scholarly journals Multifunctional Characteristics of Carbon Nanotube (CNT) Yarn Composites

2006 ◽  
Author(s):  
Corey D. Hernandez ◽  
Mei Zhang ◽  
Shaoli Fang ◽  
Ray H. Baughman ◽  
Thomas S. Gates ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Composite Materials ◽  
Mechanical Strength ◽  
Composite Structures ◽  
Initial Temperature ◽  
Strain Sensing ◽  
Flexible Membrane ◽  
Strength Tests ◽  
Weight Penalty ◽  
Sensing Characteristics

By forming composite structures with Carbon Nanotube (CNT) yarns we achieve materials capable of measuring strain and composite structures with increased mechanical strength. The CNT yarns used are of the 2-ply and 4-ply variety with the yarns having diameters of about 15–30 μm. The strain sensing characteristics of the yarns are investigated on test beams with the yarns arranged in a bridge configuration. Additionally, the strain sensing properties are also investigated on yarns embedded on the surface of a flexible membrane. Initial mechanical strength tests also show an increase in the modulus of elasticity of the composite materials while incurring a weight penalty of less than one-percent. Also presented are initial temperature characterizations of the yarns.

scholarly journals Towards Multifunctional Characteristics of Embedded Structures With Carbon Nanotube Yarns

2006 ◽  
Author(s):  
Corey D. Hernandez ◽  
Thomas S. Gates ◽  
Seun K. Kahng
Keyword(s):  
Stainless Steel ◽  
Carbon Nanotube ◽  
Strain Distribution ◽  
Composite Structures ◽  
Mechanical Tests ◽  
Strain Sensitivity ◽  
Average Strain ◽  
Silicon Rubber ◽  
Additional Weight ◽  
Sensing Characteristics

This paper presents recent results on research of achieving multifunctional structures utilizing Carbon Nanotube (CNT) yarns. The investigation centers on creating composite structures with CNT yarns to simultaneously achieve increases in mechanical strength and the ability to sense strain. The CNT yarns used in our experiments are of the single-ply and two-ply variety with the single-ply yarns having diameters on the order of 10–20 μm. The yarns are embedded in silicon rubber and polyurethane test specimens. Mechanical tests show an increase in modulus of elasticity, with an additional weight increase of far less than one-percent. Sensing characteristics of the yarns are investigated on stainless steel test beams in an electrical bridge configuration, and are observed to have a strain sensitivity of 0.7mV/V/1000 micro-strain. Also reported are measurements of the average strain distribution along the direction of the CNT yarns on square silicon rubber membranes.

Strain Sensing Characteristics of Rubbery Carbon Nanotube Composite for Flexible Sensors

2016 ◽  
Vol 16 (2) ◽  
pp. 1607-1611 ◽  
Author(s):  
Gyong Rak Choi ◽  
Hyung-Ki Park ◽  
Hoon Huh ◽  
Young-Ju Kim ◽  
Heon Ham ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Strain Sensing ◽  
Flexible Sensors ◽  
Carbon Nanotube Composite ◽  
Sensing Characteristics

Embedded carbon nanotube thread piezoresistive strain sensor performance

Sensor Review ◽  
2014 ◽  
Vol 34 (2) ◽  
pp. 209-219 ◽  
Author(s):  
Mark Schulz ◽  
Yi Song ◽  
Adam Hehr ◽  
Vesselin Shanov
Keyword(s):  
Carbon Nanotube ◽  
Composite Materials ◽  
Strain Sensor ◽  
Temperature Stability ◽  
Gauge Factor ◽  
Strain Sensing ◽  
Metallic Structures ◽  
Content Type ◽  
Sensing Properties ◽  
Sensor Performance

Purpose – Carbon nanotube (CNT) thread ' s piezoresisitive strain sensing properties of gauge factor, linearity, hysteresis, consistency, temperature stability, and bandwidth were evaluated. This evaluation was motivated by little information in literature combined with the need to understand these properties for commercial use. The paper aims to discuss these issues. Design/methodology/approach – The study here analyzes as-spun CNT thread built into unidirectional glass fiber composites and mounted onto aluminium beams with epoxy to evaluate strain sensing properties. The analyses utilize known sensor parameter definitions to quantify sensor performance. Findings – CNT thread can provide reliable and robust strain measurements for composite and metallic structures. The strain sensor performance meets or exceeds other strain sensors in performance. Research limitations/implications – CNT thread ' s piezoresistive effect is not well understood in terms of Poisson ' s ratio and nanotube contact. More research needs to be carried out to better understand this relationship and optimize the sensor thread. Practical implications – CNT thread can be utilized as a robust strain sensor for composite and metallic structures. It can also be built into composite materials for embedded strain and damage monitoring. By monitoring composite materials with the sensor thread, reliability will significantly increase. In turn, this will lower safety factors and revolutionize inspection methods for composite materials. Originality/value – This paper is the first to comprehensively evaluate key strain sensing properties of CNT thread. With all this strain sensor information in one spot, this should help expedite the use of this technology in other research and industry.

scholarly journals Strain-Sensing Characteristics of Carbon Nanotube Yarns Embedded in Three-Dimensional Braided Composites under Cyclic Loading

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Huixiao Bai ◽  
Gang Ding ◽  
Shusheng Jia ◽  
Jinguo Hao
Keyword(s):  
Carbon Nanotube ◽  
Cyclic Loading ◽  
Damage Accumulation ◽  
Three Dimensional ◽  
Progressive Damage ◽  
Strain Sensing ◽  
Braided Composites ◽  
3D Braided Composites ◽  
Sensing Characteristics ◽  
Carbon Nanotube Yarns

Carbon nanotube yarns are embedded in three-dimensional (3D) braided composites with five-axis yarns, which are used as strain sensors to monitor the damage of 3D braided composites. In the cyclic mechanical loading experiment, the strain-sensing characteristics of 3D braided composites were studied by in situ measuring the resistance change of the embedded carbon nanotube yarn. The 3D five-directional braided composite prefabricated part based on carbon nanotube yarns was developed, and the progressive damage accumulation experiments were carried out on carbon nanotube yarns and specimens embedded in carbon nanotube yarns. The research results show that there is a good correlation between the change of relative resistance of the carbon nanotube yarn and the strain of the composite specimen during cyclic loading and unloading. When the tensile degree of the specimen increases beyond a certain range, the carbon nanotube yarn sensor embedded in the specimen shows resistance hysteresis and produces residual resistance. Therefore, the fiber can better monitor the progressive damage accumulation of 3D five-direction braided composites.

scholarly journals Dynamic Nanohybrid-Polysaccharide Hydrogels for Soft Wearable Strain Sensing

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3574
Author(s):  
Pejman Heidarian ◽  
Hossein Yousefi ◽  
Akif Kaynak ◽  
Mariana Paulino ◽  
Saleh Gharaie ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Strain Sensors ◽  
Self Healing ◽  
Nano Materials ◽  
Strain Sensing ◽  
Ferric Ions ◽  
Research Activity ◽  
Adhesion Properties ◽  
High Mechanical Strength ◽  
The Moment

Electroconductive hydrogels with stimuli-free self-healing and self-recovery (SELF) properties and high mechanical strength for wearable strain sensors is an area of intensive research activity at the moment. Most electroconductive hydrogels, however, consist of static bonds for mechanical strength and dynamic bonds for SELF performance, presenting a challenge to improve both properties into one single hydrogel. An alternative strategy to successfully incorporate both properties into one system is via the use of stiff or rigid, yet dynamic nano-materials. In this work, a nano-hybrid modifier derived from nano-chitin coated with ferric ions and tannic acid (TA/Fe@ChNFs) is blended into a starch/polyvinyl alcohol/polyacrylic acid (St/PVA/PAA) hydrogel. It is hypothesized that the TA/Fe@ChNFs nanohybrid imparts both mechanical strength and stimuli-free SELF properties to the hydrogel via dynamic catecholato-metal coordination bonds. Additionally, the catechol groups of TA provide mussel-inspired adhesion properties to the hydrogel. Due to its electroconductivity, toughness, stimuli-free SELF properties, and self-adhesiveness, a prototype soft wearable strain sensor is created using this hydrogel and subsequently tested.

scholarly journals Defects and uncertainties of adhesively bonded composite joints

2021 ◽  
Vol 3 (9) ◽  
Author(s):  
Sadik Omairey ◽  
Nithin Jayasree ◽  
Mihalis Kazilas
Keyword(s):  
Composite Materials ◽  
Composite Structures ◽  
Production Efficiency ◽  
Adhesive Bonding ◽  
Detection Methods ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Wide Range ◽  
Bonded Composite

AbstractThe increasing use of fibre reinforced polymer composite materials in a wide range of applications increases the use of similar and dissimilar joints. Traditional joining methods such as welding, mechanical fastening and riveting are challenging in composites due to their material properties, heterogeneous nature, and layup configuration. Adhesive bonding allows flexibility in materials selection and offers improved production efficiency from product design and manufacture to final assembly, enabling cost reduction. However, the performance of adhesively bonded composite structures cannot be fully verified by inspection and testing due to the unforeseen nature of defects and manufacturing uncertainties presented in this joining method. These uncertainties can manifest as kissing bonds, porosity and voids in the adhesive. As a result, the use of adhesively bonded joints is often constrained by conservative certification requirements, limiting the potential of composite materials in weight reduction, cost-saving, and performance. There is a need to identify these uncertainties and understand their effect when designing these adhesively bonded joints. This article aims to report and categorise these uncertainties, offering the reader a reliable and inclusive source to conduct further research, such as the development of probabilistic reliability-based design optimisation, sensitivity analysis, defect detection methods and process development.

scholarly journals Introduction to Macroscopic Optimal Design in the Mechanics of Composite Materials and Structures

2021 ◽  
Vol 5 (2) ◽  
pp. 36
Author(s):  
Aleksander Muc
Keyword(s):  
Composite Materials ◽  
Composite Structures ◽  
Constitutive Relations ◽  
A Priori ◽  
Chemical Properties ◽  
Composite Plates ◽  
Failure Criteria ◽  
Lagrange Equations ◽  
Homogenization Methods ◽  
Mechanics Of Composite Materials

The main goal of building composite materials and structures is to provide appropriate a priori controlled physico-chemical properties. For this purpose, a strengthening is introduced that can bear loads higher than those borne by isotropic materials, improve creep resistance, etc. Composite materials can be designed in a different fashion to meet specific properties requirements.Nevertheless, it is necessary to be careful about the orientation, placement and sizes of different types of reinforcement. These issues should be solved by optimization, which, however, requires the construction of appropriate models. In the present paper we intend to discuss formulations of kinematic and constitutive relations and the possible application of homogenization methods. Then, 2D relations for multilayered composite plates and cylindrical shells are derived with the use of the Euler–Lagrange equations, through the application of the symbolic package Mathematica. The introduced form of the First-Ply-Failure criteria demonstrates the non-uniqueness in solutions and complications in searching for the global macroscopic optimal solutions. The information presented to readers is enriched by adding selected review papers, surveys and monographs in the area of composite structures.

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