Table of Contents
Password of the Lecture Note: hhyang95
1. Basics of RecurDyn
1.1 Commonly Used Terms
RecurDyn Entities
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Marker / Body / Joint / Force / Contact / Expression
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Parametric Point (PP) / Parametric Value (PV) / Subsystem / Spline / GPIN & GPOUT
Coordinate
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RecurDyn uses Cartesian coordinates.
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Absolute Coordinate: Ground inertia marker
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Local Coordinate: Body marker
Degree of Freedom (DOF)
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The number of independent motions allowed to a body.
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One general 3D-rigid-body has 6-DOF: 3 translational + 3 rotational.
1.2 Pre-Processor
RecurDyn GUI
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System button, ribbon, toolbar, working window, database, message window, status bar
GUI Basic Handling
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View: Translate (T), Rotate (R), Zoom (Mouse Wheel), Fit (F) → Customizable
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Body Rendering Mode → Each Render
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Working Plane Change: XY-Plane (Shift +X) / YZ-Plane (Shift + Y) / ZX-Plane (Shift + Z)
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Icon Control
Basic Setting
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General: Name / Shift when Pasting
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Display: Background Color / Graphical Quality / Force Display
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Gravity
1.3 Body
Rigid & Flexible
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Rigid vs Full Flexible (FFlex) vs Reduced Flexible (RFlex)
Rigid Body
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Edit Mode / Properties
Flexible: FFlex
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Meshing: AutoMesh
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Edit Mode / Properties
Flexible: RFlex
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G-Manager / Properties
1.4 Joint
What is Joint Entity?
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Definition
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Connector: Base & Action Marker
Basic Joints
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Types: Fixed, Revolute, Translational, Cylindrical, Spherical, Planar, Screw, Universal
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Revolute Joint: Creation (Body, Body, Point, Direction) & Properties
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Translational Joint: Creation (Body, Body, Point, Direction) & Properties
Joint Motion & Initial Conditions & Friction
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Motion: Specify a forced motion on the joint.
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Initial Conditions: Specify the initial position and velocity of the joint.
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Friction: Sliding & Stiction Option / Static & Dynamic Friction Coefficient / Absolute Threshold Velocity
Special Joints
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Cartesian Motion (CMotion): CMotion (G)
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OnOff Joint
Primitive Joints
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AtPoint, Inline, Inplane, Orientation, Parallel, Perpendicular, Distance
1.5 Force
What is Force Entity?
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Definition
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Connector: Base & Action Marker
Basic Forces
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Types: Axial & Rot. Axial, Translation & Rotation, Screw / Spring & Rot. Spring, Bushing, Matrix
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Axial: Creation (Body, Body, Point, Point) & Properties
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Rot. Axial: Creation (Body, Body, Point, Direction / Joint) & Properties
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Screw: Creation (Body, Body, Point, Point) & Properties
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Bushing: Creation (Body, Body, Point, Direction) & Properties
Special Forces
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Types: Beam, Plate, Tire
1.6 Contact
What is Contact Entity?
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Hertz Contact Theory → Use penetration instead of deformation
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Use the tessellation data (patch data) for contact detection
Basic Contacts
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Type: Geo Surface, Solid, Primitive
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Geo Surface: Creation (Solid, Solid / Surface, Surface)
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Solid: Creation (Solid, Solid)
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Selection of Base & Action
Contact Parameters
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Stiffness Coefficient: It can be computed by ‘Hertz Contact Theory’.
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Damping Coefficient: The value of ‘Stiffness Coefficient / 10000’ is commonly used.
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Friction: Experimental value is used. Use default value for the ‘Threshold Velocity’.
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Stiffness Exponent: The value of ‘1.5’ is recommended.
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Maximum Penetration: Depending on simulation condition
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Maximum Stepsize Factor: Depending on simulation condition
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Node & Edge Contact
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Advanced Setting: Smooth Option, CPM Option
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Normal Direction
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No. of Max Contact Points
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Faceting Control Parameters: Surface Type, Bounding Buffer Length, Plane Tolerance Factor, Max. Facet Size Factor
1.7 Expression
What is Expression Entity?
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Definition / Help
Basic Expression
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Operators:
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Arithmetic Operators: +, -, *, /, **
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Logical Operators: ||, &&
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Relational Operators: <, <=, =, >, >=, <>
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Simulation Constants: TIME, PI
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Fortran Functions: ABS, SIN, COS, TAN, ASIN, ACOS, ATAN, ATAN2, DIM, SIGN, SQRT, MIN, MAX
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Displacement / Velocity / Acceleration (Essential)
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Generic Force / Specific Force (Optional)
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Arithmetic IF: IF(f1:f2, f3, f4)
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Interpolation: AKISPL, CUBSPL, LINSPL
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General: BISTOP, IMPACT, STEP (Optional)
1.8 Parametric Value & Parametric Point & Subsystem
Parametric Value (PV)
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Reusable Value
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Used for:
1) Geometric Variables: Length, Thickness, Radius, etc.
2) Variables correlated with each other
3) Body Attitude: Euler Angle [rad]
4) Material Properties
Parametric Point (PP)
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Reusable Point (Vector)
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Used for:
1) Position of Body and Joint
2) Relative Position Using ‘Relative to’
3) Body Attitude: Coordinate Type
Subsystem
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Independent component for re-usability and user convenience → Supports Copy & Paste
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Independent Simulation, Data Base, PV, PP
Spline
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Users can create or import spline data and utilize it for predefined motion, non-linear stiffness, etc.
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RecurDyn supports the Akima spline curve fitting methods.
GPIN & GPOUT
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GPIN (General Plant Input Entity): Return calculated values from external control programs to be used in the RecurDyn model
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GPOUT (General Plant Output Entity): Return calculated values from the RecurDyn model to be used in external programs
1.9 Simulation
Simulation Types
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Dyn/Kin: Dynamic and kinematic analysis
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Static: Find the equilibrium state of the system.
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Pre: Calculate the degree of freedom of the system.
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Eigen: Eigen Analysis
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FRA: Frequency Response Analysis
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Scenario: Perform simulations in the desired type and order.
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DOE: Design of Experiment -> Parametric study through batch simulation
Simulation Setting
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Dyn/Kin General: End Time / Step / Plot Multiplier Step Factor / Output File Name / Static Analysis / Display Animation
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Dyn/Kin Parameter: Maximum Time Step / Initial Time Step / Match Solving Stepsize with Report Step
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Advanced Simulation Option: Limit of Angle in each Solving Step
1.10 Post-Processor
Animation
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Import / Export / Reload Animation (*.rad File)
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Animation Control
Camera Setting
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Standard / Following / Riding / Moving / Multi
Plot
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Results Plot / Export