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MPI 6.1 – Solver Enhancements

MPI 6.1 – Solver Enhancements. Presentation Outline. New Solver Features 3D Birefringence 3D Parallel Warp Solver Enhancements Flow Cool Warp/Fiber OPTIM Enhancements to Structural CAE Interfaces Miscellaneous. 3D Birefringence Analysis. Background: Refractive Index.

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MPI 6.1 – Solver Enhancements

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  1. MPI 6.1 – Solver Enhancements

  2. Presentation Outline • New Solver Features • 3D Birefringence • 3D Parallel Warp • Solver Enhancements • Flow • Cool • Warp/Fiber • OPTIM • Enhancements to Structural CAE Interfaces • Miscellaneous

  3. 3D Birefringence Analysis

  4. Background: Refractive Index • Refractive index is the property of a material to bend and slow down light (called retardation) nlens > nair nlens < nair

  5. ni: refractive index of principle directions Background: Anisotropy • If a material is not isotropic, the refractive index will be different in different directions • Called birefringence • Components of the light become out of phase • Components bend by differing amounts • Image becomes blurred • Crystals are an example of an anisotropic material

  6. Background: Anisotropy • Viewing birefringence with cross-polarizers • Components of the light will become out of phase after passing through the sample

  7. Background: Anisotropy • Passing through birefringent material, the components of light become: • Out of phase • Blurred image

  8. Optical Path Difference: Retardation • For a light source coming from some direction and traveling through the part, the retardation is the difference in the length of the optical path (nm) • Depends on the direction • Equivalent to how far out of phase are the two components of the light wave • Can be different at each point of an object

  9. Phase Difference • Expresses the retardation relative to the wavelength of the light (color) • Unit is radians • Still depends on the direction of the light • Can be different at each point of an object • See birefringence bands in cross-polarizers when the phase shift is more than 2p • That is when Retardation is greater than Wavelength

  10. Birefringence in Polymers • Example of Birefringence in a polymer due to Flow & post-warp induced stresses

  11. Birefringence in Polymers • Birefringence can be caused by the stresses in a polymer • Stress-Optic Law • Flow induced stresses • Post warpage residual stresses • Will not be uniform in all regions of the part • Will not be uniform through the thickness • Must use the integral form

  12. Birefringence in Polymers • Birefringence comes from the difference in refractive indices caused by residual stresses in the polymer • We do not need to know the refractive index exactly to calculate this stress difference • After ejection, deformation allows most of the thermal (shrinkage) stresses to be relaxed • The viscoelastic stresses are a significant component of the remaining stresses • Need viscoelastic material data to predict the viscoelastic stresses

  13. Birefringence: Analysis Setup • Run: 3D Flow + Warp • Check analysis option • Analysis Requirements • Birefringence license • Optical material data

  14. Material Data Inputs • Base refractive index (can be approximate) • Stress-Optical Coefficient (published values) • Relaxation times (viscoelastic measurements) • From a parallel plate rheometer • Solid and Melt phase • Need molded sample for solid phase

  15. Analysis Results • Change in refractive index: tensor (anisotropic) • Includes flow induced, and • Post-warpage residual stress effects • Retardance for light from +/- Z direction (nm) • Surface result which integrates the effect through the thickness • Phase shift for light from +/- Z direction (radians) • Surface result which integrates the effect through the thickness • Relative to the wavelength of the light

  16. Analysis Results (contd.) • Can use Custom plots to change direction of Light source and the wavelength of incident light • Need to first define a local coordinate system

  17. Birefringence Results • Change in refractive index (after Warp) • First principle direction • Cutting plane through thickness

  18. Tensor sized based on principal value Shaded Tensor Birefringence Results • Change in refractive index tensor result

  19. Retardation Birefringence Results • Retardation for light from –z direction • Surface only result (integrated through thickness

  20. Validation Experiments • Validation experiments on plaque model • (1mm & 3mm) cavities • 2 Flow rates • PMMA & COP materials • 10 duplicates are used for stabilization • Measure retardation at 45 positions in each sample

  21. Validation Experiments • Retardation: PMMA, 3mm cavity, Slow Fill Much less than one wavelength Retardation along centerline MPI (Green) Exp (Blue)

  22. MPI (Green) Exp (Blue) Validation Experiments • Retardation: COP, 2mm cavity, Fast Fill Much less than one wavelength Retardation along centerline

  23. Parallel 3D Warp Analysis

  24. Parallel 3D Warp • Solve 3D Warp analysis simultaneously on a multi-processor system (i.e., parallel solution) • For shared memory systems (SMP) • Will not support distributed memory clusters • Support on Windows & Linux (no UNIX) • No additional license required

  25. Processor Processor Memory Parallelization – Shared Memory • All processors are in the same computer and can see the full system memory • Fast data sharing • This is the “Dual Core” model used by Intel and AMD. • Intel expects 70% of all chips sold by 2007 to be dual core or more (quad-core)

  26. Analysis Setup • Parallel option not enabled by default • Does not change memory requirement • User controls: • No parallelization • Limit to a Max. number of processors • Specify number of processors

  27. Parallel 3D Warp Performance • Speed-up on Intel Pentium/Xeon (1MB L2 Cache per Processor) • 1.3 (2 processors) • 1.5 (4 processors) • Speed-up on AMD Athlon & Intel Core Duo/Extreme (2MB L2 Cache per Processor) • 1.5 (2 processors) • 2.0 (4 processors)

  28. Parallelization – Speed Up Results • Some sections of code have not yet been parallelized • This noticeably affects some large models

  29. Flow Solver Enhancements

  30. Flow Solver Enhancements • Midplane, Fusion & 3D • Improved selection of Ram-speed profiles • Explicit switchover by ram-position • Midplane & Fusion • Account for Compressive heating • 3D • 3-stage HTC • AMG Matrix solution • Fill time output at intermediate times • Barrel Compression • Entrance Pressure • Variable Thermal Properties

  31. Improved Selection of Ram-Speed Profiles • Ram-Speed Profiles split into two groups • Relative ram speed & Absolute ram speed • Old study files will use “Legacy” profiles

  32. Improved Selection of Ram-Speed Profiles • Ram-Speed Profiles split into two groups • Relative • %Flow rate vs. %shot volume • %Ram speed vs. %stroke • Absolute • Ram speed vs. ram position • Flow rate vs. ram position • %Maximum ram speed vs. ram position • Ram speed vs. time • Flow rate vs. time • %Maximum ram speed vs. time

  33. Ram-Speed Profiles • Use Relative, if • Machine unknown (or) • A recommended ram speed result is desired • Use Absolute, if • Machine data available (or) • Duplicating an existing process (or) • Switchover by ram position is used

  34. Explicit Switch-Over By Ram-Position • Velocity/pressure switch-over has new option • By ram position • Can only be used with absolute ram speed profile

  35. Compressive Heating • Compressive heating now accounted for in Midplane & Fusion • Melt temperature increases as material gets compressed Melt Temp = 310.0 C • Generally MPI 6.1 pressures will be 4% to 5% lower than MPI 6.0 MPI 6.0 MPI 6.1

  36. 3-Stage HTC in 3D Flow • 3D Flow Solver uses 3-stage Heat Transfer Coefficient (HTC) similar to Midplane & Fusion • Defaults: • 5,000 W/m2 Filling • 2,500 W/m2 Packing • 1,250 W/m2 Detached (pressure = 0) • HTC can also be set on individual elements by the element properties

  37. AMG Matrix Solver Option in 3D Flow • AMG matrix solver option to reduce analysis time

  38. AMG Matrix Solver Option in 3D Flow • Limitations: • Total memory usage increased around 30% • Does not need to be concurrent (Can swap) • Some Gas Injection and Reactive molding models showing poor performance • Currently under investigation • AMG matrix solution is not on by default • Will not be used if model size is VERY small

  39. Intermediate Fill-time result in 3D Flow • In MPI 6.0, the Coupled 3D Flow solver did not output fill time until the analysis was finished • In MPI 6.1, the Fill time result is output each time the intermediate results are written • The filling pattern can be checked while the analysis is running • # of intermediate results can be specified in the solver parameters

  40. Other 3D Flow improvements • Include barrel compression effect • Consider variable thermal properties • Include entrance pressure loss in beam contractions • These feature were previously available in Midplane/Fusion Flow • Some of these features were introduced in MPI 6.0 revisions

  41. Cool Solver Enhancements

  42. Cool Solver Enhancements • Uses multi-point thermal (Cp & K) data • New hot runner heat loss setting • HTC used in cooling • New cooling results • Metal side of the plastic/metal interface • Difference between the plastic and metal sides of the interface

  43. Single point Multi point Multi-Point Thermal Data Used • Multi-point Cp & K material data used • Previous releases used average value • Results typically will have only a subtle change

  44. New Hot Runner Heat Loss Setting • As an alternative to specifying the heat flux, insulating properties can now be set • Properties needed • Insulating layer conductance • Air gap • Set as property • Hot gate • Hot runner • Hot sprue

  45. Heat Transfer Coefficient (HTC) Used • HTC value of Packing (2500 W/m2) is used • Now the Plastic and metal at the plastic/metal interface have different temperatures • Typically only a few degrees different • The interface to Flow is the metal side of the interface which is the same value as it was in previous releases

  46. New Cooling Results • Due to use of HTC, results have been modified • The Temperature (XXX), part results have been replaced by Temperature (XXX), mold results • The result represents the mold side of the plastic metal interface • A new result • Mold-melt temperature difference (XXX), part • Shows the difference in temperature due to the HTC value • Temperature profile, part values of -1 and 1 represent the plastic surface temperature

  47. Summary of New Cooling Results

  48. Warp/Fiber Enhancements

  49. Warp Solver Enhancements • Four matrix solver options available for Midplane & Fusion, set in solver options • Automatic • Chooses the best option for the model size (new) • Direct solver • Simple matrix solver, efficient for small to medium models • AMG • Efficient for large models but takes a large amount of memory (new) • SSORCG • Formerly called iterative solver, less efficient than AMG but uses less memory

  50. MPI 6.0 rev 2 MPI 6.0 rev 3 Fiber Solver Enhancements • Improved orientation matching for top & bottom surfaces of Fusion models • This enhancement was introduced in MPI 6.0 revision 3

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