Application of shotcrete constitutive model to the time dependent behavior of TBM tunnel lining

2018 ◽  
Vol 7 (3) ◽  
pp. 1826
Author(s):  
Heyam H. Shaalan ◽  
Mohd Ashraf Mohamad Ismail ◽  
Romziah Azit
Keyword(s):  
Constitutive Model ◽  
Steel Fibre ◽  
Tunnel Lining ◽  
Time Dependent ◽  
Elastic Behaviour ◽  
Elastic Analysis ◽  
Time Dependent Behaviour ◽  
Shotcrete Lining ◽  
Creep And Shrinkage ◽  
Dependent Behaviour

Shotcrete is ordinary concrete applied to the surface under high pressure. It demonstrates a highly time-dependent behaviour after few hours of application. Traditional approaches assume a simple linear elastic behaviour using a hypothetical young modulus to investigate the time-dependency and creep effects. In this paper, a new constitutive model of shotcrete is applied to evaluate the time-dependent behaviour of a TBM tunnel lining and investigate the parameters that can influence this behaviour. The Shotcrete model is based on the framework of Elasto-plasticity and designed to model shotcrete linings more realistically. The basic data of Pahang-Selangor Raw Water Transfer Project is used for the analysis study. An attempt is made to investigate the influence of some input parameters of the shotcrete model on the time-dependent behaviour of the shotcrete lining. These parameters include the time-dependent stiffness/strength parameters, creep and shrinkage parameters and steel fibre parameters. The variation in shotcrete strength classes causes a noticeable influence on the development of shotcrete compressive strength with time, particularly during the first days of application. The creep and shrinkage strain cause a considerable reduction in the development of the shotcrete stress with time. The impact of steel fibre content is determined, and the result indicated that the development of plain shotcrete stresses with time is lower than that of the reinforced shotcrete. In addition, a comparison study is performed to analyse the tunnel lining behaviour using both shotcrete model and an elastic analysis. Significant differences in shotcrete lining stresses are achieved when using the elastic analysis while the shotcrete model results in a reasonable result that can be used for the design requirements. 

scholarly journals Numerical Analysis of TBM Tunnel Lining Behavior using Shotcrete Constitutive Model

2018 ◽  
Vol 4 (5) ◽  
pp. 1046
Author(s):  
Heyam H. Shaalan ◽  
Romziah Azit ◽  
Mohd Ashraf Mohamad Ismail
Keyword(s):  
Constitutive Model ◽  
Tunnel Lining ◽  
Time Dependent ◽  
Elastic Behaviour ◽  
Structural Behaviour ◽  
Tunnel Diameter ◽  
Time Dependent Behaviour ◽  
Shotcrete Lining ◽  
Tunnel Depth ◽  
Dependent Behaviour

Shotcrete is a fundamental support element for tunnels and underground constructions. Shortly after application, shotcrete linings undergo a high load while the ordinary concrete is not fully hardened yet. Therefore, the time-dependent behaviour of the shotcrete material must consider. Traditional approaches assume a linear elastic behaviour using a hypothetical young modulus to model this time-dependency and creep effects. In this paper, a new constitutive model of shotcrete is applied to evaluate the time-dependent behaviour of TBM tunnel lining under high in-situ stress state. The Shotcrete model is based on the framework of Elasto-plasticity and designed to account for non-linear and time-dependent behaviour for concrete material more realistically. A parametric study of the time-dependent behaviour of the shotcrete lining, using the shotcrete model, is performed. To achieve this, the influence of the lining thickness, tunnel diameter and tunnel depth on the development of the stresses and displacement of the shotcrete lining with time is investigated. The results showed that the development of the lining tensile stress with time at tunnel crown increases by increasing the lining thickness and tunnel depth, whereas it decreases by increasing of the tunnel diameter. At the tunnel sidewall, the lining compression stress with time increases with the increase of the tunnel depth and diameter, while higher lining thickness decreases the lining compressive stresses. However, the results showed the ability of the shotcrete model to simulate the structural behaviour of the shotcrete lining with time.

Time-dependent behaviour of concrete

2021 ◽  
pp. 13-40
Author(s):  
Gianluca Ranzi ◽  
Giovanni Di Luzio ◽  
Massimiliano Bocciarelli ◽  
Graziano Leoni ◽  
Ahmet Abdullah Dönmez ◽  
...  
Keyword(s):  
Composite Structures ◽  
Constitutive Models ◽  
Design Guidelines ◽  
Effective Modulus ◽  
Time Dependent ◽  
Algebraic Methods ◽  
Modulus Method ◽  
Time Dependent Behaviour ◽  
Creep And Shrinkage ◽  
Dependent Behaviour

<p>This chapter provides an introduction to the constitutive models commonly specified in design guidelines to describe the time-dependent behaviour of concrete and that can be used for the time-dependent analysis of composite structures. These formulations range from the simplest algebraic methods, such as the Effective Modulus Method that is widely recommended in design guidelines, to more sophisticated approaches that can account for creep and shrinkage effects in advanced modelling. The last part of the chapter provides a brief overview of multi-physics modelling that could be useful in predicting the concrete time-dependent response for composite construction.</p>

Introduction

2021 ◽  
pp. 1-12
Author(s):  
Gianluca Ranzi ◽  
Raymond Ian Gilbert ◽  
Graziano Leoni ◽  
Luigino Dezi ◽  
Alejandro Pérez Caldentey ◽  
...  
Keyword(s):  
Composite Structures ◽  
Constitutive Models ◽  
Design Guidelines ◽  
Effective Modulus ◽  
Time Dependent ◽  
Algebraic Methods ◽  
Modulus Method ◽  
Time Dependent Behaviour ◽  
Creep And Shrinkage ◽  
Dependent Behaviour

<p>This chapter provides an introduction to the constitutive models commonly specified in design guidelines to describe the time-dependent behaviour of concrete and that can be used for the time-dependent analysis of composite structures. These formulations range from the simplest algebraic methods, such as the Effective Modulus Method that is widely recommended in design guidelines, to more sophisticated approaches that can account for creep and shrinkage effects in advanced modelling. The last part of the chapter provides a brief overview of multi-physics modelling that could be useful in predicting the concrete time-dependent response for composite construction.</p>

A non-affine electro-viscoelastic microsphere model for dielectric elastomers: Application to VHB 4910 based actuators

2016 ◽  
Vol 28 (5) ◽  
pp. 627-639 ◽  
Author(s):  
Sara Thylander ◽  
Andreas Menzel ◽  
Matti Ristinmaa
Keyword(s):  
Constitutive Model ◽  
Viscoelastic Properties ◽  
Mechanical Energy ◽  
Electric Energy ◽  
Time Dependent ◽  
Dielectric Elastomers ◽  
Element Analysis ◽  
Time Dependent Behaviour ◽  
Macroscopic Continuum ◽  
Dependent Behaviour

Dielectric elastomers belong to a larger group of materials, the so-called electroactive polymers, which have the capability of transforming electric energy to mechanical energy through deformation. VHB 4910 is one of the most popular materials for applications of dielectric elastomers and therefore one of the most investigated. This paper includes a new micromechanically motivated constitutive model for dielectric elastomers that incorporates the nearly incompressible and viscous time-dependent behaviour often found in this type of material. A non-affine microsphere framework is used to transform the microscopic constitutive model to a macroscopic continuum counterpart. Furthermore the model is calibrated, through both homogeneous deformation examples and more complex finite element analysis, to VHB 4910. The model is able to capture both the purely elastic, the viscoelastic and the electro-viscoelastic properties of the elastomer and demonstrates the power and applicability of the electromechanically coupled microsphere framework.

Time-dependent behaviour of structural concrete made with recycled coarse aggregates. Creep and shrinkage

2016 ◽  
Vol 122 ◽  
pp. 95-109 ◽  
Author(s):  
Sindy Seara-Paz ◽  
Belén González-Fonteboa ◽  
Fernando Martínez-Abella ◽  
Iris González-Taboada
Keyword(s):  
Time Dependent ◽  
Structural Concrete ◽  
Coarse Aggregates ◽  
Time Dependent Behaviour ◽  
Creep And Shrinkage ◽  
Dependent Behaviour

scholarly journals Time-dependent Behaviour Analysis of Long-span Concrete Arch Bridge

2019 ◽  
Vol 14 (2) ◽  
pp. 227-248
Author(s):  
Yongbao Wang ◽  
Renda Zhao ◽  
Yi Jia ◽  
Ping Liao
Keyword(s):  
Concrete Structures ◽  
Time Dependent ◽  
Mean Deviation ◽  
Concrete Creep ◽  
Arch Bridge ◽  
Model Code ◽  
Time Dependent Behaviour ◽  
Creep And Shrinkage ◽  
Dependent Behaviour

This paper continues the previous study on clarifying the time-dependent behaviour of Beipanjiang Bridge ‒ a reinforced concrete arch bridge with concrete-filled steel tubular stiffened skeleton. The obtained prediction models and the Finite Element Models were used to simulate the long-term behaviour and stress redistribution of the concrete arch bridge. Three-dimensional beam elements simulated the stiffened skeleton and surrounding concrete. Then, a parameters study was carried out to analyse the time-dependent behaviour of the arch bridge influenced by different concrete creep and shrinkage models. The simulation results demonstrate that concrete creep and shrinkage have a significant influence on the time-dependent behaviour of the concrete arch bridge. After the bridge completion, the Comite Euro-International du Beton mean deviation of displacements obtained by 1990 CEBFIP Model Code: Design Code model and fib Model Code for Concrete Structures 2010 model are 3.4%, 31.9% larger than the results predicted by the modified fib Model Code for Concrete Structures 2010 model. The stresses between the steel and the concrete redistribute with time because of the concrete long-term effect. The steel will yield if the fib Model Code for Concrete Structures 2010 model is used in the analysis. The stresses in a different part of the surrounding concrete are non-uniformly distributed.

scholarly journals Application of micro-computer tomography and inverse finite element analysis for characterizing the visco-hyperelastic response of bulk liver tissue using indentation

2021 ◽  
Vol 3 (5) ◽  
Author(s):  
Rajeswara R. Resapu ◽  
Roger D. Bradshaw
Keyword(s):  
Finite Element ◽  
Liver Tissue ◽  
Loading Rate ◽  
Time Dependent ◽  
Nonlinear Material ◽  
Computational Time ◽  
List Type ◽  
Prony Series ◽  
Time Dependent Behaviour ◽  
Dependent Behaviour

Abstract In-vitro mechanical indentation experimentation is performed on bulk liver tissue of lamb to characterize its nonlinear material behaviour. The material response is characterized by a visco-hyperelastic material model by the use of 2-dimensional inverse finite element (FE) analysis. The time-dependent behaviour is characterized by the viscoelastic model represented by a 4-parameter Prony series, whereas the large deformations are modelled using the hyperelastic Neo-Hookean model. The shear response described by the initial and final shear moduli and the corresponding Prony series parameters are optimized using ANSYS with the Root Mean Square (RMS) error being the objective function. Optimized material properties are validated using experimental results obtained under different loading histories. To study the efficacy of a 2D model, a three dimensional (3D) model of the specimen is developed using Micro-CT of the specimen. The initial elastic modulus of the lamb liver obtained was found to 13.5 kPa for 5% indentation depth at a loading rate of 1 mm/sec for 1-cycle. These properties are able to predict the response at 8.33% depth and a loading rate of 5 mm/sec at multiple cycles with reasonable accuracy. Article highlights The visco-hyperelastic model accurately models the large displacement as well as the time-dependent behaviour of the bulk liver tissue. Mapped meshing of the 3D FE model saves computational time and captures localized displacement in an accurate manner. The 2D axisymmetric model while predicting the force response of the bulk tissue, cannot predict the localized deformations.

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