Welcome to Sophomore Engineering Clinic I

 Instructor Introduction  Personal Data Surveys  Sent by  Fill out ASAP Before we get started…

Sophomore Engineering Clinic Technical Communication Most products are not built by engineers. Engineers produce prototypes, product designs and process designs, lab reports and design reports Engineering Design Design is open ended, and problems are often ill-posed.

 Bottle Rocket (4 Weeks)  Research Project/Prof. Development (4 Weeks)  Some overlap with Bottle Rocket Project  Final Project (6 Weeks) Schedule

Bottle Rocket Design  Design and fabricate a rocket out of a soda bottle.  Materials:  2 L soda bottle  Foam Board  Clay  Duct Tape  Water  Rocket will be pressurized to 40 PSI

Bottle Rocket Design  Goal- Design a rocket that will fly the farthest. Only “perpendicular” distance counts.

Using Parametric Design  Parametric Design: Using parameters to define a large number of instances, and then selecting the best one.  Examples:

Developing Parametric Models  Start with a rectangle  Identify a family of shapes by defining one parameter 2 3

Parametric Model – Case I  A family with 1 parameter 2 Width Parameter = Width Height = 2 (constrained)

Parametric Model – Case I  A family with 1 parameter  Defined an infinite number of design instances 2 Width

Parametric Model – Case II  Identify the family of shapes for a constrained width 2 3

Parametric Model – Case II  A family with 1 parameter.  Defined an infinite number of design instances. Height 3 Parameter = Height Width = 3 (constrained)

Parametric Model – Case III  X- and Y-Coordinates of 3 nodes are parameters  Identify the family of shapes with one node constrained 2 3

Parametric Model – Case III  Shapes are not constrained to rectangles

An Example Parametric Model for a Fin Family  Right triangles with height to length ratio of 2:1  Size and shape of fins are defined by either height or length

For Next Week  Develop a parametric model for a rocket with 3 parameters:  Amount of water in rocket,  Mass of clay used,  1 parameter to describe a family of fins.

Constraints  Clay is placed only in front of rocket, in a rounded shape.  Exactly 3 wings, placed 120 o apart.  Duct tape is used only to secure wings and clay to bottle.  Fin size and shape belong to a family that is defined by a single parameter. (you define the appropriate parametric model for the wings)

Example test results  Holding 2 parameters constant while varying the third allows a systematic study of behavior to be recorded.  Take notes.  The optimal value of one parameter might depend on the values of the other two parameters.  Observations should influence design. Water (liters) Distance (ft)

Note:  Your grade for an upcoming report will be based on the technical description of the parametric model you develop  The grade of this report for this project will not be based on your final distance.

Assignment Requirements for Next Week:  Have your section leader ok your parametric model.  Perform experiments to determine the set of parameters that maximizes the distance.  Communicate intelligently about parametric design  The parametric model for the rocket cannot be changed after a few tests.  Choose a family of fins!

 Find your Team and Instructor  Introduce yourselves  What is your unique fact?  Video and/or Design Questions of the Day  What are you going to do to help your team succeed?  What is Design?  Any questions about project?  After Testing – Find your Instructor  Discuss observations from the first test day Before we start launching…