scholarly journals Finite element modeling of the joint action of flow slide and protective structure

2021 ◽  
Vol 21 (2) ◽  
pp. 133-142
Author(s):  
Р. Р. Gaidzhurov ◽  
N. А. Saveleva ◽  
V. А. Dyachenkov
Keyword(s):  
Finite Element ◽  
Plane Deformation ◽  
Element Model ◽  
Physical Nonlinearity ◽  
Protective Structure ◽  
Joint Work ◽  
Flow Slide ◽  
Viscoelastic Interlayer ◽  
Landslide Slope ◽  
Kinematic Instability

Introduction. In the context of the problem of plane deformation, a finite-element model of a natural landslide slope is developed. It allows for the joint work of a flow slide and a protective engineering structure. The Drucker-Prager model is used to take into account the physical nonlinearity of the slope layer material. To activate the kinematic instability, a viscoelastic interlayer is introduced into the design scheme, along which the landslide layer slides.Materials and Methods. Numerical experiments were performed using the ANSYS Mechanical software package, which implements the finite element method in the form of the displacement method. Slope discretization is performed on the basis of PLANE42 flat four-node finite elements. To simulate the displacement of the landslide layer relative to the fixed base, the combined viscoelastic elements COMBIN14 were used.Results. A physically nonlinear model of a natural landslide slope consisting of a base, a landslide layer, and a viscoelastic interlayer, is formalized. An engineering technique for analyzing the stress-strain state of the “slopeprotective structure” system has been developed, taking into account the kinematic instability of the landslide layer. A series of computational experiments was carried out.Discussion and Conclusion. Based on the calculations performed, it is shown that the proposed method enables to specify the force action of the landslide layer on the protective structure and, thereby, to increase the reliability of the risk assessment when activating the landslide process. 

Delamination in the scoring and folding of paperboard

TAPPI Journal ◽  
2012 ◽  
Vol 11 (1) ◽  
pp. 61-66 ◽  
Author(s):  
DOEUNG D. CHOI ◽  
SERGIY A. LAVRYKOV ◽  
BANDARU V. RAMARAO
Keyword(s):  
Finite Element ◽  
Plane Deformation ◽  
Strain Analysis ◽  
Local Strain ◽  
Uniaxial Stress ◽  
Material Model ◽  
Element Model ◽  
Plastic Behavior ◽  
Stress Strain ◽  
Strain Fields

Delamination between layers occurs during the creasing and subsequent folding of paperboard. Delamination is necessary to provide some stiffness properties, but excessive or uncontrolled delamination can weaken the fold, and therefore needs to be controlled. An understanding of the mechanics of delamination is predicated upon the availability of reliable and properly calibrated simulation tools to predict experimental observations. This paper describes a finite element simulation of paper mechanics applied to the scoring and folding of multi-ply carton board. Our goal was to provide an understanding of the mechanics of these operations and the proper models of elastic and plastic behavior of the material that enable us to simulate the deformation and delamination behavior. Our material model accounted for plasticity and sheet anisotropy in the in-plane and z-direction (ZD) dimensions. We used different ZD stress-strain curves during loading and unloading. Material parameters for in-plane deformation were obtained by fitting uniaxial stress-strain data to Ramberg-Osgood plasticity models and the ZD deformation was modeled using a modified power law. Two-dimensional strain fields resulting from loading board typical of a scoring operation were calculated. The strain field was symmetric in the initial stages, but increasing deformation led to asymmetry and heterogeneity. These regions were precursors to delamination and failure. Delamination of the layers occurred in regions of significant shear strain and resulted primarily from the development of large plastic strains. The model predictions were confirmed by experimental observation of the local strain fields using visual microscopy and linear image strain analysis. The finite element model predicted sheet delamination matching the patterns and effects that were observed in experiments.

scholarly journals Comparison between simplified and FE models for short-term deflection in continuous RC beams

2017 ◽  
Vol 10 (2) ◽  
pp. 415-450
Author(s):  
E. JUNGES ◽  
H.L. LA ROVERE
Keyword(s):  
Finite Element ◽  
Longitudinal Axis ◽  
Element Model ◽  
Physical Nonlinearity ◽  
Rc Beams ◽  
Short Term ◽  
Bilinear Method ◽  
Frame Element ◽  
Vertical Displacements ◽  
The One

Abstract In this work, a comparative study of different simplified methods and nonlinear finite element (FE) models used for calculating short-term deflections (vertical displacements of the longitudinal axis) in continuous reinforced concrete (RC) beams, under service loads, is performed. The simplified methods employed are the one proposed by Branson and the bilinear method recommended by the European Code CEB - Design Manual on Cracking and Deformations. Two finite element models are utilized: the first one with frame elements in which material nonlinearities are considered along the element and its cross section divided into layers, by using of constitutive relationships for steel and concrete, while the second one utilizes beam elements, with physical nonlinearity considered by means of moment-curvature diagrams, obtained from Branson equation. Several examples of continuous RC beams under service loads are analysed and the results obtained by the different models are compared taking as reference the nonlinear frame element model. A few conclusions and recommendations regarding the use of the different methods are drawn at the end of the work.

Evaluation of Mechanical Behaviors of Single-Walled Carbon Nanotubes by Finite Element Analysis

2010 ◽  
Author(s):  
Xiaoxing Lu ◽  
Zhong Hu
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element ◽  
Cross Section ◽  
Plane Deformation ◽  
Element Model ◽  
Element Analysis ◽  
Elliptical Cross ◽  
Beam Elements ◽  
Young’S Moduli ◽  
Walled Carbon Nanotubes

Based on molecular mechanics, a three-dimensional finite element model for armchair, zigzag and chiral single-walled carbon nanotubes (SWCNTs) has been developed, in which the carbon nanotubes (CNTs), when subjected to load, behave like space-frame structures. The bending stiffness of the graphite layer has been considered. The potentials associated with the atomic interactions within a CNT were evaluated by the strain energies of beam elements which serve as structural substitutions of covalent bonds. The out-of-plane deformation (inversion) of the bonds was distinguished from the in-plane deformation by considering an elliptical cross-section for the beam elements. The elastic moduli of beam elements are determined by using a linkage between molecular and continuum mechanics. A closed form solution of the sectional properties of the beam element was derived analytically and verified through the analysis of rolling a graphite sheet into a carbon nanotube. This method was validated by its application to a graphene model, and Young’s modulus of the model was found, showing agreement with the known values of graphite. Modeling of the elastic deformation of SWCNTs reveals that Young’s moduli and the shear modulus of CNTs vary with the tube diameter and are affected by their helicity. With increasing tube diameter, Young’s moduli of both armchair and zigzag CNTs are increasing monotonically and approaching to the Young’s modulus of graphite, which are in agreement with the existing theoretical and experimental results. The rolling energy per atom was computed by finite element analysis. By comparing mechanical properties with circular cross section models, it is found that the computational results of the proposed elliptical cross-section model are closer to the results from the atomistic computations. The proposed model is valid for problems where the effect of local bending of the graphite layer in a CNT is significant. This research work shows that the proposed finite element model may provide a valuable tool for studying the mechanical behaviors of CNTs and their integration in nano-composites.

LENGTH AND WIDTH EFFECTS OF METAL FILMS ON STRESS-INDUCED BENDING OF SURFACE MICROMACHINED CANTILEVER CURVED GRATING

2012 ◽  
Vol 19 (01) ◽  
pp. 1250001 ◽  
Author(s):  
JU-NAN KUO
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Plane Deformation ◽  
Beam Theory ◽  
Element Model ◽  
Metal Films ◽  
Width Ratio ◽  
Element Analysis ◽  
Close Relationship ◽  
Out Of Plane

In this study, the length and width effects of metal films on the stress-induced bending of a surface micromachined cantilever curved grating are systematically investigated. A characterization of cantilever curved gratings with various lengths and widths was conducted to observe out-of-plane deformation. A finite element model was established to analyze the deformation. Finite element analysis and experimental results indicate that the commonly used beam theory formula for predicting the deformation of surface micromachined cantilever curved gratings is not valid for these devices. Experiments show that the shape of a cantilever curved grating and residual stress have a close relationship. As the length increases, the residual stress of the metal increases, resulting in a larger out-of-plane deformation of the cantilever curved grating. The tip deflection gradually decreases as the length-to-width ratio of the cantilever curved grating increases. A more reliable shape design of metal films on the stress-induced bending of surface micromachined cantilever curved gratings can thus be achieved.

scholarly journals FINITE ELEMENT MODELLING OF INTERACTION BUILDING FRAME AND SLAB-PILE FOUNDATION

2019 ◽  
Vol 7 (1) ◽  
pp. 34-38
Author(s):  
Леонид Панасюк ◽  
Leonid Panasyuk ◽  
Галина Кравченко ◽  
Galina Kravchenko ◽  
Елена Труфанова ◽  
...  
Keyword(s):  
Finite Element ◽  
Pile Foundation ◽  
Base Plate ◽  
Element Model ◽  
Joint Work ◽  
Building Frame ◽  
Complex Scheme ◽  
Field Static ◽  
Spatial Formulation ◽  
The Finite Element Model

The article deals with the simulation of joint work of slab grillage and monolithic frame of the building by finite element method. The finite-element model is developed in the spatial formulation according to the complex scheme "upper structure-base plate-pile Foundation". The pile field was modeled by pliable rods with stiffness corresponding to the average draft of the pile field. Static and dynamic calculations are performed in the ING+software package. The results of the stress-strain state of the building frame elements demonstrate the correctness of this approach to take into account the compliance of the base.

A New Video Extensometer System for Testing Materials Undergoing Severe Plastic Deformation

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Andrea J. Felling ◽  
Darrel A. Doman
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Severe Plastic Deformation ◽  
Finite Element Model ◽  
Plane Deformation ◽  
Element Model ◽  
Cold Upsetting ◽  
Out Of Plane ◽  
Compressive Testing ◽  
Video Extensometry

Characterization of materials undergoing severe plastic deformation requires the careful measurement of instantaneous sample dimensions throughout testing. For compressive testing, it is insufficient to simply estimate sample diameter from an easily measured height and volume. Not all materials exhibit incompressibility, and friction during testing can lead to a barreled sample with diameter that varies with height. Video extensometry has the potential to greatly improve testing by capturing the full profile of a sample, allowing researchers to account for such effects. Common two-dimensional (2D) video extensometry algorithms require thin, planar samples, as they are unable to account for out-of-plane deformation. They are, therefore, inappropriate for standard compressive tests which use cylindrical samples that exhibit large degrees of out-of-plane deformation. In this paper, a new approach to 2D video extensometry is proposed. By using background subtraction, the profile of a cylindrical sample can be isolated and measured. Calibration experiments show that the proposed system has a 3.1% error on calculating true yield stress—similar to ASTM standard methods for compressive testing. The system is tested against Aluminum 2024-T351 in a series of cold upsetting tests. The results of these tests match very closely with similar tests from the literature. A preliminary finite element model constructed using data from these tests successfully reproduced experimental results. Diameter data from the finite element model undershot, but otherwise closely matched experimental data.

Dynamic stiffness formulation for the vibrations of stiffened plate structures with consideration of in-plane deformation

2017 ◽  
Vol 24 (20) ◽  
pp. 4825-4838 ◽  
Author(s):  
Xuewen Yin ◽  
Wenwei Wu ◽  
Kuikui Zhong ◽  
Hui Li
Keyword(s):  
Finite Element ◽  
Dynamic Stiffness ◽  
Plane Deformation ◽  
Element Model ◽  
The Finite Element Method ◽  
Plate Structures ◽  
Beam Elements ◽  
Stiffness Model ◽  
Out Of Plane ◽  
The Relationship

A dynamic stiffness method is presented for the vibrations of plate structures that are reinforced by eccentric stiffeners. The model incorporates both out-of-plane and in-plane deformations of the plates and the stiffeners. Based on the relationship between the forces and displacements along the common edges of the plate or beam elements, the dynamic stiffness formulae for the plate and the beam elements are derived, respectively. The globally assembled dynamic stiffness matrix is then obtained using the finite element method so that the dynamics of built-up stiffened plates can be readily addressed by using the present method. Compared to the conventional finite element model, the dynamic stiffness model can provide very accurate solutions using only one element over each uniform plate and beam member, regardless of its geometry.

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