Questions tagged [finite-element-method]
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155
questions
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17 views
Solution of st venant equations using fortran
I tried to write code to solve st venant continuity and momentum equations in FORTRAN 90, with given slope and rainfall and find out the discharge. But I stuck in the procedure to find overland flow ...
1
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0answers
16 views
Extracting load info on Abaqus with Python
I have a model on Abaqus that I've managed to run some 85 jobs on manually. Between jobs, only the loads vary, and I select these loads by resuming what I need and suppressing what I don't with my ...
0
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1answer
57 views
2D- Truss Member Analysis
I am a graduate student trying to sharpen the direct stiffness method skills. However, I am stuck at the beginning.
The problem is given in the image.
Can someone help me to write down all the nodal ...
0
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1answer
24 views
Finite Element software for chemical diffusion in liquid
I'm an engineer who needs to do FEA for the first time. I need to model chemical diffusion in a liquid in a container with specific geometry. For now fluid is assumed to be not flowing.
What ...
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9 views
How to get version from an abaqus output database file?
I want to read some data from an .odb file, but when I open it using the C++ API I always get this error message:
file.odb is from a more recent release of Abaqus.
The current Abaqus ...
1
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0answers
26 views
What is the difference between $K$ ,$K_{IC}$ and $K_t$?
I have seen three representation of stress concentration factor values $K$,$K_{IC}$ and $K_t$ now all that I know is $_I$ in suffix represents opening mode of crack.The suffix $t$ stands for tip....
0
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2answers
68 views
Why is finite elements method not part of electrical engineering curriculum?
The question is straightforward. FEM is a third year course in mechanical engineering but not generally taught in electrical. Why is this?
0
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1answer
27 views
Issue with collapsed element in LISA Finite Element Analysis
I'm new to the FEA world and trying to learn the ropes through resources available online. I've imported a model into LISA FEA that I would like to analyze, however, when I press solve to conduct my ...
1
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1answer
26 views
How do I import an .inp and an IGES together into Ansys workbench?
I have an .inp file of Ansys that is basically a mesh, that could be imported into Ansys APDL and converting to .cdb file.
But ...
0
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0answers
17 views
Simufact / MARC and Fortran
I am using Simufact from MSC Software to perform numerical simulations.
To be able to create my own sub-routines I need to have Fortran compiler installed.
Simufact manual mentions only Intel Fortran +...
0
votes
2answers
50 views
How are the location of Gausian points determined in Finite element theory?
From the finite element theory, what is remained a bit unclear for me, is that how do we know the location of gausian points where the integration is done for each specific type of element ? it is not ...
0
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1answer
40 views
Is Belytschko beam defined for 3D or 2D?
from the paper in this link , which is the Belytscko beam. I could not figure out if it is a 3D beam or a 2D one.
if you don't have access to that paper, please check the page 73 on this link.
what ...
0
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2answers
25 views
Is Model order reduction good for complex models with a lot of contact points in them?
we know that MOR ( or model order reduction ) is used to reduce the size of heavy FEM models. but if there are so many faces, edges of the part that are in contact with another part in the model or ...
0
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2answers
34 views
FEA software for Orthotropic materials
What FEA software is capable of simulating static studies on orthotropic materials such as wood? I must be able to define mechanical properties in X,Y and Z. I would also like to have access to ...
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2answers
39 views
What does stress analysis of 3D printed parts reveal vs their normal counterparts?
I have seen videos or heard about 3D printed buildings, 3D printed space shuttle parts and more. There seems to be a lot of craze developing around 3D printed manufacturing.
I have never heard anyone ...
1
vote
1answer
53 views
How is the stress concentration factor calculated in FEM?
I have written my own finite element code for a linear elastic (plane stress) problem consisting of a plate with a circular hole in the middle, fixed on one side, having a tensile force acting on the ...
2
votes
1answer
66 views
How to analyze a bent beam: Stress concentration?
I am analyzing a beam, that has a bend in it. Intuitively and inspecting FEA results using a linear solver, there is a stress concentration at the bend of this I-beam.
When I was learning about ...
1
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1answer
48 views
FEA: What is the difference between a spider of RBE2s and multiple SPCs
I am not sure what the difference is between using a spider of RBE2s. and multiple SPCs across a face. I've heard that the spider is the more accurate method as multiple SPCs make the model overly ...
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0answers
18 views
abaqus simulatioon
USING ABAQUS SIMULIA 6.13 hysteresis low cycle fatigue of isotropic and kinematic hardening .I use combine parameters but no yielding occurs and hysteresis force disp loop area is zero .I also need ...
0
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0answers
66 views
how did Abaqus integrate the predefined field (stress) into the FEA formulation
The formulation based on the dynamic virtual work equation is
Several boundary conditions can be applied. One of them which Abaqus provided is predefined field (stress). It gives the stress tensor ...
0
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0answers
45 views
Traction Force or Reaction Force
I am doing an FEA of a link plate of a chain drive system. the plate is subjected to traction force at one pin joint this particular link is in contact with the sprocket. it is also in contact with ...
0
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1answer
71 views
Finite Element Code: Convergence issues
I am trying to code a simple FEM problem. A bar is fixed at the bottom edge, and a displacement is applied at the top. I want to apply the displacement gradually , so I have divided it into a number ...
0
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1answer
25 views
Find amount of sliding between 2 surfaces
in my project I am required to find how much two surfaces slide against each other (to see how much it'll will rub against skin). Does anyone know how I can find these results?
Thanks
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43 views
Need help with FEA bar analysis problem
I'm trying to solve this
which is to find the total deformation of the bar.
I'm trying to implement the finite element approach, but I am getting way too large of numbers. Here is what I did in ...
0
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0answers
16 views
What's the methodology for adequate tetrahedralisation?
I'm running a linear elastic solver generating the tetrahedron's using tetGen. It's not clear to me though how one defines what's an acceptable tetra density that provides sufficient accuracy.
You ...
1
vote
1answer
80 views
FEA: Newton-Raphson algorithm for Dirichlet BC non-linear static analysis
I have a standard non-linear static problem to solve with FEA. I am applying displacement boundary conditions only, no external force. The equation to solve look like these:
$K(u)u=R(u)$ Eq(1)
The ...
0
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0answers
26 views
Interpolation at a face, Finite Volume Method in Computational Fluid Dynamics
I am learning CFD and I have come across an example in which the thermal conductivity needs to be interpolated at a face between two rectangular cells.
The face weighting factor is given as:
$$g = \...
0
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0answers
54 views
Analytical calculation vs FEA
In terms of calculated stress, strain, displacement etc which method yields more conservative results. Analytical calculation or numeric calculation?
0
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37 views
How to define hysteretic damping coefficients for both longitudinal and shear waves in Abaqus?
I am modelling the elastic wave propagating in the damped materials using the hysteretic damping model, but the longitudinal and shear waves usually have different damping characteristics.
How ...
0
votes
1answer
151 views
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 ...
0
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1answer
72 views
Boundary conditions in a heat transfer problem
One end of a small insulated rod is attached to a support which is maintained at a constant temperature of 473 K,and once the rod has reached a uniform temperature in its entire length the insulation ...
0
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1answer
67 views
How to get laminate stiffness matrices (ABD) in APDL ANSYS?
I am trying to perform structural analysis of composite pressure vessel in APDL/ANSYS. I have completed the solution and now I want to extract ABD matrix.Do anyone have an idea about this?
0
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1answer
261 views
Shape Functions of beam element with 3 nodes (quadratic element)
For a two node beam element there are four shape functions for four degree of freedom:
For a straight three node beam element how shape functions are?
Please note that beam is straight and not ...
0
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0answers
22 views
Source for learning Functional derivative , Gateaux derivative
I have started doing research in optimal control theory. My area of research is PDE constrained optimization.
I am facing significant difficulty in deriving the Gateaux Derivative of functionals ...
1
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1answer
30 views
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 ...
0
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1answer
43 views
Finite element method, question about the solver
So I am working with COMSOL Multiphysics and I have a very complex simulation. I have a boundary condition that evaluates to 1 if the value of a variable is 20 and 0 otherwise. I could implement my ...
0
votes
1answer
88 views
How to perform 3 point bending test by using force instead of displacement in ABAQUS?
I know you can apply displacement to a rigid body (cylindrical rod) to perform a 3 point bending test in ABAQUS. Is it possible to apply force to the rod (e.g. rod with super high young's modulus so ...
1
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1answer
54 views
How to introduce the CONSTITUTIVE equation into structure mechanics [closed]
Suppose I have stress and strain relationship and it can be simplified to the equation $\sigma=Function(\epsilon)$. This is the CONSTITUTIVE equation of the material I want to do research.
Assume ...
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0answers
66 views
How can I do engineering projects for money at home? [closed]
I am a M.Sc. graduate in mechanical engineering and I have experience with engineering software, like MATLAB, CATIA, and ABAQUS.
I want to know how I can find industrial projects like finite element ...
1
vote
1answer
48 views
Calculate surface area and outward normal of each face(non-planar) for a irregular hexahedron.
I am using the vector cross product to calculate each surface area and thus the outward normal. However, this approach fails when the surfaces are non-planar. So what is the best approach to calculate ...
1
vote
1answer
53 views
Stress Tensor decomposition into Compression & Tensile forces
I'm working on a project that does a finite element simulation of a mesh. I can output the stress tensor at each node, but I'm not so sure how to implement failure criteria.
If my material is brittle,...
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0answers
12 views
Is it possible to change a 'relaxing length' of edges for 8 node hexaedral element in 3d FEM
I am using 3D FEM with 8 node brick element to model a certain type of growth/expansion, which is not a plastic deformation. First, I apply a pressure/load and I get displacement and new position of ...
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0answers
71 views
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 ...
2
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0answers
37 views
Force exerted on the CPU socket by heatsink
I am currently designing a replacement bracket for AM4 CPU coolers that will be compatible with different cooler models and allow them to be installed facing different directions, as AM4 socket is non-...
1
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0answers
30 views
Joint Revolute or Fixed?
a shaft is driven by a motor, it is supported in two places by ball bearings and connected in third place by a motor.
how can I use this example in Ansys WB?
1. variant : two places, where the bearing ...
1
vote
1answer
167 views
Model Reduction - Export matrices from ANSYS to MATLAB
I am trying to reduce my model in ANSYS using Craig-Bampton Method.
My ultimate goal is to read system matrices, stiffness, damping and mass matrix with MATLAB.
The size of stiffness matrix that I ...
0
votes
1answer
41 views
Curve-linear vs. Cartesian coordinate systems: linear-elastic & isotropic elasticity tensor
For shell elements, is the elasticity tensor for linear-elastic & isotropic materials the same in a local curve-linear (convected) system vs. a local Cartesian system?
I wonder because ...
2
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2answers
549 views
Viscoelasticity and Hyperelastic model, history and difference
Actually, I see some papers use viscoelasticity or hyperelastic model for the same materials. It seems to me that those models were invented in different eras, and the hyperelastic is a newer model ...
1
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1answer
385 views
Meshing Complex models in abaqus
I'm trying to mesh a model of a morphing wing in Abaqus and have been running into issues. It was recommended that I partition the model into smaller parts, but it seems that the more I try to ...
0
votes
1answer
72 views
Boundary Conditions fro Static Structural Analysis of a Turbine Rotor Using FEM
I am trying to perform static structural analysis of a turbine rotor which is rotating at a given angular speed, say 1000 rad/s. I also know the pressure distribution from CFD analysis. What are the ...
