Pseudo Elastic Analysis of Carbon Reinforced Natural/Styrene-Butadiene Blend Rubber (NSBR) with Ogden Constitutive Model

2018 ◽  
Vol 928 ◽  
pp. 20-25 ◽  
Author(s):  
Li Hong Huang ◽  
Xiao Xiang Yang ◽  
Jian Hong Gao
Keyword(s):  
Constitutive Model ◽  
Experimental Results ◽  
Mullins Effect ◽  
Elastic Analysis ◽  
Stress Softening ◽  
Styrene Butadiene

In this paper, experimental results that illustrate stress softening in carbon filled natural/styrene-butadiene blend rubber (NSBR) together with Mullins effect are introduced firstly. Then, based on these data, the Ogden constitutive model is derived. The theory of pseudo-elasticity is used in the model. It is found that theory of pseudo-elasticity and Ogden constitutive model is applicable in this composite.

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. 

A finite-deformation constitutive model of particle-binder composites incorporating yield-surface-free plasticity

2021 ◽  
pp. 1-32
Author(s):  
Ankit Agarwal ◽  
Marcial Gonzalez
Keyword(s):  
Constitutive Model ◽  
Yield Surface ◽  
Finite Deformation ◽  
Large Strain ◽  
Elastic Response ◽  
Rate Equations ◽  
Internal Variables ◽  
Model Parameters ◽  
Stress Strain ◽  
Stress Softening

Abstract We present a constitutive model for particle-binder composites that accounts for finite-deformation kinematics, nonlinear elasto-plasticity without apparent yield, cyclic hysteresis, and progressive stress-softening before the attainment of stable cyclic response. The model is based on deformation mechanisms experimentally observed during quasi-static monotonic and cyclic compression of mock Plastic-Bonded Explosives (PBX) at large strain. An additive decomposition of strain energy into elastic and inelastic parts is assumed, where the elastic response is modeled using Ogden hyperelasticity while the inelastic response is described using yield-surface-free endochronic plasticity based on the concepts of internal variables and of evolution or rate equations. Stress-softening is modeled using two approaches; a discontinuous isotropic damage model to appropriately describe the softening in the overall loading-unloading response, and a material scale function to describe the progressive cyclic softening until cyclic stabilization. A nonlinear multivariate optimization procedure is developed to estimate the elasto-plastic model parameters from nominal stress-strain experimental compression data. Finally, a correlation between model parameters and the unique stress-strain response of mock PBX specimens with differing concentrations of aluminum is identified, thus establishing a relationship between model parameters and material composition.

scholarly journals Experimental results and constitutive model of the mechanical behavior of Ti6Al4V alloy at high temperature

2019 ◽  
Vol 41 ◽  
pp. 723-730
Author(s):  
Jorge Ayllón Perez ◽  
Valentín Miguel Eguía ◽  
Juana Coello Sobrino ◽  
Alberto Martínez Martínez
Keyword(s):  
High Temperature ◽  
Constitutive Model ◽  
Mechanical Behavior ◽  
Ti6al4v Alloy ◽  
Experimental Results

scholarly journals Stress-Softening in Particle-Filled Polyurethanes under Cyclic Compressive Loading

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1588
Author(s):  
Wenshuai Xu ◽  
Mangong Zhang ◽  
Yu Liu ◽  
Hao Zhang ◽  
Meng Chen ◽  
...  
Keyword(s):  
Compressive Loading ◽  
Compressive Load ◽  
Soft Materials ◽  
Constitutive Parameter ◽  
Spherical Indentation ◽  
Mullins Effect ◽  
Stress Softening ◽  
Loading And Unloading ◽  
Load Displacement ◽  
Constitutive Parameters

Elastomer compositions containing various particulate fillers can be formulated according to the specific functions required of them. Stress softening—which is also known as the Mullins effect—occurs during high loading and unloading paths in certain supramolecular elastomer materials. Previous experiments have revealed that the load–displacement response differs according to the filler used, demonstrating an unusual model of correspondence between the constitutive materials. Using a spherical indentation method and numerical simulation, we investigated the Mullins effect on polyurethane (PU) compositions subjected to cyclic uniaxial compressive load. The PU compositions comprised rigid particulate fillers (i.e., nano-silica and carbon black). The neo-Hooke model and the Ogden–Roxburgh Mullins model were used to describe the nonlinear deformation behavior of the soft materials. Based on finite element methods and parameter optimization, the load–displacement curves of various filled PUs were analyzed and fitted, enabling constitutive parameter prediction and inverse modeling. Hence, correspondence relationships between material components and constitutive parameters were established. Such relationships are instructive for the preparation of materials with specific properties. The method described herein is a more quantitative approach to the formulation of elastomer compositions comprising particulate fillers.

Plastic Flow Stress and Constitutive Model for H96 Brass Alloy

2015 ◽  
Vol 782 ◽  
pp. 130-136 ◽  
Author(s):  
Ping Zhou ◽  
Wei Guo Guo ◽  
Hai Hui Wu
Keyword(s):  
Flow Stress ◽  
Constitutive Model ◽  
Plastic Flow ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Experimental Results ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Brass Alloy ◽  
Plastic Flow Stress

To explore the thermo-mechanical response of H96 brass alloy, the quasi-static (universal-testing machine) and dynamic (the split Hopkinson pressure bar apparatus) uniaxial compression experiments have been performed under the temperatures from 293 K to 873 K and the strain rates from 0.001 s-1 to 6000 s-1, and the strains over 60% are obtained. Results show that, H96 brass alloy has strong strain hardening behavior, and it becomes weaker with the increasing temperature. In addition, this alloy is sensitive to strain rates; and, it has temperature sensitivity, the dynamic strain aging occurs at the temperature of 473 K and a quasi-static strain rate of 0.001 s-1. Based on the thermal activation dislocation mechanism, paralleled with the experimental results, a plastic flow constitutive model with the physical conception is developed. The model is suitable to predict the plastic flow stress at different temperatures and strain rates. According to comparing results, the model predictions are in good agreement with the experimental results.

Stress softening experiments in silica-filled polydimethylsiloxane provide insight into a mechanism for the Mullins effect

Polymer ◽  
2005 ◽  
Vol 46 (24) ◽  
pp. 10989-10995 ◽  
Author(s):  
David E. Hanson ◽  
Marilyn Hawley ◽  
Robert Houlton ◽  
Kiran Chitanvis ◽  
Philip Rae ◽  
...  
Keyword(s):  
Mullins Effect ◽  
Stress Softening ◽  
Insight Into

scholarly journals Behavior of wood beam connection using staples subjected to in-plane moment

2019 ◽  
Vol 258 ◽  
pp. 05008
Author(s):  
Farida Lenggani ◽  
Bambang Suryoatmono
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Solid Wood ◽  
Experimental Results ◽  
Elastic Analysis ◽  
Connection Strength ◽  
Test Results ◽  
Lateral Resistance ◽  
Wood Beams ◽  
Mechanical Fasteners

It is very frequent that solid wood beams need to be connected one to another to obtain a longer beam. In this study, the behavior of solid wood beams connections using plywood sheets as connecting elements and staples as mechanical fasteners were studied experimentally. The experimental results were compared with elastic analyses. Both beam and plywood were made of meranti (shorea). The staple type was MAX 1022J. This study was conducted on two specimens. The first specimen had two rows of staples on the front and back sides of the specimen. Each row consisted of ten staples making a total of 40 staples. The second one had three rows of staples on the front and back sides of the specimen. Each row consisted of ten staples making a total of 60 staples. From the tests, it can be concluded that each material in the connection, namely wood beam, plywood, and staples, failed. Failure mode of the wood beam was in the form of crack and tear. Failure mode of the plywood was the damage of the plywood directly contacted with the crown of the staples. Failure modes of the staples were flexural yielding. The differences between connection strength obtained from tests and elastic analyses were 8.18% for the first specimen and 0.65% for the second specimen, with the test results were higher than the elastic analyses results. It can be concluded that elastic analysis is quite accurate and conservative to estimate the strength of this type of connection, provided that the lateral resistance of connection with a staple is known.

Numerical Modeling and Analysis of Nonlinear Dynamic Response for a Bolted Joint Beam Considering Interface Frictional Contact

2018 ◽  
Author(s):  
Dongwu Li ◽  
Chao Xu ◽  
Dong Wang ◽  
Lihua Wen
Keyword(s):  
Constitutive Model ◽  
Dynamic Response ◽  
Numerical Results ◽  
Experimental Results ◽  
Bolted Joints ◽  
Interface Element ◽  
Nonlinear Stiffness ◽  
Friction Contact ◽  
Structural Dynamic ◽  
Stiffness And Damping

For an assembled structure with many bolted joints, predicting its dynamic response with high fidelity is always a difficult problem, because of the nonlinearity introduced by friction contact between jointed interfaces. The friction contact results in nonlinear stiffness and damping to a structure. To realize predictive simulation in structural dynamic design, these nonlinear behaviors must be carefully considered. In this paper, the dynamics of a multi-bolt jointed beam is calculated. A modified IWAN constitutive model, which can consider both tangential micro/macro slip and nonzero residual stiffness at macroslip phase, is developed to model nonlinear contact behaviors due to joint interfaces. A whole interface element integrating the proposed constitutive model is developed. The element is used to model the nonlinear stiffness and damping caused by bolted joints. The interface element is placed between the two contact interfaces. The other part of the beam is modeled by linear beam elements. A Matlab code is developed to realize the proposed nonlinear finite element dynamic analysis method. A hammer impact experiment for the bolt-jointed beam is conducted under different excitation force levels. The calculated nonlinear numerical results are compared with experimental results. It is shown that the effect of joint nonlinearity on structural dynamics can be observed from the response predicted by the proposed method. The numerical results agree well with the experimental results. This work validates the necessary of using nonlinear joint model for dynamic simulation of jointed structures.

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