Ch 3. Beam Shear/Moment Diagrams Multimedia Engineering Mechanics Shear andMoment Shear/MomentDiagrams MovingLoads
 Chapter 1. Stress/Strain 2. Torsion 3. Beam Shr/Moment 4. Beam Stresses 5. Beam Deflections 6. Beam-Advanced 7. Stress Analysis 8. Strain Analysis 9. Columns Appendix Basic Math Units Basic Equations Sections Material Properties Structural Shapes Beam Equations Search eBooks Dynamics Fluids Math Mechanics Statics Thermodynamics Author(s): Kurt Gramoll ©Kurt Gramoll

 MECHANICS - EXAMPLE Example Two Member Structure What is the internal moment at section a-a? Solution Reaction Forces Before a member can be cut, the reaction loads at the supports need to be determined. Since both members AB and CB are two force members, the direction of the reaction force at A and C are known. Considering the full structure, summation of forces at C gives      ΣMC = 0      -15(10) + FAB cos45 = 0      FAB = 212.1 N Member Cut at a-a Member AB can now be cut member at a-a. At the cut, both the shear and moment internal forces are unknowns. The vertical and horizontal components of the force FAB are      FAB-x = FAB-y = FAB / cos45 = 150 N Vertical and horizontal distances are shown on diagram. Summing moments at the cut gives,      ΣMcut = 0      M + 150(10)(1-cos25) - 150(10)(sin25) = 0      M = 493.4 N

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