Transient analysis of electromagnetic wave reflection from a stratified medium

2010 ◽  
Author(s):  
Qingsheng Zeng ◽  
Gilles Y. Delisle
Keyword(s):  
Electromagnetic Wave ◽  
Transient Analysis ◽  
Wave Reflection ◽  
Stratified Medium

Detection of delamination in composites by using electromagnetic penetrating radar

2014 ◽  
Vol 5 (2) ◽  
pp. 151-156
Author(s):  
Z. Mechbal ◽  
A. Khamlichi
Keyword(s):  
Electromagnetic Wave ◽  
Electromagnetic Waves ◽  
Electromagnetic Wave Propagation ◽  
Wave Reflection ◽  
Image Features ◽  
Partial Reflection ◽  
Straight Path ◽  
Reflected Signal ◽  
Short Time ◽  
Intervening Factors

Composites made from E-glass/epoxy or aramid/epoxy are frequently used in aircraft and aerospace industries. These materials are prone to suffer from the presence of delamination, which can reduce severely the performance of aircrafts and even threaten their safety. Since electric conductivity of these composites is rather small, they can propagate electromagnetic waves. Detection of delamination damage can then be monitored by using an electromagnetic penetrating radar scanner, which consists of emitting waves having the form of short time pulses that are centered on a given work frequency. While propagating, these waves undergo partial reflection when running into an obstacle or a material discontinuity. Habitually, the radar is moved at constant speed along a straight path and the reflected signal is processed as a radargram that gives the reflected energy as function of the two-way time and the antenna position.In this work, modeling of electromagnetic wave propagation in composites made from E-glass/epoxy was performed analytically. The electromagnetic wave reflection from a delamination defect was analyzed as function of key intervening factors which include the defect extent and depth, as well as the work frequency. Various simulations were performed and the obtained results have enabled to correlate the reflection pattern image features to the actual delamination defect characteristics which can provide quantification of delamination.

Electromagnetic wave reflection by rough fractal surface of semiconductor materials

2003 ◽  
Author(s):  
Leonid G. Grechko ◽  
Olexander Y. Semchuk ◽  
Victor V. Gozhenko ◽  
Anatolii A. Pinchuk
Keyword(s):  
Electromagnetic Wave ◽  
Wave Reflection ◽  
Semiconductor Materials ◽  
Fractal Surface

Electromagnetic Wave Shielding and Fire Retardant Multifunctional Polymer Composites

2008 ◽  
Vol 47-50 ◽  
pp. 77-80 ◽  
Author(s):  
Vitaliy G. Shevchenko ◽  
Vladimir P. Volkov ◽  
Alexander N. Zelenetsky ◽  
Anatoliy T. Ponomarenko ◽  
Oleg Figovsky
Keyword(s):  
Mechanical Properties ◽  
Electromagnetic Wave ◽  
Wave Reflection ◽  
Fire Retardant ◽  
Polymeric Composites ◽  
Thermal And Mechanical Properties ◽  
Frequency Range ◽  
Flame Resistance ◽  
Composites Materials ◽  
Set Up

Novel PE- and PP-based electromagnetic wave shielding and absorbing materials with low combustibility, enhanced thermal and mechanical properties, containing graphite, grinded wood and fire retardants, were developed and investigated. Their flame-resistance, thermal and mechanical properties are investigated. Electromagnetic wave reflection coefficients of the materials over the frequency range 20-40 GHz were measured; despite low concentration (10%) of functional filler, reflection coefficient can be as low as -15 dB. Criteria of incombustibility of polymeric composites are formulated: thermochemical, kinetic, thermal, physical and mass transfer. These criteria allowed to set up the principles of decreasing combustibility of polymeric composites. Materials requirements, allowing to choose the most effective shielding and fireproof systems for multicomponent composites, containing polymers, wood and other fillers, were formulated.

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