Some Considerations on the Expected Resonance Frequencies of Bridges During Proof Load Tests

Abstract Vehicle interior noise is the result of numerous sources of excitation. One source involving tire pavement interaction is the tire air cavity resonance and the forcing it provides to the vehicle spindle: This paper applies fundamental principles combined with experimental verification to describe the tire cavity resonance. A closed form solution is developed to predict the resonance frequencies from geometric data. Tire test results are used to examine the accuracy of predictions of undeflected and deflected tire resonances. Errors in predicted and actual frequencies are shown to be less than 2%. The nature of the forcing this resonance as it applies to the vehicle spindle is also examined.

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Specification for electromechanical components for electronic equipment: basic testing procedures and measuring methods. Impacttests (free components), static load tests (fixed components), endurance tests and overload tests

10.3403/00007716u ◽

2015 ◽

Keyword(s):

Static Load ◽

Electronic Equipment ◽

Testing Procedures ◽

Measuring Methods ◽

Endurance Tests ◽

Load Tests

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Specification for electromechanical components for electronic equipment: basic testing procedures and measuring methods. Impacttests (free components), static load tests (fixed components), endurance tests and overload tests

10.3403/00007704 ◽

1981 ◽

Keyword(s):

Static Load ◽

Electronic Equipment ◽

Testing Procedures ◽

Measuring Methods ◽

Endurance Tests ◽

Load Tests

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Use of instrumented static load tests on deep foundations for optimisation of geotechnical design

Proceedings of the Ninth Symposium on Field Measurements in Geomechanics ◽

10.36487/acg_rep/1508_49_wood ◽

2015 ◽

Cited By ~ 1

Author(s):

William Wood ◽

Jon Sinnreich ◽

Anthony Simmonds

Keyword(s):

Static Load ◽

Deep Foundations ◽

Load Tests ◽

Geotechnical Design

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Graphic method for assessing the margins of resistance to acoustic vibrations in the chambers of rocket engines by combustion noise

10.36652/0042-4633-2020-8-15-21 ◽

2020 ◽

pp. 15-21

Author(s):

R.A. Tsarapkin ◽

V.N. Ivanov ◽

V.I. Biryukov

Keyword(s):

Rocket Engine ◽

Spectral Characteristics ◽

Combustion Process ◽

Combustion Noise ◽

Rocket Engines ◽

Acoustic Vibrations ◽

Statistical Regression ◽

Unknown Parameters ◽

Damping Decrement ◽

Resonance Frequencies

An experimental method is proposed for estimating the damping decrements of pressure fluctuations in the combustion chambers of forced rocket engines. The method is based on the statistical processing of noise pressure pulsations in the vicinity of natural resonance frequencies for normal modes of acoustic vibrations of the reaction volume and the subsequent prediction of the instability of the combustion process relative to acoustic vibrations. Based on the theory of statistical regression for multidimensional experimental data, the problem of predicting unknown parameters of sample distributions is solved by asymptotic determination of the correlation coefficient of the damping decrement of pressure vibrations through optimal linear predictors and the Kolmogorov distribution. Keywords rocket engine, combustion chamber, acoustic vibrations, combustion noise, spectral characteristics, Kolmogorov criterion, damping decrement. [email protected]

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Optimization Analysis of Settlement Parameters for Postgrouting Piles in Loess Area of Shaanxi, China

Advances in Civil Engineering ◽

10.1155/2019/7085104 ◽

2019 ◽

Vol 2019 ◽

pp. 1-16 ◽

Cited By ~ 10

Author(s):

Zhijun Zhou ◽

Shanshan Zhu ◽

Xiang Kong ◽

Jiangtao Lei ◽

Tong Liu

Keyword(s):

Compression Modulus ◽

Summation Method ◽

Cone Penetration ◽

Optimization Analysis ◽

Loess Area ◽

Elastic Compression ◽

Settlement Calculation ◽

Side Resistance ◽

Load Tests ◽

The Relationship

The settlement calculation of postgrouting piles is complex and depends on the calculation method and parameters. Static load tests were conducted to compare the settlement characteristics of nongrouting and postgrouting piles, and three vital parameters in the layer-wise summation method were revised to predict the settlement of postgrouting piles. The elastic compression coefficient was deduced based on the Mindlin–Geddes method by considering the influence of the change in the pile side resistance distribution and end resistance ratio on the elastic compression after grouting. The relationship between the compression modulus and soil gravity stress and cone penetration resistance were established, respectively, using experimental data. The optimum value of the settlement empirical coefficient was determined using regional data. Finally, we used the postgrouting pile of the Wuqi–Dingbian expressway as a practical example. The results obtained from the layer-wise summation method after parametric optimization were close to the measured values. The results of this study provide reference data and guidance for the settlement calculation of postgrouting piles in this area.

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