Drawing

DEPCOllc

3305 Airport Drive | Pittsburg, KS 66762

12. Click Show Me, after the calculations are completed. COSMOSXpress will show a color

coded model of the axle. Blue indicates the axle is not being stressed near the material yield

point, and that the factor of safety is greater than 1. Red indicates a factor of safety less than

1, or more importantly, that the part will fail under the applied load.

13. After clicking

Show Me, click Next, and choose “Show me the stress distribution in the

model”

radio button. This feature provides a color coded graphic showing where the part is

most highly stressed. Warmer colors indicate higher stress and cooler colors indicate lower

stress.

The axle in this example maintained a factor of safety greater than 2 under a load of 60 lbs. This is

more than 7 times the maximum loading predicted by the GEARS-TrebStar simulation software.

Stress Distribution of 0.118Ǝ radius axle under 60 pound load. Courtesy of SolidWorks Corp.

COSMOSXpress Challenge

Using COSMOSXpress

determine the minimum axle

radius needed to support the

maximum load imposed by

the trebuchet used in these

examples.

Hint: The maximum stress for

this example is 7.7 pounds.

Answer

_________inches

Try This

Use your new engineering skills and knowledge to help design a real trebuchet. This may take some

time, and more than a few iterations to find the best answer, but you have the tools and skills to

create the design.

Trebuchet Design Parameters

Tools you will need to use:

Maximum Dynamic Load (P ) = 20 lbs (9kg)

Calculator

Span ( L ) 6 in. (15cm)

Flexural Formula

COSMOSXpress analysis software

GEARS-TrebStar simulation software

Use the constraints imposed by the trebuchet design parameters listed above to design a trebuchet

axle with the minimum radius necessary to support the Maximum Dynamic Load ( P ) with a factor

of safety of 2.5.

Record all your work in your notebook including the values and number of design iterations you

created. Sign and date your work.

Sample Engineering Curriculum