New sensing method of dispersion and damage detection of carbon fiber/polypropylene-polyamide composites via two-dimensional electrical resistance mapping

Author(s):  
J. M. Park ◽  
D. J. Kwon ◽  
P. S. Shin ◽  
J. H. Kim ◽  
K. L. DeVries
2011 ◽  
Vol 189-193 ◽  
pp. 2185-2190
Author(s):  
Chang Lin He ◽  
Si Rong Zhu ◽  
Xiao Yu Zhang

Based on the piezoresistive function character and the conductivity of carbon fiber smart layer (CFSL), a novel electrical resistance tomography (ERT) system of spherical and cylindrical CFSL has been developed for global health monitoring. Based on the background of the third generation nuclear containment vessel, CFSL is stuck on the surface of the structure, and the effectiveness of the ERT system is verified by virtual experiment. The image reconstruction results show that CFSL on two-dimensional curved surface has good sensing characteristics in the complex strain state. Compared with structural volumetric strain in the monitoring area, it indicates that the high electrical resistance of CFSL is distributed in the high strain area of structures, and the low electrical resistance of CFSL is just distributed in the low strain area of structures. Therefore the resistivity’s distribution of CFSL can reflect qualitatively the structural volumetric strain field.


Author(s):  
Diego L. Castañeda-Saldarriaga ◽  
Joham Alvarez-Montoya ◽  
Vladimir Martínez-Tejada ◽  
Julián Sierra-Pérez

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.


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