Fem Definition and 76 Threads

Hi, I am a engineering student and I am in apprenticeship with a mechanics lab : I am studying about Honeycomb propagation and periodic structures. I hadn't have any courses in FEM or in Bloch's theory, I've done all by myself : but there is the problem, i didn't practice or use viable courses...

Hello everyone, I am doing a project in FEM, and we first have to assess the mechanical behavior of a connecting rode in which there is a hole in the center part of height b. The connecting rode has a trapezoidal shape (when seem from the top view), so the cross section is gradually decreasing...

Hi, I am a newcomer to FEA/FEM. I am aware that for any practical purpose, software is used to solve problems. However, before I utilize software, I want to understand the process the computer goes about doing. This document is simply an attempt to summarize the solving procedure in a concise...

I have been watching Mike Foster's video series of the Finite Element Method for Differential Equations (FEM). In this episode, he solves a DE relating to temperature. As the final step, he gives the following equation: $$[K] [T] = [F]$$ In this equation, I understand that ##[K]## is the...

Hello I have alwayes seen FEM applications for static structures while each " finite element" of a bar linkage mechanisms should be subjected also to a variable inertial force besides its constant weight how do FEM softwares compute inertial forces ?

Hello I wrote a Matlab code to form the 8 by 8 stiffness matrix of a single, 4-noded element, for a plane strain problem for an isotropic element. I conduct an eigenvalue analysis on this matrix Matlabe reports 5 non-zero eigenvalue modes, and 3 zero-eigenvalue modes (as expected) Of the 3...

So, I use Ansys (well known FEM software) and get the next output for a modal analysis toy problem (If you happen to know Ansys that's a pre, but I promise it shouldn't matter). The problem is a simple beam, clamped at one end. I used 160 20-node brick elements to solve it (so no Timoshenko...

I know that if there is only one conductor providing the current density, then the current density can be used. But if you apply Maxwell's equation when there are multiple current sources, I don't know which value to use. This is not an analysis using a tool, but a problem when I develop the...

I have worked through the basics of the FEM method in 2D with rectangular elements and now am trying to learn triangular elements but need a simple enough numerical example. It seems triangular elements are far more complicated and also depend on the global coordinates thus each local stiffness...

Is there a good rubric on how to choose the order of polynomial basis in an Finite element method, let's say generic FEM, and the order of the differential equation? For example, I have the following equation to be solved ## \frac{\partial }{\partial x} \left ( \epsilon \frac{\partial u_{x}...

I want to solve the 2D heat equation $$\frac{∂^2 {T}}{ ∂x^2} + \frac{∂^2 {T}}{ ∂y^2} = 0$$ The only boundary conditions is I will specify the edge temperatures but there are no heat sources. So I create an average temperature function ##\tilde{T}## and weighting functions ##S_i## over a...

I wish to set up the node equations for a 2D heated plate with boundary conditions. I understand how to do this in 1D but have not found a suitable example problem worked out in 2D and examples I have seen are very involved and complex. @pasmith showed me you to set up the 1D problem as follows...

I am trying to understand how to apply the finite element method for a simple 1D wave equation with four elements for learning purposes. $$\frac{d^2 T(x)}{dx^2} = -f(x)$$ I am stuck because the structure of the equations set up in Numerical Methods for Engineers by Chapra and Canale as shown...

Can anyone recommend a book in which complex eigenvalue problems are treated? I mean the FEM analysis and the theory behind it. These are eigenvalue problems which include damping. I think that it is used for composite materials and/or airplane engineering (maybe wing fluttering?).

hello aside from some constraints such as an irregular integration domain, can FDM solve any type of PDE same as FEM ?

I need to find the FEM induced in a coil that rotates around the y-axis and is inside a solenoid. The coil starts in the plane yz ##r## is the radius of the coil ##n## is the number of spiral by length of the solenoid. ##N## is the number of turns of the coil ##w## is the angular velocity that...

Hi, I've just written an article about how to choose between FDTD, FEM and MoM for Electromagnetic Simulations, and also with brief reviews of some of the best Open Source alternatives out there. https://www.matecdev.com/posts/differences-fdtd-fem-mom.html I've seen that in this forum many...

does this Beam, composed of three elements and 4 nodes(considering lateral deflections and slopes) has an 8x8 global stifness matrix and if so is the global matrix calculated the same way as a 6x6 stifness matrix for the same kind of beam but only with two elements and 3 nodes

I'm new to composite materials. I've studied mechanical engineering but I am actually usually involved in hydrodynamics (in which I've done my masters). However for a project we do fluid structure interaction with composites, and as these things go, you cannot get away with the 'black box'...

Is this anyhow possible ? The system would be a wave equation modelized by a finite elements basis in space and time. Is there any method to do the limit discretization->continuum with paper and pencil ?

Basically, the summary. I forgot where I read this before, apparently FDM is much better in handling such problems, and apparently CFD in general is better dealt with FDM instead of FEM. Why is this so?

Hi all, I have performed a small static analysis with one element (C3D8). The bottom face of element is completely constrained, and the top part is displaced. In the geometrical linear analysis, the internal energy (ALLIE) and the work done (ALLWK) are equal. So, with ETOTAL = ALLIE - ALLWK...

Homework Statement translation ; we know the values of R1 = 1 ohm R2= 2 ohm R3= 6 ohm R4= 2 ohm R5= 4 ohm R6= 4 ohm we can also see the voltmeter reading a potential difference value of 8 volts , and the...

Homework Statement Hello, this is like an experiment of engineering.It is called a induction stove. The system consists of a bycicle, where I am going to pedal. This will turn a disk that have 20 small magnets around its circuference. Once the disk starts to turn, it will produce a constant...

Hi all, I have some doubts regarding the strain tensors Abaqus uses for the case of Geometrical non linear analysis. In the case of geometrically linear analysis, all the strain tensors will be equal to engineering strain, So it doesn't matter which strain tensor Abaqus uses. But for...

Hi, I am working on Maxwell version 17. I have a simple motor to analysis 2D FEM. However, when I analyze the model, I see this error. "Maxwell2d solver, process solver2d error: Internal Solver Error: 'Transient solver handles only isotropic conductivity!'. (7:07:10 PM Apr 16, 2018)" I am...

Hi all, I have a personal project I am working on in Abaqus CAE/Explicit 2017. I have a tube, that I am trying to advance into a larger tube with a bend in it. The idea is that the small tube enters and then deforms around the bend as it comes into contact with the radius of curvature of the...

I would like to simulate the vibrations of a thin film polymer in vacuum using nonlinear analysis. For this purpose I am using an FEM program I have written in MATLAB. I do not have any data regarding damping in the structure, so I am estimating the damping using stiffness-proportional-only...

Dear all I am doing a simulation of a 3 phase transformer. I am adding the excitation using external circuit in Simplorer , I am getting these error ! Can somebody comment on the error . An external simulator couldn't be setup for simulation. (12:01:33 PM May 02, 2017) Simulation completed...

Hi, my background is in mathematics, and theoretical physics. I am new to the realm of solving PDEs using Finite element methods, does anyone know of any good introductory level textbooks for course notes? I had a poke around online and couldn't find anything overly useful. Also I am...

I am doing a 2D Ansys workbench simulation ,it is nonlinear simulation due to frictionless contact, there is symmetry in the shape so I used the symmetry option to reduce the computation time and it succeeded to converge after that I tried the simulation of the whole body but it always fails...

What happens if I turned off large deflection in a simulation which has large deflection in Ansys workbench ? should the solution be totally wrong ? will it fail to solve ?

As far as I know both the friction or the frictionless contact types in Ansys doesn't prevent motion in the perpendicular direction. I have been following this tutorial https://goo.gl/w8sIlG (no need to open) but I have found something strange when I do the same but without changing the analysis...

Hi. I'm studying Finite Elements Method, I was readding a paper written by Danielle Boffi and in a part dedicated to the approximation of eigenvalues in mixed form, it's about approximating eigenvalues in the Hilbert Spaces \Phi and \Xi Then it says: "If we suppose that there exists Hilbert...

I'm in the third semester of mechanical engineering and I'm taking classes on engineering statics right now. Our professor said the he will give us a preview of finite element methods at the end of the semester. Which softwares would you recommend for learning basic structural analysis? I mean...

I am trying to numerically calculate the electric potential inside a truncated cone using the finite element method (FEM). The cone is embedded in cylindrical coordinates (r,phi,z). I am assuming phi-independence on the potential, therefore the problem is essentially 2D; I am working only with...

I am trying to set up the mass matrix for a 1D system which I want to solve using finite elements. So the mass matrix is defined as M = \int{NN^T}dL, where N is the finite element linear basis functions. I use hat functions. Say I have 10 elements, corresponding to 11 nodes running from -5...

Hi all, I have an FEM model that I am doing a modal analysis of. I wanted to check that how I am computing the physical displacement is the correct way, as I've read a lot of about normalising modes, participation factors, effective masses, etc. and I'm not 100% sure on it. I've got the...

Hey Guys! Hi Guys! Well I am new here and I have to confess that I somehow got stuck in a 3D transient electromagnetic simulation of a solenoid actuator and… I’m a mechanical engineer^^ So I would appreciate some help of you guys! 1. I imported the geometry from CAD-files. But I remodeled...

Dear all, I'm an electric engineer, and I usually work with software as Ansoft Maxwell, Matlab, Ansys, COMSOL... I need a PC for serious professional simulation, and I would like if someone can give me some tips of the characteristics I should ask for this purpose. I don't want to spend more...

Hi all, I am a final year maths student and am doing my dissertation in the finite element method. I have gotten a little stuck with some parts though. I have the weak form as a(u,v)=l(v) where: $$a(u,v)=\int_{\Omega}(\bigtriangledown u \cdot\bigtriangledown v)$$ and $$l(v)=\int_\Omega...

Homework Statement Hi, I need some help analysing this frame. First of all i bellive its hard, if not impossible, to get as detailed results by hand calculations as my softwear CSI Sap2000. Becourse of shear and axial deformation. Is it possible to obtain the stiffness matrix of this frame at...

I need to decide on whether to use Abaqus or Patran/Nastran for FEM analysis. However I am not sure what the advantages/disadvantages are of each FEM package. Also, searching on google has not come up with a list of situations where one is better compared to the other. I'm just looking for a...

Recently I created a structural vibrations simulation and would like to hear some feedback or suggestions.

Hello. I need help with the following problem: I don't know where to start. I know that the frame can be split up into one symmetric part and one symmetric+assymetric part but i forgot the theory and rules on translation and axis etc. I hope someone can help as I have to hand in the...

Hi guys, I hope this is the correct section otherwise I apologize :).The goal is to find the capacity of a non linear capacitance composed by an upper plate which has a cup shape and the lower plate which is flat. The problem is the following: by means of a FEM simulation of the Poisson...

Hi all, I have co-ordinates of 4 vertices of quadrilateral for every element in mesh. I assembled such elements by moving single, separate point in whole domain and compared it's coordinate with all vertices of quadrilateral. Above technique work properly, but it required rectangle element...

Please suggest me, how to generate weak form or functional of any partial diffrential equation ( mostely second order) in Finite Element Method. Thanks in advance.

Dear All, How important is the node numbering scheme for simple fem problems or is it important at all? It will be much easier to explain that by example, if I have following linear algebraic equations to solve with direct stiffness method \ K*\left\{X\right\}=F where K global stiffness...

Homework Statement I have this question. I need to know the diformation in P direction. Here is the question I use the symmetry and finally with a 1/4 modell I get the following: which is correct according to the instruction. K is the stiffness of the spring. which with symmetry becomes...