Questions tagged [finite-element-method]

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1answer
939 views

What are exact location of Integration Points in STRI3 element in ABAQUS?

Introduction I have a file with .rpt extension from ABAQUS which is output of a model. This .rpt contains stresses of elements and displacements of nodes in plane text format. There is an item with ...
2
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1answer
160 views

FRF based material constant optimization

I need advice on how to optimize a finite element model of a transversely isotropic material. I have modeled the material with 5 nominal moduli in Abaqus and performed an eigenvalue extraction. ...
0
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1answer
234 views

Calculate force that can be exerted by a bending actuator

I have a model of a cantilever (fixed on one end, and free on all other boundaries) that bends in response to an internal stress field. How can I calculate the amount of force this cantilever can ...
1
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1answer
156 views

FEA: Changes in initial geometry cause divergence of solution

In this previous quesiton I posted, alephzero kindly noted that many of the convergence problems I was having were due to extremely high slenderness ratios that NASTRAN did not feel comfortable ...
6
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0answers
158 views

How to simulate a crack in a PCB? [closed]

I want to break this PCB with some know force of X newtons in the bottom left tip of the PCB. The problem is that in Static Dynamics I just get infinite deformation and in explicit dynamics I really ...
2
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1answer
890 views

Deformation gradient, strain tensor from cylindrical coordinates

I do not have any engineering background but I am studying some mathematics to try and understand and solve this problem. I have a mesh (M1) in cylindrical coordinates and this deforms into a mesh (M2)...
4
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1answer
370 views

FEA: What boundary conditions am I missing?

I'm working on a 2D-model (in the xy-plane) in NASTRAN and am getting convergence problems. The main cause of these convergence problems is a "high or negative matrix factor diagonal ratio." I've ...
0
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2answers
14k views

How to distinguish primary and secondary beam in FEM formulation?

Assume that I am writing a new FEM software for structural analysis, it shouldn't really matter whether this is a frame or frame+shell element analysis tool. I understand that primary and secondary ...
1
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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 ...
7
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0answers
502 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 ...
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 ...
1
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1answer
2k views

Ansys Workbench - adding force in point

How to add force in certain point. I want to see influence of point force on my structure. (See image) That force is for example weight of some tank or something similar inside my structure. I don't ...
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 ...
4
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1answer
174 views

Determining the microstructure of steel after welding in modern computer software

How can the microstructure of steel after welding be determined in modern computer software? I am aware that there are 'classic' methods of predicting microstructures like Schaeffler, DeLong or WRC ...
5
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1answer
857 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 ...
6
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1answer
624 views

How to derive Equivalent Static Load for irregular structure modeled with FEM?

Building codes such as the Uniform Building Code (UBC) or International Building Code (IBC) require the determination of Equivalent Static Lateral Forces in order to compute $P-\Delta$ effect and to ...
1
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1answer
1k views

Rayleigh damping in Finite Element Models using beta-coefficient only [closed]

I am modelling a railway track in ANSYS where the different soil layers have different material properties (including different damping ratios). Since I know what frequency of vibrations to expect in ...
8
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1answer
2k views

Derivation of the weak form for the euler-bernoulli beam ewuations

I am master student and doing an assignment of Finite element method. In the instruction I could not understand the derivation of the weak form, which should not be difficult. I'm sorry for posting ...
1
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1answer
1k views

How to find the angle of deformation in Ansys APDL?

After solving my problem in APDL, and started doing some post-processing, I want to find how much the deformed shape has rotated (i.e. the maximum angle the furthest node has made comparing with the ...
7
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2answers
749 views

How do I use FEM to derive the torsional constant of an arbitrary shape?

In this question I ask about how to perform a first-principle derivation of the torsional constant of a section. It appears that there is no such analytical derivation for torsional constant, so my ...
4
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2answers
2k views

How to model elastic support in FEM?

I need a 8 m x 4 m x 0.6 m RC plinth (mechanical requirement) which needs to be built onto loose gravel. Obviously I am going to over excavate, back fill with selected material and bed my plinth on ...
6
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4answers
2k views

How should one model a structural model with both line elements and area elements?

I am modelling my structure using FEM, and my structure contains line elements (1D) such as beams and columns and area elements (2D) such as walls and columns. My question is that, how can I proceed ...
7
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1answer
1k views

Modeling Transient Heat Transfer between two 1-D materials

I have been working on creating a 1-D model of a material with a layer of heat resistant material stuck to it. For this I have been trying to use the implicit finite-differential method. The equations ...
5
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2answers
3k views

ANSYS Workbench/Mechanical: Automatically export chart?

I'm running a simple tensile test simulation for a single element. Under Results I made a Chart object with Stress vs Strain, which can be manually exported to a csv file by right clicking on the ...
3
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2answers
19k views

What is the difference between implicit and explicit analysis in ABAQUS?

How can I choose between Implicit or Explicit Analysis in ABAQUS for a simple rectangular composite structure with 2 layers of unidirectional lamina? I am trying to do a linear-static analysis to ...
8
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1answer
330 views

Simple Finite Element Modeling of Wall Piers

I'm working on analysis of a bridge wall-pier for dead and live loads. When modeling the pier in finite element software (LARSA), I'm running up against several modeling questions: Is it valid to ...
3
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2answers
282 views

Stiffness Method FEM - Slender Members

If a member is very slender then its length will be large compared to its cross-sectional area. I've heard and read that slender members can potentially cause the stiffness matrix of a beam/frame ...
7
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2answers
264 views

Modelling splashing water in FEA

I'm running an FEA on a vessel that has a "splashing water" effect with vibrations. The problem I'm really coming up against is what kind of Young's Modulus and Poisson's ratio to use for the fluids? ...
2
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1answer
727 views

FEM 3D truss analyzer produces forces that do not sum to zero at joints

I am writing some code for the analysis of 3D truss structures. The program is a typical implementation of the direct stiffness method for truss elements. While testing it and comparing results to ...
4
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2answers
5k views

Results for Bending Moment using BEAM188 on ANSYS APDL

I'm doing a static analysis on a uniformly loaded cantilever beam in ANSYS APDL. I'm using BEAM188 with all the default options, so it uses linear form. for the element behaviour, which I think means ...
6
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1answer
908 views

FEM modal analysis computing displacements

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 normalizing modes, ...
1
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1answer
1k views

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)?
12
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3answers
439 views

Exploiting fluid dynamics for the optimal design for gas mixing in a furnace

Background This is the standard design for a thermal furnace used in the Clauss process, which converts H2S to SO2. The main problem with the furnace is that gas mixing is rather poor and results in ...
8
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1answer
572 views

How do I best model a torque applied over a non-radial line?

I am looking to use FEA (specifically, Creo Simulate) to re-create the results of a static strength test on a part my company will be testing in our lab. Because the lab results are the ones we will ...
4
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2answers
1k views

What amplitude is used for a finite element modal analysis excitation?

In a typical finite elements analysis package, a modal analysis gives the N first natural modes, and it is possible to get the equivalent stress and total deformations for each of these frequencies. ...
8
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6answers
522 views

Can two different modeling programs be used to confirm the results of each other?

Computer Models Computer modeling is used in various engineering fields. I am specifically considering structural analysis or finite element analysis (FEA). Sometimes models are used to speed up ...
9
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0answers
1k views

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 ...
5
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2answers
496 views

Evaluating performance of heat sink designs without finite element simulation

I have the opportunity to do a few metal 3D prints for just the material cost, and would like to experiment with the performance of heat sink designs (mostly for fun). Since I have no experience ...
17
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5answers
948 views

Meshing of complex geometrical domains

When using the finite element method, I have always used either already meshed domains or very simple ones. From what I've heard, meshing complex geometries is often outsourced to specialized ...

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