Delamination detection in composite laminates using high-frequency P- and S-waves – Part II: Experimental validation

2015 ◽  
Vol 134 ◽  
pp. 1109-1117 ◽  
Author(s):  
Michele Pasquali ◽  
Walter Lacarbonara ◽  
Charles R. Farrar
Keyword(s):  
High Frequency ◽  
Composite Laminates ◽  
Experimental Validation ◽  
S Waves ◽  
Delamination Detection

scholarly journals Calculation improvement of no-load stray losses in induction motors with experimental validation

2015 ◽  
Vol 12 (3) ◽  
pp. 303-320
Author(s):  
Miloje Kostic
Keyword(s):  
High Frequency ◽  
Experimental Validation ◽  
Air Gap ◽  
New Classification ◽  
Iron Losses ◽  
Surface Iron ◽  
Space Harmonics ◽  
Rotor Cage

On the basis of the known fact that all air gap main flux density variations are enclosed by permeance slot harmonics, only one component of stray losses in rotor (stator) iron is considered in the new classification, instead of 2 components: rotor (stator) pulsation iron losses, and rotor (stator) surface iron losses. No-load rotor cage (high-frequency) stray losses are usually calculated. No-load stray losses are caused by the existence of space harmonics: the air-gap slot permeance harmonics and the harmonics produced by no-load MMF harmonics. The second result is the proof that the corresponding components of stray losses can be calculated separately for the mentioned kind of harmonics. Determination of the depth of flux penetration and calculations of high frequency iron losses are improved. On the basis of experimental validation, it is proved that the new classification of no-load stray losses and the proposed method for the calculation of the total value is sufficiently accurate.

Attenuation of High Frequency P and S Waves in the Gujarat Region, India

2010 ◽  
Vol 168 (5) ◽  
pp. 797-813 ◽  
Author(s):  
Sumer Chopra ◽  
Dinesh Kumar ◽  
B. K. Rastogi
Keyword(s):  
High Frequency ◽  
S Waves

scholarly journals MPPE/SEBS Composites with Low Dielectric Loss for High-Frequency Copper Clad Laminates Applications

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1875
Author(s):  
Jianming Guo ◽  
Hao Wang ◽  
Caixia Zhang ◽  
Qilong Zhang ◽  
Hui Yang
Keyword(s):  
Dielectric Loss ◽  
High Frequency ◽  
Composite Laminates ◽  
Printed Circuit Boards ◽  
Coefficient Of Thermal Expansion ◽  
Weight Ratio ◽  
Resin Matrix ◽  
Ceramic Powders ◽  
Low Dielectric ◽  
Low Dissipation

Copper clad laminates (CCLs) with low dissipation factor (Df) are urgently needed in the fields of high-frequency communications devices. A novel resin matrix of modified poly (2,6-dimethyl-1,4-phenylene ether) (MPPE) and styrene-ethylene/butylene-styrene (SEBS) was employed in the fabrication of high-frequency copper clad laminates (CCLs). The composites were reinforced by E-glass fabrics, which were modified with phenyltriethoxysilane (PhTES). The composite laminates obtained exhibited impressive dielectric loss of 0.0027 at 10 GHz when the weight ratio of MPPE to SEBS was 5:1. In order to modify the dielectric constant (Dk), coefficient of thermal expansion (CTE) and other performances of laminates, Li2TiO3 (LT) ceramic powders were introduced into the resin matrix. The composite laminates showed low dielectric loss of 0.0026 at 10 GHz and relatively high flexural strength of 125 MPa when the mass ratio of LT fillers to resin is 0.4. Moreover, the composite laminates all maintain low water uptake (<0.5%). The microstructure and thermal properties of composite laminates filled with LT ceramic powders were also tested. These results show that copper clad laminates prepared with modified polyphenylene ether (MPPE)/SEBS and LT ceramic fillers have strong competitiveness to fabricate printed circuit boards (PCBs) for high-frequency and high-speed applications.

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