chapter 3: shell meshing · element quality control: check panel aspect ratio: this is the ratio of...
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Copyright © 2009 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved. Copyright © 2009 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Checking and Editing Mesh
Chapter 3: Shell Meshing
Copyright © 2009 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Checking and Editing the Mesh
Edges Faces
Penetration /
Intersection Check
Load
Summation
Summary
Count
Element
Check
Checks Toolbar
Length
Distance
Mass / Area
Calc
Features
Normals
Copyright © 2009 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Checking & Editing Mesh: Nodal connection for the 2D mesh
“Edges / T-connection” Panel or Tool - Edges
“Find Attached” Panel or Tool - Find
Allow you to verify the basic quality of your elements and to the geometric qualities of those
elements
Allow to display free edges to T-connection in the model by creating 1D elements on each one
For free edges you can also equivalence nodes within a specified tolerance
Copyright © 2009 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Element quality control: check panel
Allow you to verify the basic quality of your elements and to the geometric qualities of those
elements
Check element settings
Each check can be set to use a
different solver’s check method,
or you can set every check to
use the same method. When a
specified solver doesn’t support
a certain check at all,
HyperMesh uses its own method
for that check
“Check Elements” Panel or Tool - check elems
test the connectivity of a group of
elements check for duplicate elements
Copyright © 2009 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Element quality control: check panel
Chordal deviation is the perpendicular distance
between the actual curve and the
approximating line segments.
Jacobian: This measures the deviation of an element from its ideal or
"perfect" shape, such as a triangle’s deviation from equilateral.
The Jacobian value ranges from 0.0 to 1.0, where 1.0 represents a
perfectly shaped element.
Length min. :The shortest distance from a corner node
to its opposing edge (or face, in the case of tetra
elements); referred to as “height to closest node”.
Skew of triangular elements is calculated by finding
the minimum angle between the vector from each node
to the opposing mid-side, and the vector between the
two adjacent mid-sides at each node of the element.
Copyright © 2009 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Element quality control: check panel
Aspect Ratio: This is the ratio of the longest edge
of an element to either its shortest edge or the
shortest distance from a corner node to the
opposing edge ("height to closest node").
Taper ratio for the quadrilateral element is
defined by first finding the area of the
triangle formed at each corner grid point.
These areas are then compared to one half
of the area of the quadrilateral.
Warpage: this is the amount by which an element (or in the
case of solid elements, an element face) deviates from being
planar. Since three points define a plane, this check only
applies to quads. The quad is divided into two trias along its
diagonal, and the angle between the trias’ normals is
measured.
Interior Angles These maximum and minimum values
are evaluated independently for triangles and
quadrilaterals.
Copyright © 2009 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Checking & Editing Mesh: Element normal's
“Check Normals” Panel
Allow you to verify surface or elements normal's orientation and to adjust or reverse them
Copyright © 2009 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
In HM10.0, there are options to remesh elements using the “automatic feature detection”,
“features” or the new option “lines”.
Automeshing: Remeshing
• Using any free form line, the automesh
functionality will remesh ensuring that
there is nodal seeding along the selected
line. The nodal seeding can be adjusted as
required
• Meshing regions where tight control over
mesh flow or mesh density will benefit
from this functionality. Other use cases
will also include defining weld/adhesive
lines.
This option in automesh panel allow you to remesh directly a selected group of elements
switch from surfs to elems
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Checking & Editing Mesh: 2D page
“Smooth” panel 2D – smooth
• Improves quality of selected
elements
“Quality index” panel 2D – quality index
• Set criteria for all standard quality
checks
• Simultaneously evaluate element
quality
• Combine all checks into a single
value called “composite quality
index value”
• Edit nodes and elements
interactively or by automatically
maximizing element quality
Copyright © 2009 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Allow you to mesh surfaces to optimize the quality index (QI) of the elements generated
Automeshing: The Automesh Panel
“Automesh” Panel 2D – automesh – QI optimize
On the Criteria tab, you can set the target element size,
element criteria, and the method that is used to calculate
the values. An advanced criteria option can be enabled to
give more control over the intermediate QI values, but is
usually not necessary in order to obtain a good quality
mesh
Determines whether nodes generated on a surface edge can be moved
off the surface edge when the algorithm smoothes the mesh
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Editing Mesh Tools: 1D, 2D, & 3D pages
“Edit element” panel 2D – edit element
• Combine – merge 2 or more elements into 1 single element
• Split – draw a line to cut elements
• Cleanup – interactively drag nodes to improve element quality
“Split” panel 2D – split
• Divide selected elements in a selected manner
“Replace” panel 2D – replace
• Merge 2 nodes into 1 node (elements are now connected)
“Detach” panel 2D – detach
• Disconnect selected elements from other elements
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Checking & Editing Mesh: Utility Menu
• Add washer – add a ring of quad elements around
a hole in existing mesh
• Trim Hole – add a hole to existing mesh
• Fill Hole – remove a hole from existing mesh
• Box Trim – cut elements passing through a box
shape
• Bead – add a bead shaped mesh to an existing
mesh
“Utility” Menu Geom/Mesh page – Mesh Tools