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Questions tagged [finite-element-method]

300 questions
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PATRAN Order of Operations

To preface this question, almost all of my FEA experience has come from SolidWorks, so I haven't had to deal with these types of problems. I'm designing a truss structure in PATRAN composed of 1D line elements. At some point, I have to do the…
Anonymouse
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What are the methods for assessing accuracy of FEM models?

What are the methods for assessing accuracy of FEM models? That is, to guide the development of a FEM model, and finally for assessing its reliability, what kinds of practices are used? Sometimes it might be impossible to compare a model to a…
mavavilj
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In FEA, why is the stress at an interior angle (<180 deg) is a singularity and an exterior angle (>180 deg) it is not?

If you observe the attached figure, I heard some FE analysts say that the stress at the interior corner is always a singularity (but its intensity depends on the value of interior angle) but the stress at an exterior corner is not. I cannot…
Rameez Ul Haq
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FEM of beam with unsymmetrical UDL

I have two different UDLs for 6.5m and 3m spaced side by side on a primary beam. If I were to calculate the FEM of this beam, how should I proceed as there're no formulas for situation particularly like this (unsymmetrical UDL on beam) on the FEM…
Sady
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How to determine the stiffness matrix for finite element matrix

I'm having difficulty understanding how the stiffness matrix for finite elements is obtained. I am only having a difficult time understanding how to obtain the matrix values for K from the given information, but understand how to do everything up to…
Barrett Cloud
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How accurate should Rayleigh-Ritz approximation be?

For a simply supported beam with a UDL, with boundary conditions of X=0, V=0 & X=L, V=0. Using a cubic trial function. $$V=a+bx+cx^2+dx^3$$ The following curve is obtained (Red Line). It is shown in comparison to the simple beam theory curve (Blue…
FEA42
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Rayleigh-Ritz method, calculating slope of beam?

For a simply supported beam with a UDL if the deflection is assumed to be: $$V=a+bx+cx^2+dx^3$$ What is the formula for calculating the slope? I thought it would be: $$θ=dV/dx$$ However, working through examples where I calculate the values for the…
FEA42
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Minimum number of tetra elements required, to represent a cube?

What is the minimum number of TET elements you need, in order to fully fill a cube(HEX element)?
Trenera
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What are the governing equations solved in FEA for structural mechanics?

In CFD we focus on the NS equations as the governing equations (together with other equations) and solved them using Some numerical method (usually FVM). What are the governing equations (counter parts of the NS equation) in solid mechanics?.
GRANZER
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Can boundary layer theory be applied in finite element methods as it is applied in finite volume method?

Can boundary layer theory be applied in finite element methods as it is applied in finite volume method? i.e The flow away from the boundary is considered inviscid and solved first, then the flow inside the boundary layer is solved?
EngDR
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Modelling radial Stiffness in Patran Usinf CBUSH Element

I am currently working on a project using MSC Nastran and Patran trying to model only radial stiffness between two hollow cylinders. I have been able to idealize a connection which has both radial and axial stiffness in a cylindrical coordinate…
Jack Boggs
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Do finite elements have to be planar?

Is it possible to define a finite element that isn't planar? For example the shell element shown in the picture below...
DrBwts
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Nitinol FEA using Advanced Simulation NX

Is there a tutorial on how to do non-linear FEA using Siemens Advanced Simulation NX (not remap) with Nitinol, preferably using sol 601. An example would be very helpful, I searched online but most just have Ansys or abacus examples.
user112644
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COMSOL modelling wicking of paper in 3D

I am trying to model wicking of paper in 3D, by following the tutorial for paper wicking in 2D on the COMSOL Application Library , but ran into this error: Undefined variable. Variable: phtr.pc_s2 Geometry: geom1 Boundary: 3 Failed to evaluate…
Richard Casey
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Aligning stresses from one element to another from FEM

I have a Finite Element Model (FEM) and from this model I want to transform the stresses of one element such that they align to another element's axis. Element A: Centroid: [7195, 5151, 479] Direction: [0.921, 0.374, 0.106, 0.370, -0.927, 0.047,…
Byron Piper
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