Delamination detection in composite laminates using high-frequency P- and S-waves – Part I: Theory and analysis

2015 ◽  
Vol 134 ◽  
pp. 1095-1108 ◽  
Author(s):  
Michele Pasquali ◽  
Walter Lacarbonara
Keyword(s):  
High Frequency ◽  
Composite Laminates ◽  
S Waves ◽  
Delamination Detection

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.

Delamination Detection in Woven Composite Laminates with Embedded Optical Fibers

2001 ◽  
Vol 3 (7) ◽  
pp. 492-496 ◽  
Author(s):  
P. S. Uskokovic ◽  
I. Balac ◽  
L. Brajovic ◽  
M. Simic ◽  
S. Putic ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Composite Laminates ◽  
Woven Composite ◽  
Delamination Detection ◽  
Woven Composite Laminates

Frequency-dependent Attenuation of High-frequency P and S Waves in the Upper Crust in Western Nagano, Japan

1998 ◽  
Vol 153 (2-4) ◽  
pp. 489-502 ◽  
Author(s):  
K. Yoshimoto ◽  
H. Sato ◽  
Y. Iio ◽  
H. Ito ◽  
T. Ohminato ◽  
...  
Keyword(s):  
High Frequency ◽  
Upper Crust ◽  
Frequency Dependent ◽  
S Waves

Spectral Comparison of Vertical and Horizontal Seismic Strong Ground Motions in Alluvial Basins

1998 ◽  
Vol 14 (4) ◽  
pp. 573-595 ◽  
Author(s):  
Rouben V. Amirbekian ◽  
Bruce A. Bolt
Keyword(s):  
High Frequency ◽  
Ground Motions ◽  
Frequency Content ◽  
S Waves ◽  
Anelastic Attenuation ◽  
Similar Distance ◽  
Vertical Ground ◽  
Spectral Comparison ◽  
Wave Conversion ◽  
Strong Ground

We analyze observations from the SMART2 array and the 1994 Northridge, California earthquake of spectral differences between vertical and horizontal strong seismic motions in alluvial basins. Our explanation is that the most energetic of such high-frequency vertical ground accelerations are generated by S-to-P seismic wave conversion within the transition zone between the underlying bedrock and the overlying sedimentary layers. The differences in combined scattering and anelastic attenuation for P and S waves lead to the observed spectral differences of the vertical motions between rock and deep alluvium sites. This model also accounts for the frequency content differences between the vertical and horizontal motions at sites in alluvial basins than at rock sites at similar distance ranges. The high-frequency cutoff of the acceleration power spectrum, fmax, is a useful comparison parameter. The results help in computing matched sets of synthetic ground motions above 2 Hz at alluvial sites.

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