1 / 13

Internal Forces of a given member in an Engineering Structure

Internal Forces of a given member in an Engineering Structure. Chapter 7: Forces in Beams and Cables (page 354). Dr. Claudia Genovese-Martinez. So far, you have learned:. the external forces which act on a structure (Chapter 4)

Download Presentation

Internal Forces of a given member in an Engineering Structure

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Internal Forces of a given member in an Engineering Structure Chapter 7: Forces in Beams and Cables (page 354) Dr. Claudia Genovese-Martinez

  2. So far, you have learned: • the external forces which act on a structure (Chapter 4) • the forces which hold together the members forming a structure (Chapter 6)

  3. Objective of this Chapter: • Determine the internal forces of a given member in a structure, such as: • beams • cables (Suspension bridges, transmission lines, etc.)

  4. Outline: • Analyze a: • two-force member • multi-force member • Determine the internal forces: • tension or compression • bending and shear • Examples

  5. Internal forces in members: • Let’s consider: -F F and -F: Directed along AB, opposite sense, same magnitude. B A F

  6. Internal forces in members: • Let’s cut the member AB at C -F B B -F C C A F F C -F A The new forces are equivalent to Internal Forces and must have existed in the member. F

  7. So far, we can conclude that: • In a straight two-force member: • internal forces to axial forces • In this case (tension) : • elongate under the action of internal forces B -F C C F In Compression:? -F A F

  8. Multi-force member: • Crane D D E F C C B B W G A A

  9. D E F C Multi-force member: B W G • Free-Body-Diagram of AD: A D J T Cx Cy FBE Ax A Ay

  10. Multi-force member: • Free-body diagram of the portion JD D T Force-Couple System V J M F • Equilibrium: • F and V to balance T • Couple M to balance the • moment of T about J

  11. Multi-force member: • Free-body diagram of the portions JD and AJ D T Newton’s third law: the internal forces on AJ are equivalent to an equal and opposite force-couple system. V J -F -M M J -V F Cx C Cy B FBE F: axial force V: shearing force M:bending moment at J Ax A Ay

  12. Non-straight two-force member • Internal Forces are also equivalent to a force couple system M B D F D P V P -P A C A B -V M -F D -P C

  13. Conclusion: • INTERNAL FORCES are equivalent to force couple system. • When determining INTERNAL FORCES in a member, indicate on which portion the forces are acting. • In two-force member, internal forces produce tension or compression. • In multi-force member AD, internal forces not only produce tension and compression but also shear and bending D A

More Related