scholarly journals Inspection of helicopter rotor blades with the help of guided waves and "turning modes": Experimental and finite element analysis

2013 ◽  
Author(s):  
Daniel Barnard ◽  
Sunil Kishore Chakrapani ◽  
Vinay Dayal
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Guided Waves ◽  
Rotor Blades ◽  
Helicopter Rotor ◽  
Element Analysis ◽  
Helicopter Rotor Blades

scholarly journals Shear-Actuation and Vibrometer Reception of Penetrating Ultrasonic Guided Wave Modes in Human Tibia

2020 ◽  
Vol 10 (23) ◽  
pp. 8397
Author(s):  
Anurup Guha ◽  
Michael Aynardi ◽  
Parisa Shokouhi ◽  
Cliff J. Lissenden
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Phase Velocity ◽  
Time Domain ◽  
Guided Waves ◽  
Ultrasonic Guided Waves ◽  
Appendicular Skeleton ◽  
Element Analysis ◽  
Human Tibia ◽  
Wave Modes

The hollow long bones of the human appendicular skeleton are known to support the propagation of ultrasonic guided waves, whose potential for diagnosing bone health is being investigated. In this study, ultrasonic guided waves propagating in the diaphysis of human tibia are characterized experimentally and numerically in the frequency range around 200 kHz. The experiment involves a unique combination of omni-directional shear transducer-based excitation and detection using a 1D laser Doppler vibrometer. The cluster of phase velocities obtained from a linear array of time-history data using space-time Fourier transform is found to be in the non-dispersive low-phase velocity region of the dispersion curves obtained for a tibial cross-section. Time-domain finite element analysis revealed that the displacement components normal to the surface are significant, even though the loading is from a shear transducer. Furthermore, semi-analytical finite element analysis revealed that the wave structures of the wave modes contained within the cluster of low-phase velocity modes are consistent with the displacement profiles obtained from the time-domain analysis. The experimental results show that the low-phase velocity mode cluster has sufficient intensity to propagate axially at least 85 mm in the mid-diaphyseal region.

The Design of Rotor Blades Taking Into Account the Combined Effects of Vibratory and Thermal Loads

1989 ◽  
Vol 111 (4) ◽  
pp. 610-618 ◽  
Author(s):  
R. Bahree ◽  
A. M. Sharan ◽  
J. S. Rao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Transient State ◽  
Rotor Blades ◽  
Combined Effects ◽  
Thermal Loads ◽  
Element Analysis ◽  
The Finite Element Analysis

The present work involves the design of rotor blades based on the thermal as well as centrifugal and nozzle excitation forces in the transient state. The finite element analysis has been used to calculate these stresses. The nozzle excitation forces have been modeled as a series of impulses occurring at instants of time known from the solution of kinematic equations.

Finite element analysis of guided waves in fluid-filled corrugated pipes

2007 ◽  
Vol 121 (3) ◽  
pp. 1313-1323 ◽  
Author(s):  
Matthias Maess ◽  
Jan Herrmann ◽  
Lothar Gaul
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Guided Waves ◽  
Element Analysis
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