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ENGI 1313 Mechanics I . Lecture 32: Analysis of Frames and Machines. Miscellaneous Notes. Friday November 9 Lecture Postponed Last Quiz This week of November 5-9 Method of Joints and Sections for Trusses Remaining Tutorial Sessions General sessions
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ENGI 1313 Mechanics I Lecture 32: Analysis of Frames and Machines
Miscellaneous Notes • Friday November 9 Lecture Postponed • Last Quiz • This week of November 5-9 • Method of Joints and Sections for Trusses • Remaining Tutorial Sessions • General sessions • Problems will be selected for you to complete • Problem sets will be posted during week of November 11
Miscellaneous Notes (cont.) • Mid-Terms Exams • All exams have not been collected • No Record of Mid-Term • Student numbers • 200402782 • 200565687 • 200672285 • 200714459 • Contact me immediately to resolve
Chapter 32 Objectives • to define frames and machines • to develop the equations of equilibrium for frames and machines • to determine joint forces and support reactions for frames and machines
Frames and Machines • Frames • Stationary • Support loads
Frames and Machines (cont.) • Machines • Moving parts • Transmit or alter effects of loads
Frames and Machines (cont.) • How are Frames and Machines Different from Truss Structures?
Frames and Machines (cont.) • How are Frames and Machines Different from Truss Structures? • Multi-force member(s)
Analysis of Frames and Machines • Key Steps for Analysis • Establish coordinate system • Draw FBD • Identify unknown forces and moments • Typically define rectangular components • Identify Structural Characteristics • Two-force members • Connecting members
Comprehension Quiz 32-01 • Forces common to any two connecting members act with _______ on the other member. • A) equal magnitudes but opposite sense • B) equal magnitudes and the same sense • C) different magnitudes but opposite sense • D) different magnitudes but the same sense • Answer: A
Example 32-01 • When determining the reactions at joints A, B, and C, what is the minimum number of unknowns for solving this problem? • A) 3 • B) 4 • C) 5 • D) 6 • Answer: A
Example 32-01 (cont.) • Any Structural Characteristic to Identify? FAB is a two-force member
Example 32-01 (cont.) • Use What Equilibrium Equation First?
Example 32-01 (cont.) • Can the Problem be Solved if the Two-Force Member was not Identified? • Yes • How? Apply Equilibrium Equations to Each Structural Member
Comprehension Quiz 32-02 MC • The FBD is shown. • If a couple moment was applied at C, does the FBD of member BC at Joint B change? • A) No change • B) Two forces, BX and BY • C) Two forces and a moment at B • D) One moment at B • Answer: A MC
F Comprehension Quiz 32-03 • The FBD is shown. • If an additional force is applied to member AB, does the FBD of member BC at Joint B change? • A) No change • B) Two forces, BX and BY • C) Two forces and a moment at B • D) One moment at B
F F Comprehension Quiz 32-03 • The FBD is shown. • If an additional force is applied to member AB, does the FBD of member BC at Joint B change? • A) No change • B) Two forces, BX and BY • C) Two forces and a moment at B • D) One moment at B • Answer: B
References • http://en.wikipedia.org • Hibbeler (2007) • http://wps.prenhall.com/esm_hibbeler_engmech_1