scholarly journals Termovision and electricity capacitance measurements as a evaluation of a helicopter rotor’s blades delamination

2015 ◽  
Vol 36 (1) ◽  
pp. 187-200
Author(s):  
Andrzej Gębura ◽  
Michał Poradowski
Keyword(s):  
Composite Structures ◽  
Thermal Field ◽  
Electric Heating ◽  
Essential Elements ◽  
Rotor Blades ◽  
Heat Element ◽  
Capacitance Measurements ◽  
Non Invasive ◽  
Electric Heating Element ◽  
Potential Area

Abstract The article presents essential elements reached during investigations of heat section of rotor blades which have been done in AFIT. The investigations were related to a valuation of helicopter’s rotor blades delamination. They used a method of thermal field measurement as well as a electricity capacitance between an airframe and a heat element of the installation. A suggestion of such measurements appeared during the disassembly of rotor blade heat sections when some local unglue of heat element’s tape from the structure of blade’s heating pack has seen. Spots nearby separation of adhesive are a potential area of a local temperature increase, both the electric heating element and the mechanical structure of the blade. This is especially dangerous for composite structures. Overheated composite structures characterized by reduced flexibility and becomes prone to cracking. Therefore, the possibility of non-invasive monitoring adhesive spots, without removing the blades would be particularly useful.

A review of flexible electric heating element and electric heating garments

2020 ◽  
pp. 152808372096827
Author(s):  
Shu Fang ◽  
Rui Wang ◽  
Haisu Ni ◽  
Hao Liu ◽  
Li Liu
Keyword(s):  
Electric Heating ◽  
Review Article ◽  
Electrical Heating ◽  
Cold Environment ◽  
Passive Heating ◽  
Future Perspectives ◽  
Advantages And Disadvantages ◽  
Smart Garments ◽  
Material Preparation ◽  
Electric Heating Element

Electric heating garment can improve the thermal comfort for people living and working in cold environment. Compared with passive heating materials, electrical heating shows dominant advantages on reusability, controlled temperature, safety and so on. This review article systematically introduced the material preparation, electric-thermal properties, advantages and disadvantages of the existing flexible heating elements, and elaborated the research and application progress of smart garments in detail, providing reference for the research of flexible heating elements and smart garments. And the existing challenges and the possible future perspectives were also discussed.

Infrared Thermographic Flaw Detection in Composite Laminates

1987 ◽  
Vol 109 (2) ◽  
pp. 146-150 ◽  
Author(s):  
P. V. McLaughlin ◽  
M. G. Mirchandani ◽  
P. V. Ciekurs
Keyword(s):  
Composite Laminates ◽  
Composite Structures ◽  
Thermal Field ◽  
Impact Damage ◽  
Flaw Detection ◽  
Fiber Composites ◽  
Surface Cracks ◽  
Glass Fiber Composites ◽  
Detection Tool ◽  
Detection Capabilities

Research performed to develop thermography as a routine rapid flaw detection tool for large composite structures is presented. The externally applied thermal field (EATF) technique is described whereby surface cracks or sub-surface impact damage creates detectable surface temperature perturbations when heated. EATF thermographic procedures and flaw detection capabilities in multidirectional and unidirectional graphite and glass fiber composites are described. The method’s advantages and limitations are outlined.

scholarly journals Research progress of wearable electric heating elements

2021 ◽  
pp. 117-117
Author(s):  
Shuo Gao ◽  
Runjun Sun ◽  
Yan Feng ◽  
Jingxian Hao
Keyword(s):  
Performance Evaluation ◽  
Thermal Performance ◽  
Electric Heating ◽  
Development Trend ◽  
Heating Element ◽  
Research Progress ◽  
Element Type ◽  
The Development Trend ◽  
Electric Heating Element

The research progress of electric heating elements is summarized in terms of heating element type and thermal performance evaluation. Their shortcomings are summarized, and the development trend is pointed out to provide help and direction guidance for the research of electric heating element.

scholarly journals Pengembangan Alat Kempa Panas (Hot Press) Penekanan Dongkrak Hidrolik untuk Pembuatan Papan Komposit ukuran 25 cm x 25 cm

2020 ◽  
Vol 13 (1) ◽  
pp. 25-31
Author(s):  
Junaidi Junaidi
Keyword(s):  
Flat Surface ◽  
Electric Heating ◽  
Heating Element ◽  
Surface Shape ◽  
Small Scale ◽  
Hydraulic Jack ◽  
Hot Press ◽  
Pressure Plate ◽  
Composite Board ◽  
Electric Heating Element

Human needs with wood continue to increase along with the increasing population, on the other hand Indonesia has a very large supply of wood. One way to overcome this is by substituting the use of wood from composite board products from wood or non-wood waste materials such as sawdust, coconut fiber, OPEFB fiber, bamboo fiber, bagasse and others. Composite board manufacturing technology is strongly influenced by the temperature, time and pressure contained in the hot press, either the system works manually or mechanically. The use of a hot press machine has so far been simple using an electric heating element from an iron element. For a n area of 40 cm x 40 cm board molding required 2 iron elements, the heat generated is not optimal (up to 1200 C), to heat the board to 1500 C the heating element often breaks / burns, this is certainly less efficient. Stripe heater type electric heating element is a flat plate heating element (Hot Plate) which can be used to heat a flat surface on pressing lignocellulosic material. The purpose of this research is to engineer and design and manufacture small scale heat press for 40 cm x 40 cm mold size, to test hot press and to test the physical and mechanical properties of composite boards. From the results of the manufacture of hot pressing tools obtained tool size 100 cm x 60 cm using iron profile u size 12 cm x 6 cm x 6 cm with a thickness of 0.4 cm. The pressure unit consists of a base plate measuring 40 cm x 40 cm x 1.5 cm, a pressure plate measuring 40 cm x 40 cm x 0.8 cm, a heating element measuring 40 cm x 40 cm x 0.5 cm using a power of 1.5 Kw each one. The suppressor component uses a hydraulic jack with a pressure of 50 tons. The heating element circuit is contained in the electrical panel box consisting of MCB, sign lights, thermocouple, amperemeter, and electrical wires. From the results of the heat test on the surface of the pressure plate obtained heat spread evenly on the entire surface of the plate and the pressure applied to the pressure plate is able to withstand the pressure from the hydraulic jack with a flat surface shape.

Characterization and Localization of Sub-Surface Structural Features Using Non-Contact Tomography

2016 ◽  
Author(s):  
Sumit Gupta ◽  
Kenneth J. Loh
Keyword(s):  
Damage Detection ◽  
Composite Structures ◽  
Electrical Response ◽  
Surface Damage ◽  
Structural Features ◽  
Electrical Signal ◽  
Rotor Blades ◽  
Function Generator ◽  
Manufacturing Defects ◽  
Electrical Permittivity

The main objective of this work is to develop a non-contact, non-invasive, structural health monitoring technique for surface and sub-surface damage detection in structures such as composite helicopter rotor blades. In many cases, composite structures are prone to damage in the form of cracks, delamination, and manufacturing defects, which can propagate beneath structural surfaces and cause severe component or catastrophic structural failure. The damage detection technique in this study works on the principle of electrical capacitance tomography. Different patterns of electrical field are propagated in a pre-defined sensing area. Using measurements of electrical response along boundaries of the sensing area, the permittivity distribution within that space can be reconstructed. First, a series of numerical simulations was performed by altering the electrical permittivity at different locations to simulate damage. The shapes and locations of permittivity changes were captured by the proposed technique. Second, to demonstrate its validity, an experimental test setup was built with a set of boundary electrodes. The system was connected to a function generator that supplied an electrical signal and induced electrical fields between electrodes. Capacitance between pairs of electrodes were then measured, which were used as inputs for solving the inverse permittivity reconstruction problem. Various test cases with different objects placed in the sensing area were conducted for validating this technique. The preliminary results show that the system was able to reconstruct spatial permittivity distributions and detect the presence, shapes, and locations of objects, thereby suggesting potential for damage detection.

scholarly journals FUNDAMENTAL STUDY OF Fe-Cr-Al ALLOY STEELS FOR ELECTRIC HEATING ELEMENT

1942 ◽  
Vol 28 (5) ◽  
pp. 563-574 ◽  
Author(s):  
Tokusiti Misima ◽  
Itiro Kawakatu ◽  
Yuiti Nanba
Keyword(s):  
Electric Heating ◽  
Heating Element ◽  
Al Alloy ◽  
Fundamental Study ◽  
Alloy Steels ◽  
Electric Heating Element

scholarly journals EXPERIMENTAL STUDIES OF FIRE HAZARD OF PINE NEEDLES IN LABORATORY AND FIELD CONDITIONS

Fire Safety ◽  
2018 ◽  
pp. 107-111
Author(s):  
V. Tovarianskyi ◽  
I. Pasnak
Keyword(s):  
Fire Hazard ◽  
Experimental Studies ◽  
Electric Heating ◽  
Forest Litter ◽  
Pine Needles ◽  
Time Interval ◽  
Time To Ignition ◽  
Pine Stands ◽  
Electric Heating Element ◽  
Flammable Material

Introduction. The fire hazard analysis of young pine stands was carried out. There are listed the most common sources of ignition as factors of influence on the occurrence of a fire. There is described the examples of studies on solid combustible materials` ignition, particularly, forest litter. The device developed is proposed for studying the process of forest fuels combustion. The aim of the work is determine the time to ignition of pine needles, as well as the forest litter in young pine stands by using a Device for the study of flammable material combustion using an electric heating element. Material statement. Laboratory studies have been done to ignite three types of needles of young pine plantations: fresh, inherent in the composition of forest underlay and dried needles. There was conducted an experimental studies of the time interval to the ignition of pine stands forest litter in the field condition with the use of the proposed device. Scientific novelty. It for the first time was established that the time interval before ignition of freshly cut needles exceeds by almost 4 times the meaning of this value in comparison with the dried needles. It was established that the value of the time to ignition of pine needles fallen in the forest litter, obtained from the results of field studies, with a slight deviation of its moisture, is almost the same with the values obtained in laboratory conditions. The results indicate that the forest litter in pine stands is fire-hazardous and can deal with a frequency close to ½ of a source with a temperature of 450°C, on average 25,7 seconds. There has been substantiated the expediency of using the device for the study of flammable material combustion using an electric heating element for investigating indicators of forest combustible materials` fire hazard.

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