Experimental verification of a TE01 mode converter to locate a crack in a metal pipe

2020 ◽  
Vol 64 (1-4) ◽  
pp. 465-472
Author(s):  
Takuya Katagiri ◽  
Guanren Chen ◽  
Noritaka Yusa ◽  
Hidetoshi Hashizume
Keyword(s):  
Experimental Verification ◽  
Three Dimensional ◽  
Mode Converter ◽  
Metal Pipe ◽  
Element Simulation ◽  
Te01 Mode ◽  
Dimensional Finite Element ◽  
Axial Crack ◽  
The Right ◽  
Three Dimensional Finite Element

In this study, a TE01 mode converter was developed to locate an axial crack on the inner surface of a metal pipe. Three-dimensional finite element simulation was conducted to evaluate the effect of inserted coaxial cables on the transmission characteristic of the mode converter. The result showed that the energy of TE mode microwaves leaned to transmit to one side when the cables penetrated with inclination. To demonstrate the effectiveness of the mode converter, experimental verification was conducted. The mode converter was fabricated based on the simulation result. Microwaves were emitted through the pipe wall of the converter to propagate on both sides (‘right side’ and ‘left side’) of a pipe with an artificial slit. Compared with the signals from each side, the reflection from the slit on the right side was more significant than that on the left side. This result is consistent with the numerical simulation result.

Recheck Calculation of Dahedong Trench-Buried Inverted Siphon Structure

2014 ◽  
Vol 488-489 ◽  
pp. 589-592
Author(s):  
Min Tan
Keyword(s):  
Finite Element ◽  
Simulation Analysis ◽  
Process Analysis ◽  
Three Dimensional ◽  
Inverted Siphon ◽  
Operating Process ◽  
Element Simulation ◽  
Dimensional Finite Element ◽  
Water Conveyance ◽  
Three Dimensional Finite Element

Inverted siphon structure is a common water conveyance buildings, computer as a efficient computational tool is used, this paper adopt finite element method to carry out three-dimensional finite element simulation analysis for Dahedong inverted siphon structure. Deducing variation law of the inverted siphons stress and displacement in construction process and operating process. Analysis results further verified that design scheme is reasonable and safe, it has certain application value.

scholarly journals Assessment of Substrate and TBC Damage Effects on Resonance Frequencies for Blade Health Monitoring

2022 ◽  
Vol 12 (1) ◽  
pp. 1-19
Author(s):  
Jason van Dyke ◽  
Michel Nganbe
Keyword(s):  
Natural Frequencies ◽  
Hot Spot ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Early Assessment ◽  
Element Simulation ◽  
Resonance Frequencies ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Local Plastic Deformation

The reliability of critical aircraft components continues to shift towards onboard monitoring to optimize maintenance scheduling, economy efficiency and safety. Therefore, the present study investigates changes in dynamic behavior of turbine blades for the detection of defects, with focus on substrate cracks and TBC spallation as they relate to vibration modes 1 to 6. Two‐dimensional and three-dimensional finite element simulation is used. The results indicate that TBC spallation reduces natural frequencies due to the ensuing hot spot and overall increase in temperature, leading to drops in blade stiffness and strength. Cracks cause even larger frequency shifts due to local plastic deformation at the crack that changes the energy dissipation behavior. Mode 1 vibration shows the largest shifts in natural frequencies that best correlate to the size of defects and their position. As such, it may be most appropriate for the early assessment of the severity and location of defects.

scholarly journals A finite element analysis of sacroiliac joint displacements and ligament strains in response to three manipulations

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhun Xu ◽  
Yikai Li ◽  
Shaoqun Zhang ◽  
Liqing Liao ◽  
Kai Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Sacroiliac Joint ◽  
Clinical Effect ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Ligament Strain ◽  
Dimensional Finite Element ◽  
The Right ◽  
Three Dimensional Finite Element

Abstract Background Clinical studies have found that manipulations have a good clinical effect on sacroiliac joint (SIJ) pain without specific causes. However, the specific mechanisms underlying the effect of manipulations are still unclear. The purpose of this study was to investigate the effects of three common manipulations on the stresses and displacements of the normal SIJ and the strains of the surrounding ligaments. Methods A three-dimensional finite element model of the pelvis-femur was developed. The manipulations of hip and knee flexion (MHKF), oblique pulling (MOP), and lower limb hyperextension (MLLH) were simulated. The stresses and displacements of the SIJ and the strains of the surrounding ligaments were analyzed during the three manipulations. Results MOP produced the highest stress on the left SIJ, at 6.6 MPa, while MHKF produced the lowest stress on the right SIJ, at 1.5 MPa. The displacements of the SIJ were all less than 1 mm during the three manipulations. The three manipulations caused different degrees of ligament strain around the SIJ, and MOP produced the greatest straining of the ligaments. Conclusion The three manipulations all produced small displacements of the SIJ and different degrees of ligament strains, which might be the mechanism through which they relieve SIJ pain. MOP produced the largest displacement and the greatest ligament strains.

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