Health monitoring of scarfed CFRP joints under cyclic loading via electrical resistance measurements using carbon nanotube modified adhesive films

2018 ◽  
Vol 105 ◽  
pp. 150-155 ◽  
Author(s):  
Till Augustin ◽  
Julian Karsten ◽  
Benedikt Kötter ◽  
Bodo Fiedler
Keyword(s):  
Carbon Nanotube ◽  
Cyclic Loading ◽  
Health Monitoring ◽  
Electrical Resistance ◽  
Electrical Resistance Measurements

Carbon Nanotube Composite Sensor for Structural Health Monitoring of Bridge Structures

2014 ◽  
Vol 875-877 ◽  
pp. 366-369
Author(s):  
Andy Chit Tan
Keyword(s):  
Carbon Nanotube ◽  
Health Monitoring ◽  
Electrical Resistance ◽  
Real Life ◽  
Experimental Tests ◽  
Corrosion Detection ◽  
Bridge Structures ◽  
Carbon Nanotube Composite ◽  
Composite Sensor

Bridges are important infrastructures of all nations and are required for transportation of goods as well as human. A catastrophic failure can result in loss of lives and enormous financial hardship to the nation. Although various kinds of sensors are now available to monitor the health of the structures due to corrosion, they do not provide permanent and long term measurements. This paper investigates the fabrication of Carbon Nanotube (CNT) based composite sensors for corrosion detection of structures. Multi-wall CNT (MWCNT)/Nafion composite sensors were fabricated to evaluate their electrical properties for corrosion detection. The test specimens were subjected to real life corrosion experimental tests and the results confirm that the electrical resistance of the sensor electrode was dramatically changed due to corrosion.

scholarly journals Electrical Properties Enhancement of Carbon Nanotube Yarns by Cyclic Loading

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4824
Author(s):  
Orli Weizman ◽  
Joey Mead ◽  
Hanna Dodiuk ◽  
Samuel Kenig
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Cyclic Loading ◽  
Electrical Resistance ◽  
High Performance ◽  
High Strength ◽  
Intrinsic Properties ◽  
Ambient Conditions ◽  
Resistance Value ◽  
Carbon Nanotube Yarns

Carbon nanotube yarns (CNTYs) possess low density, high conductivity, high strength, and moderate flexibility. These intrinsic properties allow them to be a preferred choice for use as conductive elements in high-performance composites. To fully exploit their potential as conductive reinforcing elements, further improvement in their electrical conductivity is needed. This study demonstrates that tensile cyclic loading under ambient conditions improves the electrical conductivity of two types of CNTYs. The results showed that the electrical resistance of untreated CNTYs was reduced by 80% using cyclic loading, reaching the resistance value of the drawn acid-treated CNTYs. Scanning electron microscopy showed that cyclic loading caused orientation and compaction of the CNT bundles that make up the CNTYs, resulting in significantly improved electrical conductivity of the CNTYs. Furthermore, the elastic modulus was increased by 20% while preserving the tensile strength. This approach has the potential to replace the environmentally unfriendly acid treatment currently used to enhance the conductivity of CNTYs.

scholarly journals Toward Structural Health Monitoring of Civil Structures Based on Self-Sensing Concrete Nanocomposites: A Validation in a Reinforced-Concrete Beam

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Diego L. Castañeda-Saldarriaga ◽  
Joham Alvarez-Montoya ◽  
Vladimir Martínez-Tejada ◽  
Julián Sierra-Pérez
Keyword(s):  
Reinforced Concrete ◽  
Damage Detection ◽  
Direct Current ◽  
Health Monitoring ◽  
Electrical Resistance ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Structural Member ◽  
Rc Beam ◽  
Electric Resistance

AbstractSelf-sensing concrete materials, also known as smart concretes, are emerging as a promising technological development for the construction industry, where novel materials with the capability of providing information about the structural integrity while operating as a structural material are required. Despite progress in the field, there are issues related to the integration of these composites in full-scale structural members that need to be addressed before broad practical implementations. This article reports the manufacturing and multipurpose experimental characterization of a cement-based matrix (CBM) composite with carbon nanotube (CNT) inclusions and its integration inside a representative structural member. Methodologies based on current–voltage (I–V) curves, direct current (DC), and biphasic direct current (BDC) were used to study and characterize the electric resistance of the CNT/CBM composite. Their self-sensing behavior was studied using a compression test, while electric resistance measures were taken. To evaluate the damage detection capability, a CNT/CBM parallelepiped was embedded into a reinforced-concrete beam (RC beam) and tested under three-point bending. Principal finding includes the validation of the material’s piezoresistivity behavior and its suitability to be used as strain sensor. Also, test results showed that manufactured composites exhibit an Ohmic response. The embedded CNT/CBM material exhibited a dominant linear proportionality between electrical resistance values, load magnitude, and strain changes into the RC beam. Finally, a change in the global stiffness (associated with a damage occurrence on the beam) was successfully self-sensed using the manufactured sensor by means of the variation in the electrical resistance. These results demonstrate the potential of CNT/CBM composites to be used in real-world structural health monitoring (SHM) applications for damage detection by identifying changes in stiffness of the monitored structural member.

Electrical Resistance and Acoustic Emission During Fatigue Testing of Pristine and High Velocity Impact SiC/SiC Composites at Room and Elevated Temperature

2016 ◽  
Author(s):  
Zipeng Han ◽  
Gregory N. Morscher ◽  
Emmanuel Maillet ◽  
Manigandan Kannan ◽  
Sung R. Choi ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Acoustic Emission ◽  
Cyclic Loading ◽  
Electrical Resistance ◽  
Fatigue Testing ◽  
Early Stage ◽  
Loading Conditions ◽  
Initial Attempt ◽  
Matrix Cracks ◽  
Sic Composites

Electrical resistance (ER) is a relatively new approach for real-time monitoring and evaluating damage in SiC/SiC composites for a variety of loading conditions. In this study, ER of woven silicon carbide fiber-reinforced silicon carbide composite systems in their pristine and impacted state were measured under cyclic loading conditions at room and high temperature (1200C). In addition, modal acoustic emission (AE) was also monitored, which can reveal the occasion of matrix cracks and fiber. ER measurement and AE technique are shown in this study to be useful methods to monitor damage and indicate the failure under cyclic loading. Based on the slope of the ER evolution, an initial attempt has been made to develop a method allowing a critical damage phase to be identified. While the physical meaning of the critical point is not yet clear, it has the potential to allow the failure to be indicated at its early stage.

Electrical resistance measurements on young balsam fir trees in relation to specific volume increment, foliar biomass, and ion content of bark and wood

1984 ◽  
Vol 14 (2) ◽  
pp. 177-180 ◽  
Author(s):  
H. Plene ◽  
R. G. Thompson ◽  
J. E. McIsaac ◽  
D. S. Fensom
Keyword(s):  
Electrical Resistance ◽  
Specific Volume ◽  
Balsam Fir ◽  
Ion Content ◽  
Volume Increment ◽  
Electrical Resistance Measurements ◽  
Foliar Biomass

Electrical resistance in young balsam fir (Abiesbalsamea (L.) Mill.) trees was inversely (nonlinear) correlated with specific volume increment, total foliar biomass, and the combined weight of the current and 1-year-old foliage. These relationships were stronger before budbreak than after. No relationship existed between concentrations of N, P, K, Ca, and Mg in the bark and wood collected around time of budbreak, and electrical resistance.

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