Simultaneous measurement of strain and temperature using the first- and second-order diffraction wavelengths of Bragg gratings

1997 ◽  
Vol 144 (3) ◽  
pp. 156 ◽  
Author(s):  
G.P. Brady ◽  
K. Kalli ◽  
D.J. Webb ◽  
D.A. Jackson ◽  
L. Reekie ◽  
...  
Keyword(s):  
Simultaneous Measurement ◽  
Bragg Gratings ◽  
Second Order ◽  
Order Diffraction

Possible approach for the simultaneous measurement of temperature and strain via first- and second-order diffraction from Bragg grating sensors

1995 ◽  
Author(s):  
Kyriacos Kalli ◽  
G. P. Brady ◽  
David J. Webb ◽  
David A. Jackson ◽  
Laurence Reekie ◽  
...  
Keyword(s):  
Simultaneous Measurement ◽  
Second Order ◽  
Bragg Grating ◽  
Order Diffraction

Second order diffraction efficiency of Bragg gratings written within germanosilicate fibres

1993 ◽  
Vol 101 (1-2) ◽  
pp. 85-91 ◽  
Author(s):  
W.X. Xie ◽  
M. Douay ◽  
P. Bernage ◽  
P. Niay ◽  
J.F. Bayon ◽  
...  
Keyword(s):  
Diffraction Efficiency ◽  
Bragg Gratings ◽  
Second Order ◽  
Order Diffraction

Second-Order Diffraction Loads on Plural Vertical Cylinder With Arbitrary Cross Sections

1987 ◽  
Vol 109 (4) ◽  
pp. 314-319
Author(s):  
K. Masuda ◽  
W. Kato ◽  
H. Ishizuka
Keyword(s):  
Boundary Value Problem ◽  
Cross Sections ◽  
Present Method ◽  
Boundary Value ◽  
Vertical Cylinder ◽  
Wave Force ◽  
Second Order ◽  
Wave Forces ◽  
Order Diffraction ◽  
Rectangular Cylinders

The purpose of the present study is development of a powerful numerical method for calculating second-order diffraction loads on plural vertical cylinder with arbitrary cross sections. According to the present method, second-order wave force can be obtained from a linear radiation potential without solving second-order boundary value problem. The boundary value problem for the radiation potential is solved with the hybrid boundary element method. The computations for circular and rectangular cylinders were carried out and compared with the experiments. In addition, second-order wave forces on twin circular cylinder are calculated with the present method.

Second-Order Difference-Frequency Loads on FPSOs by Full QTF and Relevant Approximations

2020 ◽  
Author(s):  
Espen Engebretsen ◽  
Zhiyuan Pan ◽  
Nuno Fonseca
Keyword(s):  
Near Field ◽  
Time Domain Analysis ◽  
Second Order ◽  
Difference Frequency ◽  
Irregular Waves ◽  
Mooring Line ◽  
Diffraction Radiation ◽  
Surface Integral ◽  
Order Difference ◽  
Order Diffraction

Abstract This paper investigates three different approximations of the full Quadratic Transfer Function (QTF) for calculating horizontal plane second-order difference-frequency loads on FPSOs, namely Newman’s approximation, full QTF without free surface integral and the white-noise approximation. Second-order excitation loads obtained from approximated QTFs are compared in frequency-domain with those obtained by the full QTFs computed from second-order diffraction/radiation analysis in WADAM. The comparison is performed for a new-build FPSO in a range of water depths and environmental combinations. The full QTFs from second-order diffraction/radiation analysis are further compared to empirical QTFs as identified from cross bi-spectral analysis of model test results in irregular waves. A mesh convergence study is presented for calculating full QTFs by the near-field approach in a second-order diffraction/radiation analysis. The importance of including viscous damping in heave, roll and pitch is illustrated for the mean wave-drift force in surge and sway. FPSO motions and mooring line tensions from fully-coupled time-domain analysis in OrcaFlex is compared when using approximated QTFs and full QTFs from second-order diffraction/radiation analysis.

Sign in / Sign up

Export Citation Format

Share Document