Retracted Article: 3D printed highly flexible strain sensor based on TPU–graphene composite for feedback from high speed robotic applications

2019 ◽  
Vol 7 (16) ◽  
pp. 4692-4701 ◽  
Author(s):  
Jahan Zeb Gul ◽  
Memoon Sajid ◽  
Kyung Hyun Choi
Keyword(s):  
High Speed ◽  
Thermoplastic Polyurethane ◽  
Three Dimensional ◽  
Strain Sensor ◽  
Graphene Composite ◽  
Retracted Article ◽  
3D Printed ◽  
Resistive Type ◽  
Flexible Strain Sensor ◽  
Robotic Applications

A novel, highly flexible and electrically resistive-type strain sensor with a special three-dimensional conductive network was 3D printed using a composite of conductive graphene pellets and flexible thermoplastic polyurethane (TPU) pellets.

scholarly journals Retraction: 3D printed highly flexible strain sensor based on TPU–graphene composite for feedback from high speed robotic applications

2020 ◽  
Vol 8 (7) ◽  
pp. 2597-2597 ◽  
Author(s):  
Jahan Zeb Gul ◽  
Memoon Sajid ◽  
Kyung Hyun Choi
Keyword(s):  
High Speed ◽  
Strain Sensor ◽  
Graphene Composite ◽  
3D Printed ◽  
Flexible Strain Sensor ◽  
Robotic Applications

Retraction of ‘3D printed highly flexible strain sensor based on TPU–graphene composite for feedback from high speed robotic applications’ by Jahan Zeb Gul et al., J. Mater. Chem. C, 2019, 7, 4692–4701.

Flexible strain sensor based on embedded three-dimensional annular cracks with high mechanical robustness and high sensitivity

2021 ◽  
Vol 25 ◽  
pp. 101247
Author(s):  
Duorui Wang ◽  
Xiangming Li ◽  
Hongmiao Tian ◽  
Xiaoliang Chen ◽  
Bangbang Nie ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Strain Sensor ◽  
High Sensitivity ◽  
Flexible Strain Sensor ◽  
Annular Cracks

Flexible Strain Sensor Using Additive Manufacturing and Conductive Liquid Metal: Design, Fabrication, and Characterization

2018 ◽  
Author(s):  
Austin Smith ◽  
Hamzeh Bardaweel
Keyword(s):  
3D Printing ◽  
Liquid Metal ◽  
Strain Sensor ◽  
Gauge Factor ◽  
Limiting Factor ◽  
Successful Implementation ◽  
Conductive Liquid ◽  
Fused Deposition ◽  
3D Printed ◽  
Flexible Strain Sensor

In this work a flexible strain sensor is fabricated using Fused Deposition Modeling (FDM) 3D printing technique. The strain sensor is fabricated using commercially available flexible Thermoplastic Polyurethane (TPU) filaments and liquid metal Galinstan Ga 68.5% In 21% Sn 10%. The strain sensor consists of U-shape 2.34mm long and 0.2mm deep channels embedded inside a TPU 3D printed structure. The performance of the strain sensor is measured experimentally. Gauge Factor is estimated by measuring change in electric resistance when the sensor is subject to 13.2% – 38.6% strain. Upon straining and unstraining, results from characterization tests show high linearity in the range of 13.2% to 38.6% strain with very little hysteresis. However, changes due to permanent deformations are a limiting factor in the usefulness of these sensors because these changes limit the consistency of the device. FDM 3D printing shows promise as a method for fabricating flexible strain sensors. However, more investigation is needed to look at the effects of geometries and 3D printing process parameters on the yield elongation of the flexible filaments. Additionally, more investigation is needed to observe the effect of distorted dimensions of the 3D printed channels on the sensitivity of the strain sensor. It is anticipated that successful implementation of these commercially available filaments and FDM 3D printers will lead to reduction in cost and complexity of developing these flexible sensors.

scholarly journals 3D-Printed Soft Structure of Polyurethane and Magnetorheological Fluid: A Proof-of-Concept Investigation of its Stiffness Tunability

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 655 ◽  
Author(s):  
Seong-Woo Hong ◽  
Ji-Young Yoon ◽  
Seong-Hwan Kim ◽  
Sun-Kon Lee ◽  
Yong-Rae Kim ◽  
...  
Keyword(s):  
Fused Deposition Modeling ◽  
Permanent Magnets ◽  
Thermoplastic Polyurethane ◽  
Three Dimensional ◽  
Magnetorheological Fluid ◽  
Three Dimensional Printing ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
3D Printed ◽  
Dimensional Printing

In this study, a soft structure with its stiffness tunable by an external field is proposed. The proposed soft beam structure consists of a skin structure with channels filled with a magnetorheological fluid (MRF). Two specimens of the soft structure are fabricated by three-dimensional printing and fused deposition modeling. In the fabrication, a nozzle is used to obtain channels in the skin of the thermoplastic polyurethane, while another nozzle is used to fill MRF in the channels. The specimens are tested by using a universal tensile machine to evaluate the relationships between the load and deflection under two different conditions, without and with permanent magnets. It is empirically shown that the stiffness of the proposed soft structure can be altered by activating the magnetic field.

scholarly journals A comparative analysis of the compression characteristics of a thermoplastic polyurethane 3D printed in four infill patterns for comfort applications

2021 ◽  
Vol 27 (11) ◽  
pp. 24-36
Author(s):  
Susan Erica Nace ◽  
John Tiernan ◽  
Donal Holland ◽  
Aisling Ni Annaidh
Keyword(s):  
Thermoplastic Polyurethane ◽  
Three Dimensional ◽  
Content Type ◽  
Compressive Response ◽  
Flexible Polymer ◽  
3D Printed ◽  
Postural Support ◽  
End Use ◽  
Support Surfaces ◽  
Compression Characteristics

Purpose Most support surfaces in comfort applications and sporting equipment are made from pressure-relieving foam such as viscoelastic polyurethane. However, for some users, foam is not the best material as it acts as a thermal insulator and it may not offer adequate postural support. The additive manufacturing of such surfaces and equipment may alleviate these issues, but material and design investigation is needed to optimize the printing parameters for use in pressure relief applications. This study aims to assess the ability of an additive manufactured flexible polymer to perform similarly to a viscoelastic foam for use in comfort applications. Design/methodology/approach Three-dimensional (3D) printed samples of thermoplastic polyurethane (TPU) are tested in uniaxial compression with four different infill patterns and varying infill percentage. The behaviours of the samples are compared to a viscoelastic polyurethane foam used in various comfort applications. Findings Results indicate that TPU experiences an increase in strength with an increasing infill percentage. Findings from the study suggest that infill pattern impacts the compressive response of 3D printed material, with two-dimensional patterns inducing an elasto-plastic buckling of the cell walls in TPU depending on infill percentage. Such buckling may not be a beneficial property for comfort applications. Based on the results, the authors suggest printing from TPU with a low-density 3D infill, such as 5% gyroid. Originality/value Several common infill patterns are characterised in compression in this work, suggesting the importance of infill choices when 3D printing end-use products and design for manufacturing.

Simulation and Validation of Fully 3D Printed Soft Actuators

2020 ◽  
Author(s):  
Steffi Torres ◽  
Julio San Martin ◽  
Brittany Newell ◽  
Jose Garcia
Keyword(s):  
3D Printing ◽  
Thermoplastic Polyurethane ◽  
Pharmaceutical Products ◽  
Element Analysis ◽  
Strain Behavior ◽  
Fea Model ◽  
First Case ◽  
3D Printed ◽  
Soft Actuators ◽  
Robotic Applications

Abstract Flexible actuators are a growing class of devices implemented in soft robotic applications, medical devices and processes involving food and pharmaceutical products. Such actuators have traditionally been manufactured using casting processes or other conventional methods requiring more than one fabrication step. The arrival of flexible 3D printing materials and 3D printing techniques has facilitated the creation of these flexible actuators via additive manufacturing. The work presented in this article displays the analytical characterization and experimental validation of two materials and two actuator designs. The first case presents a finite element analysis (FEA) simulated model of a bellows actuator using a photocurable flexible resin (TangoPlus FLX930) and studies the effect of printing orientation on the simulation. The simulation used a 5 parameter Mooney-Rivlin model to predict the strain behavior of the actuator under hydrostatic pressure. A second case is presented where a Thermoplastic Polyurethane actuator was 3D printed and simulated using the same FEA model and a second calibration of the Mooney-Rivlin 5 parameter model. In both cases experimental data was used to calibrate and validate the simulation. The resulting simulated strain was consistent when the printing orientation of actuators was parallel (0 degrees) to the strain direction of the actuators. Results were less consistent when a print orientation of 45 degrees was applied.

scholarly journals Evaluation of the Mechanical Properties of Porous Thermoplastic Polyurethane Obtained by 3D Printing for Protective Gear

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Hyojeong Lee ◽  
Ran-i Eom ◽  
Yejin Lee
Keyword(s):  
Tensile Strength ◽  
3D Printing ◽  
Thermoplastic Polyurethane ◽  
Three Dimensional ◽  
Protective Equipment ◽  
Shock Absorption ◽  
Protective Gear ◽  
Compression Properties ◽  
Impact Deformation ◽  
3D Printed

Three-dimensional (3D) printing is an efficient and sustainable technology useful in various manufacturing fields. The aim of this study was to investigate the applicability of thermoplastic polyurethane (TPU) as a 3D printing material and the conditions related to the use of TPU as personal protective equipment. The tensile strength, shock absorption, and compressibility were evaluated for different infill and thickness conditions. An increase in the infill rate led to an increase in the tensile strength, regardless of the sample thickness. Similarly, the compression energy increased as the infill increased. Both the shock absorption and compression properties increased as the thickness decreased under identical infill conditions. The actual shock absorption test data were compared to the results of structural analyses, which confirmed the potential for predicting impact deformation through the analysis of the tensile characteristics and the basic properties of a 3D printed material.

scholarly journals 3D-printed highly stable flexible strain sensor based on silver-coated-glass fiber-filled conductive silicon rubber

2020 ◽  
Vol 193 ◽  
pp. 108788
Author(s):  
Chen Zhao ◽  
Zhidong Xia ◽  
Xuelong Wang ◽  
Jingkai Nie ◽  
Pei Huang ◽  
...  
Keyword(s):  
Glass Fiber ◽  
Strain Sensor ◽  
Silicon Rubber ◽  
Coated Glass ◽  
3D Printed ◽  
Flexible Strain Sensor

scholarly journals Flexible Strain Sensor Based on Carbon Black/Silver Nanoparticles Composite for Human Motion Detection

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1836 ◽  
Author(s):  
Weiyi Zhang ◽  
Qiang Liu ◽  
Peng Chen
Keyword(s):  
Silver Nanoparticles ◽  
Carbon Black ◽  
Motion Detection ◽  
Thermoplastic Polyurethane ◽  
Strain Sensor ◽  
Human Motion ◽  
Tunneling Effect ◽  
Gauge Factor ◽  
Human Motion Detection ◽  
Flexible Strain Sensor

The demand for flexible and wearable electronic devices with excellent stretchability and sensitivity is increasing, especially for human motion detection. In this work, a simple, low-cost and convenient strategy has been employed to fabricate flexible strain sensor with a composite of carbon black and silver nanoparticles as sensing materials and thermoplastic polyurethane as matrix. The strain sensors thus prepared possesses high stretchability and good sensitivity (gauge factor of 21.12 at 100% tensile strain), excellent static (almost constant resistance variation under 50% strain for 600 s) and dynamic (100 cycles) stability. Compared with bare carbon black-based strain sensor, carbon black/silver nanoparticles composite-based strain sensor shows ~18 times improvement in sensitivity at 100% strain. In addition, we discuss the sensing mechanisms using the disconnection mechanism and tunneling effect which results in high sensitivity of the strain sensor. Due to its good strain-sensing performance, the developed strain sensor is promising in detecting various degrees of human motions such as finger bending, wrist rotation and elbow flexion.

scholarly journals Mechanical Properties and In Vitro Evaluation of Thermoplastic Polyurethane and Polylactic Acid Blend for Fabrication of 3D Filaments for Tracheal Tissue Engineering

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3087
Author(s):  
Asmak Abdul Samat ◽  
Zuratul Ain Abdul Hamid ◽  
Mariatti Jaafar ◽  
Badrul Hisham Yahaya
Keyword(s):  
Tissue Engineering ◽  
Polylactic Acid ◽  
Thermoplastic Polyurethane ◽  
Three Dimensional ◽  
Thermal Characteristics ◽  
Surgical Reconstruction ◽  
Scanning Calorimetry ◽  
3D Printed ◽  
Tracheal Tissue

Surgical reconstruction of extensive tracheal lesions is challenging. It requires a mechanically stable, biocompatible, and nontoxic material that gradually degrades. One of the possible solutions for overcoming the limitations of tracheal transplantation is a three-dimensional (3D) printed tracheal scaffold made of polymers. Polymer blending is one of the methods used to produce material for a trachea scaffold with tailored characteristics. The purpose of this study is to evaluate the mechanical and in vitro properties of a thermoplastic polyurethane (TPU) and polylactic acid (PLA) blend as a potential material for 3D printed tracheal scaffolds. Both materials were melt-blended using a single screw extruder. The morphologies (as well as the mechanical and thermal characteristics) were determined via scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, tensile test, and Differential Scanning calorimetry (DSC). The samples were also evaluated for their water absorption, in vitro biodegradability, and biocompatibility. It is demonstrated that, despite being not miscible, TPU and PLA are biocompatible, and their promising properties are suitable for future applications in tracheal tissue engineering.

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