TERMINOLOGY ISSUES
1
FEA QUIZ
The finer is the mesh the better are your results
true
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false
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Geometry should be represented as accurately as possible
true
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false
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Solids give the best results because they accurately model the geometry
true
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false
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High accuracy of FEA results from high processing accuracy of the computer
true
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false
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If your FEA software reports no error, the solution will be correct
true
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false
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You do not really need any error estimation, the FEA is always accurate enough
true
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false
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Higher order elements will give you more accurate results
true
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false
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First order tetrahedral solids are too stiff and should be avoided
true
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false
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Use a coarse mesh first to find stress concentration, then refine it as needed
true
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false
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If FEA results correlate well with (e.g.) strain-gauge readings, all FEA results are O.K.
true
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false
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2
FEA QUIZ
Always make the finest model possible
true
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false
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Degenerated elements are O.K. as long as they are far away from stress concentrations
true
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false
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If you want to know only displacements and do not care about stresses, then you can make a coarse model
true
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false
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Modal analysis can use coarser mesh that stress analysis
true
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false
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Finite Element Models offer a deceiving level of detail
true
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false
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Model geometry is the most readily controlled, loads less so, restrains are the most difficult to control
true
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false
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Test data always have error and may be inconsistent with FEA assumptions
true
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false
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Incompetent analysis gives, at best , unreliable results, at worst is positively misleading
true
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false
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Bad FEA gives you deceiving trust in the design
true
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false
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FEA makes good engineer better and bad engineer dangerous
true
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false
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3
#1
FUNDAMENTALS OF FEA
1.
State the objective of discretization of continuum
2.
State major assumptions in the design of a finite element
3.
How are FEA equations formulated ?
4.
What is the primary unknown in FEA?
5.
What is the nodal Degree of Freedom ( D.O.F.) ?
6.
What is the relation between total number of D.O.F and total number of nodes in the FEA model ?
7.
What is the price to pay for replacing continuum with a set of finite elements ?
4
#2
TYPES OF FINITE ELEMENTS
1.
What is a shape function ?
2.
What is the difference between h-element and p-element ?
3.
Describe major types of finite elements
4.
What are compatible elements ? Non-compatible elements ?
5.
What is a distorted element ? What are types of element distortion ?
6.
What is the difference between 1st and 2nd order element ?
7.
How do elements "communicate" between each other ?
5
#3
ACCURACY OF FEA
1.
List major steps in FEA and associated errors
2.
Sort in the order of calculation: stress, strain, displacement
3.
What is the accuracy of FEA results?
4.
What are “artificial” restraints?
5.
What is the objective of convergence analysis?
6.
What are criteria of convergence analysis?
7.
What is an h convergence, why is it called h-convergence?
8.
What is the p-convergence, why is it called p-convergence?
6
#4
TYPES OF FEA ANALYSES, MODELING TECHNIQUES
1.
What is calculated in modal analysis
2.
What is calculated in linear buckling analysis
3.
List some types of nonlinear behavior
4.
What is the fundamental difference between linear and non-linear analysis?
5.
Describe some techniques to reduce the size of finite element model
6.
Describe some problems with CAD -FEA interfacing
7