scholarly journals Burial Depth Effect of Crack on the Lcr Wave Acoustoelastic Coefficient for Stress Measurement of Laser Cladding Coating

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2823
Author(s):  
Bin Liu ◽  
Zhihao Zeng ◽  
Jiayang Gu ◽  
Shujin Chen ◽  
Peng He ◽  
...  
Keyword(s):  
Wavelet Analysis ◽  
Laser Cladding ◽  
Stress Measurement ◽  
Sampling Rate ◽  
Tensile Load ◽  
Experimental Results ◽  
Center Frequency ◽  
Burial Depth ◽  
Depth Effect ◽  
Acoustoelastic Effect

In this paper, the influence of burial depth of crack on stress measurement of laser cladding coating with the critical refracted longitudinal wave (Lcr wave) was discussed based on the Lcr wave acoustoelastic effect. The regular rectangular slots with different depths that were used to simulate the burial crack in coating was based on the equivalent theory. The experimental system including an ultrasonic wave generator, digital oscilloscope (2.5 GHz sampling rate), and two Lcr wave transducers (2.5 MHz center frequency) was used to collect the Lcr wave under different tensile loads, and the Lcr wave was denoised by using wavelet analysis technology, then the fracture morphology was observed using SEM. The results show that after the denoising by wavelet analysis technology, the signal-to-noise ratio of Lcr wave becomes bigger and the mean square deviation of Lcr wave becomes smaller. When the tensile load is within the turning point load, the difference in time of flight between Lcr wave increases linearly as the tensile load increases, and the deviation of the experimental results becomes obvious as the tensile load increases. When the tensile load is the same, as the burial depth of the slot increases, the nominal Lcr wave acoustoelastic coefficient decreases and tends to be stable gradually. At last, the experimental results are discussed based on the Lcr wave acoustoelastic effect and deformation theory, and it is analyzed that the uneven deformation caused by the interface in coating, anisotropic microstructure, and the burial crack is considered as the main reason.

scholarly journals An Improved Roadside Parking Space Occupancy Detection Method Based on Magnetic Sensors and Wireless Signal Strength

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2348 ◽  
Author(s):  
Liangliang Lou ◽  
Jinyi Zhang ◽  
Yong Xiong ◽  
Yanliang Jin
Keyword(s):  
Detection Method ◽  
Dead Zone ◽  
Sampling Rate ◽  
Vehicle Detection ◽  
Magnetic Sensors ◽  
Experimental Results ◽  
Detection Accuracy ◽  
Parking Space ◽  
Wireless Transceivers ◽  
Occupancy Detection

Smart Parking Management Systems (SPMSs) have become a research hotspot in recent years. Many researchers are focused on vehicle detection technology for SPMS which is based on magnetic sensors. Magnetism-based wireless vehicle detectors (WVDs) integrate low-power wireless communication technology, which improves the convenience of construction and maintenance. However, the magnetic signals are not only susceptible to the adjacent vehicles, but also affected by the magnetic signal dead zone of high-chassis vehicles, resulting in a decrease in vehicle detection accuracy. In order to improve the vehicle detection accuracy of the magnetism-based WVDs, the paper introduces an RF-based vehicle detection method based on the characteristics analysis of received signal strengths (RSSs) generated by the wireless transceivers. Since wireless transceivers consume more energy than magnetic sensors, the proposed RF-based method is only activated to extract the data characteristics of RSSs to further judge the states of vehicles when the data feature of magnetic signals is not sufficient to provide accurate judgment on parking space status. The proposed method was evaluated in an actual roadside parking lot and experimental results show that when the sampling rate of magnetic sensor is 1 Hz, the vehicle detection accuracy is up to 99.62%. Moreover, compared with machine-learning-based vehicle detection method, the experimental results show that our method has achieved a good compromise between detection accuracy and power consumption.

Parametric Analyses of the TROI Experimental Results by Using the TEXAS-V Code

2008 ◽  
Vol 273-276 ◽  
pp. 474-478
Author(s):  
I.K. Park ◽  
J.H. Kim ◽  
B.T. Min ◽  
S.H. Hong ◽  
H.D. Kim ◽  
...  
Keyword(s):  
Particle Size ◽  
Void Fraction ◽  
Steam Explosion ◽  
Experimental Information ◽  
Water Area ◽  
Experimental Results ◽  
Size Difference ◽  
Depth Effect ◽  
Area Effect ◽  
Melt Composition

The TEXAS-V code was tuned for TROI-13 and used for analyzing the parametric findings of the TROI experiments. The calculations for the melt composition are relatively similar to the TROI experimental results, in which the melt composition has quite an effect on the steam explosion occurrence probabilities and a steam explosion itself. The void fraction difference due to a particle size difference appears to cause this composition dependency of a steam explosion. The water depth effect in the TEXAS-V code seems to be consistent with the TROI experiments to some degree. The water area effect of the TEXAS-V calculations isn’t exactly harmonious with that of the TROI experiments. This indicates that TEXAS-V code as a 1-dimensional code or as a numerical steam explosion has a limitation in estimating an area effect. The experimental information on the particle size and the void fraction during mixing is very helpful for a verification of this relation.

Parametric Study on Rectangular Sonic Crystal

2012 ◽  
Vol 152-154 ◽  
pp. 281-286 ◽  
Author(s):  
Arpan Gupta ◽  
Kian Meng Lim ◽  
Chye Heng Chew
Keyword(s):  
Band Gap ◽  
Periodic Structure ◽  
Parametric Study ◽  
Sound Propagation ◽  
Periodic Structures ◽  
Sound Attenuation ◽  
Experimental Results ◽  
Center Frequency ◽  
Sonic Crystal ◽  
Sonic Crystals

Sonic crystals are periodic structures made of sound hard scatterers which attenuate sound in a range of frequencies. For an infinite periodic structure, this range of frequencies is known as band gap, and is determined by the geometric arrangement of the scatterers. In this paper, a parametric study on rectangular sonic crystal is presented. It is found that geometric spacing between the scatterers in the direction of sound propagation affects the center frequency of the band gap. Reducing the geometric spacing between the scatterers in the direction perpendicular to the sound propagation helps in better sound attenuation. Such rectangular arrangement of scatterers gives better sound attenuation than the regular square arrangement of scatterers. The model for parametric study is also supported by some experimental results.

Bond investigation of hybrid textile with self-compacting fine-grain concrete

2016 ◽  
Vol 46 (8) ◽  
pp. 1616-1632 ◽  
Author(s):  
Shiping Yin ◽  
Bo Wang ◽  
Fei Wang ◽  
Shilang Xu
Keyword(s):  
Tensile Load ◽  
Experimental Results ◽  
Interfacial Property ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Multiple Cracks ◽  
Textile Reinforced Concrete ◽  
Fine Grain ◽  
Resin Impregnation ◽  
Relationship Of

This paper presents an experimental investigation into the influence of bond characteristics between textile and matrix on the mechanical behavior of textile-reinforced concrete (TRC). Two types of tests were performed, i.e. pullout test and uniaxial tensile test. Self-compacting fine-grain concrete was adopted. Two kinds of hybrid textile, consisting of both carbon and E-glass yarns, were specially prepared for this study. The experimental results show that sticking sands on the textile after epoxy resin impregnation can improve the interfacial property between textile and matrix. The specimens with textile of 10 mm × 10 mm mesh have stronger bond strength than those with textile of 25 mm × 25 mm mesh, and can reach the maximum tensile strength of yarns when the initial bond length is between 30 mm and 35 mm. Moreover, sticking sands on the textile can improve the multiple cracks form and the ultimate bearing capacity of TRC under uniaxial tensile load. Specimens with textile of 10 mm × 10 mm mesh have higher first-crack loads than those with textile of 25 mm × 25 mm mesh whether or not the textile surface treatment was conducted, and also have better crack distribution. Finally, based on the experimental results from TRC under uniaxial tensile load, a double linear constitutive equation of stress–strain relationship of carbon fiber yarn is provided in this paper.

scholarly journals A Design of Wide Band and Wide Beam Cavity-Backed Slot Antenna Array with Slant Polarization

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Huiying Qi ◽  
Ke Xiao ◽  
Fei Zhao ◽  
Shunlian Chai ◽  
Wenlu Yin
Keyword(s):  
Antenna Array ◽  
Wide Band ◽  
Experimental Results ◽  
Slot Antenna ◽  
Center Frequency ◽  
Challenging Problem ◽  
Wide Beam ◽  
Limited Size

Design of antenna array under the limitation of restricted size is a challenging problem. Cavity-backed slot antenna is widely used because of its advantages of small size, wide band, and wide beam. In this paper, a design of wide band and wide beam cavity-backed slot antenna array with the slant polarization is proposed. To obtain wide band and wide beam with limited size, the inverted microstrip-fed cavity-backed slot antenna (IMF-CBSA) is adopted as the element of 1 × 4 antenna array. The slant polarized antennas and their feeding networks are adopted because of their simple structures. The performance of the proposed antenna array is verified by the simulations and experiments. The measured VSWR < 2 bandwidth is 55% at the center frequency 21.8 GHz, and the gain is larger than 12.2 dB. Experimental results demonstrate that the proposed design achieves wide band and beam with the size of 68 mm × 56 mm × 14.5 mm.

Superconducting bandpass ΔΣ modulator with 2.23-GHz center frequency and 42.6-GHz sampling rate

2002 ◽  
Vol 37 (12) ◽  
pp. 1695-1702 ◽  
Author(s):  
J.F. Bulzacchelli ◽  
Hae-Seung Lee ◽  
J.A. Misewich ◽  
M.B. Ketchen
Keyword(s):  
Sampling Rate ◽  
Center Frequency

Compared Study on Laser Cladding and Plasma Spraying of Nuclear Valve Clacks

2007 ◽  
Vol 353-358 ◽  
pp. 890-893
Author(s):  
Chun Liang Zhang ◽  
Li Ping Chen ◽  
Bin He
Keyword(s):  
High Temperature ◽  
Plasma Spraying ◽  
Laser Cladding ◽  
Base Alloy ◽  
Experimental Results ◽  
Temperature Impact ◽  
Electron Microscopes ◽  
Sprayed Coating ◽  
Plasma Sprayed ◽  
Scanning Electron Microscopes

Laser cladding of Co-base alloy on the sealing surfaces of nuclear valve clacks has been performed with a 5KW CO2 transverse flowing laser. The laser cladding was compared with plasma spraying. Both laser cladded and plasma sprayed zones were characterized by optical and scanning electron microscopes. The high temperature impact-slide wear resistance of laser cladded and plasma sprayed coatings were studied. The experimental results showed that compared with that of plasma sprayed coating, the laser cladded coating has higher microhardness, more uniform microstructure, smaller grain size, lower dilution rate, and fewer pores and impurities. The experimental results also showed that the weight loss of plasma sprayed coating during the high temperature impact-slide wear is two times larger than that of laser cladded coating.

Effect of Rare Earth Y2O3 Content on Microstructure of Gradient Bioceramic Composite Coating Produced by Wide-Band Laser Cladding

2005 ◽  
Vol 288-289 ◽  
pp. 351-354 ◽  
Author(s):  
Qi Bin Liu ◽  
Long Jiang Zou ◽  
Min Zheng ◽  
Chuang Dong
Keyword(s):  
Rare Earth ◽  
Composite Coating ◽  
Laser Cladding ◽  
Dominant Role ◽  
Monosodium Glutamate ◽  
Wide Band ◽  
Experimental Results ◽  
Ti Alloy ◽  
Y2o3 Content ◽  
Rare Earth Content

In the present paper, bioceramic coating with gradient compositional design was prepared on surface of Ti alloy by using wide-band laser cladding. Effect of rare earth Y2O3 content on gradient bioceramic composite coating was studied. The experimental results indicated that adding rare earth can refine grain. Different contents of rare earth affect formation of HA andβ-TCP in bioceramic coating. With increase of rare earth content, HA andβ-TCP were synthesized. When content of rare earth ranged from 0.4% to 0.6%, the active extent of rare earth in synthesizing HA andβ-TCP got best, which indicated that “monosodium glutamate” effect of rare earth played a dominant role. However, when rare earth content was up to 0.8%, the active extent of rare earth in synthesizing HA and β-TCP conversely went down, which demonstrated that rare earth gradually lost its catalysis in manufacturing HA andβ-TCP.

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