2. Success with ModelSmart3D Pre-Engineering Software Corporation Written by: Robert A. Wolf III, P.E. Copyright 2001, Pre-Engineering Software Corporation, All Rights Reserved Show 1

3. Success with ModelSmart3D - Part II Slide No. 2 Series Outline Show # 1 I.Possible benefits II.Introduction to bridge trusses III.Modeling for structural analysis Show # 2 IV.Using ModelSmart3D V.Extra for Experts Show # 3 VI.Optimization VII.Printing Show # 4 VIII.Building Your Model

4. Success with ModelSmart3D - Part II Slide No. 3 I. Possible Benefits 1.Practical application for math and science. 2.Create a “feel” for engineering. 3.Foster innovation. 4.Re-label mislabeled students 5.Efficient method for experimenting Motivation and Enhancement

5. Success with ModelSmart3D - Part II Slide No. 4 II. Introduction to Bridge Trusses Why build a bridge?

6. Success with ModelSmart3D - Part II Slide No. 5 A Small Foot Bridge

7. Success with ModelSmart3D - Part II Slide No. 6 Very Large Gaps How could we prevent this longer board from failing? Span

8. Success with ModelSmart3D - Part II Slide No. 7 Beams and Bending Compression in fibers Tension in fibers Neutral axis (NA) Load direction A

9. Success with ModelSmart3D - Part II Slide No. 8 Beam Cross Section Section A NA Fibers in max. compression h b Fibers in max. tension f x

10. Success with ModelSmart3D - Part II Slide No. 9 Add a Support Let’s place a pole at the mid-span. A

11. Success with ModelSmart3D - Part II Slide No. 10 Support from Above! A helicopter? Hanger T

12. Success with ModelSmart3D - Part II Slide No. 11 Supports for the Hanger Diagonals are in compression Hanger (tension)

13. Success with ModelSmart3D - Part II Slide No. 12 A Truss is Born! Let’s attach the poles to the end of the horizontals!

14. Success with ModelSmart3D - Part II Slide No. 13 Really Huge Gaps! How do you lengthen the truss? Top Chord Bottom Chord

15. Success with ModelSmart3D - Part II Slide No. 14 Learning from Beams Remember the board over the ditch?

16. Success with ModelSmart3D - Part II Slide No. 15 Trusses Bent Like Beams The top chord is in compression C The bottom chord is in tension A B

17. Success with ModelSmart3D - Part III Slide No. 16 III. Creating a Computer Model

18. Success with ModelSmart3D - Part III Slide No. 17 Simply Supported

19. Success with ModelSmart3D - Part III Slide No. 18 Identifying Possible Bridge Shapes A C E G B D F H

20. Success with ModelSmart3D - Part III Slide No. 19 Truss Design Suggestions Prat Warren Deck Warren Parker or Camel-back

21. Success with ModelSmart3D - Part III Slide No. 20 An Example Preliminary Design Sketch 4 spa. @ 3” =12” 4” 1/8” sq. Balsa – TYP. ELEVATION – Main Truss Preliminary

22. Success with ModelSmart3D - Part III Slide No. 21 2D Modeling Symbols & Coordinate System Joints (Nodes) Members Load Vectors Supports Y X Cartesian coordinate system (x,y)

23. Success with ModelSmart3D - Part III Slide No. 22 A Real Hinge Hinge Symbol Actual Hinge

24. Success with ModelSmart3D - Part III Slide No. 23 Computer Model – Locate Joints Y X J3(6,0) 3” 4” J5(12,0) J5(6,4) J1(0,0) Computer Model Sketch Scale 01” 2” J4(3,4) J6(9,4) J2(3,0) J4(9,0) Main Truss Joint #4 X = 3” Y = 4”

25. Success with ModelSmart3D - Part III Slide No. 24 Computer Model - Members Y X J3(6,0) J5(12,0) J5(6,4) J1(0,0) Computer Model Sketch Scale 01” 2” J4(3,4) J4(9,4) J2(3,0) J4(9,0) Main Truss All Members - 1/8” sq. BalsaD2

26. Success with ModelSmart3D - Part III Slide No. 25 Computer Model - Supports Y X J3(6,0) J5(12,0) J5(6,4) J1(0,0) Computer Model Sketch Scale 01” 2” J4(3,4) J4(9,4) J2(3,0) J4(9,0) Main Truss Hinge Roller All Members - 1/8” sq. BalsaD2

27. Success with ModelSmart3D - Part III Slide No. 26 Computer Model – Load(s) Y X J3(6,0) J5(12,0) J5(6,4) J1(0,0) Computer Model Sketch Scale 01” 2” J4(3,4) J4(9,4) J2(3,0) J4(9,0) Main Truss Hinge Roller 10 lbs. All Members - 1/8” sq. BalsaD2

28. Success with ModelSmart3D - Part III Slide No. 27 Let’s Think 3D Lateral Support “Roadbed” Truss Member Girder Transverse Direction

29. Success with ModelSmart3D - Part III Slide No. 28 Real Bridge Example Lateral Support Roadbed Axial loaded truss members

30. Success with ModelSmart3D - Part III Slide No. 29 End of Show 1