Assessment of Flow and Cure Monitoring Using Direct Current and Alternating Current Sensing in Vacuum Assisted Resin Transfer Molding

1999 ◽  
Author(s):  
Nitesh C. Jadhav ◽  
Uday K. Vaidya ◽  
Mahesh V. Hosur ◽  
John W. Gillespie ◽  
Bruce K. Fink
Keyword(s):  
Direct Current ◽  
Large Scale ◽  
Resin Transfer Molding ◽  
Alternating Current ◽  
Composite Panel ◽  
Current Sensing ◽  
Transfer Molding ◽  
Cure Monitoring ◽  
The Matrix ◽  
Automated Fiber Placement

Abstract Vacuum Assisted Resin Transfer Molding (VARTM) is an emerging manufacturing technique that holds promise as an affordable alternative to traditional autoclave molding and automated fiber placement for producing large scale structural parts. In VARTM, the fibrous preform is laid on a single sided tool, which is then bagged along with the infusion and vacuum lines. The resin is then infused through the preform, which causes simultaneous wetting in its in-plane and transverse directions. An effective sensing technique is essential so that comprehensive information pertaining to the wetting of the preform, arrival of resin at various locations, cure gradients associated with thickness and presence of dry spots may be monitored. In the current work, direct current and alternating current sensing/monitoring techniques were adopted for developing a systematic understanding of resin position and cure on plain weave S2-Glass preforms with Dow Derakane vinyl ester VE 411-350, Shell EPON RSL 2704/2705 and Si-AN epoxy as the matrix systems. The SMARTweave DC sensing system was utilized to conduct parametric studies a) to compare the flow and cure of resin through the stitched and non-stitched preforms, b) influence of sensor positioning, i.e., top, middle and bottom layers, c) influence of positioning of the process accessories, i.e., resin infusion point and vacuum point on the composite panel. The SMARTweave system was found to be sensitive to all the parametric variations introduced in the study. Furthermore, the results obtained from the SMARTweave system were compared to the cure monitored from embedded IDEX dielectric sensors. The results indicate that SMARTweave sensing was a viable alternative to obtaining resin position and cure, and more superior in terms of obtaining global information in contrast to the localized dielectric sensing approach.

scholarly journals Multiscale Composites: Assessment of a Feasible Manufacturing Process

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
R. Volponi ◽  
P. Spena ◽  
F. De Nicola ◽  
L. Guadagno
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Fiber ◽  
Manufacturing Process ◽  
Resin Transfer Molding ◽  
Fiber Reinforced ◽  
Transfer Molding ◽  
Macro Scale ◽  
Multiscale Composite ◽  
The Matrix ◽  
Carbon Fiber Reinforced

A very interesting field of research on advanced composite materials is the possibility to integrate new functionalities and specific improvements acting on the matrix of the composite by means of a nanocharged resin. In this way, the composite becomes a so-called “multiscale composite” in which the different phases change from nano to macro scale. For example, the incorporation of nanoscale conductive fillers with intrinsically high electrical conductivity could allow a tailoring of this property for the final material. The properties of carbon nanotubes (CNT) make them an effective candidate as fillers in polymer composite systems to obtain ultralight structural materials with advanced electrical and thermal characteristics. Nevertheless, several problems are related to the distribution in the matrix and to the processability of the systems filled with CNT. Existing liquid molding processes such as resin transfer molding (RTM) and vacuum-assisted resin transfer molding (VARTM) can be adapted to produce carbon fiber reinforced polymer (CFRP) impregnated with CNT nanofilled resins. Unfortunately, the loading of more than 0.3-0.5% of CNT can lead to high resin viscosities that are unacceptable for such kind of processes. In addition to the viscosity issues that are related to the high CNT content, a filtration effect of the nanofillers caused by the fibrous medium may also lead to inadequate final component quality. This work describes the development of an effective manufacturing process of a fiber-reinforced multiscale composite panel, with a tetra-functional epoxy matrix loaded with carbon nanotubes to increase its electrical properties and with GPOSS to increase its resistance to fire. A first approach has been attempted with a traditional liquid infusion process. As already anticipated, this technique has shown considerable difficulties related both to the low level of impregnation achieved, due to the high viscosity of the resin, and to the filtration effects of the dispersed nanocharges. To overcome these problems, an opportunely modified process based on a sort of film infusion has been proposed. This modification has given an acceptable result in terms of impregnation and morphological arrangement of CNTs in nanofilled CFRP. Finally, the developed infiltration technique has been tested for the manufacture of a carbon fiber-reinforced panel with a more complex shape.

scholarly journals Applicability of fiber Bragg grating sensors for cure monitoring in resin transfer molding processes

2020 ◽  
pp. 073168442095811
Author(s):  
Yannick Blößl ◽  
Gergely Hegedüs ◽  
Gábor Szebényi ◽  
Tamás Tábi ◽  
Ralf Schledjewski ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Resin Transfer Molding ◽  
Sol Gel ◽  
Bragg Grating ◽  
Gel Point ◽  
Strain Response ◽  
Resin System ◽  
Transfer Molding ◽  
Cure Monitoring ◽  
Fiber Bragg Grating Sensors

This article examines the use of fiber Bragg grating sensors for cure monitoring purposes in resin transfer molding processes. Within a resin transfer molding test series a thermoset epoxy-amine resin system was used in combination with a woven flax fiber reinforcement. Particular attention was paid on the location of the optical fiber sensor and its sensitive Bragg grating element inside the mold cavity. Three different installation approaches were tested and the correlation of the corresponding strain response with the actual cure state of the resin system was investigated at 50°C and 70°C isothermal cure temperature, respectively. We could demonstrate that characteristic, conspicuous strain changes are directly related to the sol–gel conversion of the thermoset polymer, which was analyzed considering different approaches for the gel-point detection based on rheological measurements. With the installation of the sensor inside a controllable, capsuled resin volume, we could achieve the most reliable strain response that provides capabilities to give in-situ information of the cure state beyond the gelation point.

Process-Oriented Determination of Preform Permeability and Matrix Viscosity during Mold Filling in Resin Transfer Molding

2015 ◽  
Vol 825-826 ◽  
pp. 822-829 ◽  
Author(s):  
Dino Magagnato ◽  
Frank Henning
Keyword(s):  
Flow Behavior ◽  
Resin Transfer Molding ◽  
Matrix Material ◽  
Low Flow ◽  
Test Fluid ◽  
Transfer Molding ◽  
Reinforced Plastics ◽  
The Matrix ◽  
Reactive Matrix

The resin transfer molding (RTM) offers great conditions for mass production of fiber reinforced plastics. In this process, preformed fiber textiles are infiltrated with matrix material (for example: epoxy resin). During the infiltration, the matrix material starts a curing process until the complete consolidation. After the de-molding and a short post-processing step, the final part is ready to use. To reduce the cycle time for the RTM manufacturing, it is necessary to model and predict the flow behavior of the matrix material in a realistic way. An important parameter is the preform permeability, which characterizes the flow resistance of fibers against the flowing matrix material.In this study a new measurement setup is presented, which is able to determine the permeability directly during the manufacturing process, with integrated pressure and temperature sensors. This approach has many advantages against conventional measurement setups, that try to recreate the RTM process with a simple replication. With these replicas, it is only possible to simulate low flow velocities and pressures. Dynamic effects that occur at higher velocities cannot be regarded. Furthermore, the new setup has the advantage that measurement artifacts, like capillarity, have a lower impact. In addition to that, the infiltration can be done with a constant viscosity test fluid as well as with reactive matrix material. Thus, it allows further determination of the time depending viscosity.

scholarly journals Research on Improved Fault Current Analysis Method for Flexible Direct Current Power Grid Considering Alternating Current Feed

2021 ◽  
Vol 9 ◽  
Author(s):  
Yinfeng Sun ◽  
Xin Xiong ◽  
Zhenhao Wang ◽  
Guoqing Li ◽  
Xueguang Wu ◽  
...  
Keyword(s):  
Equivalent Circuit ◽  
Direct Current ◽  
Large Scale ◽  
Short Circuit ◽  
Power Grid ◽  
Equivalent Circuit Model ◽  
Alternating Current ◽  
Fault Current ◽  
Dc Line ◽  
Selection Of

Flexible direct current (DC) grid can realize large-scale renewable energy, wide-area coordinated complementation, and reliable power transmission. It is an important development that can be used to support high-voltage and large-capacity flexible DC transmission in the future. The short-circuit current of the DC line is one of the important bases for the selection of key main equipment parameters such as converter valves, DC circuit breakers, and reactors in the flexible DC grid. In this paper, a flexible DC grid equivalent circuit network model with alternating current (AC) feed-in is established. Aiming at the monopolar ground fault of the flexible DC grid grounded through the metal loop, an optimized traditional matrix calculation method is proposed to obtain the accurate line fault current value. On this basis, with an actual engineering background, the equivalent circuit model of the four-terminal bipolar flexible DC power grid is established, and the influence of grounding position, grounding parameters, and current-limiting reactor on the fault current of the DC line is analyzed. Finally, simulation using the PSCAD software verifies the effectiveness and accuracy of the proposed method. The method proposed in this paper can provide the necessary bases and references for the selection of flexible DC grid equipment.

Structure Design and Manufacturing of the Composite Blade for the Icing Wind Tunnel

2014 ◽  
Vol 915-916 ◽  
pp. 721-726
Author(s):  
Ze Bin Yu ◽  
Zheng Chong Liu ◽  
Shuang Leng ◽  
Yong Cai
Keyword(s):  
Large Scale ◽  
Resin Transfer Molding ◽  
Structure Design ◽  
High Fidelity ◽  
Transfer Molding ◽  
Composite Blade ◽  
Rtm Process ◽  
Scale Temperature ◽  
Design And Manufacturing ◽  
Fan Blade

The structure design and manufacturing of the fan blade ware researched based on large-scale temperature change, high-revolution, multi-constraint conditions, high-fidelity profile and so on. The numerical modeling was performed in MSC, including strength, stiffness as well as eigenfrequency analysis, optimized to layer thickness and mass of blade. The resin transfer molding (RTM) process was used to ensure the blade geometrical tolerance. Multiform tests were provided to verify that the design and manufacturing is reasonable and the blade satisfies with application requirement.

scholarly journals A Review of Thermoplastic Resin Transfer Molding: Process Modeling and Simulation

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1555 ◽  
Author(s):  
Ageyeva ◽  
Sibikin ◽  
Kovács
Keyword(s):  
Polymer Composites ◽  
High Performance ◽  
Resin Transfer Molding ◽  
High Viscosity ◽  
Commercial Application ◽  
Future Research ◽  
Thermoplastic Resin ◽  
Molding Process ◽  
Transfer Molding ◽  
The Matrix

The production and consumption of polymer composites has grown continuously through recent decades and has topped 10 Mt/year. Until very recently, polymer composites almost exclusively had non-recyclable thermoset matrices. The growing amount of plastic, however, inevitably raises the issue of recycling and reuse. Therefore, recyclability has become of paramount importance in the composites industry. As a result, thermoplastics are coming to the forefront. Despite all their advantages, thermoplastics are difficult to use as the matrix of high-performance composites because their high viscosity complicates the impregnation process. A solution could be reactive thermoplastics, such as PA-6, which is synthesized from the ε-caprolactam (ε-CL) monomer via anionic ring opening polymerization (AROP). One of the fastest techniques to process PA-6 into advanced composites is thermoplastic resin transfer molding (T-RTM). Although nowadays T-RTM is close to commercial application, its optimization and control need further research and development, mainly assisted by modeling. This review summarizes recent progress in the modeling of the different aspects of the AROP of ε-CL. It covers the mathematical modeling of reaction kinetics, pressure-volume-temperature behavior, as well as simulation tools and approaches. Based on the research results so far, this review presents the current trends and could even plot the course for future research.

scholarly journals Inactivation of Vibrio parahaemolyticus in Effluent Seawater by Alternating-Current Treatment

2004 ◽  
Vol 70 (3) ◽  
pp. 1833-1835 ◽  
Author(s):  
Jong-Chul Park ◽  
Min Sub Lee ◽  
Dong-Wook Han ◽  
Dong Hee Lee ◽  
Bong Joo Park ◽  
...  
Keyword(s):  
Direct Current ◽  
Vibrio Parahaemolyticus ◽  
Large Scale ◽  
Alternating Current ◽  
Industrial Applications ◽  
Current Treatment ◽  
Electric Treatment ◽  
Chlorine Generation

ABSTRACT Vibrio parahaemolyticus, the cause of gastroenteritis in humans, was inactivated by alternating low-amperage electricity. In this study, the application of alternating low-amperage electric treatment to effluent seawater was investigated for the large-scale disinfection of seawater. This method was able to overcome the problem of chlorine generation that results from treatment with continuous direct current. In conclusion, our results showed that alternating-current treatment inactivates V. parahaemolyticus in effluent seawater while minimizing the generation of chlorine and that this alternating-current treatment is therefore suitable for practical industrial applications.

Sign in / Sign up

Export Citation Format

Share Document