing8,12,14,16,19, compliance4,5,8,17,20, texture2,18,21, and topology11,18,22−25. However, typical design strategies are mainly convergent, which transfers various structures into one family of metamaterials that are relatively incompatible with the others and do not fully bring combinatorial principles3,10,26 into play. Here, we report a divergent strategy that designs a clan of mechanical metamaterials with diverse properties derived from a symmetric curve consisting of serpentines and arcs. We derived this composite curve into planar and cubic unit-cells and modularized them by attaching magnetics. Moreover, stacking each of them yields two- and three-dimensional auxetic metamaterials, respectively. Assembling with both modules, we achieved three thick plate-like metamaterials separately with flexibility, in-plane buckling, and foldability. Furthermore, we demonstrated that the hybrid of paradox properties is possible by combining two of the above assembles. We anticipate that this divergent strategy paves the path of building a hierarchical library of diverse combinable mechanical metamaterials and making conventional convergent strategies more efficient to various requests. Main

An Antagonistic Flexural Unit Cell for Design of Shape Morphing Structures

Aerospace ◽  
2004 ◽  
Author(s):  
Aarash Y. N. Sofla ◽  
Dana M. Elzey ◽  
Haydn N. G. Wadley
Keyword(s):  
Shape Memory ◽  
Unit Cell ◽  
External Energy ◽  
Full Characterization ◽  
Shape Morphing ◽  
Cyclic Operation ◽  
Unit Cells ◽  
External Forces ◽  
Reversed Cyclic

An antagonistic flexural unit cell (AFC) concept for the design and fabrication of novel 2-D and 3-D lightweight shape morphing structures is introduced. A fully reversible flexural shape changing cell utilizing opposing one-way shape memory alloy (SMA) actuators is shown to require no spring-like bias elements. The SMA actuating elements are arranged such that the actuation (contraction) of one of them stretches the other one in the cell, preparing it to be actuated later to reverse a flexural displacement. This antagonistic operation allows fully reversed cyclic operation. The focus of this paper is an assessment of performance at the single cell level. The cell logically provides four possible configurations in different stages of its cycle. Two of them are of particular interest because they provide two different fixed shapes for the cell that can be maintained without the continuous supply of external energy. The final deformations of the cell and equilibrium stresses in the SMA elements depend on the amount of stored shape memory strain in each element, external forces and cell geometry. A model is developed, which allows a full characterization of the AFC. The model is used to study NiTi SMA-based AFCs and the results are therefore directly applicable to the design of shape morphing structures using such unit cells.

scholarly journals Agile reversible shape-morphing of particle rafts

Soft Matter ◽  
2021 ◽  
Author(s):  
Kyungmin Son ◽  
Jeong-Yun Sun ◽  
Ho-Young Kim
Keyword(s):  
Soft Matter ◽  
Soft Robotics ◽  
Wearable Electronics ◽  
Shape Morphing ◽  
Soft Matter Physics ◽  
External Stimuli

Materials that transform shapes responding to external stimuli can bring unprecedented innovations to soft matter physics, soft robotics, wearable electronics, and architecture. As most conventional soft actuation technologies induce large...

scholarly journals Photothermally and magnetically controlled reconfiguration of polymer composites for soft robotics

2019 ◽  
Vol 5 (8) ◽  
pp. eaaw2897 ◽  
Author(s):  
Jessica A.-C. Liu ◽  
Jonathan H. Gillen ◽  
Sumeet R. Mishra ◽  
Benjamin A. Evans ◽  
Joseph B. Tracy
Keyword(s):  
Magnetic Field ◽  
Shape Memory Polymer ◽  
Composite Films ◽  
Soft Robotics ◽  
Magnetic Actuation ◽  
New Materials ◽  
Photothermal Heating ◽  
Multiple Cycles ◽  
Permanent Shape ◽  
The Magnetic Field

New materials are advancing the field of soft robotics. Composite films of magnetic iron microparticles dispersed in a shape memory polymer matrix are demonstrated for reconfigurable, remotely actuated soft robots. The composite films simultaneously respond to magnetic fields and light. Temporary shapes obtained through combined magnetic actuation and photothermal heating can be locked by switching off the light and magnetic field. Subsequent illumination in the absence of the magnetic field drives recovery of the permanent shape. In cantilevers and flowers, multiple cycles of locking and unlocking are demonstrated. Scrolls show that the permanent shape of the film can be programmed, and they can be frozen in intermediate configurations. Bistable snappers can be magnetically and optically actuated, as well as biased, by controlling the permanent shape. Grabbers can pick up and release objects repeatedly. Simulations of combined photothermal heating and magnetic actuation are useful for guiding the design of new devices.

A Novel Method for Investigating the Frequency Dependent Behavior of Instrument Transformers

2014 ◽  
Vol 494-495 ◽  
pp. 1477-1481
Author(s):  
Yong Xin Feng ◽  
Zhao Li ◽  
Ya Qi Gao ◽  
Bing Ran Shao ◽  
Xue Wen Ding ◽  
...  
Keyword(s):  
Measurement System ◽  
Current Transformers ◽  
Frequency Dependent ◽  
Frequency Responses ◽  
System A ◽  
Dependent Behavior ◽  
Instrument Transformers ◽  
Computer Based ◽  
Novel Method ◽  
High Voltage System

This paper describes the structure and the principle of the NI DAQ based measurement system used for investigating the frequency dependent behavior of instrument transformers in the high voltage system. A computer based NI DAQ card is utilized as the data acquisition system in the new measurement system. The software digital filter and the phase locked loop are implemented to obtain the magnitude and phase angle, respectively. With this measurement system, we investigated frequency responses of several voltage and current transformers at the converter station of the Germany railway.

scholarly journals Development of an Automatic Image Cropping and Feature Extraction System for Real-Time Warping Monitoring in 3D Printing

2021 ◽  
Author(s):  
Jiarui Xie
Keyword(s):  
Real Time ◽  
Detection System ◽  
Region Of Interest ◽  
Cost Effective ◽  
Time Warping ◽  
Time Data ◽  
Fused Filament Fabrication ◽  
System A ◽  
Effective Manner

Fused Filament Fabrication (FFF) is an additive manufacturing technology that can produce complicated structures in a simple-to-use and cost-effective manner. Although promising, the technology is prone to defects, e.g. warping, compromising the quality of the manufactured component. To avoid the adverse effects caused by warping, this thesis utilizes deep-learning algorithms to develop a warping detection system using Convolutional Neural Networks (CNN). To create such a system, a real-time data acquisition and analysis pipeline is laid out. The system is responsible for capturing a snapshot of the print layer-bylayer and simultaneously extracting the corners of the component. The extracted region-of-interest is then passed through a CNN outputting the probability of a corner being warped. If a warp is detected, a signal is sent to pause the print, thereby creating a closed-loop monitoring system. The underlying model is tested on a real-time manufacturing environment yielding a mean accuracy of 99.21%.

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