17a-error-and-convergence

17a-error-and-convergence - MAE M168/CEE M135C Introduction...

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© William Klug MAE M168/CEE M135C Introduction to Finite Element Methods Lecture 17a Error and Convergence
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© William Klug Sources of Error 1. User Error: Mistakes you make with software. E.g., typos, wrong element, bad mesh, … Prevent : always double-check results, compare to prelim. analysis, refine mesh, etc. 2. Numerical Error: Finite precision of computer arithmetic. Don’t except accuracy to 20 significant digits. Single precision: 8 digits Double precision: 16 digits Usually not a problem.
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© William Klug Sources of Error 3. Modeling Error: Difference between physical system and model. Geometry, loads, BS’s, etc. E.g., airplane wing with rivets. : Can build multiple models at various resolutions and compare. Also compare to testing. Requires engineering intuition.
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© William Klug Sources of Error 4. Discretization Error: – Due to interpolation Reduce by REFINEMENT : • p-refinement: use higher order polynomial elements. • h-refinement: use more, smaller elements
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This note was uploaded on 08/09/2011 for the course MAE 168 taught by Professor Klug during the Spring '11 term at UCLA.

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17a-error-and-convergence - MAE M168/CEE M135C Introduction...

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