TY  - JOUR
A1  - Laflamme, Simon
A1  - Kollosche, Matthias
A1  - Connor, Jerome J.
A1  - Kofod, Guggi
T1  - Robust flexible capacitive surface sensor for structural health monitoring applications
JF  - Journal of engineering mechanics
N2  - Early detection of possible defects in civil infrastructure is vital to ensuring timely maintenance and extending structure life expectancy. The authors recently proposed a novel method for structural health monitoring based on soft capacitors. The sensor consisted of an off-the-shelf flexible capacitor that could be easily deployed over large surfaces, the main advantages being cost-effectiveness, easy installation, and allowing simple signal processing. In this paper, a capacitive sensor with tailored mechanical and electrical properties is presented, resulting in greatly improved robustness while retaining measurement sensitivity. The sensor is fabricated from a thermoplastic elastomer mixed with titanium dioxide and sandwiched between conductive composite electrodes. Experimental verifications conducted on wood and concrete specimens demonstrate the improved robustness, as well as the ability of the sensing method to diagnose and locate strain.
KW  - Strain gages
KW  - Structural health monitoring
KW  - Monitoring
KW  - Probe instruments
KW  - Strain gauge
KW  - Structural health monitoring
KW  - Strain monitoring
KW  - Capacitive sensor
KW  - Dielectric polymer
KW  - Stretchable sensor
KW  - Flexible membrane
KW  - Sensing skin
Y1  - 2013
U6  - https://doi.org/10.1061/(ASCE)EM.1943-7889.0000530
SN  - 0733-9399
SN  - 1943-7889
VL  - 139
IS  - 7
SP  - 879
EP  - 885
PB  - American Society of Civil Engineers
CY  - Reston
ER  - 
TY  - JOUR
A1  - Saleem, Hussam
A1  - Downey, Austin
A1  - Laflamme, Simon
A1  - Kollosche, Matthias
A1  - Ubertini, Filippo
T1  - Investigation of Dynamic Properties of a Novel Capacitive-based Sensing Skin for Nondestructive Testing
JF  - Materials evaluation
N2  - A capacitive-based soft elastomeric strain sensor was recently developed by the authors for structural health monitoring applications. Arranged in a network configuration, the sensor becomes a sensing skin, where local deformations can be monitored over a global area. The sensor transduces a change in geometry into a measurable change in capacitance, which can be converted into strain using a previously developed electromechanical model. Prior studies have demonstrated limitations of this electromechanical model for dynamic excitations beyond 15 Hz, because of a loss in linearity in the sensor's response. In this paper, the dynamic behavior beyond 15 Hz is further studied, and a new version of the electromechanical model is proposed to accommodate dynamic strain measurements up to 40 Hz. This behavior is characterized by subjecting the sensor to a frequency sweep and identifying possible sources of nonlinearities beyond 15 Hz. Results show possible frequency dependence of the materials' Poisson's ratios, which are successfully modeled and integrated into the electromechanical model. This demonstrates that the proposed sensor can be used for monitoring and evaluation of structural responses up to 40 Hz, a range covering the vast majority of the dominating frequency responses of civil infrastructures.
KW  - nondestructive testing
KW  - structural health monitoring
KW  - soft elastomeric capacitor
KW  - capacitive sensor
KW  - vibration monitoring
KW  - sensing skin
Y1  - 2015
SN  - 0025-5327
VL  - 73
IS  - 10
SP  - 1390
EP  - 1397
PB  - American Society for Nondestructive Testing
CY  - Columbus
ER  - 
TY  - JOUR
A1  - Kollosche, Matthias
A1  - Stoyanov, Hristiyan
A1  - Laflamme, Simon
A1  - Kofod, Guggi
T1  - Strongly enhanced sensitivity in elastic capacitive strain sensors
JF  - Journal of materials chemistry
N2  - Strain sensors based on dielectric elastomer capacitors function by the direct coupling of mechanical deformations with the capacitance. The coupling can be improved by enhancing the relative permittivity of the dielectric elastomer. Here, this is carried out through the grafting of conducting polymer (poly-aniline) to the elastomer backbone, leading to molecular composites. An enhancement in capacitance response of 46 times is observed. This could help to extend the possible range of miniaturization towards even smaller device features.
Y1  - 2011
U6  - https://doi.org/10.1039/c0jm03786a
SN  - 0959-9428
VL  - 21
IS  - 23
SP  - 8292
EP  - 8294
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  -