Transcript Meshing/elements in Abaqus • • Accuracy of an Abaqus analysis strongly depends on the element type , mesh density and thickness elements. During a study.

Meshing/elements in Abaqus
•
•
Accuracy of an Abaqus analysis strongly depends on the element type , mesh
density and thickness elements.
During a study on a thin- flat plate with different loading conditions , significantly
different results were obtained depending on the number of thickness elements
used.
Fig. 1. Flat Plate under uniform loading
with 2 elements through the thickness
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Problems :
- Since reduced integration
elements were used , a fine
mesh in the bending direction
was necessary.
- Only 2 elements were
present along the thickness.
- Hence Asymmetric behavior
at the edges was noticed and
a 12% error existed between
numerical and analytic results
Srisharan.G.Govindarajan
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Fig. 2. Finer mesh along the thickness
Fig. 3. Flat plate after mesh refinement along the
thickness
- Error reduced to less than 1% with a finer mesh along the thickness.
- It was observed that for an analysis using reduced integration elements in Abaqus , there exists an
optimum value for the number of thickness elements.
- To obtain a mesh independent solution , this optimum value was maintained a constant and the global
seed was changed to vary the overall mesh density.
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2
Table 1. Types of Abaqus elements
Incompatible mode elements
Fully integrated linear
elements
Reduced integration linear
elements
• Best of the linear elements
• Can represent bending
behavior well if they are not
distorted
• Element edges should be
parallel and normal to the
direction of bending
• Eg : Cantilever beam
bending analysis
• They are too stiff in bending
• Suffer from ‘shear -locking’ .
• Should not be used if the
model is to respond in
bending.
• Eg : Useful in simple
problems , contact
simulations and fully
coupled thermal stress
problems.
• They are less stiff in bending
• Suffer from ‘hourglassing’.
• This can be overcome by
using a really fine mesh
in the bending direction.
• Eg : Can be used in thinplate bending/deflection
analysis , heat transfer
problems .
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