scholarly journals Predicting the Deflection of Square Plates Subjected to Fully Confined Blast Loading

2020 ◽  
Vol 8 (12) ◽  
pp. 1031
Author(s):  
Cheng Zheng ◽  
Yiwen Wang ◽  
Xiangshao Kong ◽  
Hu Zhou ◽  
Haibao Liu ◽  
...  
Keyword(s):  
Experimental Data ◽  
Empirical Formula ◽  
Impact Load ◽  
Plate Thickness ◽  
Calculated Data ◽  
Blast Loading ◽  
Thickness Ratio ◽  
Dimensionless Number ◽  
Confined Space ◽  
Blast Energy

The main objective of this study is to conveniently and rapidly develop a new dimensionless number to characterize and predict the deflection of square plates subjected to fully confined blast loading. Firstly, based on the Kirchhoff–Love theory and dimension analysis, a set of dimensionless parameters was obtained from the governing equation representing the response of a thin plate subjected to impact load. A new dimensionless number with a definite physical meaning was then proposed based on dimensional analysis, in which the influence of bending, torsion moment and membrane forces on the dynamic response of the blast-loaded plate were considered along with the related parameters of the blast' energy, the yield strength of the material, the plate thickness and dimensions of the confined space. By analyzing the experimental data of plates subjected to confined blast loading, an approximately linear relationship between the midpoint deflection–thickness ratio of the target plate and the new dimensionless number was derived. On this basis, an empirical formula to predict the deflection of square plates subjected to fully confined blast loading was subsequently regressed, and its calculated results agree well with the experimental data. Furthermore, numerical simulations of square plates subjected to blast loading in a cuboid chamber with different lengths were performed. The numerical results were compared with the calculated data to verify the applicability of the present empirical formula in different scenarios of blast loading from explosions in a cuboid space. It is indicated that the new dimensionless number and corresponding empirical formula presented in this paper have good applicability and reliability for the deflection prediction of plates subjected to fully confined explosions in a cuboid chamber with different lengths, especially when the plates experience a large deflection–thickness ratio.

scholarly journals Dynamic response and damage analysis of steel box wall under internal blast loading

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401882260
Author(s):  
Duo Zhang ◽  
Shujian Yao ◽  
Fangyun Lu ◽  
Jiangjie Song ◽  
Yuqing Ding
Keyword(s):  
Numerical Methods ◽  
Dynamic Response ◽  
Plate Thickness ◽  
Blast Loading ◽  
Damage Mechanism ◽  
Dimensionless Number ◽  
Damage Mode ◽  
Two Dimensional ◽  
Box Models ◽  
Internal Blast Loading

Different loading conditions, different structural dimensions, or different structural materials will lead to different damage results. In this study, blast experiment of steel box model under internal explosion was conducted and the numerical methods are validated through comparison of experimental and numerical results. Then, a series of multi-box models were built, and a large number of numerical simulations considering two kinds of steel, different plate thickness ranging from 0.005 to 0.025 m, and different TNT explosive mass ranging from 5 to 2000 kg were carried out using the validated numerical methods. Two damage modes, convex damage and concave damage, were observed. The dynamic response and damage mechanism were analyzed, and the results show that the different damage modes of the first wall will lead to different damage results of the second wall. Through dimensional analysis, a two-dimensional dimensionless number for internal blast analysis was suggested. Clear physical meanings are conveyed in the dimensionless number. After that, prediction of the damage modes was studied using the proposed dimensionless number. A damage mode map was plotted based on the two-dimensional dimensionless number, and an empirical equation for rapid prediction of damage mode of steel box wall under internal blast loading is proposed.

Gas transport in a model derived from Hansen-Ampaya anatomical data of the human lung

1976 ◽  
Vol 41 (1) ◽  
pp. 115-119 ◽  
Author(s):  
M. Paiva ◽  
L. M. Lacquet ◽  
L. P. van der Linden
Keyword(s):  
Experimental Data ◽  
Transport Equation ◽  
Satisfactory Agreement ◽  
Dead Space ◽  
Empirical Formula ◽  
Molecular Diffusion ◽  
Human Lung ◽  
Gas Transport ◽  
Gas Mixing ◽  
Anatomical Data

The anatomical data of the human lung published by Hansen and Ampaya are used in a model of gas transport in the lung. The Bohr dead space is calculated from solutions of a transport equation where diffusivity is given by an empirical formula obtained by Sherer et al. A satisfactory agreement is found with experimental data obtained from simultaneous washouts of H2 and SF6 for respiratory frequencies ranging between 15 and 60 min-1 and tidal volumes between 200 and 1,800 ml. The results support the idea that molecular diffusion is the main but not the only physical phenomenom which intervenes in gas mixing during breathing.

scholarly journals Ultrafiltration concentration of whey in a pilot plant

2019 ◽  
Vol 81 (2) ◽  
pp. 41-46
Author(s):  
D. A. Rodionov ◽  
S. I. Lazarev ◽  
K. K. Polyansky ◽  
E. V. Eckert
Keyword(s):  
Experimental Data ◽  
Calculated Data ◽  
General View ◽  
Specific Flow ◽  
Milk Whey ◽  
Retention Coefficient ◽  
Tubular Type ◽  
Specific Output ◽  
Output Stream ◽  
Mathematical Expressions

Experimental data on the retention coefficient and the output specific flow are obtained. The test solutions were goat and cow's milk whey after obtaining cheese. The description, general view and technological scheme of a pilot installation of a tubular type are given. The studies were carried out on semipermeable tubular type ultrafiltration membranes manufactured by AO "ZAVKOM". Based on the studies, graphical dependences of the retention coefficient on the specific output stream were constructed and analyzed. During the analysis, it was noted that with an increase in the output specific flow of the solvent, the retention coefficient decreases. The reason for this is the boundary layers of fat and protein formed in the near-membrane layers, which prevents the passage of protein molecules through the pores of the membrane. Also during the experiment, it was noted that goat milk serum has a more oily structure and requires prior separation. For the theoretical calculation of the retention coefficient and specific output stream, mathematical expressions are developed and numerical values of the values of empirical coefficients are obtained. The developed mathematical expressions describe the experimental data with good confidence. The obtained experimental and calculated data can be used with great reliability in the calculations of mass-transported flows of substances through semipermeable membranes, as well as in engineering methods for calculating and predicting the effectiveness of the use of membrane processes for the concentration of whey.

scholarly journals LAGRANGIAN BREAKER CHARACTERISTICS FOR NONLINEAR WATER WAVES PROPAGATING ON SLOPING BOTTOMS

2011 ◽  
Vol 1 (32) ◽  
pp. 15
Author(s):  
Yang-Yih Chen ◽  
Meng-Syue Li ◽  
Hung-Chu Hsu ◽  
Ying-Pin Lin
Keyword(s):  
Experimental Data ◽  
Wave Propagation ◽  
Empirical Formula ◽  
Wave Breaking ◽  
Present Theory ◽  
Empirical Formulas ◽  
Third Order ◽  
Wave Shoaling ◽  
Theoretical Results ◽  
Sloping Bottom

In this paper, a new third-order Lagrangian asymptotic solution describing nonlinear water wave propagation on the surface of a uniform sloping bottom is presented. The model is formulated in the Lagrangian variables and we use a two-parameter perturbation method to develop a new mathematical derivation. The particle trajectories, wave pressure and Lagrangian velocity potential are obtained as a function of the nonlinear wave steepness  and the bottom slope  perturbed to third order. The analytical solution in Lagrangian form satisfies state of the normal pressure at the free surface. The condition of the conservation of mass flux is examined in detail for the first time. The two important properties in Lagrangian coordinates, Lagrangian wave frequency and Lagrangian mean level, are included in the third-order solution. The solution can also be used to estimate the mean return current for waves progressing over the sloping bottom. The Lagrangian solution untangle the description of the features of wave shoaling in the direction of wave propagation from deep to shallow water, as well as the process of successive deformation of a wave profile and water particle trajectories leading to wave breaking. The proposed model has proved to be capable of a better description of non-linear wave effects than the corresponding approximation of the same order derived by using the Eulerian description. The proposed solution has also been used to determine the wave shoaling process, and the comparisons between the experimental and theoretical results are presented in Fig.1a~1b. In addition, the basic wave-breaking criterion, namely the kinematical Stokes stability condition, has been investigated. The comparisons between the present theory, empirical formula of Goda (2004) and the experiments made by Iwagali et al.(1974), Deo et al.(2003) and Tsai et al.(2005) for the breaking index(Hb/L0) versus the relative water depth(d0/L0) under two different bottom slopes are depicted in Figs 2a~2b. It is found that the theoretical breaking index is well agreement with the experimental results for three bottom slopes. However,for steep slope of 1/3 shown in Fig 2b, the result of Goda‘s empirical formula gives a larger value in comparison with the experimental data and the present theory. Some of empirical formulas presented the breaking wave height in terms of deepwater wave condition, such as in Sunamura (1983) and in Rattanapitikon and Shibayama(2000). Base on the results depicted in Fig. 3a~3b, it showed that the theoretical results are in good agreement with the experimental data (Iwagali et al. 1974, Deo et al.2003 and Tsai et al. 2005) than the empirical formulas. The empirical formula of Sunamura (1983) always predicts an overestimation value.

scholarly journals IMPROVEMENT OF THE ROUGHNESS FORECASTING MODEL OF COATING OF NON-RIGID ROAD PAVEMENT COATING

2021 ◽  
Vol 4 (164) ◽  
pp. 71-76
Author(s):  
A. Batrakova ◽  
H. Sarkisian ◽  
E. Zakharova
Keyword(s):  
Experimental Data ◽  
Service Life ◽  
Pearson Correlation ◽  
Safety Margin ◽  
Calculated Data ◽  
Statistical Processing ◽  
Theoretical Models ◽  
Rigid Pavement ◽  
Improved Model ◽  
Over Time

To ensure safe, comfortable driving at high speeds, a strong, even surface is required for the entire life of the pavement. In this regard, the issue of predicting changes in the equality of coverage over time is very important. The article considers the peculiarities of changing the longitudinal equality of the road surface. Purpose is to improve the model of forecasting the equality of non-rigid pavement. Methods – analytical and experimental. The analysis of existing decisions on the issue of forecasting the equality of coverage is performed. The most important factors influencing the change in the equality of road coverage have been identified. Based on the analysis of theoretical models and a number of experimental data, an improved model for predicting the equality of coverage of non-rigid pavement is proposed. MathCAD and MS Excel were involved in the development of an improved model that takes into account the most important factors. The model of change of coverage roughness, where increase in the roughness index over time is considered as a function of such parameters, is improved: the modulus of pavement elasticity (actual or required); the number of load cycles for t years of pavement operation; the share of trucks in the traffic flow; the factor of safety margin of the pavement structure. The adequacy of the developed model of changing the roughness of coverage is confirmed by statistical processing of experimental data obtained by the thesis author and other researchers on public roads with different service life, and calculated data under the theoretical model. The Pearson correlation coefficient between experimental and calculated data is more than 0.95, which indicates the adequacy of the developed model. Compared to the well-known models of forecasting coverage roughness, the improved model allows to apply a wider range of values of the general equivalent modulus of elasticity of pavement design (from 100 MPa to 600 MPa) and to receive forecast values of roughness for service life of non-rigid pavement over 5 years.

EVALUATION OF THE STRESSED DEFORMED STATE OF MAIN GAS PIPELINES RUNNING IN PERMANENTLY FROZEN GROUNDS

2020 ◽  
pp. 58-63
Author(s):  
M. M. Sidorov ◽  
N. I. Golikov ◽  
R. P. Tihonov
Keyword(s):  
Experimental Data ◽  
Calculated Data ◽  
Gas Pipeline ◽  
Loss Of Stability ◽  
Portable Equipment ◽  
Ray Method ◽  
X Ray ◽  
Deformed State ◽  
Pipeline Monitoring

The work evaluates the stress deformed state of the section of the interfield gas collecting main, running in permanently frozen grounds. The object of research is a section of a pipeline with an arched discharge formed as a result of loss of stability as a result of thermal erosion of permanently frozen grounds to disturbance of the vegetation cover. The determination of stresses was carried out by the X-ray method using portable equipment. The experimental data were analyzed with the calculated. The calculated data were obtained by measuring the spatial position of the gas pipeline section. The obtained values of the acting stresses and the estimates of the critical indicators of the gas pipeline monitoring section made it possible to reasonably estimate the stress state. The methodology for determining the acting stresses of pipelines using portable X-ray equipment can be successfully applied to estimate the stressed-deformed state of pipeline systems running in the zone of permafrost.

Simple Semiempirical Method of Calculating van der Waals Interactions in Thin Films from Lifshitz Theory

1976 ◽  
Vol 31 (12) ◽  
pp. 1584-1588 ◽  
Author(s):  
Chr. St. Vassilieff ◽  
I. B. Ivanov
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Empirical Formula ◽  
Van Der Waals ◽  
Semiempirical Method ◽  
Simple Expression ◽  
Van Der Waals Interactions ◽  
Dispersion Dependence ◽  
Satisfactory Accuracy ◽  
Lifshitz Theory

AbstractThe influence of different representations of the dispersion dependence ε (i ξ) on calculating van der Waals interactions from Lifshitz theory is studied. It is shown that with satisfactory accuracy ε (i ξ) can be described by means of Krupp's empirical formula [ε (i ξ) -1]/[ε (i ξ) +1] = a · exp(-b ξ). Making use of that formula a simple expression for the Hamaker function A (h, T) is obtained. Numerical calculations are carried out, the results being compared with those of other authors and with experimental data.

Hyperconjugation In Trialkylboranes Shown By Indirect Nuclear Spin-Spin Coupling Constants. Experimental Data And Density Functional Theory (Dft) Calculations

2005 ◽  
Vol 60 (3) ◽  
pp. 259-264 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Oleg L. Tok
Keyword(s):  
Experimental Data ◽  
Dft Calculations ◽  
Density Functional ◽  
Calculated Data ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Functional Theory ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
C Nmr

Trimethylborane (1), triethylborane (2), 1,3-dimethyl-1-boracyclopentane (3), 1-methyl-1- boracyclohexane (4), 9-methyl- and 9-ethyl-9-borabicyclo[3.1.1]nonane [5(Me) and 5(Et)], and 1- boraadamantane (6) were studied by 11B and 13C NMR spectroscopy with respect to coupling constants 1J(13C,11B) and 1J(13C,13C). Results of DFT calculations at the B3LYP/6-311+g(d,p) level of theory show satisfactory agreement with the experimental data. Hyperconjugation arising from C-C σ bonds adjacent to the tricoordinate boron atom is indicated, in particular for 1-boraadamantane (6), by the optimised calculated structures, and by the experimental and calculated data 1J(13C,13C). The calculated magnitude of 1J(13C,1H) for carbon atoms adjacent to boron becomes significantly smaller if the optimised structures suggest hyperconjugative effects arising from these C-H bonds

Strength and Deformation of Combined Beams with Side Reinforced Plates

2019 ◽  
Vol 968 ◽  
pp. 234-239
Author(s):  
Talyat Azizov ◽  
Oleksii Melnik ◽  
Oleksandr Myza
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Experimental Studies ◽  
Calculated Data ◽  
Concrete Plate ◽  
Combined Action ◽  
Strength And Deformation ◽  
Concrete Plates ◽  
Good Agreement

The results of experimental studies of combined beams consisting of a stone part, reinforced with side reinforced concrete plates are given. Experimentally shown the viability of the proposed structures. The conditions for ensuring the combined action of a stone beam and a reinforced concrete plate are given. Cases are shown when one-sided plates can be used and when double-sided reinforced concrete plates can be used. A comparison of experimental data with the data calculated by the authors developed methods is given. A good agreement between theoretical and calculated data is shown.

scholarly journals Dynamic Takagi-Sugeno Model for the Control of Ultrasonic Motor

2011 ◽  
Vol 2011 ◽  
pp. 1-9
Author(s):  
Shi Jingzhuo ◽  
Lv Lin ◽  
Zhang Yu
Keyword(s):  
Experimental Data ◽  
Fuzzy Model ◽  
Calculated Data ◽  
Fuzzy Reasoning ◽  
Ultrasonic Motor ◽  
Driving Voltage ◽  
Driving System ◽  
Position Controller ◽  
Sugeno Model ◽  
Takagi Sugeno

Model of ultrasonic motor is the foundation of the design of ultrasonic motor's speed and position controller. A two-input and one-output dynamic Takagi-Sugeno model of ultrasonic motor driving system is worked out using fuzzy reasoning modeling method in this paper. Many fuzzy reasoning modeling methods are sensitive to the initial values and easy to fall into local minimum, and have a large amount of calculation. In order to overcome these defects, equalized universe method is used in this paper to get clusters centers and obtain fuzzy clustering membership functions, and then, the unknown parameters of the conclusions of fuzzy rules are identified using least-square method. Different experimental data that are tested with different operational conditions are used to examine the validity of the fuzzy model. Comparison between experimental data and calculated data of the model indicates that the model can well describe the nonlinear characteristics among the frequency, amplitude of driving voltage and rotating speed. The proposed fuzzy model can be used to analyze the performance of ultrasonic motor driving system, and also can be used to design the speed and position controller of ultrasonic motor.

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