An Ultrasonic Rayleigh Wave Transducer and its Application to Nondestructive Pressure Measurement

2015 ◽  
Vol 742 ◽  
pp. 11-16 ◽  
Author(s):  
Zhang Wei Ling ◽  
Wei Yong Cai ◽  
Chao Li ◽  
Wei Can Guo
Keyword(s):  
Time Delay ◽  
Rayleigh Wave ◽  
Pressure Measurement ◽  
Engineering Application ◽  
Measurement Model ◽  
Ultrasonic Waves ◽  
Effect Of Temperature ◽  
Maximum Absolute Error ◽  
Piezoelectric Elements ◽  
Wave Transducer

An ultrasonic Rayleigh wave transducer was designed for nondestructive pressure measurement in vessels. Using polyimide resin as the wedge material, the Rayleigh wave transducer had two piezoelectric elements which were placed in the same wedge with a certain distance. Variations in pressure and temperature of vessels can affect the velocity of ultrasonic waves, which will affect variations in time delay in receiving of the same Rayleigh wave with the two piezoelectric elements of the designed transducer. Based on the acoustoelasticity principle and considered the effect of temperature, a practical correlation model between the time delay and both the pressure and temperature of vessels was developed. Using an air vessel as a specimen, Rayleigh wave transducers were arranged in the axial direction of the vessel. The results of temperature experiments show that effect of changes in temperature on time delay agree with the theoretical results. With the calculation temperature compensation in pressure experiment, the relationship between the variations in the time delay caused by changes of pressure and the pressure is established. The pressure measurement results show that the measurement model is effective and the maximum absolute error is 0.09 MPa, which could be acceptable in engineering application.

A Generalized Model for Residual Stress Caused by Thermal Mismatch in Multilayer Structures

2011 ◽  
Vol 704-705 ◽  
pp. 1284-1290
Author(s):  
Yu Mei Bai ◽  
Ying Qiang Xu ◽  
Tao Zhang
Keyword(s):  
Residual Stress ◽  
Thermal Expansion ◽  
Temperature Variation ◽  
Analytical Model ◽  
Layer Structure ◽  
Engineering Application ◽  
Effect Of Temperature ◽  
Multilayer Structures ◽  
Coating System ◽  
Thermal Expansion Mismatch

An analytical model based on multilayer structure with thermal expansion mismatch caused by temperature gradients was established to predict the residual stress in the system. The solution obtained from the model is independent of the number of layers. Three simplified models: bi-layer structure, coating system and film system with great compatibility are developed considering different engineering application. And the bilayer structure is verified by Stoney’s equation under the same conditions. Tri-layer coating system ZrO2/ Al2O3/1Cr18Ni9Ti is established in order to research the effect of temperature variations on the residual stress between different layers. The results suggested the stress has obvious mutation in coating interface with different temperature variation. And the residual stress with different temperature variation in different layers is larger than that with identical temperature variation. Key words: multilayer structures; residual stress; analytical model; thermal expansion mismatch; temperature variation

Contact Pattern Measurement by Means of Ultrasonic Waves: Art of Present and Some Improvements of its Performance

1983 ◽  
Vol 105 (2) ◽  
pp. 237-241 ◽  
Author(s):  
Yoshimi Ito ◽  
Shuzo Itoh
Keyword(s):  
Contact Pressure ◽  
Pressure Measurement ◽  
Ultrasonic Waves ◽  
Joint Surface ◽  
Contact Pattern ◽  
Good Characteristic ◽  
Focus Type ◽  
Type Transducer

To understand the contact characteristics of a joint surface, it is necessary and indispensable to measure the contact pressure. There have, however, been very few contributions to the method of measuring the contact pressure when comparing it with other methods to detect the properties of engineering surfaces. The contact pressure measurement by means of ultrasonic waves (ultrasonic contact pressure measurement) is surely an effective method as ascertained by earlier works, and thus in this paper some improvements of its performance by using a focus type transducer have been reported, also referring to its art of the present. The measurement using a focus type transducer shows a fairly good characteristic as compared with that using a conventional transducer, especially from the aspect of the resolution ability of the contact pattern.

A time-delay calibrated method for cornea hysteresis and intraocular pressure measurement

2015 ◽  
Vol 23 (2) ◽  
pp. 340-345
Author(s):  
Kuo-Jen Wang ◽  
Che-Liang Tsai ◽  
Wai Wang ◽  
Long Hsu ◽  
Ken-Yuh Hsu
Keyword(s):  
Intraocular Pressure ◽  
Time Delay ◽  
Pressure Measurement

scholarly journals Effect of temperature on the physical changes and drying kinetics in plum (Prunus domestica L.) Pozegaca variety

2011 ◽  
Vol 17 (3) ◽  
pp. 283-289 ◽  
Author(s):  
Milovan Zivkovic ◽  
Sveto Rakic ◽  
Radojka Maletic ◽  
Dragan Povrenovic ◽  
Milos Nikolic ◽  
...  
Keyword(s):  
Effective Diffusivity ◽  
Absolute Error ◽  
Drying Kinetics ◽  
Effect Of Temperature ◽  
Coefficient Of Determination ◽  
Maximum Absolute Error ◽  
Nonlinear Regression Models ◽  
Regression Error ◽  
Physical Changes ◽  
Model Correlation

In this study, drying kinetics of autochthonous variety Pozegaca plum was examined in a laboratory dryer at three temperatures. The whole plum fruits, together with the kernels were subjected to the drying process. The effect of drying has been examined at temperatures 55, 60 and 75?C, with a constant air velocity of 1.1 m s-1. The corresponding experimental results were tested using six nonlinear regression models. Coefficient of determination (R2), standard regression error (SSE), model correlation coeficient (Vy), as well as the maximum absolute error (?Y) showed that logaritmic model was in good agreement with the experimental data obtained. During drying of plums, the effective diffusivity was found to be between 5.6?10-9 for 55?C and 8.9?10-9 m2 s-1 at 75?C, respectively. The physical characteristics of the fresh (lenght 39.64 mm and width 29.15 mm) and dried (lenght 37.52 mm and width 22.85 mm) plum fruit were determined. Finally, by chemical analysis, the content of micro-and macro41 elements (Fe, Mn, Cu, B and N, F, K, Ca, Mg, S) in the skin and flesh of the dried product, prunes, has been established.

Novel Mechatronic Sensors for Irregular Movements of Autonomous Land Vehicles

2020 ◽  
Vol 18 (4) ◽  
pp. 280-287
Author(s):  
Rahma Boucetta ◽  
Radwen Bahri ◽  
Saloua Bel Hadj Ali
Keyword(s):  
Time Delay ◽  
Fundamental Principle ◽  
Ultrasonic Waves ◽  
Ultrasound Waves ◽  
Land Vehicles ◽  
Hazardous Environments ◽  
Online Implementation ◽  
Accurate Perception ◽  
Physical Phenomena ◽  
To Receive

In this paper, novel sensors using physical phenomena deduced from ultrasound waves are proposed to overcome problems of cost, availability and adaptability in the measure of position, velocity and tilt of Autonomous Land Vehicles. The true challenge for the Autonomous Land Vehicles concerns essentially the accurate perception of hazardous environments to receive faithful information about reality. Current sensors used nowadays are viewed very expensive, complicated and unable to give accurate measures without time delay. For that, our contribution is located in this context. At first, fundamental principle of ultrasonic waves and their specific physical properties are described to introduce their use in the proposed sensors. Mechatronic concepts of sensors are then detailed with the corresponding mathematical models. Indeed, online implementation and real time experiences are conducted to verify the effectiveness of measurements.

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