Validation of a purely elastic model and a finite element model for a screw press

2019 ◽  
Author(s):  
Jean-François Mull ◽  
Camille Durand ◽  
Cyrille Baudouin ◽  
Régis Bigot ◽  
Marc Borsenberger
2014 ◽  
Vol 553 ◽  
pp. 769-773 ◽  
Author(s):  
E.A. Flores-Johnson ◽  
J.G. Carrillo ◽  
R.A. Gamboa ◽  
Lu Ming Shen

In this work, a 3D finite-element model of the ballistic impact of a multi-layered plain-woven aramid fabric style 720 (Kevlar®129 fibre, 1420 denier, 20×20 yarns per inch) impacted by a 6.7-mm spherical projectile was built at the mesoscale in Abaqus/Explicit by modelling individual crimped yarns. Material properties and yarn geometry for the model were obtained from reported experimental observations. An orthotropic elastic model with a failure criterion based on the tensile strength of the yarns was used. Numerical predictions were compared with available experimental data. It was found that the finite-element model can reproduce the physical experimental observations, such as the straining of primary yarns and pyramidal-shaped deformation after perforation. The permanent deformation of fabric targets predicted by the numerical simulations was compared with available experimental results. It was found that the model fairly predicted the permanent deformation with a difference of about 21% when compared with experiments.


Author(s):  
Adrian T. DeWald ◽  
Michael R. Hill

This paper presents a methodology for predicting the residual stress resulting from laser peening treatment of arbitrary 3D bodies. The model consists of three basic steps. First, the inputs to the model are derived from residual stress measurements made on laser peened blocks of the pertinent material. The measured residual stress in the blocks consists of residual stress caused directly by laser peening and residual stress required for equilibrium. The laser peening induced residual stress is converted into an equivalent strain distribution that reproduces the stress state in an elastic model of the original body (called eigenstrain). Second, a finite element model representing the geometry of the actual part is constructed. Third, the laser peening induced eigenstrain is input into the finite element model at the locations where laser peening is to be applied (arbitrary coverage area). Solving for equilibrium provides a prediction for the residual stress resulting from laser peening treatment. The modeling procedure is verified using comparisons with residual stress measurements for specimens containing corner fillets of various sizes. The model predictions correlate well with the residual stress measurements over the range of conditions studied.


2016 ◽  
Vol 846 ◽  
pp. 440-445
Author(s):  
Prabin Pathak ◽  
Yi Xia Zhang

A new simple, efficient and accurate finite element model denoted as FEM-B is developed for the analysis of structural behavior of FRP strengthened RC beams with bond-slip effect. Geometric nonlinearity and material nonlinear properties of concrete and steel rebar are accounted for this model. Concrete, steel, FRP and adhesive are modelled as Solid 65, Link 180, Shell181 and Solid 45 respectively. Concrete is modelled using Nitereka and Neal’s model for compression, isotropic and linear elastic model before cracking for tension and strength gradually reduces to zero after cracking, whereas steel is assumed to be elastic perfectly plastic material. The material of FRP is considered to be linearly elastic until rupture, and adhesive is assumed to be linearly elastic. The bond slip between concrete, adhesive and FRP is based on the bilinear law, which is modelled using spring element Combin 39.The developed new finite element model FEM-B is validated against experimental results, and demonstrates to be effective for the structural analysis of FRP strengthened RC beams.


2014 ◽  
Vol 644-650 ◽  
pp. 402-405
Author(s):  
Cong Bin Yang ◽  
Liang Gu ◽  
Qiang Li

Soil constitutive model was established based on elastic model and Mohr-Coulomb model. Simplified common form track shoe was determined for finite element modeling. Loading and boundary conditions were determined based on the actual driving conditions of the vehicle. Meshing was based tetrahedron. Finite element model was compared with experiment to verify the validity.


2018 ◽  
Vol 188 ◽  
pp. 04009
Author(s):  
Kyriakos Grigoriadis ◽  
Anastasios Zavos ◽  
Pantelis G. Nikolakopoulos

This study focuses on the creation of an isothermal elastic model to highlight, through stresses, the occurrence of plastic deformation in certain crank angles under extreme dry conditions inside an internal combustion engine. The stresses that are exported from this analysis are pointing out not only the necessity for an elastoplastic model to be created, but also the importance of predicting the correct friction coefficient, as pointed out by both the contact surface stress and those in depth of the two bodies in contact. A comparison between two coefficients of frictions and one frictionless case is conducted. The comparison between the finite element model and the adhesion mathematical model of Johnson, Kendall and Roberts (JKR), seals the importance of the interaction forces, acting on the common solid surface, in the pursuit of defining a propriate contact patch. Furthermore, a three-dimensional model is proposed for further investigation, highlighting the importance of modelling surface’s micro asperities for a solid stress analysis.


Author(s):  
Ines Guissouma ◽  
Ridha Hambli ◽  
Amna Rekik ◽  
Audrey Hivet

Human skin is a complex multilayered multiscale material that exhibits nonlinear and anisotropic mechanical behavior. It has been reported that its macroscopic behavior in terms of progression of wrinkles induced by aging is strongly dependent on its microscopic composition in terms of collagen fibers in the dermis layer. In the present work, a multiscale four-layer 2D finite element model of the skin was developed and implemented in Matlab code. The focus here was to investigate the effects of dermal collagen on the macroscopic mechanical behavior of the skin. The skin was modeled by a continuum model composed of four layers: the Stratum Corneum, the epidermis, the dermis, and the hypodermis. The geometry of the different layers of the skin was represented in a 2D model with their respective thicknesses and material properties taken from literature data. The macroscopic behavior of the dermis was modeled with a nonlinear multiscale approach based on a multiscale elastic model of collagen structure going from cross-linked molecules to the collagen fiber, combined with a Mori-Tanaka homogenization scheme. The model includes the nonlinear elasticity of the collagen fiber density, the fiber radius, the undulation, and the fiber orientation. An axial tension was applied incrementally to the lateral surfaces of the skin model. A parametric study was performed in order to investigate the effect of the collagen constituents on the macroscopic skin mechanical behavior in terms of the predicted macroscopic stress-strain curve of the skin. The results of the FE computations under uniaxial tension showed that the different layers undergo different strains, leading to a difference in the transversal deformation at the top surface. In addition, the parametric study revealed a strong correlation between macroscopic skin elasticity and its collagen structure.


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