ANSYS Explicit Dynamics Update Mai Doan Mai.Doan@ansys.com +1 512 687 9523 1/32
ANSYS Explicit Dynamics Update Outline Introduction Solve Problems that were Difficult or Impossible in the Past Structural Dynamics and Explicit Dynamics Complex Interactions (Contact) Enhanced Productivity with Release 14 Speed Improvements 2D Problems in Workbench Easier Meshing New TET element Better Insight Into Results Automation New Physics 2/32
Problems Addressed by Explicit Dynamics Complex reality made easy through simulation Damage to products from impact Consumer or commercial product drop Manufacturing process with large plastic deformation High speed fragment or object impact High speed collision of large objects Cracking of brittle materials in products Explosion near structures 3/32
Nature of Explicit Dynamics Problems Short duration localized phenomena Transient dynamic wave propagation o Gases, Liquids, Solids and their Interaction (FSI) Nonlinear o Material behavior o Contact/Interaction Large deformations o Large strains & strain rates Material failure 4/32
What is ANSYS Explicit Dynamics Explicit Dynamics, (like Structural Dynamics) models the response of structures: from quasi static to severe loadings Applications in: Manufacturing, Consumer Products, Aerospace, Defense, Heavy Equipment, Oil and Gas, Turbo machinery, ANSYS Edge: User Productivity, Ease of Use, Seamless CAD to Solution Environment (ANSYS Workbench) Used by small and large organization world wide, over 800 ANSYS Explicit Dynamics customers. Used to design products, protect products, improve processes 5/32
Solution Methods Compared Explicit Solution (Explicit Dynamics) Time is an independent variable that is "explicitly" advanced according to a stability criteria limited by the speed of shock waves in the smallest element Local Response From shock waves created by impact or other loadings Resulting in deformation and material failure Implicit Solution (Structural Dynamics, aka Mechanical) Time is not an independent variable and is "implicitly" advanced according to convergence criteria State variables being computed are not time dependent Collection of equations represent the relationship of all elements in the problem Equations solved implicitly with advanced matrix solutions Global Response From loads applied mostly uniformly to the whole system. 6/32
Factors Influencing Calculation Times For Implicit Solutions model size (number of DOF) size respectively grade of nonlinearity number of time steps to simulate For Explicit Solution size of the critical time step characteristic element length sound of speed in materials (Young s moduli & density) model size (number of elements) Length of the physical time to be simulated 7/32
New Uses of Explicit Solver No convergence problems in highly nonlinear problems No equilibrium iteration needed Material failure and erosion easy to model High frequencies are naturally resolved because of small time steps Implicit explicit switching capability for efficiency Suited to a wide range of complex nonlinear problems 8/32
Explicit GUI is the Same as Structural 9/32
Extend the Range of Structural Problems Drop test simulations (short time dynamic range, high frequencies) Problems including complex contact situations (large geometrical nonlinearities) Problems including sophisticated material damage and failure (large nonlinearities, element erosion) Load limit analyses (large deformations, large nonlinearities) Manufacturing simulations (large deformations, large nonlinearities) High speed Dynamic analyses (failure, fragmentation, blast wave structure interaction) 10/32
Complex Contact Example Crimping Equivalent Stress Crimping process of seven wires. Changing contact surfaces Self contact Severe deformation Effective Plastic Strain 11/32
Complex Contact Failing Window Crank Window Crank Mechanism Equivalent Stress Effective Plastic Strain 12/32
Non linear Material Response Hyper elastic CV Boot 13/32
Material Failure and Complex Contact 14/32
Productivity Further Enhanced with R14 Painless problem setup Complex geometries easier to mesh with TET elements New NBS TET avoids shear locking Fast solutions using 2 D Insight into part interactions Reaction force trackers implemented Generalized Shell Discrete element, variable thickness shells Import Polyflow and other forming simulation results Direct Access to results for convenient analysis and processing Composites Layered composites (shells) 15/32
Painless problem setup New Tetrahedral Element Nodal Based Strain (NBS) formulation Overcomes both volume and shear locking Particularly valuable in low velocity applications involving complex geometry (consumer drops like mobile phones, nuclear equipment drops) Low deformations and bending dominates problems Isotropic elasticity, plasticity including failure Testing has shown that an Hourglass coefficient (Puso factor) of 0.1 should be used No longer Beta in Release 14 16/32
NBS TET Accuracy Beam Bending Case Average End % Deflection ANP Tet 0.178 21.1% NBS Tet 0.146 0.7% MAPDL 0.147 0.0% 17/32
NBS TET Example Self Piercing Rivet 18/32
NBS TET Example Drop Test, Tablet PC Stress Contours Front View 19/32 Stress Contours Rear View, Cover Invisible
Fast solutions using 2 D 2D Plain Strain and Axisymmetric solid analyses supported for Explicit Dynamics 2D pre and post processing exposed Plain Strain Axisymmetric axis of symmetry now in y direction to be consistent with other ANSYS analysis types 20/32
Fast solutions using 2 D Bullet Example 21/32
Insight into part interactions Direct and quick results of reaction forces Allows capture of high frequency content in response Scoped to Boundary Condition Fixed, Displacement, Velocity, Remote Displacement Scoped to Geometry Selection Reaction Forces, Contact Forces, Euler/Lagrange Coupling forces Results can be filtered 22/32
Example Boundary Reaction Tracker Force reaction at each of 4 supports of component subject to impact loading 23/32
Example FSI Force Tracker External force time history due to fluid jet impinging on deformable surface (filtered at 10,000Hz) 24/32
Generalized Shell Discrete Thickness Import Shell Thickness from External Data Example Import from ANSYS Polyflow Polyflow is a Finite Element based CFD tool used for simulating the processing of materials such as polymers, glass, metals and concrete Processes modeled include extrusion, blow molding, thermoforming, fibre drawing Polyflow results (of predicted thickness) can now be exported to Mechanical and Explicit Dynamics Blow Molding with Polyflow Initial polymer J shape (above) Final thickness (below) 25/32
Discrete Thickness Example Import from Polyflow Complete Virtual Prototyping and Testing capability in ANSYS Workbench for packaging manufacturing: Simulate blow molding or thermal forming process to get final thickness distribution Perform stress and deformation analysis with the variable thickness map (top load, crush, drop etc.) 26/32
Discrete Thickness Shell Example Complete Virtual Prototyping in ANSYS Workbench Simulate blow molding or thermal forming process to get final thickness distribution with POLYFLOW Perform drop test of product filled with water 27/32
Direct Access to Results Design Assessment Introduced in Workbench to enable customized post processing of Mechanical systems Programmable/scriptable means to access results Explicit Dynamics can now be an upstream system for Design Assessment 28/32
Design Assessment Display Fragments Equivalent plastic strain Fragment Volume 29/32
Composites Data Integration with ACP ACP: Built upon a documented Workbench SDK, EVEN has developed addins to introduce ACP as a component system inside Workbench Typical Workbench system: file management and standard actions like Update, Duplicate Consume materials from Engineering Data 30/32
ACP Workflow Example Insertion into schematic flow Explicit * (Autodyn) Implicit (MAPDL) Parameter Support Allows for inclusion as part of Design Exploration 31/32
Composite Example CFRP Baseball bat with spiral CRFP reinforcement 32/32
Summary ANSYS Explicit Dynamics Extends the power of Structural Dynamics for Problems that were Difficult or Impossible in the Past Release 14 Provides Further Productivity Enhancements Speed Improvements Easier Problem Setup Better Insight Into Simulated Results Improved Automated Use Convenient Composite Modeling 33/32