What is Fem: Definition and 86 Discussions

Fem2Fem was an American techno group in the 1990s who released three albums. With actress Lezlie Deane of Freddy's Dead: The Final Nightmare as a member, Fem2Fem were the first and openly lesbian pop group to chart, although the band did contain straight women in addition to open homosexuals. But only some of the members of Fem2Fem were lesbians, and according to Michelle Crispin their intentions at the beginning were to promote a healthy view of sexuality with their music, regardless of sexual orientation. However, an appearance by the band in the December 1993 issue of Playboy magazine and the non-political nature of their sapphic lyrics led to criticism by some in the LGBT community that the band was trying to make a fast buck off playing to the prurient interests of a heterosexual male audience.

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1. Static B.C & first moment of area of connecting rod

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...
2. B Solving PDEs via FEM: A Gut Check of the Procedure

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...
3. B Incorporating boundary conditions in the Finite Element Method (FEM)

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...
4. How does FEM software compute inertial forces?

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 ?
5. MATLAB FEM, Matlab and the modes of an element

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...
6. Modal mass and kinetic energy in FEM modal analysis

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...
7. A A question about current density in finite element analysis

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...
8. I FEM Method in 2D with Triangular Elements

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...
9. A FEM basis polynomial order and the differential equation order

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}...
10. I Solving 2D Heat Equation w/ FEM & Galerkin Method

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...
11. I FEM 2D Node Equations: Setting Up & Examples

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...
12. I FEM Method for the Wave Equation

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...
13. Engineering Book considering FEM analysis for complex eigenvalues (incl. damping)

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?).
14. I Can FDM solve any type of PDE same as FEM?

hello aside from some constraints such as an irregular integration domain, can FDM solve any type of PDE same as FEM ?
15. Why Does the Trigonometric Function in the FEM Calculation Differ?

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...
16. How to Choose Between FDTD, FEM and MoM | Open-Source Codes

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...
17. What size is the Global Stiffness Matrix in this Example?

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
18. Poisson ratios for Orthotropic materials (composites)

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'...
19. I Mixed topic : from FEM to analytical solution via limits?

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 ?
20. A FDM vs FEM: Which is Better for CFD?

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?
21. Total energy (ETOTAL) is not zero and increasing (Abaqus)?

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...
22. Find the resistance and EMF in a circuit

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...
23. How to measure the magnetic field/ induced fem in a system

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...
24. Which strain tensor is used by Abaqus?

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...
25. Solving 2D FEM Error with Maxwell Version 17

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...
26. Abaqus FEA Problem - Displacing an Entire Part at Once

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...
27. Methods for Damping High Frequencies in FEM Thin Film Model?

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...
28. ANSYS MAXWELL SIMPLORER Solution Error

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...
29. A FEM for Solving PDEs: Beginner Textbooks & Fluid Flow

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...
30. FEM - eigenvectors from eigensystem

Homework Statement It's not really a homework so I will try to be as clear as possible. Hopefully, somebody will understand me and be able to help. I used Euler-Bernoulli theory to analyze the dynamics of a free-free beam (for the problem it is not important to understand what it is). If one...
31. Can complicated models with web openings be accurately analyzed with a 5x5 mesh?

I am using Abacus 6.13 for development of FEM for test setup on shear capacity of cold formed steel section. it has some complicated interactions with those interaction only solid section model gives answers.but with web openings on section it has convergence problems. i tried with different...
32. Ansys 2D Workbench Simulation: Symmetry & Convergence

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...
33. Large Deflection Ansys: Solving w/o Large Deflection?

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 ?
34. Friction-less / Friction contacts in Ansys

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...
35. How can we derive equation 5.177 using the Remainder Theorem?

Could someone please explain me how can we get equation 5.177? Thank you so much for your help
36. MBS vs FEM: Differences Explained for PF Users

Hello PF Users! First of all spent a good time at forum. I'm a newbie about this topics but i wonder why we need MBS (Multibody Simulation) Simpack, Adams etc.? Why the FEM programs don't fullfill the MBS capabilities? abaqus
37. A FEM, Space embedding doubt

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...
38. Software for learning structural analysis and FEM?

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...
39. Can You Help With Finite Element Analysis in Cylindrical Coordinates?

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...
40. FEM: periodic boundary conditions (1D)

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...
41. What is the correct way to compute physical displacement in FEM modal analysis?

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...
42. Transient FEM Simulation of a Solenoid Actuator with MAXWELL

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...
43. How to figure out Mcr (elastic critical moment) beams (abaqus)

I would like to figure out Mcr(elastic critical moment) and Mpl (Maximum plastic moment) in a beam due to buckling in abaqus. How to model material non linearity. How to model geometric imperfection (slightly crooked beams) Is there any way to import I section (rolled) profiles instead of...
44. PC Characteristics: Simulation FEM professional purpose

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...
45. FEM: How the weak form is related to an inner product

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...
46. FEM, FEA, Frame, Moment, Shear, find Stiffness Matrixx

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...
47. Comparing Abaqus/Patran/Nastran for FEM Analysis

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...
48. Structural Vibrations Analysis & Simulation

Recently I created a structural vibrations simulation and would like to hear some feedback or suggestions.
49. FEM stiffness matrix for simple frame exploiting symmetry

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...
50. How to get capacitance from potential FEM

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...