Questions tagged [finite-element-method]

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ANSYS APDL Shape memory effect option of SMA not working

I am trying to define the material properties of a shape memory alloy material in ANSYS APDL V15. There are material properties for Superelastic materials (SUPE option) and material properties for ...
7
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0answers
500 views

Incompressible 2D pressure-driven flow: for Navier-Stokes equations in nondimensional form, how should I express pressure boundary conditions?

*I have updated this question. I'm using two codes for modeling incompressible, two-dimensional flow out of a tank. My fluid dynamics experience is pretty basic; I'm using the codes to understand a ...
5
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1answer
91 views

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 ...
5
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1answer
855 views

How can we derived the equivalent Lumped Mass Model for irregular building and how to calculate the errors?

Intuitively, building can be represented as a lumped mass model ( the taller the merrier!): Assuming a building is a lumped mass cantilever column also makes the global stability checks easier ...
4
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1answer
591 views

Interference fit problem in ANSYS Workbench 16.1 - how do I get rid of pressure/displacement raisers?

I have an interference fit problem of two perfect cylinders modelled in 2D using symmetry. The overall interface pressure is around 20MPa lower than the hand calculations and I get non-uniform ...
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0answers
28 views

How do FE solvers solve the case of panel buckling under pure shear?

How do FE solvers solve the case of panel buckling under pure shear? The main problem is that global matrix of initial stess is singular in that case. One method is to apply some forces that shear is ...
3
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2answers
156 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. The part was not a straight I-...
2
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0answers
20 views

Solidworks Simulation- Large displacement with Inertia Relief

I'm trying to use the Solidworks simulation package to solve for the stresses inside a body as it accelerates (very rapidly). Because I expect some small features to deform quite a bit, I need to use ...
2
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0answers
30 views

Can the critical buckling load from non-linear FE calculation be higher than the one from linear?

Let's consider a FE buckling calculation without plasticity. Is there theoretically any chance that the non-linear analysis will give a higher buckling load than the linear one?
2
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0answers
47 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-...
2
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0answers
51 views

Bolted joint junker test with finite element method

Anybody knows a tutorial to make a finite element analysis for bolted joints like junker test(fastener vibration) in Solidworks or Ansys?
2
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0answers
561 views

how to release specific degree of freedom in ANSYS Workbench?

I'm designing a truss which has 9 elements in ANSYS Workbench. since it is a truss, all of the elements are truss elements and can not tolerate momentum. I used <...
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0answers
20 views

Pin connection on beam - FEA analysis

I am establishing a MatLab FEA code for determining the stiffness of a structure. Diagram of the structure is added below. I have established a code for determining the stiffness of the structure, but ...
1
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0answers
21 views

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 ...
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0answers
16 views

Ansys Fluent - Turbulent model and mesh

I am currently working on a project that involves CFD simulation on ANSYS and i need some help as it has got me stuck. I am designing a faucet atomizer and it's functioning is similar to a nozzle. I ...
1
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1answer
36 views

How to repeat on ABAQUS FEM simulations without reloading the mesh?

I would like to perform several FEM simulations on a given mesh with ABAQUS, where only the orientation of an element set would change in between. Currently, I'm just generating several inp files (...
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0answers
17 views

Linear FEM: Infinitesima Strain tensor at different element mesh

Hi guys, I am solving an exercise for a course of Computational Continuum Mechanics. Briefly, my question is how can i compute the infinitesimal strain tensor at different nodes of the finite element ...
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0answers
21 views

In Nastran, how to ignore fatal error due to failed convergence and move on to next subcase?

At the moment the whole analysis stops when 1 subcase fails to converge. How can I keep the analysis going such that all subcases are are run, even if they all might produce an error? I'm pretty sure ...
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0answers
21 views

Assign a name to surface in CAD STEP file

I have a CAD model designed in FreeCAD and need to export it to a STEP file (neutral CAD format) to be used in numerical anaysis software. I would like to assign names to selected surfaces in order to ...
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0answers
34 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 ...
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0answers
30 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....
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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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137 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 ...
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1answer
322 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 ...
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1answer
617 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 ...
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0answers
94 views

Modeling Rotation and Translation of surface B.C. in Abaqus

I am trying to model a test which has grips that can translate in X and Y directions, as well as rotate. I have been trying to model this using constraints and a reference point but have not been able ...
1
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1answer
301 views

Debugging Ansys ACT C# Extensions

I'm using the Ansys ACT Api with C# to create an extension for Ansys (Mechanical). When developing the extension I need to build a dll file from C# code (using Visual Studio). My problem is that ...
1
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1answer
105 views

Modelling acoustic instruments — predicting frequencies, decays, levels, and phases of modes of a circular membrane (drum head)

I have been working on some acoustic synthesis software for modelling several acoustic instruments. I am using the principle of modal synthesis, where every mode of vibration is individually ...
1
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0answers
40 views

Where to fix part in moment setup for FEA

I'm working on a project that involves supporting a distributed load on a bar that is held up by a moment at one end of a lever arm. My goal is to assess how much the bar bends under the distributed ...
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0answers
542 views

How does Abaqus calculate reaction force?

I wrote a UEL for one element and compared to a reference UEL (FEM), where the results agreed satisfactorily, except the reaction force. The stress, strain, strain energy all were pretty accurate. I ...
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0answers
30 views

Searching for Anterior Cruciate Ligament MRI Images for Finite Element Model.

I'm searching for 3D MRI images for generating an mesh to be used in a Finite Element Modeling project. My group has access to a low-resolution CT scan and cadaver knees, but we don't have any good ...
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0answers
385 views

How to convert solid part to shell part in Abaqus?

I want to compare the same model with solid shape and shell shape, since my model is big, I am wondering if there is a way to convert the solid part into a shell in Abaqus easily without creating a ...
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0answers
1k views

Calculate the Euler buckling load of a column using the finite element method

I am trying to find the buckling load of following column: I started from the system of equations $P = (K + K_g(N))U$, where $K$ is the stiffness matrix of a single 2D frame element and $K_g$ is the ...
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0answers
332 views

Beam element stiffness matrix for variable area cross section with mass and shear center not coinciding

I would like to find the full (12 by 12) Timoshenko beam element stiffness matrix for a variable cross section with mass center axis and elastic center does not coincide. I have the full stiffness ...
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0answers
27 views

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 ...
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0answers
1k views

Creating a custom field output in ABAQUS

I want to create a custom field output in ABAQUS. For the purpose of proof on concept, I want to display the maximum shear stress as calculated from the Mohrs circle, as discussed here for a 2D shell. ...
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0answers
92 views

External FEA confirmation

The exact question Assuming you have outsourced a FEA of a structural design (steel tubes and sheet metal, bolts and welds design): What would you look for in the report to have confidence in the ...
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0answers
142 views

How to simulate Ground Penetrating Radar system?

We have a project which requires Ground Penetrating Radar(GPR). We got a student license of NI AWR software and Ansys HFSS (high frequency structural simulator). Are those the correct software for ...
1
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0answers
296 views

“Set redefined” Error When Running a Restart Job in Abaqus 6.12-1

Using Abaqus 6.12-1, I am trying to submit a restart job with an added step. I've followed exactly the instructions in section 19.6.5 of Abaqus 6.12-1 CAE user's manual, but receive this error: A ...
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0answers
787 views

Linking ANSYS workbench with excel

I was trying to use the new interface of ANSYS Workbench to couple ANSYS with Excel without learning Python. I'm having problems because I can only set one parameter in Excel, like one cell. Once I ...
1
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1answer
36 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 ...
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0answers
5 views

Remote point vs point mass in Ansys

I have seen the feature of promoting a point mass to remote point and I cannot figure out what are the use cases of using that feature. I understood that you can add command snippet below remote point ...
0
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1answer
42 views

What is the meaning of “load case consistent” in stress analysis terms?

I’m a (junior) stress engineer and have been tasked with sizing a lug. Various loadcases have been run through FEM and loads have been distributed into the lug bolt for each. In other words, each ...
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0answers
30 views

Why is the functional of an elastic system equal to it's total potential energy and why is it stationary at it's minimum?

Okay this was even quite difficult to formulate but let's start with some statement's in my FEM book: Elastic continuum has a functional which is equal to it's total potential energy Elastic system ...
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1answer
34 views

Analytical solution of thermal stress in a bi-metallic cylinder

As a side project I have looked to solve using Python an analytical solution for one-dimensional transient heat transfer in a thick cylinder with cladding on the inside surface, wherein the fluid in ...
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0answers
4 views

Magnetization characteristics and static characteristics of SR motor from Ansys Maxwell. Part II

Continuing the topic: Magnetization characteristics and static characteristics of SR motor from Ansys Maxwell Are there any people in the community who are more or less familiar with Ansis Maxwell's ...
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33 views

Provide stability for a 3D object with a support structure

This is a follow-up to this question. I wonder if structural engineering tools like Finite Element etc. might help create such support structures. If so, how?
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42 views

ABAQUS UMAT SDVINI problem

I'm trying to write a UMAT code for unsaturated soil model and I need to define some state parameters. I found that I can do that by using SDVINI subordinate. Should I put it at the and of UMAT? How ...
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0answers
18 views

Simulating heat conduction on a 1-D Fin

I am trying to simulate the heat conduction on a 1-D fin. The problem I am having is that I do not know how to properly calculate the temperature in the last point of my 1-D grid. We were asked not to ...
0
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0answers
22 views

Defining appropriate test function spaces for the finite element solution of Euler's fluid equations

I have the following coupled equations for the conservation of mass and momentum of a compressible fluid \begin{equation} \rho_t + (\rho u)_z = 0, \end{equation} $$ (\rho u)_t + (\rho u^2)_z + \...