Spring 2008, MET 415 - FEA
Applications I
Prof. Dave Johnson, dhj1@psu.edu, Penn State - Erie, The Behrend College
Workbench Simulation Approach
Before
attaching the geometry, you can specify several options that determine the
characteristics of the geometry you choose to import [Project > Model >
Geometry, then Preference in the Details Area]. These options are:
- solid
bodies,
- surface
bodies,
- line
bodies,
- parameters,
- attributes,
- named
selections,
- material
properties;
- Analysis
Type (2-D or 3–D),
- allowing
CAD associativity,
- Importing
coordinate systems, etc.
Material:
Structural Steel (default) –or– new –or– import from library
Stiffness
Behavior: Flexible (default) or Rigid
Nonlinear
Material Effects: Yes (default) or No
Connections:
contact regions, joints, or springs
Mesh:
mesh controls (help links to WB Meshing Help)
Define an
Analysis Type: New Analysis
Analysis
Settings: automatically inserted under the Analysis Type
Settings/Values
are shown in the Details Area
- Multiple
Load Steps are defined under Analysis Settings
- RMB
on the “Timeline” bar gives options for legend
- Worksheet
TAB can be used to show load step settings
- Initial
Conditions may be required
- Transient
structural or thermal
- Pre-stressed
analyses
- If
needed, define in the Details Area
Loads:
·
Are defined at the “End Time”
of each Load Step
·
Can be step-applied or ramped
(default) over substeps
·
Can be defined as constant,
tabular, or from a function (equation)
Supports (fixed, frictionless,
compression-only) do not change over time.
Solve
Review
Results
Generate
an HTML Report
ANALYSIS
TYPES:
·
Static
Structural Analysis
o
Help includes detailed example of
sequentially tightening 3 of 6 bolts around a flange.
o
An example/practice file is
provided (bolts.dsdb) for ALL WB installations.
(Sequenced Analysis Steps with Bolt Preload conditions)
o
Bolts.dsdb: 27 parts assembly, 51
automatic contact regions
·
Flexible
Dynamic Analysis
o
Structural dynamics –
time-history analysis
o
Example/practice tip vibration of
cantilever beam
·
Rigid
Dynamic Analysis (kinematics)
o
Output:
forces, displacement, acceleration (no stress or strain)
·
Modal
Analysis
o
Determine natural frequencies of a
system
o
Linear material/conditions ONLY
·
Harmonic
Response Analysis
o
Forced vibration (sustained cyclic
input load)
o
Example: H-shaped structure
- Linear Buckling Analysis (Eigenvalue
buckling)
- Quick,
but often non-conservative results
- Predicts
the theoretical buckling strength of an ideal elastic structure
- Example
– simply-supported plate w/compressive edge load
- Random
Vibration Analysis
- Determine
response of system to random dynamic input – car, earthquake, etc.
- Example
– PC board w/chips
·
Shape
Optimization Analysis (Topological Optimization)
o
Best us of material – based on
stiffness, not on stress or strain
o
Linear conditions ONLY
o
Example: H-shaped structure
·
Steady-State
Thermal Analysis
o
Heat transfer without start-up or
shutdown effects – loads don’t vary over time
o
Determine temperature or heat flow
- Example
– PC board w/chips
·
Transient
Thermal Analysis
o
Heat transfer with loads that vary
over time
o
Determine temperature, heat flow,
energy storage
- Example
– PC board w/chips
·
Magnetostatic
Analysis
o
Static magnetic field analysis –
not varying with time
o
Example – actuator: magnetic
field can create force on parts leading to deformation and stress
2D Models:
- The
model must be in the x-y plane.
- You
can specify a 2-D analysis ONLY when you attach the model. After attaching,
you cannot change from a 2-D analysis to a 3-D analysis or vice versa
- You
can apply all loads and supports in a 2-D analysis except for the following:
Bolt Pretension Load, Line Pressure, Simply Supported, and Fixed Rotation.
- A
Pressure load can only be applied to an edge.
- A
Bearing Load and a Cylindrical Support can only be applied to a circular
edge.
- For
analyses involving axisymmetric behavior, a Rotational Velocity load can
only be applied about the y-axis.
SYMMETRY:
- DesignModeler
can slice a full model and retain only the symmetry portion
- When
Simulation attaches to a symmetry model from DesignModeler,
- a
Symmetry folder is placed in the tree
- each
Symmetry Plane is given a Symmetry Region object in the tree.
- Named
Selection objects are created for each symmetry edge or face.
- For
models generated originally as symmetry models,
- You
may create a Symmetry folder and manually identify Symmetry Region objects
- OR
– use Frictionless Support
- Symmetry
– geometry & loads reflect across symmetry plane
- ANTI-Symmetry
– used rarely, more difficult to interpret
- Periodic
– repeating pattern about an axis or along an axis
FLUID-STRUCTURE
INTERACTION
- Multiphysics
- Involves
CFD (fluid flow analysis) and structural (static or dynamic) analysis
WIZARDS
- Help
you set up an analysis
- Wizards
available within Simulation
- Safety
factors, stresses and deformation
- Fatigue
life and safety factor
- Natural
frequencies and mode shapes
- Optimizing
the shape of a part
- Heat
transfer and temperatures
- Magnetostatic
results
- Contact
region type and formulation