solver enhancements and research directions - pezy … · solver enhancements and research...
TRANSCRIPT
Solver Enhancements and Research Directions
Dr. Franco Costa
June 2016
Autodesk® Moldflow® Insight
Senior Research Leader
© 2016 Autodesk
Validation
Moldflow 2017
Current Developments
Research Projects & Collaborations
Outline
© 2016 Autodesk
Highly Instrumented Box Tool with Conformal Channels
Validation: Transient Cool (FEM)
© 2016 Autodesk
PA 6 material molded 30wt% Glass Fiber
Cool (FEM) using Conduction solver
Agreement on temperature rise and timing
Validation: Transient Cool (FEM)
© 2016 Autodesk
simhub.autodesk.com Validation Reports
Technical papers
What’s New
How to Videos
Where to Find Validation Reports
© 2016 Autodesk
Mold Cooling Analysis for 2K-Overmolding
Cool (FEM), Transient results across multiple cycles
© 2016 Autodesk
Select “Transient from production start-up”
Mold Cooling Analysis for 2K-Overmolding
Set up one cycle
Results span two cycles
© 2016 Autodesk
Cool (FEM) An initial Flow (Gas)
analysis is done to determine the gas core
Conduction or Flow on Every Iteration for part temperatures
3D Cool analysis for Gas Injection Molding
© 2016 Autodesk
Update the empirical relations for heat transfer coefficients from the cooling circuits at low/medium Reynolds numbers
Molding trials in the Instrumented Mold Unfilled PP
Coolant Heat Transfer for Low Reynolds Number
AMI 2017
AMI 2016
Measured Data
© 2016 Autodesk
Allow user routines for selected properties and calculations User-coded routines in a DLL
Example Template provided
AMI 2016 : User viscosity routine
AMI 2017 : PVT & Core-shift
Future: Fiber Orientation ?
Curing ?
HTC ?
3D Flow “Solver API” Framework
© 2016 Autodesk
SolverUserHb3dInitialize
SolverUserHb3dAnalysisSetup
SolverUserHb3dViscosity & SolverUserHb3dSpecificVolumeAtNode
SolverUserHb3dCoreShiftSolve
SolverUserHb3dTimeStepComplete
SolverUserHb3dCleanup
User DLL defined call-back functions
Initialize
Setup
Cleanup
Read Study File
Flow Calculation
Blank User Function
Viscosity & PVT
Temperature Calculation
Next Time Step
Next Iteration
Core Shift
© 2016 Autodesk
Implement via Solver API for PVT Allow other researchers to test
alternative PVT models
U. of Budapest have developed in-mold PVT measurement at high cooling rates Amorphous material
Presented at CONNECT!2014 Moldflow User Meeting
Cooling Rate effect on PVT
© 2016 Autodesk
Implement a cooling rate dependent PVT model in a user Solver API routine Shrinkage: Prediction vs Measured
Cooling Rate effect on PVT
© 2016 Autodesk
Output Cooling Rate at phase transition
Linear shrinkage prediction is lowered slightly
Cooling Rate effect on PVT: Solver API
© 2016 Autodesk
3D Flow Core-Back for Microcellular foaming
Chemical Blowing Agent Foaming
Allow overmolding of thermoset with thermoplastic & vice-versa
Improve accuracy of fiber orientation around the gate.
Increase the upper limit of initial fiber length and allow up to 100 mm long fibers in the simulation.
RSC model can be used for disk-like fillers (aspect ratio less than 1)
3D Warp Allow Mesh Aggregation when isolating causes of warp
Allow Anisotropic properties for part-inserts
Induction Heating for foaming processes (Microcellular and Chemical Blowing Agent)
DOE: Additional process variables and results
Other Improvements in Moldflow 2017
© 2016 Autodesk
• Cool for 2K-Overmolding
• Cool for Gas
• Core-back for Foaming
• Chemical Blowing Agent• Anisotropic Part Inserts
• New 3D Mesher
• Thermoset Inserts
• Fiber Model Controls
• Low Reynolds Number
• Enhanced Results & DOE
• Solver API extended
Moldflow Insight 2017
© 2016 Autodesk
Disclaimer
We may make statements regarding planned or future
development efforts for our existing or new products and
services. These statements are not intended to be a promise or
guarantee of future delivery of products, services or features but
merely reflect our current plans, which may change. Purchasing
decisions should not be made based upon reliance on these
statements.
The Company assumes no obligation to update these forward-
looking statements to reflect events that occur or circumstances
that exist or change after the date on which they were made.
© 2016 Autodesk
Improve 3D Fiber Orientation in Core Layer
Measured data provided by BASF
BASF PA 50%GF
• Investigating
• Orientation models
• Implementation
• Approximations
• Preliminary Results
© 2016 Autodesk
Preliminary Results
Higher concentration of fibers in the core region (through thickness)
Prediction of Fiber Migration
Measured data: G.M. Vélez-García, Compos. Part A-Appl. Vol 43: 104-113 (2012)
30wt% GF/PBT, 1.38mm thick, Center-Gated Disk
© 2016 Autodesk
Next Phases: Stress evolution
Detachment from mold (before ejection)
Consider viscoelastic stress relaxation
3D Residual Stress Shrinkage Model
Phase 1: Thermo-viscous-Elastic Model
Assume full mold constraintStandard AMI
Shrinkage Model
Warp Benchmark Case from Braun:
Measured Combined Deflection at
edges: 1.60mm
1.26mm
1.68mm
© 2016 Autodesk
0.00%
0.50%
1.00%
1.50%
2.00%
2.50%
3.00%
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
In-plane Shrinkages
Experimental Current Model 3D Residual Stress Model
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Cha
ng
e in
Corn
er A
ng
le
Corner Angle Change
Experiments Current Model 3D Residual Stress Model
3D thermo-viscous-elastic model
In-cavity residual stresses are calculated until room temperature
Takes advantage of material shrinkage measurement data if available
3D Residual Stress Shrinkage Model
© 2016 Autodesk
Improving accuracy of weld-strength models for future use in Helius-AME
Weld Surface Strength -3D
© 2016 Autodesk
Mat Orientation
Resin Transfer Molding 3D
Non-Newtonian, non-isothermal flow
(Melt: 30C, Mold:150C)
Anisotropic permeability
Include Vacuum pressure & Gravity
ResultsDegree of Cure, Volumetric shrinkage,
Part Thickness, Permeability, etc.Pressure During Filling
© 2016 Autodesk
• “Free slip”, or slip without friction, is equivalent to the capability offered in TP -2016
• “With friction”: a slip velocity model, with slip velocity being a function of shear stress, is applied
Wall Slip (3D) – Slip Friction Coefficient
© 2016 Autodesk
Accurate 3D flow simulation Flow pattern
Velocity & pressure field
Temperature field
Inertia effect
Wall-slip effect
Metal Injection Molding
Accurate Material propertiesMaterial testing
Data fitting
Powder concentration predictionDetect black line defect
Fill time Powder concentration
Low concentration regions, possible black
line defects
© 2016 Autodesk
Using embedded Nastran FEA solution
Useful to check for balanced ejection and avoid visible stress marks
Ejection Analysis: Force from Ejectors
© 2016 Autodesk
Enhancement on Robustness Enhancement of detecting contact surface between plastic
product and mold core
Enhancement on Accuracy Residual Stress from flow -> initial strain for Nastran
Automatic Detecting based
on ejectors movement direction
User check, add or remove surface
elements manually
Final contact surface
Von Mises Stress During Ejection
Ejection Force
© 2016 Autodesk
Previously, mold blocks are represented by regions.
If inserts are present, users need to stitch contact interfaces to form mold internal boundary
Create CAD Bodies for Mold Block Creation & Meshing
CAD body for mold block
Contact
Face
Now we can create CAD bodies for mold blocks.
Users do NOT need to stitch contact interfaces manually
Surface mesh for mold block
© 2016 Autodesk
Apply appropriate edge length and chord angle on faces automatically
Large bodies have larger edge lengths
Similar edge lengths on contact interfaces
Chord angle applied on faces with high curvature except for fillets
No big increases in element counts
Users do not need to deal with small faces individually
Surface meshes will be more smooth than previous versions
Auto Sizing for CAD
© 2016 Autodesk
• Fiber Orientation
• Fiber and particle migration
• 3D Residual Stress
• PulseTM Cooling• Weld-line Surface Strength
• 3D RTM / Infusion
• Wall Slip with Friction
• Metal Injection Molding
• Ejection Force
• Easier Mold Meshing• Auto sizing for CAD meshing
Current Developments
© 2016 Autodesk
Improve on the bubble nucleation modeling, dependent on pressure history, and local stresses around fillers (talc, fiber)
Vahid Shaayegan presented at AU2015
Microcellular Bubble Nucleation– University of Toronto
© 2016 Autodesk
Thermoplastic Injection OverMolding of composites
Interface Aniform draping solution to Moldflow Warp analysis of the combined structure
Model bond strength
Injection Overmolding of Continuous Fibers Composites - TPRC
© 2016 Autodesk
Model non-recoverable deformation and resistance of a continuous fiber composite being compression overmolded
Composite Overmolding – Huazhong University
© 2016 Autodesk
Prediction of long fiber breakage during melting in injection barrel
Aim: Initial fiber length distribution for polymer at the sprue tip
Fiber Breakage in Barrel– University of Bradford
© 2016 Autodesk
Prediction of fiber orientation and breakage during injection molding of “long” carbon fiber thermoplastics
2mm to 12mm
Long Carbon Fiber Injection Molded:PNNL, Toyota, UIUC, Plasticomp, Magna, Virginia Tech
© 2016 Autodesk
50%wt LCF/PP (slow-fill)
Long Carbon Fiber Project – Phase 1
C C
30wt%LCF/PP slow fill
Location C
Fiber Orientation Fiber Length
© 2016 Autodesk
US DOE funding to develop ICME for carbon fiber draped and compression molded parts (Automotive)
Autodesk invited to provide process modeling of
Compression molding
Fiber Orientation
Local fiber volume fraction
Chopped Carbon Fiber Compression
© 2016 Autodesk
Model the viscosity reduction which occurs due to high shear and leads to advanced flow at part edges
Aim: Improve fill pattern & air-trap prediction
Racetrack / Flow Imbalance– Budapest University (BUTE)
© 2016 Autodesk
Mold to observe flow imbalances after different flow lengths
Racetrack / Flow Imbalance– Budapest University (BUTE)
© 2016 Autodesk
Model the change in viscosity due to filler migration, fiber orientation and fiber breakage
Improve: Fiber orientation
Pressure prediction
Add Filler Volume Fraction effect
Filler effect on Viscosity - RMIT
© 2016 Autodesk
Calculate the mold life and approximated range of cycles
Will use Autodesk Nastran fatigue solver
Support rapid heating cycle molding
Consider 3 major causes of mold damage
Mold Fatigue - Seeking Industrial Collaborators
Fatigue Module
Clamping-force-
induced Stress
Thermal Stress
Pressure-induced
Stress
© 2016 Autodesk
Flow instability
Looking for collaboration / case-studies (aimed at Automotive parts)
Surface Appearance (Tiger Stripes)
© 2016 Autodesk
Microcellular Foaming
Composite Overmolding
Long Fiber Breakage & Orientation
Long Carbon Fiber Injection Molding & Compression Molding (SMC)
Flow advancement at part edges
Viscosity Effects / Fiber
Mold Fatigue
Tiger Stripes
Summary of Long Term Research Collaborations
© 2016 Autodesk
Some New API Scripts….
MapOvermold including Fiber Orientation
3D Surface Shrink
3-2-1 Warp Deflection