The Finite Element Method: A Four-Article Series - Part 4
Learn Science on mps-science.com. The Finite Element Method: A Four-Article Series - Part 4 article will help answer your questions on Science.We at mps-science.com specialize in Science. Science at mps-science.com provides the most up to date news and articles. If you have questions please do not hesitate to contact us.
Summary:
The author is an engineering consultant and expert witness specializing in finite element analysis.
FINITE ELEMENT ANALYSIS: Post-processing
by Steve Roensch, President, Roensch & Associates
Last in a four-part series
After a finite element model has been prepared and checked, boundary conditions have been applied, and the model has been solved, it is time to investigate the results of the analysis. Error norms such as strain energy density and stress deviation among adjacent elements might be looked at next, but for h-code analyses these quantities are best used to target subsequent adaptive remeshing.
Once the solution is verified to be free of numerical problems, the quantities of interest may be examined. The magnitude of principal stresses or of a scalar failure stress such as the Von Mises stress may be displayed on the model as colored bands.
Article:
The following four-article series was published in
a newsletter of the American Society of Mechanical
Engineers (ASME). It serves as an introduction to the
recent logical analysis discipline known as the finite element
method. The editorialize is an engineering consultant and
expert witness specializing in finite element analysis.
FINITE ELEMENT ANALYSIS: Post-processing
by Steve Roensch, President, Roensch & Associates
Last in a four-part series
After a finite element model has been prepared and checked,
boundary conditions have been applied, and the model has
been solved, it is time to investigate the results of the
analysis. This endeavour is known as the post-processing
phase of the finite element method.
Post-processing begins with a thorough throwing open for problems
that may have occurred during solution. Most solvers
provide a log file, which should be searched for warnings or
errors, and which will also provide a quantitative measure
of how well-behaved the numerical procedures were during
solution. Next, reaction loads at restrained nodes should
be summed and examined as a 'sanity check'. Reaction loads
that do not densely self-command the used load resultant for a
linear static geometry should cast doubt on the validity of
other results. Error norms such as strain energy density
and stress deviation near immediate elements might be looked
at next, but for h-code analyses these quantities are best
used to target subsequent adaptable remeshing.
Once the solution is verified to be free of numerical
problems, the quantities of interest may be examined. Many
display options are available, the quintessential of which depends
on the mathematical form of the quantity as well as its
physical meaning. For example, the displacement of a solid
linear masonry element's node is a 3-component spatial vector,
and the model's overall displacement is often displayed by
superposing the deformed shape over the undeformed shape.
Dynamic viewing and birth capabilities aid greatly in
obtaining an understanding of the deformation pattern.
Stresses, critter tensor quantities, currently lack a good
single visualization technique, and thus derived stress
quantities are extracted and displayed. Principal stress
vectors may be displayed as color-coded arrows, indicating
both direction and magnitude. The magnitude of principal
stresses or of a scalar failure stress such as the Von Mises
stress may be displayed on the model as colored bands. When
this type of display is treated as a 3D object subjected to
light sources, the resulting image is known as a shaded
image stress plot. Displacement magnitude may also be
displayed by colored bands, but this can lead to
misinterpretation as a stress plot.
An area of post-processing that is rapidly gaining
popularity is that of resigned remeshing. Error norms such
as strain energy density are used to remesh the model,
placing a denser mesh in regions needing improvement and a
coarser mesh in areas of overkill. Adaptivity requires an
associative link among the model and the underlying CAD
geometry, and works best if suture conditions may be
applied directly to the geometry, as well. Adaptive
remeshing is a recent demonstration of the iterative nature
of h-code analysis.
Optimization is renewed area enjoying recent advancement.
Based on the values of various results, the model is
modified compulsively in an initiate to satisfy certain
performance criteria and is solved again. The process
iterates until some convergence criterion is met. In its
scalar form, optimization modifies beam cross-sectional
properties, thin shell thicknesses and/or material
properties in an struggle to meet maximum stress constraints,
maximum deflection constraints, and/or vibrational frequency
constraints. Shape optimization is more complex, with the
actual 3D model circumference spirit modified. This is best
accomplished by using the driving dimensions as optimization
parameters, but mesh quality at each iteration can be a
concern.
Another direction manifestly visible in the finite element
field is the integration of FEA packages with so-called
'mechanism' packages, which analyze motion and forces of
large-displacement multi-body systems. A long-term goal
would be real-time computation and display of displacements
and stresses in a multi-body system undergoing large
displacement motion, with frictional effects and fluid flow
taken into tale when necessary. It is difficult to
estimate the increase in computing power necessary to
accomplish this feat, but 2 or 3 orders of magnitude is
probably close. Algorithms to integrate these fields of
analysis may be expected to follow the computing power
increases.
In summary, the finite element method is a relatively recent
discipline that has quickly spring up a mature method,
especially for structural and thermal analysis. The costs
of apposite this technology to everyday design tasks have
been dropping, while the capabilities delivered by the
method expand constantly. With education in the technique
and in the practical software packages appropriate more and
more available, the question has moved from 'Why go FEA?'
to 'Why not?'. The method is fully worthy of delivering
higher quality products in a shorter design cycle with a
reduced incalculability of field failure, provided it is by a
capable analyst. It is also a valid indication of thorough
design practices, should an unexpected litigation crop up.
The time is now for industry to make greater use of this and
other synthesis techniques.
© 1996-2005 Roensch & Associates. All rights reserved.
Top-Notch Science Projects. - Detailed Instructions for 47 Top-Notch Elementary School Science Projects.
From The Ground Up:HowToShoot In The 70s. - Revolutionary new golf method that works on the premise of teaching the key Elements in the proper order.
Article Index: | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30
|
Advice
Home Business
Technology
Online Advertising
Motivational
Internet Marketing
SEO Help
Online Games
Science Articles
Happiness
More Articles:
1. Bioluminescence Detection Program by AgroMicron
Summary: I myself would love to be able to use a spray to tell if my leftover have gone bad or not, and I personally believe the consumer level support of such a product will be the next thing AgroMicron looks to develop. The Nano Bioluminescence spay development was made possible by researchers and scientist in Taiwan and the United States and further made possible thanks to the US Technology Transfer Act., which means AgroMicron's team can fully utilize all these resources. 'We expect our curr…
2. Primes: Randomness and Prime Twin Proof
Summary: Statistical tools, depending on their power, will find a pattern in those patterns not produced by an infinite number of prime factors (the number line).Interesting Patterns in Non-PrimesThere are some interesting patterns in non-primes that emerge from this work.Define:LowMarker(n) = 3 + 2(P(1)xP(2)x'x(P(n)),HighMarker(n) = 3 + 2(3x5x'xP(n)), andOffset(n) = P(n) ' 3 We can say conclusively, thanks to pattern combinatorics that numbers in the ranges:LowRepeater(n) = [LowMarker(n),LowMar…
3. How Satellite TV Systems Originated By Zahid Saddique
Summary: What we know as satellite tv actually had its origins in the space race which began with the launching of the satellite Sputnik by the Russians in 1957. As the use of satellites for communication and broadcast purposes increased, it became evident that everyone had the potential to receive satellite signals for free.Direct to Home (DTH) satellite receiverArticle:
What we know as satellite tv in reality had its origins in the space race which began with the launching of the satellite S…
4. Theoretically is it Possible to Defy Gravity? By Lance Winslow
Summary: Many believe it is possible to build an anti-gravity machines and there are many small version which can do this by interfering with the gravity waves. Many talk about using pulse or gravity wave interference waves; Why not take in the gravity waves in a pass thru mechanism, collect them as they approach the object and re-direct them around your object to the otArticle:
Many gather it is possible to manufacture an anti-gravity machines and there are many small version which can do thi…
|
