Customer Training Material. Oblique Projectile Impact. ANSYS Explicit STR. ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

Transcription

1 Workshop 14 Oblique Projectile Impact Introduction to ANSYS Explicit STR WS14-1

2 Workshop Goal and Procedure Goal: Perform oblique impact / penetration analysis (with erosion) Procedure: Create an Explicit Dynamics (ANSYS) Analysis System Project Select the units system and define the materials Import and mesh the armor geometry Define analysis settings (including erosion), initial conditions, boundary conditions and body interactions Solve and review the results WS14-2

3 Step 1 Create the Project Schematic Start ANSYS Workbench and follow the sequenced steps using the abbreviations shown below: DC = Double Click with Left Mouse Button SC = Single Click with Left Mouse Button RMB = Right Mouse Button Selection D&D = Drag and Drop = Hold Left Mouse Button down on item while dragging it to new location and then release it (i.e., Copy or Move) 1. Create an ANSYS Explicit Dynamics Analysis System Project DC WS14-3

4 Step 2 Specify the Project Units 2.a Select MKS for the Project Units from the Units List provided 2.b Request that Native Applications in Workbench have their values be Displayed in the Project Units 2.c Check those unit systems to Suppress from appearing in the Units List Note: Engineering Data is native in Workbench, but Mechanical is NOT at this time (but will be in the future). WS14-4

5 Step 3 Define Engineering Data Material DC 3a 3.a EdittheEngineering the Engineering Data cell to add a material to the default library. 3.b Select explicit materials to load in an existing material model. 3.c Scroll down and add CART BRASS, LEAD, RUBBER1 and STEEL 4340 The book symbol confirms it has been added WS14-5

6 Step 3 Define Engineering Data Material SC 3.d Check the materials have been added to engineering data 3.c We will use these materials as they are without modification WS14-6

7 Step 3 Define Engineering Data Material... 3.g Return to the Project Schematic 3.h Save the Project by selecting the Save As... icon and Browse to the directory indicated by your instructor. Use the name Oblique_penetration for the Project name. Note: Saving the Project saves all of the important files. The Project may also be Archived, in which all of the supporting files are compressed and saved in one file. WS14-7

8 Step 4 Import the Geometry RMB SC 4.a Import the geometry by the procedure shown. Do NOT Double Click on the Geometry et y cell... 4.b Browse to the DesignModeler 11.0 SP1 geometry file named: oblique_penetration.agdb WS14-8

9 Step 5 Edit the Model in Mechanical 5.a Edit the model in Workbench Mechanical. RMB Since Edit is the default action, double-clicking on the Model cell is also acceptable here. SC 5.b Select the MKS Units system Recall that Mechanical is not native in Workbench, so the Units here may not match the Project Units Note: Although the unit system used for data entry and post-processing is the MKS system, the actual unit system used by the AUTODYN solver is the mm-mg-ms system, because it provides higher accuracy. This will be shown later when the Analysis Settings are discussed. WS14-9

10 Step 5 Edit the Model in Mechanical... 5.c Define the materials for each part in turn (multiple parts can be selected by holding the ctrl key): plate 1 and plate 2 - steel 4340 rubber spacer1 rubber spacer 4 - rubber1 steel washer 1 steel washer 8 - steel 4340 bolt1 bolt 4 - steel 4340 bullet case - cart brass bullet core - lead WS14-10

11 Step 5 Edit the Model in Mechanical... 5.d Material assignments can then be checked : -Select Geometry -Under Display Style select material -The screen plot will then color the model by material WS14-11

12 Step 5 Edit the Model in Mechanical... 5.e Delete the Bonded Contact Regions RMB 5.f Review the existing Body Interaction specifications WS14-12

13 Step 5 Edit the Model in Mechanical... 5.f Review the automatically created symmetry plane 5.g Save the Project WS14-13

14 Step 6 Mesh Model 6.a Select the Mesh branch 6.b Specify the Mesh Details: Physics Preference = Explicit Element Size = meters 6.c Apply a Patch Independent Tetrahedrons method to the two parts which make up the bullet (via RMB Mesh > Insert > Method) 6.d Set the element size to meters WS14-14

15 Step 6 Mesh Model 6.e Apply a body sizing to the two plates (via RMB Mesh > Insert > Sizing) 6.f Select the two plates and click Apply on the geometry line 6.g Under type select Sphere of Influence - select ZX plane as the sphere centre - set sphere radius to 004meters set the element size to meters 6.h Generate the mesh (via RMB on the Mesh branch > generate mesh) WS14-15

16 Step 7 Define the Analysis Settings 7.a Specify the Analysis Settings: End Time = seconds SC 7.b Note the Solve Units = mm, mg, ms The mm, mg, ms unit system is the most accurate in most simulations, so it is the only one currently available for solution. o Although more solver unit systems will be available in the future, any unit system in the dropdown list may be used to enter data and/or display the results. WS14-16

17 Step 7 Define the Analysis Settings... 7.c Keep the remaining defaults Note: There are multiple ways to control the erosion of an element. In this case, the element will only erode when the geometric strain reaches 150%. 7.d Ensure retain inertia of eroded material is set to YES 7.d Use the default number of data sets to save during the solution. WS14-17

18 Step 8 Apply Initial Condition to bullet 8.a Apply initial velocity to bullet: Select Initial Conditions in the Outline tree Select the body filter Select the two bullet bodies (while holding ctrl) RMB on selected bodies Insert > velocity Enter a velocity of 800 m/s Select the direction box Click on one of the long edges of the bullet If the red arrow points the wrong way, click the arrow icon to reverse it Apply the selection WS14-18

19 Step 9 Insert Result Items to Post-process RMB SC 9.a Insert a Total Deformation plot request under the Solution branch RMB SC 9.b 9b Insert setan Equivalent (von-mises) Stress plot under the solution branch 9.c Save the project on the project page WS14-19

20 Step 10 Run the AUTODYN Simulation SC 10.a Select Solver Output under Solution Information and Solve the simulation. The Solver Output shows the run statistics, including the estimated clock time to completion. Any errors or warnings are also noted. Termination due to wrapup time reached is expected here. WS14-20

21 Step 11 Review the Results 11.a Select Total Deformation and Show the Elements under True Scale. - note the eroded nodes which show up as red dots (these can be turned off under the view menu) SC WS14-21

22 Step 11 Review the Results b Animate the results by setting the controls shown below and then pressing the Animation button. For transient dynamics, the default Distributed mode can be inadequate, as it just linearly interpolates between saved results. The Result Sets mode is often best, as it uses the actual saved data. To review a static result, just click on the desired Time or Value from the Tabular Data and use the RMB to pick Retrieve This Result. The given state will then be shown. Pick these 2 first Pick this to Then pick this save the animation RMB WS14-22