WMIntroductoryTutorial.pdf

Welcome to Working Model

Working Model is the result of a 15-year collaborative effort between professional engineers and software specialists. We are

committed to providing you easy-to-use , engineering software that makes you more productive, and saves time and money on

hardware prototyping, testing, and virtual product development.

To begin, install Working Model and go through each step of the demonstration described below.

Installing Working Model

3. When the “Choose Folder” window appears, click [OK].

4. For a step-by-step introductory tutorial, turn to the next page.

1. Insert the Working Model CD into the CD-Rom drive and

follow the installation instructions

2. When prompted for a serial number, enter “ DEMO ” or enter

your licensed serial number

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Starting Working Model

1. Ensure that Working Model is installed on your computer.

2. From the Windows Menu, click on Programs, then Working Model, and

then Working Model. This opens a simulation.

4 Graphing the Pendulum’s Motion

1. To graph the pendulum’s motion, click on the rectangle. Under the Measure

menu, select Position, then select Rotation Graph.

2. To collect data, click . Note: Data can be displayed as a graph, bar chart,

or number, and can be changed while running the simulation by clicking the on

the top left-hand corner of the graph. Click .

3. The graph shows the pendulum’s amplitude and frequency. To make the graph

larger, click on the graph and drag its lower right-hand corner to the right.

1 Creating a Falling Block

1. The first simulation is Newton’s first experiment, dropping a block.

2. To draw a rectangle, click on the Rectangle tool, then click in the workspace and

draw a long thin rectangular block.

3. To run the simulation and see the block fall due to gravity, click

4. Click

to reset the simulation.

5 Changing Gravity

1. To change gravity, click on the World menu, select Gravity, type the value 20

m/sec 2 in the input box, and click [OK].

2. Click and observe that, in agreement with theoretical and experimental

predictions, the pendulum has a higher natural frequency. Click

2 Adding a Velocity Vector

1. To add a velocity vector, click on the rectangle.

2. From the Define menu, click on Vectors and then Velocity.

3. Click

Note: Working Model was designed to be easy-to-use . For example, in this

exercise, the only time you need to touch the keyboard is to enter the value 20.

and observe that the vector changes magnitude as the block falls.

4. Click

Optional: To show the velocity vector’s x and/or y component, click on the Define

menu, select Vector Display, and check the X and/or Y box.

3 Making a Pendulum

1. To make a pendulum, click on the Pin joint tool and then click on the upper left-

hand corner of the rectangle.

2. Click and observe that the vector changes magnitude and direction as the

pendulum moves. Click

6 Adding Air Resistance

1. Under the World menu, select Air Resistance, click on Low Speed, and accept

the default air resistance value of 0.3 kg/(m*s) by clicking [OK].

2. Click

Optional: Each click on at the bottom of the screen advances one frame.

and observe the exponentially decaying oscillations. Click

7 Adding a Spring

1. To add a spring, click on the Spring tool. Click on the upper right-hand corner of

the block and stretch the spring up and to the right.

2. Click and observe the pendulum's higher natural frequency and new

equilibrium position. Click

9 Collisions with a Smooth Polygon

1. To create a smooth polygon, click on the Curved Polygon tool, click in the

workspace in a few locations. Double-click to close the polygon.

(If your rectangle is high on the screen, click to zoom to extents.)

2. Click to start the simulation and observe that the curved polygon bounces

and rolls on top of the rectangle. Automatic collision and contact is a very useful

feature in Working Model (even the elastic and frictional properties of objects may

be varied). Click

Note: Collision sound/motion sound can be added to a simulation. To add a

collision sound, click on the curved polygon, select the Measure menu, and

choose Hear the Collision. (Windows only; computer speakers required)

8 Controlling the Spring Constant

1. To control the spring constant, click on the spring. Under the Define menu, select

New Control, then select Spring Constant.

2. The slider that controls the spring will appear in the left-hand side of the

workspace. To move the slider's location closer to the spring, click on its title and

drag it next to the spring.

3. To see the effect of varying the spring constant, click and observe that the

pendulum angle is a function of the spring-constant (move the slider up and down

while the simulation is running). Click

10 Smart Editor

1. Working Model's Smart Editor allows the user to change an object's position and

orientation while keeping constraints intact.

2. To change the orientation of the rectangle, click on the rectangle and drag the

mouse to rotate the rectangle counterclockwise so that it is nearly vertical as shown

below. (If necessary, click to view to extents.)

11 Creating a Cam-Follower Mechanism

1. To add a motor to the curved polygon, click on the Motor tool, and then click on

the curved polygon.

2. Click and observe that the rectangle's motion is determined by the shape

of the curved polygon and the motor's speed. Click

Optional: The properties of any object can be modified by double-clicking on any object (e.g., the

rectangle, pin point, graph, spring, spring-constant control).

The appearance or geometry of an object can be modified by clicking on the object, selecting the

Window menu and selecting Appearance or Geometry.

12 Creating a Flexible Beam

1. To convert the rectangle into a flexible beam (Flexbeam), click on the rectangle.

2. Under the Script menu, select Flexbeam.

3. In the “Flexible Body Information” dialog box, accept the default values and click

[OK]. Click [OK] in the “No Flexbeam Undo” dialog Box.

4. Click to start the simulation and observe that the formerly rigid rectangle is

now acting as a Flexbeam. Change the values of the “EI” and ‘Damping - Bending”

sliders to change the Flexbeam’s stiffness and damping. Click

16 Adding Colors to DXF Objects

1. Objects that are imported from a DXF file are treated the same as objects

created within Working Model. You can change their appearance, measure their

velocity, acceleration, etc.

2. To add color to the crane, click on the crane.

3. Under the Window menu, click on Appearance.

4. In the Appearance window, note that the fill pattern is currently set as “no.” Click

on the drop-down menu and change it to another pattern.

5. Click on the fill color drop-down menu and change the fill color to blue.

6. Close the Appearance window.

7. To change the color of the other objects, repeat steps 2 to 6.

8. Click

to start the simulation. Click

17 Running Demo Files

1. Under the Script menu, click on “Run All Demo Files”.

2. Sit back and enjoy a series of demos on a variety of engineering topics.

13 Animation Step and Integrator Error

1. To change accuracy, select the World menu and then Accuracy…

2. Select an Integrator Error small enough to meet your accuracy requirements.

14 Importing DXF Files

1. Open a new simulation by selecting the File menu and clicking on New.

2. To import a DXF file, select the File menu and click on Import.

3. In the Import window, navigate to the directory where Working Model is installed,

for example, C:\Program Files\WorkingModel and then select the sub-directory

WMIntroduction.

4. Select the file WMDXFDemo.dxf and click [Import]. This imports the DXF objects

(a crane, wrecking ball, a Working Model logo, and an abandoned building).

5. Click

18 Creating a Movie

1. You can create a movie from any Working Model simulation.

2. To see an example, select menu, then Programs, then WorkingModel,

then WMIntroduction, and then double-click on WorkingModelMoneyBowl.avi.

and watch all the objects fall due to gravity. Click

15 Simulating a Building Demolition

1. To anchor the base of the building, click on the Rigid Joint tool, then click on the

base of the building.

2. To anchor the crane, click on the Rigid Joint tool, then click on the crane.

3. To fix the Working Model logo to the crane, click on the Rigid Joint tool, then click

on the Working Model logo.

4. To attach the wrecking ball to the crane with a rope, click on the Rope tool, then

single-click on the ball, and then single-click on the crane to create a rope.

5. Click and observe that Working Model detects the shape of the imported

DXF objects and automatically calculates how they collide. Click

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3. Select an Animation Step that produces smooth visual results.

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