Development of a Flexible Dielectric Sensor for Flow Monitoring of the Liquid Resin Infusion Process

Pouchias, Athanasios; Cunningham, Paul; Stein, Jasmin; Kazilas, Mihalis

doi:10.3390/s19235292

Cited by 10 publications

(6 citation statements)

References 43 publications

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“…Unlike parallel‐plate capacitors, coplanar capacitors with electrodes of definite lengths in the same plane can be used to detect variations in the permittivity of nearby media. [ 18,19 ] When using coplanar electrodes, the tested material can be examined from one side, instead of examining the material between or around the electrodes as in the case of using electrodes facing each other. Among the reported liquid‐level sensors: load‐cell‐based sensors are widely considered due to long‐term reusability, but are bulky; IR, optical, and ultrasound sensors have also gained considerable interest due to their precise monitoring, but encompass a bit complex setup; on the other hand, capacitive‐type liquid level sensors can sense different materials without direct contact and are quite simple, compact design space, and low‐power consumption, but require additional programming for monitoring infusion bags of different liquids and bag materials.…”

Section: Resultsmentioning

confidence: 99%

Hydrogel‐Based Real‐Time Wireless Liquid Level Monitoring System for Size‐Independent Infusion Bags

Shin

Lee

Gupta

et al. 2022

Adv Elect Materials

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exposure of medical practitioners to pathogens while facilitating efficient consultation. With the help of wearable sensors, several basic but important information such as blood pressure, temperature, and electrocardiogram can be shared with doctors at any time over the Internet, which not only facilitate real-time diagnosis but also reduces the number of direct doctor consultation, hospital stay, and hospital readmission. Intravenous (IV) drip infusion is commonly used in hospitals to treat critically ill patients. However, this procedure is laborious and requires the constant monitoring or supervision of the administration because it can last for more than an hour. It is nontrivial to continuously examine the amount of IV fluid drip, which comprises a small curative tube called a catheter that infuses a saline-based electrolyte solution into the patient's bloodstream and provides readily available nutrition to assist in the patient's recovery. Typically, the fluid inside the drip bottle is monitored by the doctor or nurse visiting the patient's bed; health professionals must replace the drip bag just before the saline solution is depleted. This procedure is tedious, and in some cases, the nurse's tasks may be disrupted, and/or additional personnel or staff may be required. In the current COVID-19 pandemic, the situation is even more complex and not a good practice. To address this issue, wireless liquid-level sensors based on capacitive-type, [5][6][7][8] load cell, [9,10] optical, [11] and infrared sensors [12] have been proposed. In the case of capacitive-type liquid-level sensors, flexible conductive plates separated by a distance in a coplanar configuration are mostly adopted. On the other hand, hydrogel-based conductors are fascinating due to their electrical conductivity, transparency, self-healable, stretchability, and tunable to desired functionality by modifying the crosslinking chemistry. Considering their high stretchability (>100%), a positive attribute, size-independent infusion bag liquid-level monitoring can be realized. Hydrogel-based devices, considering their stretchability a major functionality, such as strain sensors, [13,14] triboelectric nanogenerators, [15,16] and supercapacitors [17] have been reported to date. To the state-of-art of hydrogel-based devices, there were no reports on liquid level sensors based on hydrogel electrodes in a coplanar configuration.This paper introduces a coplanar capacitive-type liquid level sensor based on stretchable hydrogel electrodes integrated with a flexible printed circuit board (FPCB). The sensor can be attached to the outer surface of an infusion bag for real-time wireless monitoring. Regardless of the size of the infusion bag,The monitoring of saline levels during medication has become a tedious process for practitioners. Regardless of the infusion bag size, real-time wireless monitoring is essential in the healthcare medical sector. This paper demonstrates a size-independent infusion bag liquid level monitoring system based on highly stretchable (...

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Section: Resultsmentioning

confidence: 99%

Hydrogel‐Based Real‐Time Wireless Liquid Level Monitoring System for Size‐Independent Infusion Bags

Shin

Lee

Gupta

et al. 2022

Adv Elect Materials

View full text Add to dashboard Cite

show abstract

“…In many cases, visual monitoring is used to validate other measurement techniques [ 64 , 65 , 66 , 67 , 68 , 69 , 70 ]. Its main limitation is the impossibility of observing flow inside the composite structure, especially when a large sample is considered; however, it remains the simplest and most cost-effective method for permeability measurement.…”

Section: Measurement Methodsmentioning

confidence: 99%

“…In addition, constant distance and parallelism between armatures are required. Pouchias et al [ 69 ] designed a flexible dielectric sensor suitable for complex shape molds. This sensor consisted of two co-planar rectangular electrodes placed on the surface of the preform for flow front monitoring and a ground-backplane to reduce the effects of parasitic capacitances, all coated with a dielectric polyimide layer to prevent contact of the sensor with other conductive elements.…”

Section: Measurement Methodsmentioning

confidence: 99%

An Overview of the Measurement of Permeability of Composite Reinforcements

2023

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Liquid composite molding (LCM) is a class of fast and cheap processes suitable for the fabrication of large parts with good geometrical and mechanical properties. One of the main steps in an LCM process is represented by the filling stage, during which a reinforcing fiber preform is impregnated with a low-viscosity resin. Darcy’s permeability is the key property for the filling stage, not usually available and depending on several factors. Permeability is also essential in computational modeling to reduce costly trial-and-error procedures during composite manufacturing. This review aims to present the most used and recent methods for permeability measurement. Several solutions, introduced to monitor resin flow within the preform and to calculate the in-plane and out-of-plane permeability, will be presented. Finally, the new trends toward reliable methods based mainly on non-invasive and possibly integrated sensors will be described.

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“…with several conventional fabric types. Developments have been made to overcome this issue, e.g., by insulating the sensor with a dielectric material and optimization of the sensor characteristics (Pouchias et al, 2019;Caglar et al, 2021a). However, these types of sensors have not yet been employed to study unsaturated flow phenomena to-date.…”

Section: Non-transparent Fiber Reinforced Polymersmentioning

confidence: 99%

Capillary Effects in Fiber Reinforced Polymer Composite Processing: A Review

et al. 2022

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Capillarity plays a crucial role in many natural and engineered systems, ranging from nutrient delivery in plants to functional textiles for wear comfort or thermal heat pipes for heat dissipation. Unlike nano- or microfluidic systems with well-defined pore network geometries and well-understood capillary flow, fiber textiles or preforms used in composite structures exhibit highly anisotropic pore networks that span from micron scale pores between fibers to millimeter scale pores between fiber yarns that are woven or stitched into a textile preform. Owing to the nature of the composite manufacturing processes, capillary action taking place in the complex network is usually coupled with hydrodynamics as well as the (chemo) rheology of the polymer matrices; these phenomena are known to play a crucial role in producing high quality composites. Despite its importance, the role of capillary effects in composite processing largely remained overlooked. Their magnitude is indeed rather low as compared to hydrodynamic effects, and it is difficult to characterize them due to a lack of adequate monitoring techniques to capture the time and spatial scale on which the capillary effects take place. There is a renewed interest in this topic, due to a combination of increasing demand for high performance composites and recent advances in experimental techniques as well as numerical modeling methods. The present review covers the developments in the identification, measurement and exploitation of capillary effects in composite manufacturing. A special focus is placed on Liquid Composite Molding processes, where a dry stack is impregnated with a low viscosity thermoset resin mainly via in-plane flow, thus exacerbating the capillary effects within the anisotropic pore network of the reinforcements. Experimental techniques to investigate the capillary effects and their evolution from post-mortem analyses to in-situ/rapid techniques compatible with both translucent and non-translucent reinforcements are reviewed. Approaches to control and enhance the capillary effects for improving composite quality are then introduced. This is complemented by a survey of numerical techniques to incorporate capillary effects in process simulation, material characterization and by the remaining challenges in the study of capillary effects in composite manufacturing.

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Development of a Flexible Dielectric Sensor for Flow Monitoring of the Liquid Resin Infusion Process

Cited by 10 publications

References 43 publications

Hydrogel‐Based Real‐Time Wireless Liquid Level Monitoring System for Size‐Independent Infusion Bags

Hydrogel‐Based Real‐Time Wireless Liquid Level Monitoring System for Size‐Independent Infusion Bags

An Overview of the Measurement of Permeability of Composite Reinforcements

Capillary Effects in Fiber Reinforced Polymer Composite Processing: A Review

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