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Finite Element AnalysisIntroduction to
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What This Presentation Covers
Introduction to Different Numerical Method
Introduction to FEM - Concept & Philosophy
Practical Application of FEA
Need & Advantages of Finite Element Analysis
Different Professional FEA Tools/Software
Steps involved in any Finite Element AnalysisBest Practices Approach
Types of Analysis
Introduction to Finite Element Analysis
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Objective of this Session
By the End of this session, You will be able to :
Understand and apply the Concept of FEM / FEA on Actual practical
day-to-day / complex problems
Understand Different Type of Analysis covered in FEA
Prepare a suitable FE model for a given problem
Know the Behavior of different type of FE Elements used , Concept of FE
Mesh , Loads and Boundary Condition
Step by Step approach followed in any Finite Element Analysis
Introduction to Finite Element Analysis
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Introduction to FEA
Methods to Solve Any Engineering Problem
Analytical Method Numerical Method Experimental Method
Classical Approach
100% Accurate Results
Applicable only for Simple problems like
Cantilever , simply supported beams and
Cylinders etc..
Complete in itself
Mathematical Approach
Approximate, Assumptions Made
Applicable to real life complicated problems
Results can not be believed blindly and
must be verified by experimental methods
and Hand Calculations.
Actual Measurement
Time Consuming , Needs expensive setup
Applicable only if physical prototype is
available
Results can not be believed blindly and
Minimum 2 or more prototypes must be
tested.
Although applicable to simple shaped
geometries only , Analytical methods areconsidered as Closed form solutions i.e.
100% Accurate
Finite Element Method: Linear , Nonlinear ,
Buckling , Thermal, Dynamics & Fatigueanalysis
Boundary Element Method:Acoustics /NVH analysis
Finite Volume Method: CFD
(Computational Fluid Dynamics) &
Computational Electromagnetic
Finite Difference Method: Thermal & Fluid
Flow analysis (in combination with FVM)
-Strain Gauge
- Photo elasticity- Vibration measurement (accelerometers)
- Sensors for Temp & pressure etc- Fatigue test
Introduction to Finite Element Analysis
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Different Numerical Methods
Finite Element Method (FEM) :Very Popular Method based upon discretization of component into Finite number of blocks (elements)
Applications : Linear, Nonlinear, Thermal, Dynamics , Buckling and Fatigue Analysis
Boundary Element Method (BEM) :Its a very powerful and efficient technique to solve acoustics and NVH problems
Just like Finite Element Method, it also requires Nodes and Elements but as the name suggest, it considers only
the outer boundary of the domain
Finite Volume Method (FVM) :All Computational Fluid Dynamics (CFD) soft wares are based upon FVM.
Unit Volume is considered in Finite Volume Method (similar to Elements in Finite Element Method)
Variable properties at nodes are Pressure , Velocity , Area , Mass etc.
It is based on NavierStoke equations ( Mass ,Momentum and Energy Conservation equations)
Finite Difference Method (FDM) :Finite Element and Finite Difference share many common things.
In general, Finite difference Method is described as a way to solve difference equation.It uses Taylors series to convert differential equation into algebraic equation. Higher order terms neglected.
Is it possible to use all the above listed methods (FEA ,BEM , FVM, FDM)
to solve same problem (say Cantilever problem)?Answer : YES ! But the difference is in Accuracy achieved , programming ease and time
required to obtain the solution
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Are FEA and FEM different ?
Finite Element Analysis (FEA) and Finite Element Method (FEM) both areone & the same.
FEA is a method/process based upon FEM
Term FEA is more popular in industries while FEM at Educationcenters
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Why Finite Element Method ?
FEA is the most widely applied computer simulation method in Engineering.
It is very closely integrated with CAD/CAM applications.
It is very well proven , tested and validated method for simulating any complex
practical scenario in the area of Structural ,Thermal ,Vibration etc..
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Application of FEM in Engineering
Mechanical / Aerospace / Civil Engineering / Automobile EngineeringStructural Analysis ( Static / Dynamic , Linear / Non-Linear )
Thermal Analysis ( Steady State / Transient )
Electromagnetic Analysis
Geomechanics
Biomechanics
etc.
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Practical Applications of FEA
Aerospace Domain
Automotive Domain
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Practical Applications of FEA
Hi-Tech /Electronics
Medical Devices
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and many more .
Practical Applications of FEAIntroduction to Finite Element Analysis
I d i Fi i El A l i
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Advantages of FEA
Cost
Design Cycle time
No. of Prototypes
Testing
Design Optimization
Introduction to Finite Element Analysis
I t d ti t Fi it El t A l i
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Available Commercial FEA Tools/Software Packages
Introduction to Finite Element Analysis
I t d ti t Fi it El t A l i
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Analysis Types
Introduction to Finite Element Analysis
Structural Analysis
Static Analysis
Linear Non-Linear
Dynamic Analysis
Modal
Analysis
Harmonic
AnalysisRandom
Analysis
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Steps involved in FEA
Understanding the Problem (Thermal , Structural, Dynamic etc)
Element Selection (Solid , Shell , Beams etc)
Deciding the Boundary Conditions (Constraints , Connections etc..)
Load Application (Point , Surface , Body loads etc..)
Solution(Solver , Sub step / Time step , Nonlinearity etc)
In-Depth study & interpretation of Analysis Results (Sanity Checks)
Post processing of Results (Deflection , Stress , Strain etc..)
Report Preparation
Observation and Conclusion from the Analysis (MoS Calcs, Design ok)
Suggestion and Recommendation for Design Changes, if required.
Pre
Processing
Solution
Post
Processing
Introduction to Finite Element Analysis
Introduction to Finite Element Analysis
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FEM Philosophy in layman terms
The Philosophy of FEA can be explained with a small example such as Measuring the Perimeter of a Circle
If one need to evaluate the perimeter of a circle without using the conventional
formula (2*pi*r), FEA approach is analogous to Dividing the circle into a number of
segments and joining the points using Straight lines
Since it is very easy to measure the length of straight line. Measure the length of
one line and multiply it by No. of lines to get the perimeter.
Approximate results.isnt it ?
What if we want to achieve more
accurate result?
Introduction to Finite Element Analysis
Introduction to Finite Element Analysis
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Concept of Discretization (Meshing)
Physical System FE Model
Introduction to Finite Element Analysis
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Concept of Discretization (Meshing)
Concept of FEM is all about Discretization (Meshing) i.e. Dividing abig structure/component into small discrete Blocks (Nodes and
Element concept)
But why do we do this Meshing ???
No. of Points =
DoF per point = 6
Total No of Equations to be solved
= * 6 =
No. of Points = 8
DoF per point = 6
Total No of Equations to be solved
=8 * 6 = 48
From Infinite to FiniteHence the
Term Finite Element Method
Introduction to Finite Element Analysis
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Concept of Discretization (Meshing)
Introduction to Finite Element Analysis
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Concept of Discretization (Meshing)
Parameters deciding the Quality of Mesh :Aspect ratio
Skew / Warpage
Element internal Angles
and more
Bad Quality FEA
Good Quality FEA
Better the Mesh Quality , Better the Accuracy
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Introduction to Finite Element Analysis
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Types of Contacts used in FEA
Introduction to Finite Element Analysis
Bonded Contact
This is the default configuration and applies to all contact regions( surfaces, solids, faces, edges). If contact
Regions are bonded, then no sliding or separation between faces or edges is allowed. This type of contact
Allows for a linear solution since the contact length/area will not change during the application of the load.
Eg: Welding, Glued connection, Bolted connection.
No Separation Contact
This contact setting is similar to the bonded case. It only applies to regions of faces(for 3D solids) or edges
(for 2D plates). Separation of the geometries in this contact is not allowed, but small amount of frictionless
Sliding can occur along contact geometries.
Frictionless Contact
This contact setting models standard unilateral contact, that is normal pressure equals to zero if separation
occurs. Thus gaps can form in the model between bodies depending on the loading. This solution is non linear
because the area of contact may change as the load is applied. A zero coefficient of friction is assumed,thus allowing free sliding. The model should be well constrained when using this contact setting.
Frictional Contact
In this contact setting, the two contacting geometries can carry shear stresses upto a certain magnitude across their interface before
they start sliding relative to each other. This state is known as sticking. The model defines an equivalent shear stress at which sliding
on the geometry begins as a fraction of contact pressure. Once the shear stress exceeded, the two geometries will slide relative to
each other.
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Types of Boundary Conditions, Loads & Results
Boundary Conditions :
Fixed Boundary Conditions (U , ROT etc.. = 0)
Prescribed Displacements (U , ROT , Temp etc.. 0)
Loads:
Point /Concentrated Load (Force)Surface Load (Pressure , Flux etc..)
Body Load (Temp , Inertia g etc..)
Results:
Displacement
Reaction Forces
Stresses /Strains (Equivalent Von Mises , Directional & Principal )
Temperature etc..
y
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Best Practices Approach
Plan your analysisAnalysis type (Static/Dynamic, Linear/Non-Linear etc..)
Material Details (isotropic/orthotropic , Constant/Temp dependent)
Choice of Elements and Meshing (2D/3D , Hex / Tet)
Results Evaluation (Detailed Post processing) Verification (Sanity Checks , Test data match)
y
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Thanks !