The Calculation of the Two-Layer Beam Model on an Elastic Basis with Variable Modulus of Subgrade Reaction

2013 ◽  
Vol 351-352 ◽  
pp. 566-569 ◽  
Author(s):  
Vladimir Igorevich Andreev ◽  
Alena Vladimirovna Matveeva ◽  
Elena Vjacheslavovna Barmenkova
Keyword(s):  
Lower Layer ◽  
Single Layer ◽  
Beam Model ◽  
Constant Modulus ◽  
Subgrade Reaction ◽  
Variable Rigidity ◽  
Modulus Of Subgrade Reaction ◽  
Variable Modulus ◽  
Internal Forces ◽  
Elastic Basis

In the present paper is given the calculation of the two-layer and the single-layer beam models on an elastic basis with variable and constant modulus of subgrade reaction. The two-layer beam is the beam of variable rigidity, the lower layer simulates the foundation, and the upper - the structure, at the same time is considered the weight of each layer. In the results of calculations of beams, as the two-layer and the single-layer, the values of the internal forces and stresses are obtained more with variable modulus of subgrade reaction than with constant. With consideration of the two-layer and the single-layer beam models with the same characteristics of the base, the values of internal forces, generated in two-layer beams, are obtained much more.

The Modeling of the Real Building Object by Using the Model of a Two-Layer Beam of Variable Rigidity on an Elastic Basis

2012 ◽  
Vol 204-208 ◽  
pp. 3596-3599 ◽  
Author(s):  
Andreev Vladimir Igorevich ◽  
Barmenkova Elena Vjacheslavovna
Keyword(s):  
Numerical Methods ◽  
Lower Layer ◽  
System Structure ◽  
Simplified Model ◽  
Sandwich Beams ◽  
Variable Rigidity ◽  
The Real ◽  
Methods Of Calculation ◽  
Elastic Basis ◽  
Real Building

In the present paper is given the calculation of the real building object by using the model of a two-layer beam of variable rigidity on an elastic basis. The lower layer of a two-layer beam simulates the foundation, and the upper - the structure, at the same time is considered the weight of each layer. The characteristics of the upper layer change on length. To solve this problem were used an analytical and numerical methods of calculation. On the basis of the calculations can make the following conclusion: for the calculation of system «structure-foundation-basis» for the stage of pre-proposals it is advisable to apply the simplified model as sandwich beams and plates on elastic basis.

The hydraulics of two flowing layers with different densities

1986 ◽  
Vol 163 ◽  
pp. 27-58 ◽  
Author(s):  
Laurence Armi
Keyword(s):  
Lower Layer ◽  
Single Layer ◽  
Critical Conditions ◽  
Hydraulic Jumps ◽  
Flow Configurations ◽  
Pass Through ◽  
Bottom Depth ◽  
Downstream Flow ◽  
Energy Equations ◽  
Simple Flow

This is a theoretical and experimental study of the basic hydraulics of two flowing layers. Unlike single-layer flows, two-layer flows respond quite differently to bottom depth as opposed to width variations. Bottom-depth changes affect the lower layer directly and the upper layer only indirectly. Changes in width can affect both layers. In fact for flows through a contraction control two distinct flow configurations are possible; which one actually occurs depends on the requirements of matching a downstream flow. Two-layer flows can pass through internally critical conditions at other than the narrowest section. When the two layers are flowing in the same direction, the result is a strong coupling between the two layers in the neighbourhood of the control. For contractions a particularly simple flow then exists upstream in which there is no longer any significant interfacial dynamics; downstream in the divergent section the flow remains internally supercritical, causing one of the layers to be rapidly accelerated with a resulting instability at the interface. A brief discussion of internal hydraulic jumps based upon the energy equations as opposed to the more traditional momentum equations is included. Previous uniqueness problems are thereby avoided.

scholarly journals Characteristics of Oceanic Warm Cloud Layers within Multilevel Cloud Systems Derived by Satellite Measurements

Atmosphere ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 465 ◽  
Author(s):  
Yuhao Ding ◽  
Qi Liu ◽  
Ping Lao
Keyword(s):  
Double Layer ◽  
Lower Layer ◽  
Single Layer ◽  
Distribution Patterns ◽  
Radar Data ◽  
Multilayered Structures ◽  
Layer System ◽  
Cloud Systems ◽  
Warm Cloud ◽  
Double Layer System

Low-level warm clouds are a major component in multilayered cloud systems and they are generally hidden from the top-down view of satellites with passive measurements. This study conducts an investigation on oceanic warm clouds embedded in multilayered structures by using spaceborne radar data with fine vertical resolution. The occurrences of warm cloud overlapping and the geometric features of several kinds of warm cloud layers are examined. It is found that there are three main types of cloud systems that involve warm cloud layers, including warm single layer clouds, cold-warm double layer clouds, and warm-warm double layer clouds. The two types of double layer clouds account for 23% and in the double layer occurrences warm-warm double layer subsets contribute about 13%. The global distribution patterns of these three types differ from each other. Single-layer warm clouds and the lower warm clouds in the cold-warm double layer system they have nearly identical geometric parameters, while the upper and lower layer warm clouds in the warm-warm double layer system are distinct from the previous two forms of warm cloud layers. In contrast to the independence of the two cloud layers in cold-warm double layer system, the two kinds of warm cloud layers in the warm-warm double layer system may be coupled. The distance between the two layers in the warm-warm double layer system is weakly dependent on cloud thickness. Given the upper and lower cloud layer with moderate thickness of around 1 km, the cloudless gap reaches its maximum when exceeding 600 m. The cloudless gap decreases in thickness as the two cloud layers become even thinner or thicker.

scholarly journals Nonlinear subgrade reaction solution for circular tunnel lining design based on mobilized strength of undrained clay

2018 ◽  
Vol 55 (2) ◽  
pp. 155-170 ◽  
Author(s):  
Dong-ming Zhang ◽  
Kok-Kwang Phoon ◽  
Qun-fang Hu ◽  
Hong-wei Huang
Keyword(s):  
Design Method ◽  
Large Strain ◽  
Tunnel Lining ◽  
Subgrade Reaction ◽  
Circular Tunnel ◽  
Nonlinear Solution ◽  
Reaction Solution ◽  
Tunnel Convergence ◽  
Tunnel Lining Design ◽  
Internal Forces

This paper presents a nonlinear solution of a radial subgrade reaction–displacement (pk–ur) curve for circular tunnel lining design in undrained clay. With the concept of soil shear strength nonlinearly mobilized with shear strain, an analytical solution of pk is obtained using the mobilized strength design method. Two typical deformation modes are considered, namely oval and uniform. A total of 197 orthogonally designed cases are used to calibrate the proposed nonlinear solution of pk using the finite element method with the hardening soil model. The calibration results are summarized using a correction factor, η, which is defined as the ratio of pk_FEM to pk_MSD. It is shown that η is correlated to some input parameters. If this correlation is removed by a regression equation, f, the modified solution f(pk_MSD) agrees very well with pk_FEM. Although in reality the mobilized soil strength varies with principal stress direction, it is found that a simple average of plane strain compression and extension results is sufficient to produce the above agreement. The proposed nonlinear pk–ur curve is applied to an actual tunnel lining design example. The predicted tunnel deformations agree very well with the measured data. In contrast, a linear pk model would produce an underestimation of tunnel convergence and internal forces by 2–4 times due to the overestimation of pk at a large strain level.

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