Workshop 5B
Localized Yielding
Workbench-Mechanical
Structural Nonlinearities
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-1 Inventory #002660
Workbench Mechanical Structural Nonlinearities
Workshop 5B: Localized Yielding Workshop Supplement
Goal
Introduce Metal Plasticity to the Workshop 4A
problem and compare its effect on results
(contact pressure and preload) Tip
Insulator
Model Description
2D Axisymmetric model of injection molding
machine nozzle tip assembly
Materials:
Tool Steel for Housing (760Mpa Yield Strength)
Copper alloy for Tip (280Mpa Yield Strength)
Titanium for Insulator
Housing
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-2 Inventory #002660
Workbench Mechanical Structural Nonlinearities
Workshop 5B: Localized Yielding Workshop Supplement
Model Description (contd)
Contact Pairs:
A. Frictionless contact at
Housing to Nozzle tip face
seal
B. Bonded contact at Nozzle tip
To insulator
C. Bonded contact at threaded
connection between Housing
and Nozzle tip (thread details
not modeled)
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-3 Inventory #002660
Workbench Mechanical Structural Nonlinearities
Workshop 5B: Localized Yielding Workshop Supplement
Model Description (contd)
Thermal Boundaries:
A. Hot manifold @ 220C
B. Cold manifold plate @50C
C. Nozzle tip band heater @ 80 Watts
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-4 Inventory #002660
Workbench Mechanical Structural Nonlinearities
Workshop 5B: Localized Yielding Workshop Supplement
Model Description (contd)
Structural Boundaries
A. Frictionless Support @
Nozzle Housing Flange
B. Frictionless Support @
Insulator
melt
Structural Loads channel
1st loadstep reconciles wall
interference fit between
housing and tip face seal
2nd loadstep reads in
temperatures from steady
state thermal run
3rd loadstep applies pressure
to melt channel wall.
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-5 Inventory #002660
Workbench Mechanical Structural Nonlinearities
Workshop 5B: Localized Yielding Workshop Supplement
Steps to Follow:
If you already have Workbench open from a previous run, start a new
analysis with Utility Menu>File>New
Browse for and open W5B-Offset.wbpj project file.
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-6 Inventory #002660
Workbench Mechanical Structural Nonlinearities
Workshop 5B: Localized Yielding Workshop Supplement
The Project Schematic should look like the picture below.
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-7 Inventory #002660
Workbench Mechanical Structural Nonlinearities
Workshop 5B: Localized Yielding Workshop Supplement
Highlight the Engineering Data Cell and
double click to open
Verify the predefined material properties
Verify that the units are in Metric
(Tonne,mm,) system.
If not, fix this by clicking on
Utility Menu>Units>Metric(Tonne, mm,..)
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-8 Inventory #002660
Workbench Mechanical Structural Nonlinearities
Workshop 5B: Localized Yielding Workshop Supplement
Highlight the Copper NL and Stainless Steel NL materials to
confirm that the plasticity models have been defined with
Bilinear Isotropic laws as show below.
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-9 Inventory #002660
Workbench Mechanical Structural Nonlinearities
Workshop 5B: Localized Yielding Workshop Supplement
Return to the project schematic page
Double click (or RMB=>Edit) on the Thermal Model Cell to open
Mechanical Session
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-10 Inventory #002660
Workbench Mechanical Structural Nonlinearities
Workshop 5B: Localized Yielding Workshop Supplement
Highlight the Housing and Nozzle Tip components
In the Details Window, turn Nonlinear Effects ON to include the plasticity
effects
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-11 Inventory #002660
Workbench Mechanical Structural Nonlinearities
Workshop 5B: Localized Yielding Workshop Supplement
Execute a SOLVE
The convergence now takes over 20 iterations, up from just 9 (WS4A)
when all materials were considered linear elastic.
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-12 Inventory #002660
Workbench Mechanical Structural Nonlinearities
Workshop 5B: Localized Yielding Workshop Supplement
Post process the contact pressure
Notice the dramatic difference in pressure distribution at the seal face as
well as the peak value when compared with same results published in
workshop 4A
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-13 Inventory #002660
Workbench Mechanical Structural Nonlinearities
Workshop 5B: Localized Yielding Workshop Supplement
Post process the preload at the frictionless contact resulting from the
interference fit as before. Compare the preload with workshop 4A.
Note, the change in preload is not nearly as dramatic as that of the contact
pressure. Why?
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-14 Inventory #002660
Workbench Mechanical Structural Nonlinearities
Workshop 5B: Localized Yielding Workshop Supplement
Highlight the Solution Branch
RMB>Insert>Strain>Equivalent Plastic Strain
Note: Yielding is concentrated locally at the melt channel wall. Material
remains elastic across most of the seal face. Hence, preload does not
change very much.
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-15 Inventory #002660
Workbench Mechanical Structural Nonlinearities
Workshop 5B: Localized Yielding Workshop Supplement
Post process equivalent stress and compare to results published at
end of workshop 4A.
ANSYS, Inc. Proprietary April 30, 2009
2009 ANSYS, Inc. All rights reserved. WS5B-16 Inventory #002660
