IET 450: FEA Written Exam
How is the Stress-Strain Curve related to FEA?
Analyzes the elastic region of the stress-strain curve
Linear Vs. Non-Linear FEA Analysis
Linear: where stresses remain in the linear elastic range of the used material (not deformed)
Non-Linear: large deformations, elasto-plastic material (past its elastic capabilities)
Interpretation of FEA Simulation
Safety Factor: if the maximum stress is higher than the yield strength... Von Misses Stress,
Displacement- if the effects of a restraints and loads are insignificant or not
Structural properties of a material in Catia
Young's Modulus, Poisson's Ratio, Density, Thermal Expansion, Yield Strength
Difference between linear and parabolic meshses
Linear-4 nodes (better for square objects)
Parabolic-10 nodes (better for circular objects)
Short comings of FEA in Catia
Material Linearity, Small Strains, Limited Contact Capabilities, Limited Dynamics, Beam and
Shell Formulation
What is needed to do mesh refinement/optimization?
Starting mesh, give mesh size and sag- If manual
What is the procedure to do mesh refinement/optimization?
Keep running smaller and smaller mesh sizes until the maximum stress changes
insignificantly
Manual mesh refinement
Input mesh size, sag size, parabolic/linear- can add local mesh for additional layers
Automated Mesh refinement
New Adaptivity Entity--> select mesh (objective error)-->Compute with Adaptivity
(iteration,min size)
, Mesh Shapes for 3D objects in FEA
Linear Tetrahedron Meshing, Parabolic Tetrahedron Meshing
Mesh Shapes for 2D objects in FEA
Linear Triangle Meshing, Parabolic Triangle Meshing,
Mesh Shapes for 1D objects in FEA
Linear Beam Meshing, Parabolic Beam Meshing
Advanced Meshes in Advanced Mesh Toolbar
Linear/Parabolic Triangle and Quadrangle Meshes
Two ways to apply symmetry in FEA
Surface Slider or User-defined restraint in directions you don't want it to move
Ways to apply material properties in Catia
Part Design Workbench: Apply Material
Generative Structural Analysis: User Material
Shrink Fit and Overlap amount in pressure fitting connection property
Use half of the diametrical interference, If the overlap is .002 in, the the input amount is .001
in
Clamping methods in Catia
Clamp(face,edge,point), User-defined restraint, Mechanical Restraints (slider, pivot, etc.)
Smooth virtual part is treated as a:
point, when clamping
Procedure to check/solve Factorized Matrix Computation error
If a part fly's away- To solve turn on the deformation mesh and animate the part/assembly.
From there determine the best restraint to use to prevent movement, that doesn't deform in
an unnecessary way
Type of load for self-weighted case
Acceleration
How is the Stress-Strain Curve related to FEA?
Analyzes the elastic region of the stress-strain curve
Linear Vs. Non-Linear FEA Analysis
Linear: where stresses remain in the linear elastic range of the used material (not deformed)
Non-Linear: large deformations, elasto-plastic material (past its elastic capabilities)
Interpretation of FEA Simulation
Safety Factor: if the maximum stress is higher than the yield strength... Von Misses Stress,
Displacement- if the effects of a restraints and loads are insignificant or not
Structural properties of a material in Catia
Young's Modulus, Poisson's Ratio, Density, Thermal Expansion, Yield Strength
Difference between linear and parabolic meshses
Linear-4 nodes (better for square objects)
Parabolic-10 nodes (better for circular objects)
Short comings of FEA in Catia
Material Linearity, Small Strains, Limited Contact Capabilities, Limited Dynamics, Beam and
Shell Formulation
What is needed to do mesh refinement/optimization?
Starting mesh, give mesh size and sag- If manual
What is the procedure to do mesh refinement/optimization?
Keep running smaller and smaller mesh sizes until the maximum stress changes
insignificantly
Manual mesh refinement
Input mesh size, sag size, parabolic/linear- can add local mesh for additional layers
Automated Mesh refinement
New Adaptivity Entity--> select mesh (objective error)-->Compute with Adaptivity
(iteration,min size)
, Mesh Shapes for 3D objects in FEA
Linear Tetrahedron Meshing, Parabolic Tetrahedron Meshing
Mesh Shapes for 2D objects in FEA
Linear Triangle Meshing, Parabolic Triangle Meshing,
Mesh Shapes for 1D objects in FEA
Linear Beam Meshing, Parabolic Beam Meshing
Advanced Meshes in Advanced Mesh Toolbar
Linear/Parabolic Triangle and Quadrangle Meshes
Two ways to apply symmetry in FEA
Surface Slider or User-defined restraint in directions you don't want it to move
Ways to apply material properties in Catia
Part Design Workbench: Apply Material
Generative Structural Analysis: User Material
Shrink Fit and Overlap amount in pressure fitting connection property
Use half of the diametrical interference, If the overlap is .002 in, the the input amount is .001
in
Clamping methods in Catia
Clamp(face,edge,point), User-defined restraint, Mechanical Restraints (slider, pivot, etc.)
Smooth virtual part is treated as a:
point, when clamping
Procedure to check/solve Factorized Matrix Computation error
If a part fly's away- To solve turn on the deformation mesh and animate the part/assembly.
From there determine the best restraint to use to prevent movement, that doesn't deform in
an unnecessary way
Type of load for self-weighted case
Acceleration
