1.1 FINITE ELEMENT ANALYSIS (FEA)
• Why?: When we have to find an effect (stress, strain, flux, etc) which is distributed throughout a volume, and is too difficult to calculate by hand.
• How: Break a part into discrete chunks (elements), Apply driving functions, constraints, etc., then solve for physical effects.
- different types of elements may be used in a FEM mesh
- elements that are too deformed will yield poorer results
- if a field variable will be subject to a large change over an area, then smaller elements should be used to improve the approximation.
• CAD systems will often allow a user to manually, and automatically mesh a part.
• Generative meshing algorithms will
- mesh a part roughly,
- solve the problem using the rough mesh,
- identify elements with large errors,
- reduce the element sizes in the critical areas,
- resolve the problem to obtain a more accurate result.
• Errors of 10% or more are easy to get using FEA systems. Care must be taken when examining results.
• Boundary conditions used in FEA systems include,
- x, y, and/or z positions fixed
- x, y, and/or z axis rotations fixed.
- applied force
- applied moment
- Still a research topic, and many various methods are available
- Generally the computer breaks geometry into subsections
********* Include Automeshing figure
********* Include Ideas FEM notes
********** Include my FEM notes