DETERMINATION OF THE COMPRESSIVE STRESS OF A RAIL USING THE EFFECT OF ACOUSTOELASTICITY AND STRAIN GAUGE

2021 ◽  
pp. 14-23
Author(s):  
L. N. Stepanova ◽  
A. N. Kurbatov ◽  
S. I. Kabanov ◽  
E. S. Tenitilov ◽  
V. L. Kojemyakin ◽  
...  
Keyword(s):  
Strain Gauge ◽  
Steel Sample ◽  
Ultrasonic Waves ◽  
Ultrasonic Vibrations ◽  
Compression Stress ◽  
Accuracy Class ◽  
Compressive Stresses ◽  
Load Cells ◽  
Steel 20

A method for monitoring the compression stress in a rail and a sample made of steel 20 using the effect of acoustoelasticity and strain gauge has been developed. Wire load cells were pasted to the opposite sides of the rail and the sample. Measurements, recording and processing of strain gauge information was carried out by a certified microprocessor strain gauge system MMTS-64.01 with accuracy class 0.2. To control the compression stress, the developed microprocessor-based ultrasonic system “Akusto-1” was used, which operates on the basis of the acoustoelasticity effect. The angle of input of ultrasonic vibrations, equal to 18°. This allowed to excite longitudinal, transverse and transformed waves in the object. Compressive stresses in the rail and steel sample were carried out by 250-ton loading machine “PSY-250”. Longitudinal and transformed ultrasonic waves were used to control compressive stresses. A comparative analysis of the experimental and calculated dependences of compressive stresses on the load obtained by acoustic, tensometric and computational methods is performed. The reliability of the experimental and calculated results was controlled by a certified microprocessor strain gauge system MMTS-64.01.

scholarly journals Use of the AE Effect to Determine the Stresses State in AAC Masonry Walls under Compression

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3459
Author(s):  
Radosław Jasiński ◽  
Krzysztof Stebel ◽  
Paweł Kielan
Keyword(s):  
Ultrasonic Waves ◽  
Image Correlation ◽  
Masonry Walls ◽  
Acceptable Error ◽  
Compressive Stresses ◽  
Deformation State ◽  
Hydrostatic Stresses ◽  
Stress States ◽  
The Impact ◽  
Masonry Units

Safety and reliability of constructions operated are predicted using the known mechanical properties of materials and geometry of cross-sections, and also the known internal forces. The extensometry technique (electro-resistant tensometers, wire gauges, sensor systems) is a common method applied under laboratory conditions to determine the deformation state of a material. The construction sector rarely uses ultrasonic extensometry with the acoustoelastic (AE) method which is based on the relation between the direction of ultrasonic waves and the direction of normal stresses. It is generally used to identify stress states of machine or vehicles parts, mainly made of steel, characterized by high homogeneity and a lack of inherent internal defects. The AE effect was detected in autoclaved aerated concrete (AAC), which is usually used in masonry units. The acoustoelastic effect was used in the tests described to identify the complex stress state in masonry walls (masonry units) made of AAC. At first, the relationships were determined for mean hydrostatic stresses P and mean compressive stresses σ3 with relation to velocities of the longitudinal ultrasonic wave cp. These stresses were used to determine stresses σ3. The discrete approach was used which consists in analyzing single masonry units. Changes in velocity of longitudinal waves were identified at a test stand to control the stress states of an element tested by the digital image correlation (DIC) technique. The analyses involved density and the impact of moisture content of AAC. Then, the method was verified on nine walls subjected to axial compression and the model was validated with the FEM micromodel. It was demonstrated that mean compressive stresses σ3 and hydrostatic stresses, which were determined for the masonry using the method considered, could be determined even up to ca. 75% of failure stresses at the acceptable error level of 15%. Stresses σ1 parallel to bed joints were calculated using the known mean hydrostatic stresses and mean compressive stresses σ3.

Determination of the strain fields in the area of concentrators by strain gauge readings for orthotropic elements

1982 ◽  
Vol 18 (1) ◽  
pp. 67-70
Author(s):  
A. L. Brushkovskii ◽  
L. P. Litvinenko
Keyword(s):  
Strain Gauge ◽  
Strain Fields

Determination of the foaming parameters of polyurethane compositions from the velocity of longitudinal ultrasonic waves

1979 ◽  
Vol 15 (3) ◽  
pp. 316-317 ◽  
Author(s):  
V. M. Mel'nikov ◽  
�. A. Putnin'sh ◽  
V. O. Putninya ◽  
V. P. Karlivan
Keyword(s):  
Ultrasonic Waves ◽  
Longitudinal Ultrasonic Waves

Experimental and Theoretical Rotordynamic Characteristics of a Hybrid Journal Bearing

1997 ◽  
Vol 119 (1) ◽  
pp. 132-141 ◽  
Author(s):  
J. T. Sawicki ◽  
R. J. Capaldi ◽  
M. L. Adams
Keyword(s):  
Journal Bearing ◽  
Operating Conditions ◽  
Dynamic Force ◽  
Test Results ◽  
Force Measurements ◽  
Lubrication Equation ◽  
Load Cells ◽  
Theoretical Predictions ◽  
Stiffness And Damping

This paper describes an experimental and theoretical investigation of a four-pocket, oil-fed, orifice-compensated hydrostatic bearing including the hybrid effects of journal rotation. The test apparatus incorporates a double-spool-shaft spindle which permits independent control over the journal spin speed and the frequency of an adjustable-magnitude circular orbit, for both forward and backward whirling. This configuration yields data that enables determination of the full linear anisotropic rotordynamic model. The dynamic force measurements were made simultaneously with two independent systems, one with piezoelectric load cells and the other with strain gage load cells. Theoretical predictions are made for the same configuration and operating conditions as the test matrix using a finite-difference solver of Reynolds lubrication equation. The computational results agree well with test results, theoretical predictions of stiffness and damping coefficients are typically within thirty percent of the experimental results.

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