Enhanced lumped circuit model for smart nanocomposite cement-based sensors under dynamic compressive loading conditions

Abstract

Smart composite nanostructured materials represent one of the fastest-growing areas of interest among scientists in recent years and, in particular, Carbon NanoTube (CNT) cement-based composites are attracting more and more attention. These composites exhibit self-sensing capabilities providing measurable variations of their electrical properties under the application of mechanical deformations. Together with this exceptional property, the similarity and compatibility between these composites and structural concrete suggest the possibility of developing distributed embedded strain-sensing systems with substantial improvements in the cost-effectiveness in applications to large-scale concrete structures. In order to design and optimize CNT reinforced cement based dynamic sensors, it is fundamental to develop theoretical models capable of simulating the relationship between dynamic mechanical strains and the effective electrical conductivity. This paper presents an electromechanical modeling of the Direct Current (DC) electrical resistance of CNT reinforced cement paste sensors based on a piezoelectric/piezoresistive lumped circuit. The model represents an enhanced version and a generalization of another model previously proposed by the authors. Previously published experimental results have been used as validation benchmark. In particular, experimental tests concerning the characterization of the step response under unloaded conditions, steady state response under harmonic loadings and sweep analyses are considered. The results demonstrate that the newly proposed model is superior in comparison to the previous one in reproducing the dynamic response of the sensors when subjected to harmonic mechanical loads. Overall, an excellent agreement between theoretical predictions and experimental results is achieved.

Recent Progress in Nanomaterials for Modern Concrete Infrastructure: Advantages and Challenges

“…For instance, cement-based composites with CNTs have strain-sensing abilities, which may allow the measurement of their electrical resistance under applied loads [74]. It represents an advantage to obtain strain-sensing concrete structure systems for structural health monitoring [75,76].…”

Theoretical Determination of the Stabilization Time in Galvanostatic EIS Measurements: The Simplified Randles Cell

“…The only difference is that while analytical solutions can be deduced for simple systems, as the simplified Randles cell; more complex systems may require the use of numerical methods. Viologen-based electrochromic display [51] 116 Ω 32 Ω 9.4 F 14 s…”

“…Furthermore, Randles cell has been used for modelling ionic liquid systems, such as a surfactant/salt/water ternary system [49], and an ionic liquid/oil interface [50]. Finally, some examples of exotic systems that have been modelled using the Randles EEC can be found in literature: carbon nanotube cement-based composites [51], a viologen-based electrochromic device [52], SiO2 layers [53], and the gum Arabic-Chitosan complexation process in bulk solution [54]. These are just some of the countless examples of the application of the Randles cell, available in literature.…”

Synthesis and Characterization of Cement/Carbon-Nanotube Composite for Structural Health Monitoring Applications

“…During the composite manufacturing with CNTs charge, copper anodes were embedded in order to collect information associated with the electrical behavior. Electric resistance characterization methodology setup was made on the following work [24]. The samples electric resistance was measured by connecting an external DAQ system to electrodes embedded in the cement/CNTs composite.…”