Spring 2010, MET 415 - FEA Applications I

Prof. Dave Johnson, psuprofdj@psu.edu, Penn State - Erie, The Behrend College

Debriefing: HW-2A & Working Plane

ELEMENT Type > Add/Edit/Delete > OPTIONS

Choose element behavior:  plane  stress,  plane  strain, and axisymmetric.

Note:  s_Z = 0 for cases of plane  stress and s_Z ≠ 0 for cases of plane  strain  

ANSYS does NOT check your UNITS !

Your job is: make sure dimensions, loads, and material data units are   consistent

SmartSizing

• Computes estimated element edge lengths for all lines in the areas or volumes being meshed
• The edge lengths on these lines are then refined for curvature and for proximity of other features in the geometry.

Working Plane – construction plane

            Can also be a  cutting  tool (divide areas or lines by WP)

            Why re-align with global Cartesian ?   when unsure of WP orientation or position

            What is “global Cartesian” ?   global = at ANSYS origin; Cartesian = straight line, not polar or cyl.

  OVERLAP  Operation:
A new area is created which is equal to the common area of the original set of areas. New areas are created by trimming the original areas to make room for the new area. All areas share common lines and keypoints at their boundaries.

 DELETE > LINES > Pick, ALL – does NOT destroy your model.

• Which lines are NOT deleted ?  any line which is an edge of any area is kept

• Why were extra (unused) lines in your model ?  "mistakes,"not deleted completely

Stress Contour plots:

• Use Nodal Solution (AVG) = smoothed

• Don't use Element Solution (NOAVG) = jagged

Stress Hand calc – WHERE ?  (specific point and direction)

• Treat as a cantilever.  What is M, c, and I ?
• Is cantilever a valid approximation ?

GLUE vs. OVERLAP Operations ?

• GLUE works where parts meet at edges or faces, but fails if parts overlap

• OVERLAP handles overlapping bodies PLUS bodies that meet at edges or faces.