- •Table of Contents
- •Chapter 1: Probabilistic Design
- •1.1. Understanding Probabilistic Design
- •1.1.1. Traditional (Deterministic) vs. Probabilistic Design Analysis Methods
- •1.1.2. Reliability and Quality Issues
- •1.2. Probabilistic Design Terminology
- •1.3. Using Probabilistic Design
- •1.3.1. Create the Analysis File
- •1.3.1.1. Example Problem Description
- •1.3.1.2. Build the Model Parametrically
- •1.3.1.3. Obtain the Solution
- •1.3.1.4. Retrieve Results and Assign as Output Parameters
- •1.3.1.5. Prepare the Analysis File
- •1.3.2. Establish Parameters for Probabilistic Design Analysis
- •1.3.3. Enter the PDS and Specify the Analysis File
- •1.3.4. Declare Random Input Variables
- •1.3.5. Visualize Random Input Variables
- •1.3.6. Specify Correlations Between Random Variables
- •1.3.7. Specify Random Output Parameters
- •1.3.8. Select a Probabilistic Design Method
- •1.3.8.1. Probabilistic Method Determination Wizard
- •1.3.9. Execute Probabilistic Analysis Simulation Loops
- •1.3.9.1. Probabilistic Design Looping
- •1.3.9.2. Serial Analysis Runs
- •1.3.9.3. PDS Parallel Analysis Runs
- •1.3.9.3.1. Machine Configurations
- •1.3.9.3.1.1. Choosing Slave Machines
- •1.3.9.3.1.2. Using the Remote Shell Option
- •1.3.9.3.1.3. Using the Connection Port Option
- •1.3.9.3.1.4. Configuring the Master Machine
- •1.3.9.3.1.5. Host setup using port option
- •1.3.9.3.1.6. Host and Product selection for a particular analysis
- •1.3.9.3.2. Files Needed for Parallel Run
- •1.3.9.3.3. Controlling Server Processes
- •1.3.9.3.4. Initiate Parallel Run
- •1.3.10. Fit and Use Response Surfaces
- •1.3.10.1. About Response Surface Sets
- •1.3.10.2. Fitting a Response Surface
- •1.3.10.3. Plotting a Response Surface
- •1.3.10.4. Printing a Response Surface
- •1.3.10.5. Generating Monte Carlo Simulation Samples on the Response Surfaces
- •1.3.11. Review Results Data
- •1.3.11.1. Viewing Statistics
- •1.3.11.2. Viewing Trends
- •1.3.11.3. Creating Reports
- •1.4. Guidelines for Selecting Probabilistic Design Variables
- •1.4.1. Choosing and Defining Random Input Variables
- •1.4.1.1. Random Input Variables for Monte Carlo Simulations
- •1.4.1.2. Random Input Variables for Response Surface Analyses
- •1.4.1.3. Choosing a Distribution for a Random Variable
- •1.4.1.3.1. Measured Data
- •1.4.1.3.2. Mean Values, Standard Deviation, Exceedence Values
- •1.4.1.3.3. No Data
- •1.4.1.4. Distribution Functions
- •1.4.2. Choosing Random Output Parameters
- •1.5. Probabilistic Design Techniques
- •1.5.1. Monte Carlo Simulations
- •1.5.1.1. Direct Sampling
- •1.5.1.2. Latin Hypercube Sampling
- •1.5.1.3. User-Defined Sampling
- •1.5.2. Response Surface Analysis Methods
- •1.5.2.1. Central Composite Design Sampling
- •1.5.2.2. Box-Behnken Matrix Sampling
- •1.5.2.3. User-Defined Sampling
- •1.6. Postprocessing Probabilistic Analysis Results
- •1.6.1. Statistical Postprocessing
- •1.6.1.1. Sample History
- •1.6.1.2. Histogram
- •1.6.1.3. Cumulative Distribution Function
- •1.6.1.4. Print Probabilities
- •1.6.1.5. Print Inverse Probabilities
- •1.6.2. Trend Postprocessing
- •1.6.2.1. Sensitivities
- •1.6.2.2. Scatter Plots
- •1.6.2.3. Correlation Matrix
- •1.6.3. Generating an HTML Report
- •1.7. Multiple Probabilistic Design Executions
- •1.7.1. Saving the Probabilistic Design Database
- •1.7.2. Restarting a Probabilistic Design Analysis
- •1.7.3. Clearing the Probabilistic Design Database
- •1.8. Example Probabilistic Design Analysis
- •1.8.1. Problem Description
- •1.8.2. Problem Specifications
- •1.8.2.1. Problem Sketch
- •1.8.3. Using a Batch File for the Analysis
- •1.8.4. Using the GUI for the PDS Analysis
- •Chapter 2: Variational Technology
- •2.1. Harmonic Sweep Using VT Accelerator
- •2.1.1. Structural Elements Supporting Frequency-Dependent Properties
- •2.1.2. Harmonic Sweep for Structural Analysis with Frequency-Dependent Material Properties
- •2.1.2.1. Beam Example
- •Chapter 3: Adaptive Meshing
- •3.1. Prerequisites for Adaptive Meshing
- •3.2. Employing Adaptive Meshing
- •3.3. Modifying the Adaptive Meshing Process
- •3.3.1. Selective Adaptivity
- •3.3.2. Customizing the ADAPT Macro with User Subroutines
- •3.3.2.1. Creating a Custom Meshing Subroutine (ADAPTMSH.MAC)
- •3.3.2.2. Creating a Custom Subroutine for Boundary Conditions (ADAPTBC.MAC)
- •3.3.2.3. Creating a Custom Solution Subroutine (ADAPTSOL.MAC)
- •3.3.2.4. Some Further Comments on Custom Subroutines
- •3.3.3. Customizing the ADAPT Macro (UADAPT.MAC)
- •3.4. Adaptive Meshing Hints and Comments
- •3.5. Where to Find Examples
- •Chapter 4: Rezoning
- •4.1. Benefits and Limitations of Rezoning
- •4.1.1. Rezoning Limitations
- •4.2. Rezoning Requirements
- •4.3. Understanding the Rezoning Process
- •4.3.1. Overview of the Rezoning Process Flow
- •4.3.2. Key Commands Used in Rezoning
- •4.4. Step 1: Determine the Substep to Initiate Rezoning
- •4.5. Step 2. Initiate Rezoning
- •4.6. Step 3: Select a Region to Remesh
- •4.7. Step 4: Perform the Remeshing Operation
- •4.7.1. Choosing a Remeshing Method
- •4.7.1.1. Remeshing Using a Program-Generated New Mesh (2-D)
- •4.7.1.1.1. Creating an Area to Remesh
- •4.7.1.1.2. Using Nodes From the Old Mesh
- •4.7.1.1.3. Hints for Remeshing Multiple Regions
- •4.7.1.1.4. Generating a New Mesh
- •4.7.1.2. Remeshing Using a Generic New Mesh (2-D and 3-D)
- •4.7.1.2.1. Using the REMESH Command with a Generic New Mesh
- •4.7.1.2.2. Requirements for the Generic New Mesh
- •4.7.1.2.3. Using the REGE and KEEP Remeshing Options
- •4.7.1.3. Remeshing Using Manual Mesh Splitting (2-D and 3-D)
- •4.7.1.3.1. Understanding Mesh Splitting
- •4.7.1.3.2. Geometry Details for Mesh Splitting
- •4.7.1.3.3. Using the REMESH Command for Mesh Splitting
- •4.7.1.3.4. Mesh-Transition Options for 2-D Mesh Splitting
- •4.7.1.3.5. Mesh-Transition Options for 3-D Mesh Splitting
- •4.7.1.3.7. Improving Tetrahedral Element Quality via Mesh Morphing
- •4.7.2. Mesh Control
- •4.7.3. Remeshing Multiple Regions at the Same Substep
- •4.8. Step 5: Verify Applied Contact Boundaries, Surface-Effect Elements, Loads, and Boundary Conditions
- •4.8.1. Contact Boundaries
- •4.8.2. Surface-Effect Elements
- •4.8.3. Pressure and Contiguous Displacements
- •4.8.4. Forces and Isolated Applied Displacements
- •4.8.5. Nodal Temperatures
- •4.8.6. Other Boundary Conditions and Loads
- •4.9. Step 6: Automatically Map Variables and Balance Residuals
- •4.9.1. Mapping Solution Variables
- •4.9.2. Balancing Residual Forces
- •4.9.3. Interpreting Mapped Results
- •4.9.4. Handling Convergence Difficulties
- •4.10. Step 7: Perform a Multiframe Restart
- •4.11. Repeating the Rezoning Process if Necessary
- •4.11.1. File Structures for Repeated Rezonings
- •4.12. Postprocessing Rezoning Results
- •4.12.1. The Database Postprocessor
- •4.12.1.1. Listing the Rezoning Results File Summary
- •4.12.1.2. Animating the Rezoning Results
- •4.12.1.3. Using the Results Viewer for Rezoning
- •4.12.2. The Time-History Postprocessor
- •4.13. Rezoning Restrictions
- •4.14. Rezoning Examples
- •4.14.1. Example: Rezoning Using a Program-Generated New Mesh
- •4.14.1.1. Initial Input for the Analysis
- •4.14.1.2. Rezoning Input for the Analysis
- •4.14.2. Example: Rezoning Using a Generic New Mesh
- •4.14.2.1. Initial Input for the Analysis
- •4.14.2.2. Exporting the Distorted Mesh as a CDB File
- •4.14.2.3. Importing the File into ANSYS ICEM CFD and Generating a New Mesh
- •4.14.2.4. Rezoning Using the New CDB Mesh
- •Chapter 5: Mesh Nonlinear Adaptivity
- •5.1. Mesh Nonlinear Adaptivity Benefits, Limitations and Requirements
- •5.1.1. Rubber Seal Simulation
- •5.1.2. Crack Simulation
- •5.2. Understanding the Mesh Nonlinear Adaptivity Process
- •5.2.1. Checking Nonlinear Adaptivity Criteria
- •5.2.1.1. Defining Element Components
- •5.2.1.2. Defining Nonlinear Adaptivity Criteria
- •5.2.1.3. Defining Criteria-Checking Frequency
- •5.3. Mesh Nonlinear Adaptivity Criteria
- •5.3.1. Energy-Based
- •5.3.2. Position-Based
- •5.3.3. Contact-Based
- •5.3.4. Frequency of Criteria Checking
- •5.4. How a New Mesh Is Generated
- •5.5. Convergence at Substeps with the New Mesh
- •5.6. Controlling Mesh Nonlinear Adaptivity
- •5.7. Postprocessing Mesh Nonlinear Adaptivity Results
- •5.8. Mesh Nonlinear Adaptivity Examples
- •5.8.1. Example: Rubber Seal Simulation
- •5.8.2. Example: Crack Simulation
- •Chapter 6: 2-D to 3-D Analysis
- •6.1. Benefits of 2-D to 3-D Analysis
- •6.2. Requirements for a 2-D to 3-D Analysis
- •6.3. Overview of the 2-D to 3-D Analysis Process
- •6.3.1. Overview of the 2-D to 3-D Analysis Process Flow
- •6.3.2. Key Commands Used in 2-D to 3-D Analysis
- •6.4. Performing a 2-D to 3-D Analysis
- •6.4.1. Step 1: Determine the Substep to Initiate
- •6.4.2. Step 2: Initiate the 2-D to 3-D Analysis
- •6.4.3. Step 3: Extrude the 2-D Mesh to the New 3-D Mesh
- •6.4.4. Step 4: Map Solution Variables from 2-D to 3-D Mesh
- •6.4.5. Step 5: Perform an Initial-State-Based 3-D Analysis
- •6.5. 2-D to 3-D Analysis Restrictions
- •Chapter 7: Cyclic Symmetry Analysis
- •7.1. Understanding Cyclic Symmetry Analysis
- •7.1.1. How the Program Automates a Cyclic Symmetry Analysis
- •7.1.2. Commands Used in a Cyclic Symmetry Analysis
- •7.2. Cyclic Modeling
- •7.2.1. The Basic Sector
- •7.2.2. Edge Component Pairs
- •7.2.2.1. CYCOPT Auto Detection Tolerance Adjustments for Difficult Cases
- •7.2.2.2. Identical vs. Dissimilar Edge Node Patterns
- •7.2.2.3. Unmatched Nodes on Edge-Component Pairs
- •7.2.2.4. Identifying Matching Node Pairs
- •7.2.3. Modeling Limitations
- •7.2.4. Model Verification (Preprocessing)
- •7.3. Solving a Cyclic Symmetry Analysis
- •7.3.1. Understanding the Solution Architecture
- •7.3.1.1. The Duplicate Sector
- •7.3.1.2. Coupling and Constraint Equations (CEs)
- •7.3.1.3. Non-Cyclically Symmetric Loading
- •7.3.1.3.1. Specifying Non-Cyclic Loading
- •7.3.1.3.2. Commands Affected by Non-Cyclic Loading
- •7.3.1.3.3. Plotting and Listing Non-Cyclic Boundary Conditions
- •7.3.1.3.4. Graphically Picking Non-Cyclic Boundary Conditions
- •7.3.2. Solving a Static Cyclic Symmetry Analysis
- •7.3.3. Solving a Modal Cyclic Symmetry Analysis
- •7.3.3.1. Understanding Harmonic Index and Nodal Diameter
- •7.3.3.2. Solving a Stress-Free Modal Analysis
- •7.3.3.3. Solving a Prestressed Modal Analysis
- •7.3.3.4. Solving a Large-Deflection Prestressed Modal Analysis
- •7.3.3.4.1. Solving a Large-Deflection Prestressed Modal Analysis with VT Accelerator
- •7.3.4. Solving a Linear Buckling Cyclic Symmetry Analysis
- •7.3.5. Solving a Harmonic Cyclic Symmetry Analysis
- •7.3.5.1. Solving a Full Harmonic Cyclic Symmetry Analysis
- •7.3.5.1.1. Solving a Prestressed Full Harmonic Cyclic Symmetry Analysis
- •7.3.5.2. Solving a Mode-Superposition Harmonic Cyclic Symmetry Analysis
- •7.3.5.2.1. Perform a Static Cyclic Symmetry Analysis to Obtain the Prestressed State
- •7.3.5.2.2. Perform a Linear Perturbation Modal Cyclic Symmetry Analysis
- •7.3.5.2.3. Restart the Modal Analysis to Create the Desired Load Vector from Element Loads
- •7.3.5.2.4. Obtain the Mode-Superposition Harmonic Cyclic Symmetry Solution
- •7.3.5.2.5. Review the Results
- •7.3.6. Solving a Magnetic Cyclic Symmetry Analysis
- •7.3.7. Database Considerations After Obtaining the Solution
- •7.3.8. Model Verification (Solution)
- •7.4. Postprocessing a Cyclic Symmetry Analysis
- •7.4.1. General Considerations
- •7.4.1.1. Using the /CYCEXPAND Command
- •7.4.1.1.1. /CYCEXPAND Limitations
- •7.4.1.2. Result Coordinate System
- •7.4.2. Modal Solution
- •7.4.2.1. Real and Imaginary Solution Components
- •7.4.2.2. Expanding the Cyclic Symmetry Solution
- •7.4.2.3. Applying a Traveling Wave Animation to the Cyclic Model
- •7.4.2.4. Phase Sweep of Repeated Eigenvector Shapes
- •7.4.3. Static, Buckling, and Full Harmonic Solutions
- •7.4.4. Mode-Superposition Harmonic Solution
- •7.5. Example Modal Cyclic Symmetry Analysis
- •7.5.1. Problem Description
- •7.5.2. Problem Specifications
- •7.5.3. Input File for the Analysis
- •7.5.4. Analysis Steps
- •7.6. Example Buckling Cyclic Symmetry Analysis
- •7.6.1. Problem Description
- •7.6.2. Problem Specifications
- •7.6.3. Input File for the Analysis
- •7.6.4. Analysis Steps
- •7.6.5. Solve For Critical Strut Temperature at Load Factor = 1.0
- •7.7. Example Harmonic Cyclic Symmetry Analysis
- •7.7.1. Problem Description
- •7.7.2. Problem Specifications
- •7.7.3. Input File for the Analysis
- •7.7.4. Analysis Steps
- •7.8. Example Magnetic Cyclic Symmetry Analysis
- •7.8.1. Problem Description
- •7.8.2. Problem Specifications
- •7.8.3. Input file for the Analysis
- •Chapter 8: Rotating Structure Analysis
- •8.1. Understanding Rotating Structure Dynamics
- •8.2. Using a Stationary Reference Frame
- •8.2.1. Campbell Diagram
- •8.2.2. Harmonic Analysis for Unbalance or General Rotating Asynchronous Forces
- •8.2.3. Orbits
- •8.3. Using a Rotating Reference Frame
- •8.4. Choosing the Appropriate Reference Frame Option
- •8.5. Example Campbell Diagram Analysis
- •8.5.1. Problem Description
- •8.5.2. Problem Specifications
- •8.5.3. Input for the Analysis
- •8.5.4. Analysis Steps
- •8.6. Example Coriolis Analysis
- •8.6.1. Problem Description
- •8.6.2. Problem Specifications
- •8.6.3. Input for the Analysis
- •8.6.4. Analysis Steps
- •8.7. Example Unbalance Harmonic Analysis
- •8.7.1. Problem Description
- •8.7.2. Problem Specifications
- •8.7.3. Input for the Analysis
- •8.7.4. Analysis Steps
- •Chapter 9: Submodeling
- •9.1. Understanding Submodeling
- •9.1.1. Nonlinear Submodeling
- •9.2. Using Submodeling
- •9.2.1. Create and Analyze the Coarse Model
- •9.2.2. Create the Submodel
- •9.2.3. Perform Cut-Boundary Interpolation
- •9.2.4. Analyze the Submodel
- •9.3. Example Submodeling Analysis Input
- •9.3.1. Submodeling Analysis Input: No Load-History Dependency
- •9.3.2. Submodeling Analysis Input: Load-History Dependency
- •9.4. Shell-to-Solid Submodels
- •9.5. Where to Find Examples
- •Chapter 10: Substructuring
- •10.1. Benefits of Substructuring
- •10.2. Using Substructuring
- •10.2.1. Step 1: Generation Pass (Creating the Superelement)
- •10.2.1.1. Building the Model
- •10.2.1.2. Applying Loads and Creating the Superelement Matrices
- •10.2.1.2.1. Applicable Loads in a Substructure Analysis
- •10.2.2. Step 2: Use Pass (Using the Superelement)
- •10.2.2.1. Clear the Database and Specify a New Jobname
- •10.2.2.2. Build the Model
- •10.2.2.3. Apply Loads and Obtain the Solution
- •10.2.3. Step 3: Expansion Pass (Expanding Results Within the Superelement)
- •10.3. Sample Analysis Input
- •10.4. Top-Down Substructuring
- •10.5. Automatically Generating Superelements
- •10.6. Nested Superelements
- •10.7. Prestressed Substructures
- •10.7.1. Static Analysis Prestress
- •10.7.2. Substructuring Analysis Prestress
- •10.8. Where to Find Examples
- •Chapter 11: Component Mode Synthesis
- •11.1. Understanding Component Mode Synthesis
- •11.1.1. CMS Methods Supported
- •11.1.2. Solvers Used in Component Mode Synthesis
- •11.2. Using Component Mode Synthesis
- •11.2.1. The CMS Generation Pass: Creating the Superelement
- •11.2.2. The CMS Use and Expansion Passes
- •11.2.3. Superelement Expansion in Transformed Locations
- •11.2.4. Plotting or Printing Mode Shapes
- •11.3. Example Component Mode Synthesis Analysis
- •11.3.1. Problem Description
- •11.3.2. Problem Specifications
- •11.3.3. Input for the Analysis: Fixed-Interface Method
- •11.3.4. Analysis Steps: Fixed-Interface Method
- •11.3.5. Input for the Analysis: Free-Interface Method
- •11.3.6. Analysis Steps: Free-Interface Method
- •11.3.7. Input for the Analysis: Residual-Flexible Free-Interface Method
- •11.3.8. Analysis Steps: Residual-Flexible Free-Interface Method
- •11.3.9. Example: Superelement Expansion in a Transformed Location
- •11.3.9.1. Analysis Steps: Superelement Expansion in a Transformed Location
- •11.3.10. Example: Reduce the Damping Matrix and Compare Full and CMS Results with RSTMAC
- •Chapter 12: Rigid-Body Dynamics and the ANSYS-ADAMS Interface
- •12.1. Understanding the ANSYS-ADAMS Interface
- •12.2. Building the Model
- •12.3. Modeling Interface Points
- •12.4. Exporting to ADAMS
- •12.4.1. Exporting to ADAMS via Batch Mode
- •12.4.2. Verifying the Results
- •12.5. Running the ADAMS Simulation
- •12.6. Transferring Loads from ADAMS
- •12.6.1. Transferring Loads on a Rigid Body
- •12.6.1.1. Exporting Loads in ADAMS
- •12.6.1.2. Importing Loads
- •12.6.1.3. Importing Loads via Commands
- •12.6.1.4. Reviewing the Results
- •12.6.2. Transferring the Loads of a Flexible Body
- •12.7. Methodology Behind the ANSYS-ADAMS Interface
- •12.7.1. The Modal Neutral File
- •12.7.2. Adding Weak Springs
- •12.8. Example Rigid-Body Dynamic Analysis
- •12.8.1. Problem Description
- •12.8.2. Problem Specifications
- •12.8.3. Command Input
- •Chapter 13: Element Birth and Death
- •13.1. Elements Supporting Birth and Death
- •13.2. Understanding Element Birth and Death
- •13.3. Element Birth and Death Usage Hints
- •13.3.1. Changing Material Properties
- •13.4. Using Birth and Death
- •13.4.1. Build the Model
- •13.4.2. Apply Loads and Obtain the Solution
- •13.4.2.1. Define the First Load Step
- •13.4.2.1.1. Sample Input for First Load Step
- •13.4.2.2. Define Subsequent Load Steps
- •13.4.2.2.1. Sample Input for Subsequent Load Steps
- •13.4.3. Review the Results
- •13.4.4. Use Analysis Results to Control Birth and Death
- •13.4.4.1. Sample Input for Deactivating Elements
- •13.5. Where to Find Examples
- •Chapter 14: User-Programmable Features and Nonstandard Uses
- •14.1. User-Programmable Features (UPFs)
- •14.1.1. Understanding UPFs
- •14.1.2. Types of UPFs Available
- •14.2. Nonstandard Uses of the ANSYS Program
- •14.2.1. What Are Nonstandard Uses?
- •14.2.2. Hints for Nonstandard Use of ANSYS
- •Chapter 15: State-Space Matrices Export
- •15.1. State-Space Matrices Based on Modal Analysis
- •15.1.1. Examples of SPMWRITE Command Usage
- •15.1.2. Example of Reduced Model Generation in ANSYS and Usage in Simplorer
- •15.1.2.1. Problem Description
- •15.1.2.2. Problem Specifications
- •15.1.2.3. Input File for the Analysis
- •Chapter 16: Soil-Pile-Structure Analysis
- •16.1. Soil-Pile-Structure Interaction Analysis
- •16.1.1. Automatic Pile Subdivision
- •16.1.2. Convergence Criteria
- •16.1.3. Soil Representation
- •16.1.4. Mudslides
- •16.1.5. Soil-Pile Interaction Results
- •16.1.5.1. Displacements and Reactions
- •16.1.5.2. Forces and Stresses
- •16.1.5.3. UNITY Check Data
- •16.2. Soil Data Definition and Examples
- •16.2.1. Soil Profile Data Definition
- •16.2.1.1. Mudline Position Definition
- •16.2.1.2. Common Factors for P-Y, T-Z Curves
- •16.2.1.3. Horizontal Soil Properties (P-Y)
- •16.2.1.3.1. P-Y curves defined explicitly
- •16.2.1.3.2. P-Y curves generated from given soil properties
- •16.2.1.4. Vertical Soil Properties (T-Z)
- •16.2.1.4.1. T-Z curves defined explicitly
- •16.2.1.4.2. T-Z curves generated from given soil properties
- •16.2.1.5. End Bearing Properties (ENDB)
- •16.2.1.5.1. ENDB curve defined explicitly
- •16.2.1.5.2. ENDB curves generated from given soil properties
- •16.2.1.6. Mudslide Definition
- •16.2.2. Soil Data File Examples
- •16.2.2.1. Example 1: Constant Linear Soil
- •16.2.2.2. Example 2: Non-Linear Soil
- •16.2.2.3. Example 3: Soil Properties Defined in 5 Layers
- •16.2.2.4. Example 4: Soil Properties Defined in 5 Layers with Mudslide
- •16.3. Performing a Soil-Pile Interaction Analysis
- •16.3.2. Mechanical APDL Component System Example
- •16.3.3. Static Structural Component System Example
- •16.4. Soil-Pile-Structure Results
- •16.5. References
- •Chapter 17: Coupling to External Aeroelastic Analysis of Wind Turbines
- •17.1. Sequential Coupled Wind Turbine Solution in Mechanical APDL
- •17.1.1. Procedure for a Sequentially Coupled Wind Turbine Analysis
- •17.1.2. Output from the OUTAERO Command
- •Chapter 18: Applying Ocean Loading from a Hydrodynamic Analysis
- •18.1. How Hydrodynamic Analysis Data Is Used
- •18.2. Hydrodynamic Load Transfer with Forward Speed
- •18.3. Hydrodynamic Data File Format
- •18.3.1. Comment (Optional)
- •18.3.2. General Model Data
- •18.3.3. Hydrodynamic Surface Geometry
- •18.3.4. Wave Periods
- •18.3.5. Wave Directions
- •18.3.6. Panel Pressures
- •18.3.7. Morison Element Hydrodynamic Definition
- •18.3.8. Morison Element Wave Kinematics Definition
- •18.3.9. RAO Definition
- •18.3.10. Mass Properties
- •18.4. Example Analysis Using Results from a Hydrodynamic Diffraction Analysis
- •Index
- •ОГЛАВЛЕНИЕ
- •ВВЕДЕНИЕ
- •1.1. Методология проектирования технологических объектов
- •1.2. Компьютерные технологии проектирования
- •1.3. Системы автоматизированного проектирования в технике
- •1.4. Системы инженерного анализа
- •2.2.1. Создание и сохранение чертежа
- •2.2.2. Изменение параметров чертежа
- •2.2.3. Заполнение основной надписи
- •2.2.4. Создание нового вида. Локальная система координат
- •2.2.5. Вычерчивание изображения прокладки
- •2.2.6. Простановка размеров
- •2.2.7. Ввод технических требований
- •2.2.8. Задание материала изделия
- •2.3. Сложные разрезы в чертеже детали «Основание»
- •2.3.1. Подготовка чертежа
- •Cохранить документ.
- •2.3.2. Черчение по сетке из вспомогательных линий
- •2.3.3. Изображение разрезов
- •2.4. Чертежи общего вида при проектировании
- •3.1. Интерфейс программы
- •3.2. Общее представление о трехмерном моделировании
- •3.3. Основные операции геометрического моделирования
- •3.3.1. Операция выдавливания
- •3.3.2. Операция вращения
- •3.3.3. Кинематическая операция
- •3.3.4. Построение тела по сечениям
- •3.4. Операции конструирования
- •3.4.1. Построение фасок и скруглений
- •3.4.2. Построение уклона
- •3.4.3. Сечение модели плоскостью
- •3.4.4. Сечение по эскизу
- •3.4.5. Создание моделей-сборок
- •3.5. Разработка электронных 3D-моделей тепловых устройств
- •3.5.1. Электронные модели в ЕСКД
- •3.5.2. Электронные «чертежи» в ЕСКД
- •3.5.4. Электронная модель сборочного изделия «Газовая горелка»
- •ГЛАВА 4. ИНЖЕНЕРНЫЙ АНАЛИЗ ГАЗОДИНАМИКИ И ТЕПЛООБМЕНА В ANSYS CFX
- •4.1. Область применения ANSYS CFX
- •4.2. Особенности вычислительного процесса в ANSYS CFX
- •4.3. Программы, используемые при расчетах в ANSYS CFX
- •4.4. Организация процесса вычислений в среде пакета Workbench
- •4.4.1. Графический интерфейс пользователя
- •5.1. Постановка теплофизических задач в ANSYS Multiphysics
- •5.2. Решение задач в пакете ANSYS Multiphysics
- •5.2.1. Графический интерфейс пользователя
- •5.2.2. Этапы препроцессорной подготовки решения
- •5.2.3. Этап получения решения и постпроцессорной обработки результатов
- •5.3.5. Нестационарный теплообмен. Нагрев пластины в печи с жидким теплоносителем
- •5.4.1. Температурные напряжения при нагреве
- •БИБЛИОГРАФИЧЕСКИЙ СПИСОК
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Chapter 12: Rigid-Body Dynamics and the ANSYS-ADAMS Interface
The ADAMS software marketed by MSC Software is one of several special-purpose programs used to simulate the dynamics of multibody systems.
One drawback of the ADAMS program is that all components are assumed to be rigid. In the ADAMS program, tools to model component flexibility exist only for geometrically simple structures. To account for the flexibility of a geometrically complex component, ADAMS relies on data transferred from finiteelement programs. The ANSYS-ADAMS Interface is a tool provided by ANSYS, Inc. to transfer data from Mechanical APDL to the ADAMS program.
The following ANSYS-ADAMS interface topics are available:
12.1.Understanding the ANSYS-ADAMS Interface
12.2.Building the Model
12.3.Modeling Interface Points
12.4.Exporting to ADAMS
12.5.Running the ADAMS Simulation
12.6.Transferring Loads from ADAMS
12.7.Methodology Behind the ANSYS-ADAMS Interface
12.8.Example Rigid-Body Dynamic Analysis
12.1. Understanding the ANSYS-ADAMS Interface
Use the ANSYS-ADAMS Interface whenever you want to include flexibility of a body in an ADAMS simulation. Flexibility can be an important aspect in a multibody system, for example, to recognize resonances or to accurately simulate forces and movements of the components. Often, the flexibility of a system
is not negligible. A typical example is the model of a piston moving in an engine. The movement of the piston significantly depends on the flexibility of the crankshaft and/or the connecting rod. Because
the geometry of a connecting rod can be complex, the ANSYS-ADAMS Interface can be used to account for the connecting rod flexibility.
To use the ANSYS-ADAMS Interface, you first model a flexible component using standard commands. While building the model, you must give special attention to modeling interface points where joints will be defined in ADAMS. The next step is to use the ANSYS-ADAMS Interface to write a modal neutral file (Jobname.MNF) that contains the flexibility information for the component. This file is written in the format required by ADAMS/Flex, an add-on module available for ADAMS. See Exporting to
ADAMS (p. 318) for details on how to use the ANSYS-ADAMS Interface to create the .MNF file. For a complete description of the method used to create the modal neutral file and the information it contains, see The Modal Neutral File (p. 325).
After performing the dynamic simulation in ADAMS, you can use the export capabilities of ADAMS to create an input file containing accelerations and rotational velocities of the rigid part and forces acting in the joints of the component. You can then import the to perform a stress analysis. See Transferring Loads from ADAMS (p. 321) for details on how to import the loads and perform a subsequent static structural analysis.
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The process for transferring flexible components to ADAMS and forces back to Mechanical APDL consists of these general steps:
1.Build the model.
2.Model interface points.
3.Export to ADAMS (and create the modal neutral file).
4.Run the ADAMS simulation using the modal neutral file.
5.Transfer resulting loads from ADAMS to Mechanical APDL and perform a static analysis.
For more information and an example analysis, see Methodology Behind the ANSYS-ADAMS Interface (p. 325) and Example Rigid-Body Dynamic Analysis (p. 326).
12.2. Building the Model
To use the ANSYS-ADAMS Interface, you must first create a complete finite element model in Mechanical APDL.
When building your model, consider that:
•The interface is designed to support most element types that have displacement degrees of freedom. Exceptions are axisymmetric elements (for example, PLANE25) and explicit dynamic elements (for example, SOLID164).
•Only linear behavior is allowed in the model. If you specify nonlinear elements, they are treated as linear. For example, if you include nonlinear springs (like COMBIN39), their stiffnesses are calculated based on their initial status and never change.
•Material properties can be linear, isotropic or orthotropic, constant or temperature-dependent. You must define both Young's modulus (EX, or stiffness in some form) and density (DENS, or mass in some form) for the analysis. Nonlinear properties are ignored.
•Damping is ignored when the interface computes the modal neutral file (Jobname.MNF). Damping of the flexible component can be added later in the ADAMS program.
•The ADAMS program requires a lumped mass approach (LUMPM,ON). This requirement results in the following special considerations.
–For most structures that have a reasonably fine mesh, this approximation is acceptable. If a model has a coarse mesh, the inertia properties may have errors. To determine what the effect will be, start a modal analysis with and without LUMPM,ON and compare the frequencies.
–When using SHELL181, set KEYOPT(3) = 2 to activate a more realistic in-plane rotational stiffness. SHELL181 KEYOPT(3) = 2 is also a good choice if the elements are warped.
–When using two dimensional elements, the corresponding ADAMS model must lie in the X-Y-plane. Remember that ADAMS models are always three dimensional. The 2-D flexible component transferred will not have any component in the Z-direction.
–Nodes of a plane element only have two degrees of freedom: translations in the X- and Y-direction. Thus, no moment loads (forces, joints) can be applied in the ADAMS analysis. Likewise, nodes of a solid element only have translational degrees of freedom.
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Modeling Interface Points |
•You cannot apply constraints (D command) to the model. Also, make sure that no master degrees of freedom (M command) were defined in an earlier analysis.
12.3. Modeling Interface Points
When building a model that will be used in an ADAMS simulation, an important consideration is how to represent interface points within the structure. An interface point is a node that will have an applied joint or force in the ADAMS program. Keep in mind that, in ADAMS, the forces can only be applied to interface points.
The number of interface points used will determine the number of constraint modes for the model. Constraint modes are the static shapes assumed by the component when one degree of freedom of an interface point is given a unit deflection while holding all other interface degrees of freedom fixed. The number of constraint modes is equal to the number of degrees of freedom of all interface points.
(For 3-D models, the interface points have 6 DOF; therefore, each interface point has 6 constraint modes.)
You must pay special attention to modeling interface points for these reasons:
•An interface point must have six degrees of freedom (except for 2-D elements).
•Force (applied directly or via a joint) should be applied to the structure by distributing it over an area rather than applying it at a single node.
•If there is no node in the structure where you can apply the force or joint in ADAMS (for example, a pin center), you need to create a geometric location for that point.
Use the following guidelines to determine the best way to model the interface points for your structure:
•To ensure that all your loads will be projected on the deformation modes in the ADAMS simulation, you must define all nodes where you are going to apply a joint or a force as interface points.
•Interface points in Mechanical APDL must always have six degrees of freedom, except for 2-D elements. If your model consists of solid elements, use constraint equations or a spider web of beam elements (as shown in Figure 12.1: Connecting a Structure to an Interface Point (p. 318)) to ensure that the interface node has 6 degrees of freedom.
•A good practice for modeling interface points is to reinforce the area using beam elements or constraint equations. Using one of these techniques will distribute the force over an area rather than applying it to a single node, which would be unrealistic.
–If you use a spider web of beam elements, use a high stiffness and a small mass for the beams. Otherwise, you will alter the stiffness and mass of your model, which could result in eigenmodes and frequencies that do not represent the original model.
–If you use constraint equations, we recommend using contact elements and the internal multipoint constraint (MPC) algorithm (see Surface-based Constraints in the Contact Technology Guide) to attach the interface node. As an alternative to the MPC method, you may use constraint equation commands such as CE and CERIG (for example, CERIG,MASTE,SLAVE,UXYZ, where MASTE is the interface node). (Avoid the RBE3 command since problems can occur with the master degrees of freedom.) If you use constraint equations, mesh the interface point with a MASS21 element (use KEYOPT(3) = 0) that has small (negligible) inertias.
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