Rigid Dynamic

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11.0 New Features

ANSYS, Inc. Proprietary

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1-1

Rigid Dynamic Analysis

in Workbench

Rigid Dynamic Analysis

in Workbench


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1-211.0 New Features


Training Manual

ANSYS v11.0

Introduction

Rigid Dynamic Analysis:

Calculates dynamic response of an assembly of rigid bodies.

Can be used to study the kinematics of an assembly.

Bodies are linked via joints and springs.


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ANSYS v11.0

Rigid Dynamics

Inputs and outputs are forces, moments, displacements, velocities

and accelerations.

All parts are assumed rigid (no stress/strain).

Viscous damping is accounted for via spring definitions.


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Training Manual

ANSYS v11.0

Rigid Dynamic Setup

Solid geometry is used to define the model (no mult ibody parts).

Parts are considered rigid so density is the only required material

property.

To begin a rigid dynamic analysis parts must have their stiffnessbehavior f lagged as rigid.


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Training Manual

ANSYS v11.0

D. Joint Types

There are 9 available joint types in Simulation:

Fixed Joint

Revolute Joint

Cylindrical Joint

Translational Joint

Slot Joint

Universal Joint

Spherical Joint

Planar Joint

General Joint

Remember, joint DOF are with respect to the joints reference

coordinate system.

Examples follow . . .


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Training Manual

ANSYS v11.0Dynamics

Joint Types

Revolute Cylindrical

TranslationalSlot

Spherical

Planer

Universal


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ANSYS v11.0

Joint Types

Revolute Joint:

Constrained DOF: UX, UY, UX, ROTX, ROTY

FreeFixed


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ANSYS v11.0

Joint Types

Cylindrical Joint:

Constrained DOF: UX, UY, ROTX, ROTY

Fixed

Free


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ANSYS v11.0

Joint Types

Translational Joint:

Constrained DOF: UX, UZ, ROTX, ROTY, ROTZ

Fixed

Free


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ANSYS v11.0

Joint Types

Slot Joint:

Constrained DOF: UY, UZ

Fixed

Free


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ANSYS v11.0

Joint Types

Universal Joint:

Constrained DOF: UX, UY, UZ, ROTY

Fixed

Free


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ANSYS v11.0

Joint Types

Spherical Joint:

Constrained DOF: UX, UY, UZ

Fixed

Free

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ANSYS v11.0

Joint Types

Planar Joint:

Constrained DOF: UZ, ROTX, ROTY

Fixed

Free

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ANSYS v11.0

Joint Types

Fixed Joint:

Constrained DOF: All

General Joint:

Constrained DOF: Fixed All, Free X, Free Y, Free Z, Free All

General joints allow configurations not covered by the basic joints shown

on the previous pages.

A free body must be linked to ground using a general BTG joint with

Free All specified (recall that all bodies must be defined such that apath to ground exists via joints).

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Springs

Springs can be added from the BTG or BTB

menus.

In BTG a reference CS is used to locate the

ground location.

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ANSYS v11.0

Rigid Dynamic Solution Setup

From the New Analysis menu choose

Rigid Dynamic .

The Analysis Setting branch contains the

controls for setting up the analysis: Number of steps

Time step controls

Output controls

Solver tolerances

Note, additional steps are generally used

when loads are applied or removed or

when load histories undergo abrupt

changes.

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ANSYS v11.0

Rigid Dynamic Solution Setup

For rigid dynamic analysis only inertial loads (acceleration and/or

gravity) are used. No loads or supports are used as in flexible body

analyses.

Joint conditions are used to apply all other loads as constants ortime varying using tabular or functional definitions.

Once inserted each joint in the model is

available via the drop down list in the

joint condition details.

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Joint Conditions

Joint condit ions can be defined

as constant, tabular or as a

function.

Tabular data can be input in thetable in Simulation or in the

Engineering Data application.

Once entered in Simulation the

data can be saved to the ED

application.

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Joint Conditions

Functional joint conditions can

be entered in the details or

defined in the ED application.

From the EDA choose to Insert

New Load History .

Select the appropriate type and

indicate the data is in the form of

a function.

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ANSYS v11.0

Joint Conditions

Various mathematical

functions and arithmetic

operators can be used to

construct functions using

time as an independentvariable.

The function is displayed in

function and graphical

formats.

Can type in functions or

choose to insert them.

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ANSYS v11.0

Rigid Dynamic Postprocessing

Results available from rigid dynamic analyses are deformations,

velocities, accelerations and various probe results.

As with other analysis types results may be scoped to entire

assemblies or to individual parts, surfaces, edges or points.

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ANSYS v11.0

Rigid Dynamic Postprocessing

Rigid dynamic results are graphical, tabular or animations.

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ANSYS v11.0

Rigid Dynamic Demonstration

Body to Body

Revolute

Body to Body

Revolute

Body to

Ground

Revolute

Body to Body

Translational

Body to

Ground Fixed

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ANSYS v11.0


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11.0 New Features LectureWorkbench Simulation

Flexible Dynamic Analysis

11.0 New Features LectureWorkbench Simulation

Flexible Dynamic Analysis

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Training Manual

Introduction

If inertial effects are significant, the use of static structural analyses

is not sufficient in determining the dynamic response of a system

Flexible dynamic analysis in Workbench Simulation 11.0 provides

users with the abil ity to determine the dynamic response of thesystem under any type of time-varying loads.

Unlike rigid dynamic analyses, bodies can be either rigid or flexible. For

flexible bodies, nonlinear materials can be included, and stresses and

strains can be output. Flexible dynamic analysis is

also known as time-history

analysis ortransient

structural analysis.

Assembly shown here is f rom an Autodesk Inventor sample model

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Dynamics

From Rigid to Flexible

Step 1 - Add Flexible Dynamics

Analysis to solution leg of tree

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Dynamics


Step 2 - Change partdefinit ion from Rigid to

Flexible

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Dynamics


Step 3 - Preview Flexible

Part Mesh

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Dynamics


Step 4 - Set Analysis

Options for time step etc.

and solve

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Training Manual

Loads and Supports

For f lexible bodies, any type of load or support can be applied

For rigid bodies, acceleration load and joint conditions are available

Multiple Steps are supported for load histories:

Similar to the static case, user can easily define multiple steps

As shown below, loads, supports, and joints may be deactivated or

activated at any step simply by right-clicking on the Timeline. This gives

the user flexibil ity in the load definition.

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Training Manual

Postprocessing Probe Results

The Probe tool has also been enhanced at 11.0 to include more

results, including Energy, Reactions, Joint results, and Spring results

After a Probe result is added, the Timeline and Tabular Data views show

the values. From the Tabular Data view, the user can check/uncheck thecolumns to show what will be displayed in the Timeline

A New Chart and Table can also be added to create customized charts

and tables for output purposes.

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Flexible Dynamic Demonstration

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Documents

Rigid Dynamic