scholarly journals Numerical simulations for the dynamics of flexural shells

2020 ◽  
Vol 25 (4) ◽  
pp. 887-912 ◽  
Author(s):  
Xiaoqin Shen ◽  
Luisa Piersanti ◽  
Paolo Piersanti
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Initial Conditions ◽  
Original Model ◽  
Point Of View ◽  
Dynamic Loads ◽  
Computational Point ◽  
Variational Equations ◽  
Numerical Tests ◽  
Membrane Shell

In this paper, we study a model describing the displacement of a linearly elastic flexural shell subjected to given dynamic loads from the computational point of view. The model under consideration takes the form of a set of hyperbolic variational equations posed over the space of admissible linearised inextensional displacements, and a set of initial conditions. Since the original model is not suitable for the implementation of a finite element method, we conduct the experiments on the corresponding penalised model. It was recently shown that the solution to such a penalised model is a good approximation of the solution to the original model. Numerical tests are therefore conducted on the the penalised model; the approximation of the solution to the penalised model is obtained via Newmark’s scheme, which is then implemented and tested for shells having the following middle surfaces: a portion of a cylinder and a portion of a cone. For the sake of completeness, we also present the results of the numerical tests related to a model describing the displacement of a linearly elastic elliptic membrane shell under the action of given dynamic loads.

Computer simulation of optical radiation scattering by aerosol media

2020 ◽  
Vol 86 (8) ◽  
pp. 43-48
Author(s):  
V. V. Semenov
Keyword(s):  
Finite Element Method ◽  
Computer Simulation ◽  
Finite Element ◽  
Optical Radiation ◽  
Light Transmission ◽  
Initial Conditions ◽  
Practical Significance ◽  
The Finite Element Method ◽  
Dispersed Medium ◽  
Element Method

Development of the technologies simulating optical processes in an arbitrary dispersed medium is one of the important directions in the field of optical instrumentation and can provide computer simulation of the processes instead of using expensive equipment in physical experiments. The goal of the study is simulation of scattering of optical radiation by aerosol media using the finite element method to show a practical significance of the results of virtual experiments. We used the following initial conditions of the model: radius of a spherical particle of distilled water is 1 μm, wavelength of the incident optical radiation is 0.6328 μm, air is a medium surrounding the particle. An algorithm for implementation of the model by the finite element method is proposed. A subprogram has been developed which automates a virtual experiment for a group of particles to form their random arrangement in the model and possibility of changing their geometric shape and size within predetermined intervals. Model dependences of the radiation intensity on the scattering angle for single particle and groups of particles are presented. Simulation of the light transmission through a dispersed medium provides development of a given photosensor design and determination of the minimum number of photodetectors when measuring the parameters of the medium under study via analysis of the indicatrix of scattering by a group of particles.

scholarly journals Stress and strain analysis from dynamic loads of mechanical hand using finite element method

2018 ◽  
Vol 352 ◽  
pp. 012017 ◽  
Author(s):  
Iskandar Hasanuddin ◽  
Husaini ◽  
M. Syahril Anwar ◽  
B.Z. Sandy Yudha ◽  
Hasan Akhyar
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Strain Analysis ◽  
Dynamic Loads ◽  
Stress And Strain ◽  
Mechanical Hand ◽  
Element Method

Elasto-plastic analysis of a rotating model conical turbine disc

1975 ◽  
Vol 10 (3) ◽  
pp. 167-171 ◽  
Author(s):  
F Ginesu ◽  
B Picasso ◽  
P Priolo
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Limit Analysis ◽  
Point Of View ◽  
Complete Analysis ◽  
The Finite Element Method ◽  
Computational Simplicity ◽  
Rotating Shell ◽  
Good Agreement ◽  
Element Method

Results on the plastic collapse behaviour of an axisymmetric rotating shell, obtained by Limit Analysis and the Finite Element Method, are in good agreement with experimental data. The Finite Element Method, though computationally rather costly, permits, however, a more complete analysis of elasto-plastic behaviour. For the present case, the Limit Analysis has the advantage of greater computational simplicity and leads to a quite satisfactory forecast of collapse speed from the engineering point of view.

Moving Path Analysis of a Cannonball Colliding onto Water

2011 ◽  
Vol 120 ◽  
pp. 414-417
Author(s):  
Joon Sik Youn ◽  
Young Hun Jung ◽  
Han Seok Bang ◽  
Hae Suk Lee ◽  
Yeon Sik Cho ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Path Analysis ◽  
Normal Force ◽  
Initial Conditions ◽  
Moving Path ◽  
Element Method

When a cannonball collides onto water, it can ricochet several times because normal force is generated larger than the weight. In order to determine the moving path, an analysis is done to calculate the position and velocity of the cannonball and the force acting on the cannonball using a finite element method. It is shown that the cannonball motion depends on the initial conditions such as cannonball shape, firing velocity, and firing angle.

scholarly journals Analysis of Subgrid Stabilization Method for Stokes-Darcy Problems

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
Kamel Nafa
Keyword(s):  
Finite Element ◽  
Stokes Equations ◽  
Fluid Motion ◽  
Mixed Finite Elements ◽  
Point Of View ◽  
Darcy Law ◽  
Element Formulation ◽  
Computational Point ◽  
Galerkin Finite Element ◽  
Darcy Problem

A number of techniques, used as remedy to the instability of the Galerkin finite element formulation for Stokes like problems, are found in the literature. In this work we consider a coupled Stokes-Darcy problem, where in one part of the domain the fluid motion is described by Stokes equations and for the other part the fluid is in a porous medium and described by Darcy law and the conservation of mass. Such systems can be discretized by heterogeneous mixed finite elements in the two parts. A better method, from a computational point of view, consists in using a unified approach on both subdomains. Here, the coupled Stokes-Darcy problem is analyzed using equal-order velocity and pressure approximation combined with subgrid stabilization. We prove that the obtained finite element solution is stable and converges to the classical solution with optimal rates for both velocity and pressure.

scholarly journals The Influence of Mesh Granularity on the Accuracy of FEM Modelling of the Resonant State in a Microwave Chamber

2021 ◽  
Vol 11 (17) ◽  
pp. 7932
Author(s):  
Anna Ostaszewska-Liżewska ◽  
Dominika Kopala ◽  
Jakub Szałatkiewicz ◽  
Roman Szewczyk ◽  
Peter Råback
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Open Source ◽  
Resonant State ◽  
Point Of View ◽  
Tetrahedral Mesh ◽  
Efficient Design ◽  
Resonant States ◽  
Main Barrier ◽  
Element Method

Microwave technology is widely used in different areas of advanced industry when energy must be provided to water-containing and other materials. The main barrier in the development of microwave devices is the possibility of efficient design by modelling a microwave system in a resonant state. For technical systems, the finite element method is widely used. However, the convergence process in the microwave finite element solver is sophisticated. The process itself and the influence of mesh granularity on the accuracy of modelling of microwave chambers in resonant states have not been investigated previously. The present paper aims to fill this gap. The resonance conditions of a microwave chamber were tested from the point of view of spatial resolution of the tetrahedral mesh used for open-source ELMER FEM software. The presented results experimentally determine the limits of accuracy of the geometry of microwave resonant chamber finite element method-based models. The determined values of microwave resonant chamber dimension tolerances should be considered for both open-source and commercial software for microwave modelling.

scholarly journals Numerical Analysis of the Ability of a Floating Vehicle to Overcome a Water Obstacle

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Krzysztof Kosiuczenko ◽  
◽  
Robert Sosnowicz ◽  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Analysis ◽  
Computational Model ◽  
Difficult Problem ◽  
Point Of View ◽  
Vehicle Safety ◽  
Extreme Conditions ◽  
The Finite Element Method ◽  
Element Method

The paper presents the results of simulation tests of the entry of a floating transporter to a water obstacle. The simulation tests were performed with the use of LS Dyna program, based on the finite element method (FEM). The computational model was developed and used in the simulation of the manoeuvre of entering the water obstacle for the extreme conditions, which are described by NATO standards. For a model, as an example vehicle, the floating transporter PTS-M was used. The results of the application of the elaborated model confirmed the possibility to utilise the method to verify the behaviour of a vehicle in a very important and difficult problem from the point of view of vehicle safety conditions.

Modal Analysis of Automotive Steering System Based on Finite Element Method

2011 ◽  
Vol 121-126 ◽  
pp. 2085-2090 ◽  
Author(s):  
Shu Ming Chen ◽  
Deng Feng Wang ◽  
Gang Ping Tan ◽  
Jian Ming Zan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Modal Analysis ◽  
Excitation Frequency ◽  
Steering System ◽  
Point Of View ◽  
Steering Wheel ◽  
Exciting Frequency ◽  
Wheel Vibration ◽  
Element Method

In order to understand the vibration characteristics of the steering system and provide suggestions for improvement, a model of the steering system was created based on finite element method (FEM). Also, the modal analysis of the steering system was presented, and the first twenty step modes were calculated and analyzed. The steering system was also evaluated from the resonance point of view. The result shows that the frequency of the first step mode is 31.578 Hz which is higher than the exciting frequency of the engine; also, the road roughness excitation frequency has a minor influence on steering wheel vibration.

A Probabilistic Extended Finite Element Approach: Application to the Prediction of Bone Crack Propagation

2007 ◽  
Vol 348-349 ◽  
pp. 77-80 ◽  
Author(s):  
Jorge Grasa ◽  
José Antonio Bea ◽  
Manuel Doblaré
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Crack Propagation ◽  
Extended Finite Element Method ◽  
Partition Of Unity ◽  
Point Of View ◽  
Extended Finite Element ◽  
Neck Fracture ◽  
Element Approach ◽  
Element Method

The Extended Finite Element Method (XFEM), has become a well-known tool to simulate crack propagation problems using non-structured meshes avoiding the remeshing process usually needed in this type of problems and allowing the inclusion of appropriate shape functions that reflect the asymptotic displacement field, near the crack tip, via a partition of unity fracture approach. However, in this kind of numerical applications, all the variables involved have been considered as deterministic (defined by a single given value), despite the well-known uncertainty associated to many of them (external loads, geometry and material properties, among others). The combination of the XFEM and probabilistic techniques is here proposed and formulated allowing treating fracture mechanics problems from a probabilistic point of view. We present the implementation of this probabilistic extended finite element method and apply it to the prediction of the appearance and propagation of a femur’s neck fracture under probabilistic loads.

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