scholarly journals Energy-Based Approach for the Analysis of a Vertically Loaded Pile in Multi-layered Non-linear Soil Strata

Author(s):  
Prakash Ankitha Arvan ◽  
Madasamy Arockiasamy

Abstract Numerous studies have been reported in published literature on analytical solutions for a vertically loaded pile installed in a homogeneous single soil layer. However, piles are rarely installed in an ideal homogeneous single soil layer. This study presents an energy-based approach to obtain displacements in an axially loaded pile embedded in multi-layered soil considering soil non-linearity. A simple power law based on published literature is used where the soil is assumed to be nonlinear-elastic and perfectly plastic. A Tresca yield surface is assumed to develop the soil stiffness variation with different strain levels that defines the non-linearity of the soil strata. The pile displacement response is obtained using the software MATLAB R2019a and the results from the energy-based method are compared with those obtained from the field test data as well as the finite element analysis based on the software ANSYS 2019R3. It is observed that the results obtained from the energy-based method are in better agreement with the field measured values than those obtained from the FEA. The approach presented in this study can be extended to piles embedded in multi-layered soil strata subjected to different cases of lateral loads as well as the combined action of lateral and axial loads. Furthermore, the same approach can be extended to study the response of the soil to group piles.

2020 ◽  
Vol 205 ◽  
pp. 05019
Author(s):  
Arash Saeidi Rashk Olia ◽  
Dunja Perić

Predictions of responses of a single energy pile to a combined mechanical and thermal loading are presented. They were obtained from computational and analytical models. The former model provided predictions based on a coupled thermal hydro-mechanical finite element analysis while the predictions of the latter were obtained from the recently derived analytical solutions. The energy pile is surrounded by a single uniform soil layer underlain by a very stiff bedrock. Two scenarios of temperature history were considered. In the first scenario the pile remained in a net heated state while the second one induced a net cooled state. In both loading scenarios a compressive axial load was applied at the pile head prior to the thermal loading. The net heating induced an upward axial displacement, tensile strain and compressive stress while the net cooling induced a downward vertical pile displacement, compressive strain and tensile stress. In spite of different methods of obtaining the soil stiffness for computational and analytical models the predictions of the axial pile displacement, stress and strain show a very good agreement.


2017 ◽  
Vol 45 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Alexey Mazin ◽  
Alexander Kapustin ◽  
Mikhail Soloviev ◽  
Alexander Karanets

ABSTRACT Numerical simulation based on finite element analysis is now widely used during the design optimization of tires, thereby drastically reducing the time investment in the design process and improving tire performance because it is obtained from the optimized solution. Rubber material models that are used in numerical calculations of stress–strain distributions are nonlinear and may include several parameters. The relations of these parameters with rubber formulations are usually unknown, so the designer has no information on whether the optimal set of parameters is reachable by the rubber technological possibilities. The aim of this work was to develop such relations. The most common approach to derive the equation of the state of rubber is based on the expansion of the strain energy in a series of invariants of the strain tensor. Here, we show that this approach has several drawbacks, one of which is problems that arise when trying to build on its basis the quantitative relations between the rubber composition and its properties. An alternative is to use a series expansion in orthogonal functions, thereby ensuring the linear independence of the coefficients of elasticity in evaluation of the experimental data and the possibility of constructing continuous maps of “the composition to the property.” In the case of orthogonal Legendre polynomials, the technique for constructing such maps is considered, and a set of empirical functions is proposed to adequately describe the dependence of the parameters of nonlinear elastic properties of general-purpose rubbers on the content of the main ingredients. The calculated sets of parameters were used in numerical tire simulations including static loading, footprint analysis, braking/acceleration, and cornering and also in design optimization procedures.


2020 ◽  
Vol 57 (3) ◽  
pp. 448-452 ◽  
Author(s):  
A.S. Lees ◽  
J. Clausen

Conventional methods of characterizing the mechanical properties of soil and geogrid separately are not suited to multi-axial stabilizing geogrid that depends critically on the interaction between soil particles and geogrid. This has been overcome by testing the soil and geogrid product together as one composite material in large specimen triaxial compression tests and fitting a nonlinear failure envelope to the peak failure states. As such, the performance of stabilizing, multi-axial geogrid can be characterized in a measurable way. The failure envelope was adopted in a linear elastic – perfectly plastic constitutive model and implemented into finite element analysis, incorporating a linear variation of enhanced strength with distance from the geogrid plane. This was shown to produce reasonably accurate simulations of triaxial compression tests of both stabilized and nonstabilized specimens at all the confining stresses tested with one set of input parameters for the failure envelope and its variation with distance from the geogrid plane.


1991 ◽  
Vol 113 (1) ◽  
pp. 93-101 ◽  
Author(s):  
S. M. Kulkarni ◽  
C. A. Rubin ◽  
G. T. Hahn

The present paper, describes a transient translating elasto-plastic thermo-mechanical finite element model to study 2-D frictional rolling contact. Frictional two-dimensional contact is simulated by repeatedly translating a non-uniform thermo-mechanical distribution across the surface of an elasto-plastic half space. The half space is represented by a two dimensional finite element mesh with appropriate boundaries. Calculations are for an elastic-perfectly plastic material and the selected thermo-physical properties are assumed to be temperature independent. The paper presents temperature variations, stress and plastic strain distributions and deformations. Residual tensile stresses are observed. The magnitude and depth of these stresses depends on 1) the temperature gradients and 2) the magnitudes of the normal and tangential tractions.


2013 ◽  
Vol 831 ◽  
pp. 137-140
Author(s):  
Kang Min Lee ◽  
Liu Yi Chen ◽  
Rui Li ◽  
Keun Yeong Oh ◽  
Young Soo Chun

Coupling beams resist lateral loads efficiently is well known in coupled wall systems. In many cases, geometric limits result in coupling beams that are deep in relation to their clear span. Coupling beams with small depth-to-span ratio shall be reinforced with two intersecting groups of diagonally placed bars symmetrical along the mid-span. It's always hard to optimize construction projects. This paper used the finite element software (Abaqus) to analysis and simulate the nonlinear behavior of a new reinforcement called head bar and compared the results to the current standards.


The composite structural element under study is a carbon fiber wrapped, steel I section reinforced concrete column. The wrapped CFRP is under tension and reinforced concrete under radial compression. The aim of the research is to determine the behavior of the composite structural element under axial loads. The Stress-strain characteristics and load bearing capacity of control and CFRP wrapped tubular columns were determined experimentally. Further, Finite element analysis of steel, reinforced concrete and CFRP wrapped concrete columns sections, was conducted using ANSYS Workbench 15.0 software. The experimental and analytical results were compared.


2014 ◽  
Vol 891-892 ◽  
pp. 17-23 ◽  
Author(s):  
Sudip Basack

The ocean environment necessitates the pile foundation supporting the offshore structures to be designed against cyclic load, moments and torques initiated by a combined action of waves, wind, tides, currents, etc. Such a complex loading condition induces progressive degradation in the pile-soil interactive performance introducing significant reduction in bearing capacity with increased settlement and displacements. The Author has carried out extensive experimental (laboratory model tests) and theoretical investigations (boundary element analysis) to study the salient features of this degradation and developed a design methodology for offshore pile foundation. The works conducted and the major conclusions drawn are highlighted in this paper.


2000 ◽  
Author(s):  
Bhavani V. Sankar ◽  
Manickam Narayanan ◽  
Abhinav Sharma

Abstract Nonlinear finite element analysis was used to simulate compression tests on sandwich composites containing debonded face sheets. The core was modeled as an elastic-perfectly-plastic material, and the face-sheet as elastic isotropic. The effects of core plasticity, face-sheet and core thickness, and debond length on the maximum load the beam can carry were studied. The results indicate that the core plasticity is an important factor that determines the maximum load.


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