COPYRIGHT DASSAULT SYSTEMES Generative Assembly Structural Analysis CATIA Training Exercises Version 5 Release 8 March 2002 EDU-CAT-E-GAS-FX-V5R8
COPYRIGHT DASSAULT SYSTEMES Complete exercise of Bolt assemblyp.3 Create assembly constraintsp.4 Create connections from constraintsp.6 Static analysis of the bolt assemblyp.8 2. Foot peg Assembly Connectionsp Static Analysis of the Foot peg Assemblyp Frequency Analysis of the Foot peg Assemblyp Engine Assembly Modal Analysisp Pressure Fitting Connection between Rod and Axisp Landing Gear Assemblyp.26 Create Static analysis and connectionsp.29 Static analysisp.31 Frequency analysisp Under-pressure Tank Tightnessp.36 Create assembly constraints and analysis connectionsp.39 Apply pressure and Virtual Bold Tightening connectionsp.40 Static analysisp.41 Hints and Tips p.44 Table of Contents
COPYRIGHT DASSAULT SYSTEMES min. Complete Exercise Bolt Assembly Analysis In this exercise, you will do a complete exercise on a bolt assembly, from the constraints application to the static analysis, through connections and bolt tightening application.
COPYRIGHT DASSAULT SYSTEMES Complete Exercise Bolt Assembly : Create assembly constraints In this step you will create coincidence and contact assembly constraints.
COPYRIGHT DASSAULT SYSTEMES Load: BoltAssembly.CATProduct Do It Yourself Enter the Assembly design workbench. Create assembly constraints : Put a coincidence constraint between screw axis and bottom hole. Put a coincidence constraint between holes from top and bottom parts. Put a contact constraint between faces from screw and top parts. Put contact constraints between faces from top and bottom parts, and from screw and bottom parts.
COPYRIGHT DASSAULT SYSTEMES Complete Exercise Bolt Assembly : Create connections from constraints In this step you will create Fastened and Bolt Tightening connections from assembly constraints (Generative Structural Analysis workbench).
COPYRIGHT DASSAULT SYSTEMES The Bolt Tightening connection will take into account the screw pre-tension effect. Note that we can also apply this command without screw with the Virtual Rigid Bolt Tightening connection. We choose fastened connections because the surfaces are supposed to be always in contact. The Bolt Tightening connection also handle incompatible meshes. Do It Yourself Create contact connections : Select the two first contact constraints, and then create fastened connections. Create Bolt Tightening connection : Select the last contact constraint, and select Bolt Tightening connection. Choose a 500 N Tightening force and an opposite orientation.
COPYRIGHT DASSAULT SYSTEMES Complete Exercise Bolt Assembly : Static analysis of the bolt assembly In this step you will perform a static analysis of the assembly and visualize the results.
COPYRIGHT DASSAULT SYSTEMES Do It Yourself Create Static Analysis of the bolt assembly : Apply clamps back of the two cubes. Launch static analysis. Show Von Mises results. Select results only for the screw in selecting the Von Mises icon with the contextual menu (Generate Image), then the OCTREE screw mesh.
COPYRIGHT DASSAULT SYSTEMES Fundamental Steps Create assembly constraints : Create coincidence constraints. Create contact constraints. Create connections from constraints : Create fastened connections. Create Bolt Tightening connection. Static Analysis : Compute static analysis of a bolt assembly. Visualize Von Mises results. Show results for a single part of the assembly
COPYRIGHT DASSAULT SYSTEMES Recap Exercise Foot peg Assembly Connections In this exercise you will apply connections to the foot peg assemblys part constraints You will use : Slider Connections Fastened connections Contact connections with springs 15 min.
COPYRIGHT DASSAULT SYSTEMES Do It Yourself Apply slider connections to the pin and the large face Apply a fastened connection to the small face on the raised pad Peg Peg mount Small face Pin Large face Load: CATGASFootPeg_1.CATProduct
COPYRIGHT DASSAULT SYSTEMES Recap Exercise Static Analysis of the Foot peg Assembly In this exercise you will perform a static analysis on the foot peg assembly. You will use : Static Pre-Processing Computation Post-Processing 15 min.
COPYRIGHT DASSAULT SYSTEMES Do It Yourself Apply a clamp on the back surface of the peg mount, and a surface slider on the cylindrical surface of the foot peg Apply a distributed load of 3000N along the z axis (facing downwards) to the top surface of the peg. Use compass so that the force is defined relatively to the part Compute Von Mises Stress with parabolic elements (for both parts of the assembly). Adjust the color palette in order to visualize the areas where the assembly is most likely to fail Load: CATGASFootPeg_Static.CATAnalysis
COPYRIGHT DASSAULT SYSTEMES Connections Comparison contact-contact-contact : max = 1.64 mm contact-slider-slider : max = 1.52 mm fastened-slider-slider : max = 1.01 mm We can see that there is a difference of 60% between the first case, supposed too rigid, and the last one, closer to reality. Fastened or contact Slider or contact
COPYRIGHT DASSAULT SYSTEMES Recap Exercise Frequency Analysis of the Foot peg Assembly In this exercise you will perform a frequency analysis on the foot peg assembly. You will use : Frequency Pre-Processing Restrained Modes Computation Post-Processing 15 min.
COPYRIGHT DASSAULT SYSTEMES Do It Yourself Apply a clamp on the back surface of the peg mount Compute using the default linear elements Create and animate a displacements image of the 5th dynamic mode Apply a surface slider on the cylindrical surface of the foot peg Animate 5th mode and compare Load: CATGASFootpeg_Frequency.CATAnalysis
COPYRIGHT DASSAULT SYSTEMES Fundamental Steps Static Analysis : Apply a clamp and a surface slider. Apply a distributed load. Use of the compass to define forces relatively to the part. Computing Von Mises stress with parabolic elements. Adjusting color palette (fail detection). Frequency Analysis : Create and animate a displacements image of a given mode. Change a connection, animate and compare with the previous step.
COPYRIGHT DASSAULT SYSTEMES Additional Exercise Engine Assembly Modal Analysis In this exercise you will learn how to compute an Assembly of several Parts, and more especially compute Natural Frequencies and the associated Mode Shapes of the Assembly. Skills needed : Creating Restraints Launching a Computation Displaying Results 60 min.
COPYRIGHT DASSAULT SYSTEMES Design Intent : Engine Assembly Modal Analysis Defining the most realistic Connections (fasten, slider, etc.) between the different parts (rods, pistons, pins and crankshaft) Defining the most realistic Restraints on the assembly (slider, clamp, etc.) Analyzing Natural Frequencies and the associated Mode Shapes
COPYRIGHT DASSAULT SYSTEMES Design Process: Engine Assembly Modal Analysis Create Connections between Parts 1 Apply Restraints on the Assembly 2 Compute 3 Display Results 4
COPYRIGHT DASSAULT SYSTEMES Do It Yourself Create the following connections: Fastened Connections between Pistons and Pins Fastened Connections between Pins and Rods Slider Connections between Rods and Crankshaft Create the following restrains: Restrain Translation 1 and 3 on the Cylindrical Surfaces of the Pistons, in order to release only the Motion of Pistons in the liner Restrain the rods in order to avoid the axial motion along the crankshaft Restrain the crankshaft on the bearings (radial motion and axial motion) Launch the computation Display Natural Frequency number 8, the associated Mode Shape and Von Mises Stress values Load: CATGAS_Engine.CATProduct
COPYRIGHT DASSAULT SYSTEMES Fundamental Steps Create connections between parts : Fastened connections. Slider connections. Create restraints on the assembly: Restrain translations and rotations from the advanced restraints tool.. Display results : Display a given natural frequency. Display the associated mode shape. Display the Von Mises values.
COPYRIGHT DASSAULT SYSTEMES Additional Exercise Pressure Fitting Connection between Rod and Axis In this exercise, you will learn how to create a Pressure Fitting Connection. 20 min.
COPYRIGHT DASSAULT SYSTEMES Design Intent : Pressure Fitting Connection between Rod and Axis Create Pressure fitting connection between the two parts with a overlap of 1e-005 mm. Clamp the Rod in the inner surface. Compute and visualize the Stress Von Mises. Remesh locally only the inner rod surface between the 2 parts with a mesh size of 2 mm. Recompute, visualize the Stress Von Mises and modify the visualization amplitude modulation with a deform coefficient of Clamps Load: CATGAS_contact.CATProduct Pressure fitting connection
COPYRIGHT DASSAULT SYSTEMES min. Master Exercise Landing Gear Assembly In this exercise you will perform both a Static and a Frequency Analysis on an Assembly of Parts. You will use : Connections Pre-Processing Tools Image Tools Result Management Tools
COPYRIGHT DASSAULT SYSTEMES Frequency Analysis Configuration Static Analysis Configuration (Split) Design Intent: Landing Gear Assembly Create and Name Static Analysis Create connections on the Assembly Constraints Define Static Pre-Processing Features (Loads and Restraints) Compute and Analyze Results Create and Name Frequency Analysis Define Frequency Pre-Processing Features (Mass Equipment and Restraints) Compute and Analyze Results
COPYRIGHT DASSAULT SYSTEMES Create Static Analysis and Connections 1 Perform Static Analysis 2 Open the Landing Gear CATProduct and create Frequency Analysis 3 Perform Frequency Analysis 4 Design Process: Landing Gear Assembly
COPYRIGHT DASSAULT SYSTEMES min. Master Exercise Landing Gear Assembly : Create Static Analysis and Connections In this step you will : create a static analysis of the landing gear apply materials to its parts define the physical connections existing between the different parts of the assembly save the Analysis Document
COPYRIGHT DASSAULT SYSTEMES Load: CATGASLandingGear_1. CATProduct Do It Yourself Create Static Analysis and Connections : Apply steel to the leg, titanium to the rings, and steel to the flanges Open GAS Workbench and create Static Analysis of the landing gear Apply fastened connections between LandingGearLeg and both Rings Apply slider connections between rings and flanges Save the analysis document under the name CATGASLandingGear_1.CATAnalysis.
COPYRIGHT DASSAULT SYSTEMES min. Master Exercise Landing Gear Assembly : Static Analysis In this step you will perform a static analysis on the landing gear assembly
COPYRIGHT DASSAULT SYSTEMES Load: CATGASLandingGear_1. CATAnalysis Do It Yourself Static Analysis : Apply clamps on the drilled surfaces of both flanges, and restrain legs rotation around its axis Apply a pressure of 40000N on the bottom part of the leg cylinder Create a Von Mises Stress Image. Localize maximum stress area
COPYRIGHT DASSAULT SYSTEMES min. Master Exercise Landing Gear Assembly : Frequency Analysis In this step you will perform a frequency analysis on the landing gear assembly
COPYRIGHT DASSAULT SYSTEMES Load: CATGASLandingGear_2. CATAnalysis Do It Yourself Frequency Analysis : Apply clamps on the drilled surfaces of both flanges Restrain the rotation of the leg around its axis, on both sides Compute with default settings Animate the 4 th mode and zoom to visualize the connections between ring and flange
COPYRIGHT DASSAULT SYSTEMES Fundamental Steps Create Static Analysis and Connections : Apply material. Open a new static analysis. Create slider end fastened connections. Static Analysis : Apply clamps. Apply a pressure. Create a Von Mises analysis. Ask for the maximum stress area. Frequency Analysis : Restrain rotation from the advanced restraints tool. Computing from the previous static analysis and animation of a given mode.
COPYRIGHT DASSAULT SYSTEMES min. Additional Exercise Under-pressure tank Tightness Analysis In this exercise you will learn how to compute a Tightness analysis in the case of an under- pressure tank. You will : Create assembly constraints and analysis connections. Apply pressure and Virtual Bolt Tightening connections. Perform a static analysis.
COPYRIGHT DASSAULT SYSTEMES Design Intent : Under-pressure tank Tightness Analysis Creating assembly constraints and analysis connections Applying a pressure and Virtual Bolt Tightening connections Performing a static analysis of the tank. Post-processing of the pressure.
COPYRIGHT DASSAULT SYSTEMES Create constraints and connections between Parts 1 Apply a pressure and Bolt Tightening connections 2 Analyse and display Results 3 Design Process: Under-pressure tank Tightness Analysis
COPYRIGHT DASSAULT SYSTEMES Load: Tank_Assembly.CATProduct With only three assembly constraints, we will not be able to apply Virtual Bolt Tightening connections on the four bolt areas. So, we must use analysis connections, which not over-constrain the model. Step 1 – Create assembly and analysis connections Create Assembly constraints and connection : Coincidence between a Tank hole and a Cover hole. Another coincidence on opposites holes. Contact constraint between the tank and the cover. Enter the Generative Structural Analysis workbench. Apply a contact connection. Create Analysis connections : Enter the Analysis Connections workbench. Distant connection between a tank hole surface and the corresponding cover hole surface. Repeat this operation three times for the others bolts areas.
COPYRIGHT DASSAULT SYSTEMES Step 2 – Apply a pressure and Virtual Bolt Tightening connections Apply a pressure : Apply a 500 Pa pressure on all the internal surfaces. Create Virtual Bolt Tightening connections : Select the Virtual Bolt Tightening advanced connection icon. Select an analysis connection (only Distant Analysis connections). Enter a 5000 N Tightening force. Repeat for the others virtual bolts.
COPYRIGHT DASSAULT SYSTEMES We can see that there is a mm maximum displacement, and a zero pressure (detachment) around bolts all along the surface contact. Step 3 – Static Analysis (1/2) Apply clamp on the back of the tank. Launch a static analysis. Visualize displacements (Average-Iso). Select Generate Image on Static Case Solution icon, and Pressure fringe. In Selections, choose Tank mesh. Adjust visualization in the Color Map editor.
COPYRIGHT DASSAULT SYSTEMES The blue areas, where there is no pressure contact, are smaller than the first case. They could be completely removed by adding Bolts. Load: Tank_Analysis_Modified.CATAnalysis Use smaller mesh size and sag for the contact surface. Step 3 – Static Analysis (2/2) Enter GPS and load Tank_Analysis_Modified. Launch a static analysis. Visualize displacements (Average-Iso). Select Generate Image on Static Case Solution icon, and Pressure fringe. In Selections, choose tank mesh. Adjust visualization in the Color Map editor.
COPYRIGHT DASSAULT SYSTEMES Fundamental Steps Create assembly constraints and analysis connections : Coincidence and contact constraints. Contact and Distant Analysis connections. Apply a pressure and Virtual Bolt Tightening connections: Create a pressure on surfaces. Create Virtual Bolt Tightening connections from analysis connections. Static Analysis : Compute a static analysis. Visualize Average-Iso displacements. Show the maximum detachment. Visualize Pressure fringe. Adjust colours palette.
COPYRIGHT DASSAULT SYSTEMES Hints and Tips Dont forget to apply the corresponding material on the part. To visualize results, select applies customized view. Information about analysis (time and space disk used) is stored in the Ficel file. To check the volumic mesh quality, go in FMS workbench. When a CATPart has both part body and open body, it is necessary to hide the part body or you will not have access to the boundaries for restraints and/or loads. When performing analysis on a CATProduct with many openbodies, do Tools, external View on each surface by switching to each openbody. Be very rigorous and methodical while creating connections, particularly in large assembly. For example, you can give the same name for a connection and its constraint.