Contact Stress State in Elastic Layers

2009 ◽  
Author(s):  
Sergiu Spinu ◽  
Emanuel Diaconescu
Keyword(s):  
Stress State ◽  
Quadratic Form ◽  
Elastic Layer ◽  
Numerical Approach ◽  
Pressure Distributions ◽  
Influence Coefficients ◽  
Discrete Counterpart ◽  
Layer Contact ◽  
Elastic Layers ◽  
Continuous Formulation

This paper presents the discrete counterpart of an existing continuous formulation for an elastic layer loaded symmetrically. The influence coefficients based numerical approach allows for computing contact stresses induced in the elastic layer by arbitrary shaped indenters. The newly developed code is validated against existing pressure distributions in layer contact for quadratic form punches.

Bounds on the Maximum Contact Stress of an Indented Elastic Layer

1971 ◽  
Vol 38 (3) ◽  
pp. 608-614 ◽  
Author(s):  
Y. C. Pao ◽  
Ting-Shu Wu ◽  
Y. P. Chiu
Keyword(s):  
Half Space ◽  
Contact Stress ◽  
Elastic Layer ◽  
Theory Of Elasticity ◽  
Contact Conditions ◽  
Practical Applications ◽  
Method Of Solution ◽  
Elastic Layers ◽  
Maximum Contact ◽  
Contact Stress Distribution

This paper is concerned with the plane-strain problem of an elastic layer supported on a half-space foundation and indented by a cylinder. A study is presented of the effect of the contact condition at the layer-foundation interface on the contact stresses of the indented layer. For the general problem of elastic indenter or elastic foundation, the integral equations governing the contact stress distribution of the indented layer derived on the basis of two-dimensional theory of elasticity are given and a numerical method of solution is formulated. The limiting contact conditions at the layer-foundation interface are then investigated by considering two extreme cases, one with the indented layer in frictionless contact with the half space and the other with the indented layer rigidly adhered to the half space. Graphs of the bounds on the maximum normal stress occurring in indented elastic layers for the cases of rigid cylindrical indenter and rigid half-space foundation are obtained for possible practical applications. Some results of the elastic indenter problem are also presented and discussed.

Residual strength of underground structures in service

2016 ◽  
Vol 53 (6) ◽  
pp. 988-999 ◽  
Author(s):  
Taous Kamel ◽  
Ali Limam ◽  
Claire Silvani
Keyword(s):  
Stress State ◽  
Residual Strength ◽  
Underground Structure ◽  
Numerical Approach ◽  
The Finite Element Method ◽  
Underground Structures ◽  
Weathering Processes ◽  
Working Face ◽  
Metro Tunnel ◽  
Loss Of Strength

Old tunnels suffer from deterioration and it is necessary to assess their residual strength to properly organize their repair and strengthen them. The stress state of underground structures evolves over time, firstly because of the advancement of the working face during construction, then due to gradual changes in soil properties and mechanical properties of materials composing the infrastructures, such as reduction of cohesion, loss of strength and (or) stiffness, etc. These changes are caused by combined actions such as creep and (or) weathering processes as well as the appearance of cracks that induce redistribution of stresses and therefore strains. This study investigates tunnels and galleries of the Paris underground. Macromodeling based on the finite element method allows consideration of different scenarios of tunnel-lining deterioration, specifically at the extrados of the galleries or tunnels. To understand changes in the stress state, and also damage occurrence and associated redistributions (stress and strain), it is necessary to model the delayed deformations. To model the infrastructure behavior, a time-dependency approach has been chosen. This approach can quantify the damage and predict the residual strength of this type of underground structure. An elastic–viscoplastic constitutive model with strain-softening is used to reproduce the appearance of the degraded zones and their behavior. The results obtained with the numerical approach reproduce Paris metro tunnel behavior, corroborate geoendoscopy results, clarify their interpretation, and improve the management of infrastructure repairs.

Adhesive Contacts for Graded-Elastic Coatings Using Fourier Series Decomposition

2011 ◽  
Author(s):  
S. J. Chidlow ◽  
W. W. F. Chong ◽  
M. Teodorescu ◽  
N. D. Vaughan
Keyword(s):  
Fourier Series ◽  
Analytic Solution ◽  
Adhesive Contact ◽  
Solution Technique ◽  
Control Case ◽  
Principal Stresses ◽  
Pressure Distributions ◽  
Surface Deflection ◽  
Elastic Layers ◽  
Adhesive Contacts

We propose a semi-analytic solution technique to determine the subsurface stresses and local deflections resulting in an adhesive contact of graded elastic layers. Identical pressure distributions, typical for a Maugis parameter λ = 1, were applied to a range of graded elastic coatings. The principal stresses and surface deflection in both regions (graded elastic layer and substrate) are computed in terms of Fourier series. This control case has the advantage that the response of different coatings can be easily monitored and compared.

scholarly journals Investigation of the influence of the railroad track on the stress state of the tunnel lining

2018 ◽  
Vol 239 ◽  
pp. 01020
Author(s):  
Mikhail Pleshko ◽  
Alexei Revyakin ◽  
Natalia Malishevskaya
Keyword(s):  
Stress State ◽  
Numerical Model ◽  
Stress Distribution ◽  
Elastic Layer ◽  
Tunnel Lining ◽  
Railway Track ◽  
Deformation Characteristics ◽  
Railroad Track ◽  
Circular Tunnel ◽  
Moving Vehicles

Tunnel lining takes significant loads from moving vehicles. The consequences of their impact depend on the design of the railway track and the deformation characteristics of its elements. For their study, a numerical model of a circular tunnel has been developed. As a result of the model calculation, the values of the main vertical stresses in the main tunnel structures were obtained. It is established that with increasing loads from the wheel to the rail from 100 to 200 kN, the voltage on average increases by 50%. The stress distribution is affected by the rigidity of the elastic layer. When it increases, the vertical stresses in the sub-rail support decrease nonlinearly, while in traveling concrete they increase nonlinearly.

Plane Contact of an Elastic Layer Supported by a Winkler Foundation

1990 ◽  
Vol 57 (4) ◽  
pp. 974-980 ◽  
Author(s):  
J. P. Dempsey ◽  
Z. G. Zhao ◽  
L. Minnetyan ◽  
H. Li
Keyword(s):  
Elastic Layer ◽  
Beam Theory ◽  
Contact Problems ◽  
Finite Depth ◽  
Winkler Foundation ◽  
Isotropic Layer ◽  
Line Load ◽  
Plane Contact ◽  
Pressure Distributions ◽  
Flexible Foundation

Plane contact problems of an elastic, homogeneous, and isotropic layer supported by a Winkler foundation are studied in this paper. The elastic layer has a finite depth and infinite in-plane dimensions. The upper surface of the layer is in plane contact with a rigid indenter. The particular applications studied in this paper are formulated by first providing the solution for a line load. For the case of a rigid cylinder, the upper portion of the load deflection response is modeled using beam theory with wrapping. The contact pressure distributions for the relatively flexible foundation cases can be accurately determined from the wrapping theory.

scholarly journals Numerical approach for estimation of stress strain state of deep tunnels

2019 ◽  
Vol 97 ◽  
pp. 04064
Author(s):  
Adilov Farkhadjan ◽  
Yuldoshev Bakhtiyor ◽  
Abirov Rustam ◽  
Miralimov Mirzakhid
Keyword(s):  
Stress State ◽  
Theoretical Calculation ◽  
Fractured Rocks ◽  
Strain State ◽  
Numerical Approach ◽  
Static Case ◽  
Stress Strain ◽  
Deep Excavations ◽  
Stress Strain State

Numerical approach and results of theoretical calculation of deep tunnels are described in this issue. Here described surrounding continuum is fractured rocks. Calculation provided in static case. Results of this investigation aimed for estimation of stress state and development of strengthening measures of deep excavations.

scholarly journals Contact problem of an elastic plug in an elastic region

1975 ◽  
Vol 19 (2) ◽  
pp. 229-241
Author(s):  
G. P. Steven
Keyword(s):  
Contact Problem ◽  
Contact Pressure ◽  
Finite Length ◽  
Three Dimensional ◽  
Elastic Region ◽  
Influence Coefficient ◽  
Shear Stresses ◽  
Pressure Distributions ◽  
Influence Coefficients ◽  
Strain Discontinuity

AbstractThe contact problem investigated in this paper may be more fully described as a three dimensional elastic body with a circular hole through it; inside this tunnel is press fitted a solid elastic plug of finite length. Shear stresses are taken to be absent along the contact interface.An influence coefficient technique is used to model the governing integral equation. For the elastic region the displacement influence coefficients due to bands of constant pressure are determined using a numerical quadrature on Fourier integrals. However, the plug, being of finite length, requires the superposition of two separate solutions to boundary value problems before the displacement influence coefficients can be determined.Contact pressure distributions are presented for a sample of parameter variations and also for a case where hydrostatic pressure is present in the tunnel in the elastic region. Despite both components being elastic the imposition of a constant interference displacement along the interface still gives rise to the characteristic singularity in contact pressure at the edges of contact due to the strain discontinuity at these points.

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