scholarly journals A viscoelastic viscoplastic constitutive model including mechanical degradation: Uniaxial transient finite element formulation at finite strains and application to space truss structures

2015 ◽  
Vol 39 (5-6) ◽  
pp. 1725-1739 ◽  
Author(s):  
T.A. Carniel ◽  
P.A. Muñoz-Rojas ◽  
M. Vaz
Author(s):  
Aurelio Dominguez ◽  
Ramin Sedaghati ◽  
Ion Stiharu

In this study a new nonlinear hysteresis dynamic model is employed to simulate the hysteresis behavior of a commercial MR damper. The model determines the hysteresis force considering the amplitude, frequency and current excitation as independent variables. Subsequently, based on this model, the finite element formulation of the MR damper is developed and is incorporated into the finite element formulation of the whole space truss structures with embedded MR dampers. A direct integration method with inner iterative algorithm is applied to obtain the solution of the resulting nonlinear system. The experimental study has also been conducted to validate the simulation. For the experimental set-up, a 3-Dimensional space truss structure with 4 bays in which one of the members can be replaced by MR damper has been fabricated. The experimental results have shown a good agreement with the mathematical simulation. It has been demonstrated that the vibration can be efficiently suppressed by the controllable MR dampers.


2015 ◽  
Vol 32 (5) ◽  
pp. 1372-1390 ◽  
Author(s):  
Sanka Dilshan Ekanayake ◽  
D.S. Liyanapathirana ◽  
Chin Jian Leo

Purpose – EPS geofoam has been widely used in embankment construction, slope stabilisation, retaining walls, bridge approaches and abutments. Nevertheless, the potential of EPS geofoam as an engineering material in geotechnical applications has not been fully realised yet. The purpose of this paper is to present the finite element formulation of a constitutive model based on the hardening plasticity, which has the ability to simulate short-term behaviour of EPS geofoam, to predict the mechanical behaviour of EPS geofoam and it is implemented in the finite element programme ABAQUS. Design/methodology/approach – Finite element formulation is presented based on the explicit integration scheme. Findings – The finite element formulation is verified using triaxial test data found in the literature (Wong and Leo, 2006 and Chun et al., 2004) for two varieties of EPS geofoam. Performance of the constitute model is compared with four other models found in the literature and results confirm that the constitutive model used in this study has the ability to simulate the short-term EPS geofoam behaviour with sufficient accuracy. Research limitations/implications – This research is focused only on the short-term behaviour of EPS geofoam. Experimental studies will be carried out in future to incorporate effects of temperature and creep on the material behaviour. Practical implications – This formulation will be applicable to finite element analysis of boundary value problems involving EPS geofoam (e.g. application of EPS geofoam in ground vibration isolation, retaining structures as compressible inclusions and stabilisation of slopes). Originality/value – Finite element analysis of EPS geofoam applications are available in the literature using elastic perfectly plastic constitutive models. However, this is the first paper presenting a finite element application utilising a constitutive model specifically developed for EPS geofoam.


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