A Flexible Strain Sensor Based on a Conductive Polymer Composite for in situ Measurement of Parachute Canopy Deformation

Abstract

A sensor based on a Conductive Polymer Composite (CPC), fully compatible with a textile substrate and its general properties, has been developed in our laboratory, and its electromechanical characterization is presented herein. In particular the effects of strain rate (from 10 to 1,000 mm/min) and of repeated elongation cycles on the sensor behaviour are investigated. The results show that strain rate seems to have little influence on sensor response. When submitted to repeated tensile cycles, the CPC sensor is able to detect accurately fabric deformations over each whole cycle, taking into account the mechanical behaviour of the textile substrate. Complementary information is given concerning the non-effect of aging on the global resistivity of the CPC sensor. Finally, our sensor was tested on a parachute canopy during a real drop test: the canopy fabric deformation during the critical inflation phase was successfully measured, and was found to be less than 9%.

Binary Zr–Ni/Co metallic glass films: Role of the structural state on their durability

“…The targeted composition were obtained using the procedure detailed in a previous study [16]. The films' thickness was determined by the step method performed on glass slides with an Altisurf profilometer, equipped with an inductive probe allowing an accuracy of about 20 nm [42].…”

“…The Zr-44 at.% Co TFMG crystallization mechanism is governed by a multistep nucleation process [42,43]. The amorphous structure is stable up to 440°C, temperature where the amorphous matrix coexists with the first cubic CoZr intermetallic compound (Fig.…”

On the verification and validation of a spring fabric for modeling parachute inflation

“…Researchers have studied parachute inflation with different methods including empirical analysis (Potvin, 1998), semi-numerical simulation , and through experiments . During the inflation sequence, the canopy not only experiences extreme increase in internal volume and large loading, but also involves geometric and material nonlinearities which make it a highly challenging event to model from a dynamic structures perspective (Cochrane et al, 2010). Parachute inflation consists of a sequence of dynamically animated stages.…”

Electro-Conductive Sensors and Heating Elements Based on Conductive Polymer Composites in Woven Structures

“…As coating solution, the conductive polymer composite based on dispersion of carbon black particles (Printex® L6) in polymer (Evoprene® 007) solution, using chloroform as a solvent was chosen (Cochrane et al, 2007(Cochrane et al, , 2010. In order to characterize the sensitivity and adherence of the coating on different substrates, the 35 % carbon black solution was coated on different yarns (71 tex cotton spun yarns; 482.3 tex polyethylene monofilament and 25 tex polyamide monofilament).…”

“…Several different coating techniques for intelligent textile structures exist -the one chosen for both applications was developed in our laboratory (Cochrane et al, 2007(Cochrane et al, , 2010) based on dispersed carbon black particles (Printex® L6) in a polymer solution (Styren-Butadien-Styren or latex), using a solvent. In the first part of this chapter, a new approach of NDE (Non Destructive Evaluation) using fibrous sensors inserted inside composite woven reinforcements during their weaving is presented.…”