· Introduction to Dynamic Simulation

· Introduction

· Dynamic Simulation

· Simulate and analyze dynamics of assembly in motion under various load conditions

· Export load conditions to Stress Analysis

· Stress Analysis

· Parts response to dynamic loads at any point in assembly's range of motion

· Dynamic Simulation

· Numerous Workflows

· Basics explored here

· We learn

· Basic differences between Dynamic Simulation environment and Assembly environment

· Convert Mate and Insert constraints

· Into standard joints

· One joint at a time

· Manually creating joints

· Running dynamic simulation to see how joints, loads, and component structures interact as a dynamic mechanism

· Welding components within Dynamic Simulation to create rigid, unified structures

· Applying forces

· Using Input and Output graphers

· Defining joint properties

· Exporting and applying Dynamic Simulation loads in Stress Analysis (page 1)

· Open Sample Model

· Active project: tutorial_files

· Open: Gate.iam

· Save As: Gate-tutorial.iam

· To see how the assembly moves, drag the door

· Save often (page 2)

· Degrees of Freedom

· Main tool bar

· Click Applications > Dynamic Simulation

· Dynamic Simulation environment becomes active

· Differences between Dynamic Simulation and the Assembly environment

·

· Though both have to do with creating mechanisms, there are some critical differences between Dynamic Simulation and the Assembly environment.

· Both environments

· Have creating mechanisms

· Build functional mechanism

· Basic difference

· Degrees of freedom

· Dynamic Simulation

· Components have zero degrees of freedom by default

· Build joints to create degrees of freedom

· Assembly environment

· Components in have six degrees of freedom when unconstrained and ungrounded

· We add constraints to restrict degrees of freedom

· Adds to functional mechanism

· Dynamic, real-world influences of various kinds of loads to create a true kinematic chain (page 3)

· Assembly constraints

· Constraints have no effect on a dynamic simulation

· Drag Door component

· It moves

· Although we are in Dynamic Simulation, we are not yet running a simulation. Since a simulation is not active, the assembly is free to move

· Simulation panel (bottom of browser)

· Click Run button

· Assembly is completely grounded and does not move

· Simulation mode is active

· Drag door

· It does not move

· We will

· Complete workflows to get a better understanding of Dynamic Simulation application (page 4)

· Convert constraints

· Simulation Panel

· Click Construction Mode button

· Simulation mode exits

· We return to Dynamic Simulation construction mode

· Create joints

· Apply loads

· Assembly mode added constraints

· Some can be converted into Dynamic Simulation standard joints

· Automatic conversion

· Click Dynamic Simulation Settings tool

· Clear check box

· Automatically Update Translated Joints (dimmed, not checked already)

· Click OK

· Any joints in assembly are deleted

· We do this so we can learn to manually convert or add these joints

· It also demonstrates the value of this function (page 5)

· Convert Constraints

· Click Convert Assembly Constraints tool

· Convert Assembly Constraints dialog

· Select two components

· Door component

· Pillar component

· Two mate constraints exist

· Axial constraint between hinge axes

· Face-to-face constraint between hinge top and bottom flat faces

· Check both checkboxes for two mate constraints

· Together both mate constraints function like a revolution joint

· Click OK

· We see in browser

· Revolution joint under Standard Joints

· Door component moved from Grounded to Mobile Groups category (page 6)

· Define Gravity

· We will

· Define first force to test joint

· See basic simulation workaction

· In Browser

· External Loads node

· Gravity node

· Right-click

· Select Define Gravity

· Or Double-click Gravity node

· Clear check box to Suppress gravity

· Gravity activated

· Click OK

· Drag door about 10 degrees counter clockwise (page 7)

· Run a Simulation

· Simulation Panel

· Final Time field: Enter 10 s

· Images field: Becomes 1000

· Tip: Look at tooltips

· Click Run

· Door component moves

· With acceleration and deceleration

· In response to the force of gravity and inertia of part

· Note

· Gravity direction vector

· No up or down

· Direction as we set it

· No damping forces

· Mechanism is lossless

· Angle of swing remains same

· Click Construction Mode button (page 8)

· Simulation Panel

· Final Time field controls total time available for a simulation

· Images field controls the number of image frames available for a simulation

· Try

· Enter 100 in Images field

· Door moves 10 times faster to and fro

· Change back to 1000

· Click Construction Mode button

· Filter field

· 1

· All frames play

· 5

· Every fifth frame plays

· Edit in simulation mode

· Not when simulation is running

· Click Screen Refresh button

· Simulation will run without graphics (page 9)

· Weld Parts

· We need Certain parts move as a rigid body

· No joint required

· Bracket and Door parts can move as a rigid body

· Use Weld feature to create rigid body

· Welded body functions like a subassembly

· Dynamic Simulation browser

· Expand Grounded

· Select both bracket and door

· Select bracket

· Ctrl + Click door

· Right-click bracket:1 or door:1

· Select Weld Parts

· Welded groups node gets added under Mobile Groups with items

· door:1 node

· bracket:1 node (page 10)

· Add Remaining Joints

· We use

· Convert Assembly Constraints tool

· Insert Joint tool

· Click Convert Assembly Constraints tool

· In graphics

· Select

· pillar part

· Link part

· Check both check boxes for Mate 3 and Mate 4

· Click Apply

· Select Link and Jack Body

· Check both Mate 5 and Mate 6 checkboxes

· Click OK (page 11)

· Use Insert Joint Tool

· We could convert constraints but will manually create joints

· Click Insert Joint tool

· Drop-down list

· Select Cylindrical (page 12)

· Joints Table

· Insert Joint dialog

· Click Display joints table button

· Joints Table dialog

· Categories

· Joints

· Click thumbnail for Rolling Joints

· Bottom of dialog shows available joints in category

· Click Standard Joints thumbnail (in Categories)

· Click Cylindrical (in Joints:)

· Click OK

· Closes Joints table dialog (thumbnail display) (page 13)

· Z Axis

· Z direction for both components must be same

· Order of selection is important

· Component 1

· Select cylindrical surface of the jack body (zoom in first)

· Right-click graphics window

· Select Continue

· Component 2

·

· Select the cylindrical surface of Jack Stem part

· Here

· Z directions are same already

· Switch Z and Switch X buttons available

· We can redo selections by clicking component selection buttons (page 14)

· Joint Triad (axes display)

· Joint triad

· Is local to selected geometry and not other coordinate systems in assembly

· Uses shapes (arrow heads) not colors

· Arrow heads

· X vector has one

· Y vector has two

· Z vector has three

· Tip: Change size of triad display

· Dynamic Simulations Settings tool

· Dynamic Simulations Settings dialog

· Click More >>

· Enter value in 3D Frames field (page 15)

· Create Joint

· Drag jack stem close to bracket, but far enough away for you to see the hole on bracket

· Click Insert Joint tool

· Joint menu

· Select hole on jack stem clevis

· Right-click > Continue

· Select hole on bracket

· Click OK

· Click Run in Simulation Panel

· Parts move as one

· Click Stop

· Click Cosntruction Mode button (page 16)

· Create Joint

· Contact joint between door and pillar parts to stop door when it reaches tab stop

· Click Insert Joint tool

· Joint drop down menu

· Select 2D Contact (way down)

· Select bottom face of door

· Select point on tab stop (where lower arc meets shorter vertical line on front face of tab stop)

· Click OK

· Invert Vector

· Right-click n°6:2D Contact (door:1, pillar:1)

· Select Properties

· Click Invert normal button for parent part Click OK (page 17)

· Run Simulation

· Isometric

· Simulation Panel

· Images: 4000 Click Play

· Door contacts tab stop

· Click Stop

· Click Construction Mode button

· Door swing is not controlled by gravity alone

· Need to add a device or mechanism

· Drag door close to tab stop (page 18)

· Create Spring

· Click Insert Joint tool

· Select Spring/Damper/Jack from pull-down menu

· Select circular edge on jack body (center of arc is used)

· Select circular edge on jack stem (rotate view)

· Click OK

· Spring is created

· Spring active by default

· Specify spring stiffness

· Right-click Spring/Damper/Jack node

· Select Properties

· Stiffness field

· Enter 1 N/mm

· Expand dialog (with more button >>)

· Type menu

· Select Spring Damper

· Click OK (page 19)

· Run Simulation

· Isometric view

· Drag door to about 5° on xy plane

· Click Run on Simulation Panel

· Simulation continues till damper on spring overcomes inertia of door

· Increase stiffness to 3 N/mm

· (had to decrease length to 98 mm, was red, OK button was dimmed)

· Click OK

· Click Play

· Simulation is faster now (page 20)

· Add Damping

· We reduce abruptness of door swing near tab stop

· Right-click Spring node > Properties

· Enter 1 N/mm in Damping field

· Edit Spring size (cosmetic only, properties remain same)

· Dimensions section

· Radius: 11 mm

· Wire Radius: 5 mm

· Click OK

· Rate of swing is damped and tab stop is approached more gently (page 22)

· Create a Force

· Return to Construction Mode

· Click the Force tool

· (Rotate view 180 to view from other side)

· Select vertex on door (away from jack body)

· Select edge near vertex (towards jack body)

· Click Flip Direction button

· Magnitude: 10 N

· Click OK

· Isometric view

· Drag door to near tab stop

· Run simulation

· The force opens and holds door open (page 23)

· Edit the Force

· Let's assume the gate should open urther

· Return to Construction Mode

· Right-click Force1

· Edit Force

· Magnitude: 45 N

· Run simulation

· Gate opens is left open more

· Display force vector

· Edit Force1

· Force dialog

· Expand dialog

· Check Display

· Click OK

· Run simulation

· Force direction is fixed (page 23)

· Edit the Force

· Double-click Force1 node

· Click Associative load button

· Click OK

· Run simulation

· Force direction keeps its relative position to door

· Return to Construction Mode (page 24)

· Create Torque Damping

· Right-click n°1:Revolution (door:1, pillar:1)

· Select Properties

· Click dof 1 (R) tab

· Click Edit Joint Torque button

· Select Enable Joint Torque check box

· Damping field: 50 N mm s/deg

· Click OK

· Note node icon changes to include torque

· Run simulation

· Cyclic motion of door is overcome by dampening

· Return to Construction Mode (page 25)

· Input Grapher

· Damping value is constant like the force

· We can change it to be variable

· Right-click n°1:Revolution (door:1, pillar:1)

· Select Properties

· Click dof 1 (R) tab

· Click Edit Joint Torque button

· Click Input Grapher icon next to Damping field (page 26)

· Input Grapher

· Input Grapher varies joint torque

· Vertical axis represents torque load Horizontal axis represents time

· Torque plot represented by red line

· Double-click line near 0.25 time value to add new datum point

· Double-click line near 0.75 time value to add another datum point

· Four datum points define three sectors

· Each sector represents condition of damping value

· We will move datum points to plot changes in velocity to create variable damping (page 27)

· Input Grapher

· Select first sector

· Click between first two points

· Starting Point section

· X1 and Y1 fields = 0 in the are set to 0

· Ending Point section

· X2 field 0.5 s

· This is ending time value for selected sector

· Enter 70 N mm in the Y2 field

· This is peak load value for selected sector

· Select second sector

· X2 = 1.1 s

· Y2 = 70 N mm

· Select third sector

· X2 = 2.2 s

· Y2 = 0 N mm

· Joint Properties dialog

· Click OK

· Run simulation

· Variable damping modifies motion of gate

· (not discernible)

· Return to Construction Mode (page 28)

· Output Grapher

· We use Output Grapher to

· Analyze a simulation

· Export a load to Stress Analysis

· First make changes to joints

· Right-click n°1:Revolution (door:1, pillar:1)

· Select Properties

· Click dof 1 (R) tab

· Click Edit Joint Torque button

· Clear check mark next to Enable joint torque

· Click OK

· Right-click Spring/Damper/Jack

· Select Properties

· Damping field: 0.3 N s/mm

· Click OK (page 29)

· Output Grapher

· Right-click n°1:Revolution (door:1, pillar:1)

· Select Properties

· Click dof 1 (R) tab

· Click Edit Joint Torque button

· Select check mark next to Enable joint torque

· Click OK

· Damping field: Enter 50 N mm s/deg

· Click OK

· Click Ouput Grapher tool

· Output Grapher browser

· Expand n°2:Revolution (pillar:1, link:1)

· Expand the Force folder

· Select fr[2.1]

· Click Run button on Simulation Panel

· Ouput Grapher displays visual representation of force

· Note: Graph scale adjusts automatically to fit the curve.

· Return to Construction Mode (page 30)

· Export load to Stress Analysis

· Dynamic Simulation panel bar

· Click AIP Stress Analysis

· Click OK

· FEA Load-Bearing Faces Selection dialog box

· Click link:1

· Click Revolution (pillar:1, link:1)

· Graphics Window

· Link part

· Select two cylindrical faces of corresponding revolution joint

· Click OK

· Run simulation

· Note: Selection boxes for time steps in Output Grapher are available only in simulation mode

· Output Grapher

· Time steps pane

· Click the 0.4 s, 0.935 s, and 3.0 s time steps

· Close Output Grapher

· Exports load on link part at those points in simulation to Stress Analysis (page 31)

· Import load into Stress Analysis

· In-place edit Link part

· Main menu

· Applications > Stress Analysis

· Click Motion Loads tool

· Click OK to message: Load was successfully created

· Click Stress Analysis Update tool

· Stress analysis is performed on link part and results appear in graphics window

· Note: These stress results pertain to specified point in simulation (page 32)

· Summary

· Dynamic Simulation allows desired results to be achieved using one of many workflows

· We learned

· Understanding basic differences between Dynamic Simulation application and regular assembly environment

· Automatically convert relevant assembly constraints to Dynamic Simulation standard joints

· Converting relevant assembly constraints to Dynamic Simulation standard joints one at a time

· Manually creating joints

· Running a dynamic simulation to see how joints, loads, and component structures interact as a moving, dynamic mechanism

· Welding components within Dynamic Simulation to create rigid, unified structures

· Applying forces

· Using the Input and Output graphers

· Defining joint properties

· Exporting and applying Dynamic Simulation loads in Stress Analysis

· Note: Help files have more information (page 33)