Smart Cure Monitoring Method of Carbon/Epoxy Laminates Using Electric Capacitance Change with Applied Alternating Current Frequency

2005 ◽  
pp. 2903-2908
Author(s):  
Takaomi Inada ◽  
Akira Todoroki
Keyword(s):  
Alternating Current ◽  
Capacitance Change ◽  
Monitoring Method ◽  
Current Frequency ◽  
Cure Monitoring ◽  
Electric Capacitance

Smart Cure Monitoring Method of Carbon/Epoxy Laminates Using Electric Capacitance Change with Applied Alternating Current Frequency

2005 ◽  
Vol 297-300 ◽  
pp. 2903-2908 ◽  
Author(s):  
Takaomi Inada ◽  
Akira Todoroki
Keyword(s):  
Dielectric Constant ◽  
Composite Laminates ◽  
Epoxy Composite ◽  
Alternating Current ◽  
Capacitance Change ◽  
Degree Of Cure ◽  
Resistance Change ◽  
Monitoring Method ◽  
Current Frequency ◽  
Cure Monitoring

Authors have developed an electric resistance change method for delamination monitoring of carbon/epoxy composite laminates. The method employs reinforcement fibers as sensors; electrodes are co-cured. Co-cured electrodes for delamination monitoring are adopted in the present study as sensors for monitoring the degree of cure. This study proposes a new method using electrical capacitance change for monitoring the degree of cure without using additional sensors. Applying alternating current between electrodes during the cure process provides dielectric properties of carbon/epoxy composites. As with the conventional cure monitoring method using extra dielectric sensors, the degree of cure of composites is monitored by measuring the dielectric constant of composites. The dielectric constant of epoxy resin changes concomitant with change of frequency of applied alternating current (AC). Using dependency of the applied AC frequency of the dielectric constant, the degree of cure is measured directly. The proposed method is applied to single and multi-ply carbon/epoxy composite laminates. The method demonstrates excellent estimations of the degree of cure without additional sensors.

scholarly journals The Means to Improve Water Treatment and to Enhance Power Engineering Performance of the Water Source Heat Pump

2018 ◽  
Vol 61 (4) ◽  
pp. 372-380 ◽  
Author(s):  
L. R. Junussova ◽  
S. K. Abildinova ◽  
M. B. Aliyarova ◽  
S. V. Chicherin ◽  
T. Ja. Junussov
Keyword(s):  
Water Treatment ◽  
Heat Pump ◽  
Natural Water ◽  
Alternating Current ◽  
Power Engineering ◽  
Current Frequency ◽  
Heat Pump Unit ◽  
Wide Range ◽  
Compressor Performance

The subject matter of the paper is related to scientific-and-theoretical basis of power engineering characteristics of heat pump directly depending on the quality of treated water for reliable and uninterrupted operation of heat pump evaporator and compressor. On the basis of experimental data, energy parameters of the heat pump are calculated. The method of the combined technology of the heat pump “water – air” operation is considеred, the efficiency of which is based on the preliminary improvement of the quality of water softened with the use of a membrane ultrafiltration unit. This solution made it possible to reduce the load on the filters and to exclude the use of chemical reagents used in the classical schemes of water heating facilities. In order to improve the operation of the heat pump compressor, a method based on altering the speed of rotation of the shaft by means of electronic microprocessor devices has been proposed. To regulate the compressor performance, a frequency converter with a wide range of alternating current frequency is used. The intervals of alteration of frequency of the alternating current corresponding to energy-efficient values of coefficient of transformation of energy of the heat pump are investigated. The values of the energy conversion coefficient of the heat pump obtained in the course of experiments and determined by calculation are consistent within the experimental errors with the regulation of the compressor performance. The suggested experimental device made it possible to determine the dependence of the main characteristics of the unit of the heat pump unit on the number of revolutions of the compressor and to find out an effective range of its control (50–180 %). The development of advanced technologies for natural water treatment under conditions of increased anthropogenic loads on natural water sources is a priority one among the fundamental and applied research in the field of water treatment.

scholarly journals Non-Intrusive Monitoring Algorithm for Resident Loads with Similar Electrical Characteristic

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1385
Author(s):  
Sheng Wu ◽  
Kwok L. Lo
Keyword(s):  
Neural Network ◽  
Probability Distribution ◽  
Bp Neural Network ◽  
Distribution Curve ◽  
Electrical Characteristics ◽  
Monitoring Methods ◽  
Monitoring Method ◽  
Current Frequency ◽  
Operation Pattern ◽  
Load Monitoring

Non-intrusive load monitoring is a vital part of an overall load management scheme. One major disadvantage of existing non-intrusive load monitoring methods is the difficulty to accurately identify loads with similar electrical characteristics. To overcome the various switching probability of loads with similar characteristics in a specific time period, a new non-intrusive load monitoring method is proposed in this paper which will modify monitoring results based on load switching probability distribution curve. Firstly, according to the addition theorem of load working currents, the complex current is decomposed into the independently working current of each load. Secondly, based on the load working current, the initial identification of load is achieved with current frequency domain components, and then the load switching times in each hour is counted due to the initial identified results. Thirdly, a back propagation (BP) neural network is trained by the counted results, the switching probability distribution curve of an identified load is fitted with the BP neural network. Finally, the load operation pattern is profiled according to the switching probability distribution curve, the load operation pattern is used to modify identification result. The effectiveness of the method is verified by the measured data. This approach combines the operation pattern of load to modify the identification results, which improves the ability to identify loads with similar electrical characteristics.

Online Control for the Processing of Urea Resin Moulding Compounds

2009 ◽  
Vol 36 (7) ◽  
pp. 1-5
Author(s):  
W. Stark ◽  
Ch. Kürten
Keyword(s):  
Reaction Rate ◽  
Time Window ◽  
Crosslinking Reaction ◽  
Chemical Crosslinking ◽  
Mould Temperature ◽  
Monitoring Method ◽  
Cycle Times ◽  
Cure Monitoring ◽  
Whole Process ◽  
Cure Time

Urea resin moulding compounds belong to the class of thermosetting materials. They undergo a chemical crosslinking reaction in the mould, giving them outstanding heat resistance. In contrast to thermoplastic materials, thermosets need a critical cure time before the glass transition temperature shifts sufficiently for the hot parts to be stable enough to be demoulded. The cycle times are therefore significantly longer. One possible means of reducing the cycle time would be to increase the mould temperature. As is generally known, increasing the temperature by 10 K doubles the reaction rate. However, a faster reaction rate reduces the time window available for demoulding the cured parts, and the whole process becomes more vulnerable to variations in process parameters and compound composition. By the use of an online cure monitoring system it should be possible to control the process even at higher mould temperatures. In this article the dielectric cure monitoring method is tested in the manufacture of injection moulded parts and its potential for process control is discussed.

The Resistive-Acoustic Method of Monitoring Industrial Sludge Plume

2015 ◽  
Vol 770 ◽  
pp. 679-685 ◽  
Author(s):  
Artem Bykov ◽  
Oleg Kuzichkin ◽  
Nikolay Dorofeev
Keyword(s):  
Soil Moisture Content ◽  
Acoustic Method ◽  
Acoustic Monitoring ◽  
Practical Application ◽  
Electrical Parameters ◽  
Monitoring Method ◽  
Industrial Sludge ◽  
Current Frequency ◽  
Energy Complex ◽  
The Relationship

The paper deals with the resistive-acoustic monitoring method for early industrial spill detection on fuel and energy complex sites. The paper analyzes major indirect geophysical techniques used for oil plume detection. The scientific grounds for the application of the resistive-acoustic monitoring method are given. The paper considers the possibility of spotting medium non-uniformity by means of total resistance registration with the site non-uniformity localization due to seismic-acoustic effects. The relationship between soil electrical parameters and electric current frequency at varying soil moisture content is presented. Practical application of the resistive-acoustic method for oil-sludge spill monitoring on fuel and energy complex sites is described.

A New Method of Wireless Health Monitoring for SMA Composite Structure Based on Micro-Capacitance Measurement

2011 ◽  
Vol 467-469 ◽  
pp. 1410-1415
Author(s):  
Jiang Yuan ◽  
Yu Tian Chen ◽  
Zi Xue Qiu ◽  
Xing Tian Yao ◽  
Jing Ya Wu
Keyword(s):  
Health Monitoring ◽  
Composite Structure ◽  
Internal State ◽  
Measurement Data ◽  
Capacitance Measurement ◽  
Wireless Health ◽  
Capacitance Change ◽  
Monitoring Method ◽  
Wireless Monitoring ◽  
Lcr Meter

In order to achieve the real-time monitoring internal state of composite specimen embedded shape memory alloy wires, a new wireless monitoring method in which PS021 is used to measure the capacitance change of composite structure is proposed. The micro-capacitance measuring principle of PS021 and the design of hardware and software of system are introduced in detail. The capacitance signal between some two wires of composite structure embedded SMA is measured by the PS021 module, and the measurement data are processed by C8051F330 micro-controller and wirelessly sent to PC by PTR4000. Compared the tested results with that of the high precision LCR meter, experimental results show that the relative error of system is less than 4.5%.

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