# Questions tagged [finite-element-method]

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### How can I determine the best thicknesses of a circular plate to achieve minimum weight and high strength?

I want to design a circular plate made from iron ductile material, So I want to determine the best thicknesses of the profile (t1,t2,t3,...etc) as shown in the image tyo achieve the best plate weight ...
22 views

### What is the difference between maximum principal strain and maximum in-plane principal strain?

For the purpose of answering/explaining this, it does not need to be restricted to strains (i.e., it can be stresses too). I am mainly trying to understand when to use which one (i.e., if I am ...
30 views

### FEA meshing of irregular geometry

I work on the simulation of sand particles and usually use tetrahedral free-meshing to represent their complex geometries for finite element analysis. I have recently spent some time looking into ...
128 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 ...
26 views

### Deformation Due to Material Removal and Residual Stress

Suppose I have a piece of metal (of arbitrary geometry) with some residual stress profile. I then remove a chunk of the metal and the piece of metal deforms (due to the residual stress). For ...
303 views

### What is the difference between Frictional non-linearity and Geometric non-linearity in FEA? (In terms of Stiffness matrix)

For geometric non-linearity, we know that as the geometry changes during the analysis, the global stiffness matrix changes since it already is a function of geometry of the structure. What I want to ...
18 views

### Checking if a Residual Stress Field Achieves Mechanical Equilibrium

Suppose I told you the Cauchy Stress Tensor at every point inside a chunk of metal. And, yes, I know this means that I would need to tell you about an infinite number of points - let's ignore that ...
1 vote
24 views

### What is the meaning of the traction continuity condition in the generalized momentum balance (continuum mechanics)?

In Nonlinear Finite Elements for Continua and Structures by Belytschko and al. it is stated: As we have already noted, the strong form, or generalized momentum balance, consists of the momentum ...
1 vote
67 views

### Why do Eigenmodes of a rigid system also diagonalize the Mass and the stiffness matrix seperately?

To set up my question, I will briefly recap the derivation that is usually given for eigenmodes of a system: If there is no force present, and a body is described by a vector $u$, then the equations ...
23 views

### Beam deflection for FEA model validation

I'm trying to validate an FE model that I'm using by comparing to a simplified analytical solution to the problem. The part I'm analyzing is a lug that is constrained on one end and has a point load ...
1 vote
901 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 ...
61 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 ...
24 views

### Creating a state-space representation (.m format, Matlab) via Simcenter 3D (NASTRAN) using Component Mode Synthesis Reduction

I'm trying to create a state-space representation of my FE-model using a "Component Mode Synthesis Reduction" (general form of Craig-Brampton reduction). The picture underneath shows (...
1 vote
3k 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 ...
223 views

### In FEM, what is the difference between a single element with a quadratic shape function and two elements with linear shape functions?

Using Finite Element Analysis to obtain a Weak form of a PDE, what is the difference between the two cases: A single element with a quadratic shape function Two elements with linear shape functions. ...
58 views

### Determining the critical load of a fixed beam with non-uniform cross-section?

I am a computer scientist, not a mechanical engineer, so it is absolutely possible that I am missing some basic understanding here. I have a beam that is fixed in both ends and my goal is to ...
11 views

### Specific Heat, Pore Fluid In ABAQUS

I want to model a problem that the theory behind is in the "Coupled Pore Fluid Flow and Stress Analysis" context that there is in the ABAQUS online documentation, version 2022. The link to ...
30 views

### New to AutoCAD, trying to accomplish a simple task of trying to simulate how much force can a U channel withstand

Sorry if my question or parts of it seem vague or stupid, I'm fairly new to mechanical engineering. I'm part of a team that is building a simulator platform and I am mostly at the helm of the software ...
1 vote
66 views

### Finite Element Method for Spherical Objects

I am familiar with the procedure of the FEM for simple planar objects like truss and etc. but my question would be whether it would be possible to use this method to calculate the stiffness or ...
13 views

### Deformation in nano timescales for stress > UTS

I am investigating the deformation of high-strength carbon steel past its UTS, subject to extreme pressures of order 1e+19 Pa, but applied in small timescales (100-500 ns). For a material, such as ...
24 views

### Define material from Ogden–Holzapfel two-fiber strain-energy function in Ansys

I'm trying to do a FSI simulation with properties, described in this paper and for the structural properties, the authors use an Ogden–Holzapfel two-fiber strain-energy function to describe the solid ...
1 vote
28 views

### Displacement vectors and linearised angles vectors from local finite element frame to rotated global frame

$s=R\tilde{s}$ is fine, but why $\theta=R\tilde{\theta}$? Namely: why vectors of linearised rotations $\theta_i$ and $\theta_j$ (at nodes $I$ and $j$ respectively) are rotated like they were vector ...
40 views

### Iterative Method through FEM

Due to reasons, I can not fully describe the process explicitly so I will be using substitutes to represent the variables. Nomenclature: x - an independent variable y - another independent variable Fz ...
3k views

### How to avoid contact penetration in Ansys?

I am trying to simulate contact between a flat rigid plate and a sphere. I am applying a load on the flat rigid plate and the sphere is flexible. How can I avoid this flat from penetrating into the ...
1 vote
208 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 ...
14 views

### 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] ...
1 vote
254 views

### 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 ...
161 views

### Imposing/ensuring a constant mass flow rate in turbulent flow simulation

I'm trying to simulate using Finite Elements (non commercial software) the Tube Bundle benchmark problem: http://cfd.mace.manchester.ac.uk/ercoftac/doku.php?id=cases:case078&s[]=tube&s[]=...
12 views

### Deformation Under High Pressure

If a FEA model suggests that a material deforms in a certain way for a max pressure of 1e+11, 1e+13, 1e+15, can it be suggested that the same "direction" of deformation would be true? I have ...
1 vote
64 views

### Is there a specific way to simulate porous structures?

I tried to simulate an axial compression test for a lattice (porous) structure but It takes too much time and it doesn't give me the right answer (when I compare with experimental results). So, I was ...
39 views

### Benchmarking Geometrically Exact Beams: Clarification Needed on Material Density?

In an early paper on Simo, I came across an example titled "Cantilever 45-degree bend subject to fixed and follower end load". A force of $600N$ and $300N$ was applied at the end, resulting ...
81 views

### FreeCAD: FemAnalysis Python module missing

After trying to execute the GMSH macro by psicofil I got an error: ...
754 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 ...
26 views

### Is there a way to program a buckling analysis of an arbitrary shape, using a standard programming language/libraries (not Abaqus)?

I am trying to develop a program in Python that runs a few different basic analyses for optimization like minimizing compliance and buckling. I want to use machine learning to try to develop a fast (...
3k 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 vote
190 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 (...
25 views

### Simulating the Impact of Bicycling on Hip Joint Cartilage

Sorry if this question comes off as obvious. I have more of a biology/clinical research background, and I have almost 0 experience with FEA. I have 50 sequential data points of the hip joint angles of ...
64 views

### Preliminary way to estimate damping quality factor (Q) from a SolidWorks FEM

I am analyzing the modal response of a structural FEM for a spacecraft structures course. I'm using Solidworks Simulation Premium. Need first mode to be above 40Hz and the damping Q-factor (quality ...
337 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-...
1 vote
553 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 vote
74 views

### Are there any advantages of using BEM for contact problem over FEM, apart from lesser computational cost?

FEM - Finite Element Method BEM - Boundary Element Method If we had access to "enough" computational resources (to discretize the entire volume domain in FEM to the same degree of fineness, ...
107 views

### Boundary conditions for Clevis fork (linear elasticity)

consider the Clevis fork domain (see here for an image https://www.traceparts.com/it/product/camloc-motion-control-h1-stainless-steel-clevis?CatalogPath=TRACEPARTS%3ATP01001005&Product=10-12112014-...
91 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
1 vote
85 views

### Why is the amount of force/moment transfer occurring between bodies in FEA is independent of mesh size?

So I read somewhere that the mesh size won't effect the amount of force transfer occurring between bodies if several bodies are in contact, and a global force is applied somewhere. I wanted to know ...
15 views

### Clarification on the location of stress and strain output value in Abaqus

Today, I had a discussion with my teacher about the location of stress and strain output in Abaqus. I believe that Abaqus outputs stress and strain based on Gauss integration points. However, my ...
14 views

### Designing a Torsional Rotary Flexure - Finite Element Freeware?

I am interested in designing and building a flexure based telescope tracking accessory. The core of the design would be what I think is called a "rotary flexure" or "Twist-it" or ...
10 views

### How can I input the equation below in Abaqus （Operate on XY Data） with certain condition? Where fi=5+5i and frequency range is between 300-950; S=189

Where fi=5+5i and frequency range is between 300-950; S=189.
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### Boundary condition of vibrating flange in ANSYS mechanical

I have a structure with both sides a having flange. The vibration comes to plant from one of the flanges. The structure has it's own fixed support on its bottom, bearing its weight. I assumed force is ...