Numerical Solution of Prestressed Foundation - Subsoil Interaction Using FEM

2020 ◽  
Vol 832 ◽  
pp. 81-88 ◽  
Author(s):  
Radim Čajka ◽  
Jaroslav Navrátil
Keyword(s):  
Numerical Solution ◽  
Numerical Integration ◽  
Half Space ◽  
Structural Strength ◽  
Elastic Half Space ◽  
Isoparametric Element ◽  
Foundation Soil ◽  
Fem Model ◽  
Interaction Task ◽  
Internal Forces

This paper deals with prestressed foundation - soil interaction. For interaction task is used FEM model of thick slab with shear influence which is supported by structural strength modified elastic half-space. The calculation of deformations, internal forces and contact stresses in subsoil is performed iteratively by means of isoparametric element and numerical integration. The results of settlement and stress of non-prestressed/prestressed slab - subsoil interaction are compared on example.

Time Effects on Settlement of Rigid Pile Composite Foundation: Simplified Models

2018 ◽  
Vol 15 (07) ◽  
pp. 1850066 ◽  
Author(s):  
Meijuan Xu ◽  
Pengpeng Ni ◽  
Guoxiong Mei ◽  
Yanlin Zhao
Keyword(s):  
Numerical Integration ◽  
Half Space ◽  
Unsaturated Soils ◽  
Pressure Coefficient ◽  
Closed Form Solution ◽  
Elastic Half Space ◽  
Composite Foundation ◽  
Model Parameters ◽  
Time Effects ◽  
Rigid Pile

The behavior of pile composite foundation is studied using the flexibility method. During the analysis, determination of the flexibility matrix (settlement) is critical. However, conventional methods of Winkler and elastic half-space foundation models are incapable of considering the time effects of soil consolidation and creep. The foundation model of Zaretsky and Tsytovich [1965] can be used to evaluate settlement for unsaturated soils, but the complexity of numerical integration over an arbitrary loading area hinders its application. In this paper, a novel scheme is proposed for numerical integration by rotating the loading surface using the equiareal transformation technique. Therefore, a simplified closed-form solution is developed to calculate time dependent settlement for foundation soils. The efficacy of the proposed technique is demonstrated using illustrative examples of an elastic half-space, a rigid raft foundation without piles, and rigid pile composite foundations with multiple piles under surface loading. Furthermore, parametric study is conducted to evaluate the sensitivity of model parameters. The permeability [Formula: see text] and Poisson’s ratio [Formula: see text] are found to be important, whereas pore pressure coefficient [Formula: see text] and degree of saturation [Formula: see text] are less significant in the calculation.

THREE-DIMENSIONAL SURFACE CRACK ANALYSIS OF ELASTIC HALF-SPACE UNDER ROLLING CONTACT LOAD

2009 ◽  
Vol 06 (02) ◽  
pp. 317-332 ◽  
Author(s):  
MENG-CHENG CHEN ◽  
HUI-QIN YU
Keyword(s):  
Numerical Solution ◽  
Integral Equations ◽  
Half Space ◽  
Three Dimensional ◽  
Elastic Half Space ◽  
Rolling Contact ◽  
Contact Load ◽  
Hypersingular Integral ◽  
Space Body ◽  
Planar Crack

In this work a three-dimensional planar crack on the surface of elastic half-space was analyzed under rolling contact load. The stresses interior to an elastic half-space body under rolling contact load and those produced by an infinitesimal displacement jump loop for the elastic half-space body were used to reduce the planar crack problem to the solution of a system of two-dimensional hypersingular integral equations with unknown displacement jump. The ideas of finite element discretization were employed to construct numerical solution schemes for solving the integral equations. An appropriate treatment of the associated hypersingular integral in the numerical solution to the integral equations was proposed in Hadamard's finite-part integral sense. The numerical results showed that the present procedure yields solutions with high accuracies. The stress intensity factors near the crack front edge under rolling contact load were indicated in graphical form with varying the crack shape, the radius of rolling contact zone and the friction coefficients, respectively. In addition, the influence of the lubricant infiltrating the crack surfaces on the crack propagation was also discussed in the paper.

scholarly journals The use of modelling of impacts exerted by means of transport on the environment for ensuring safety

2018 ◽  
Vol 188 (2) ◽  
pp. 162-175
Author(s):  
Joanna Bril ◽  
Edward Rydygier
Keyword(s):  
Rigid Body ◽  
Half Space ◽  
Dynamic Properties ◽  
Elastic Half Space ◽  
Transport Systems ◽  
Concentrated Force ◽  
Foundation Soil ◽  
Infinite Mass ◽  
Model Research ◽  
Surface Rayleigh Wave

The article presents the model research on impacts exerted by means of transport on the structures. In modelling the dynamics of transport systems the dynamic properties of the ground forming the foundation soil for tracks or roadways have been taken into account. The ground has been modelled as an elastic half-space. The dynamics of an infinite mass band being in contact with an elastic half-space has been investigated. As part of the research on impacts exerted by means of transport on structures a model of a problem has been examined where an automotive vehicle, representing a concentrated force in motion, is in contact with a roadway described as a rigid body coupled with an elastic half-space. It has been demonstrated that a surface (Rayleigh) wave propagates in the ground, being a continuous (elastic) medium, and acts on a structure modelled as a rigid body. The research results have been presented in the form of vertical and horizontal transmittances of the ground for different frequencies of loading with different unit forces.

Accuracy of Stress Analysis Using Numerical Integration of Elastic Half-Space

2013 ◽  
Vol 300-301 ◽  
pp. 1127-1135 ◽  
Author(s):  
Radim Čajka
Keyword(s):  
Finite Element ◽  
Stress Analysis ◽  
Numerical Integration ◽  
Half Space ◽  
Elastic Half Space ◽  
Rigidity Matrix ◽  
Interaction Solutions ◽  
Proposed Model ◽  
Isoparametric Elements

In case of constructions placed on subsoil, it is necessary to create a rigidity matrix for the element subsoil. That rigidity matrix should be then added up in respective positions with the rigidity matrix of an element. To clarify the proposed model of the subsoil, a method is derived for determination of vertical subsoil stress analysis under any shape of a slab construction by means of numerical integration and theory of isoparametric elements using the Jacobian transformation. This approach is rather original and represents the key contribution of this work in interaction solutions. Using the proposed approach, the method can be employed for any shape of a finite element.

Study on overflow problem of numerical integration for layered elastic half-space systems

2017 ◽  
Vol 19 (6) ◽  
pp. 1476-1488
Author(s):  
Yuan Pang ◽  
Peiwen Hao ◽  
Chuanchao Zheng ◽  
Haiwei Zhang ◽  
Lei Bu ◽  
...  
Keyword(s):  
Numerical Integration ◽  
Half Space ◽  
Elastic Half Space ◽  
Space Systems

The Singularity at the Apex of a Bonded Wedge-Shaped Stamp

1979 ◽  
Vol 46 (3) ◽  
pp. 577-580 ◽  
Author(s):  
K. S. Parihar ◽  
L. M. Keer
Keyword(s):  
Eigenvalue Problem ◽  
Numerical Solution ◽  
Integral Equations ◽  
Half Space ◽  
Singular Integral ◽  
Green's Functions ◽  
Green’S Functions ◽  
Singular Integral Equations ◽  
Elastic Half Space

The problem of determining the singularity at the apex of a rigid wedge bonded to an elastic half space is formulated by considerations of Green’s functions for the loaded half space. The eigenvalue problem is reduced to finding the solution of a coupled pair of singular integral equations. A numerical solution for small wedge angles is given.

Torsion of a Rigid Cylinder Embedded in an Elastic Half Space

1976 ◽  
Vol 43 (3) ◽  
pp. 419-423 ◽  
Author(s):  
J. E. Luco
Keyword(s):  
Numerical Solution ◽  
Integral Equations ◽  
Half Space ◽  
Elastic Constants ◽  
Elastic Half Space ◽  
Integral Representations ◽  
Axially Symmetric ◽  
Stress Singularities ◽  
Rigid Cylinder ◽  
Perfect Bonding

A study is made of the axially symmetric torsion of a rigid cylinder partially embedded into a layered elastic half space. The problem is formulated on the basis of perfect bonding between the cylinder and the surrounding material. Integral representations are used to reduce the problem to the solution of two integral equations. Stress singularities of fractional order are obtained along the perimeter of the base of the cylinder. A numerical solution of the integral equations is used to obtain the torque-twist relationship for different embedment depths and for different values of the elastic constants.

Unbalanced Response of a Large Rotor-Pedestal-Foundation System Using an Elastic Half-Space Soil Model

1980 ◽  
Vol 102 (2) ◽  
pp. 311-319 ◽  
Author(s):  
R. L. Ruhl ◽  
T. F. Conry ◽  
R. L. Steger
Keyword(s):  
Half Space ◽  
Test Data ◽  
Equations Of Motion ◽  
Element Model ◽  
Elastic Half Space ◽  
Support Structure ◽  
Foundation Soil ◽  
Soil Model ◽  
Applied Forces ◽  
Large Rotor

The unbalanced response of a large rotor-pedestal-foundation system using an elastic half space soil model was determined. The effective stiffness and damping terms between the foundation and soil were determined from the elastic half space soil model. The rigid body equations of motion of the foundation were derived subject to applied forces from the bearing-support structure and from the springs and dashpots representing the soil. An impedance matrix representing the relationship between the bearing-support structure forces and the corresponding displacements was then derived and matched with the finite element model of the turborotor system. The analytical results of this investigation were compared with test data from a recirculating gas fan at a power plant installation. There was very good agreement between the analysis and the test data. This is the first time a realistic coupling of rotor models and foundation-soil models has been accomplished. This method of analysis should be the basis for the design of rotor-bearing-foundation-soil systems.

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