【構造力学】#24 単純梁にモーメント荷重がかかった場合の反力の求め方を解説！

This channel provides easy-to-understand explanations of structural mechanics, physics, and architectural structural design. Recommended for those studying architecture and science and mathematics. This video clearly explains how to calculate the reaction force when a moment load is applied to a simple beam. Moment load on a simple beam?! Learn how to draw shear force diagrams (Q diagrams) and bending moment diagrams (M diagrams). https://kentikukozosekkei.com/archive... What is a couple? A simple explanation based on three conditions! https://kentikukozosekkei.com/archive... Understand the formula for the moment of a couple! An easy-to-understand explanation using examples! https://kentikukozosekkei.com/archive... [Quoted from Net Architecture School] Example Look at the diagrams below and find the Q and M diagrams. Explanation Assuming reaction forces First, we'll assume and calculate the reaction forces. Since no horizontal forces are acting in this problem, we will omit the horizontal reaction force and N diagram. Now, in fact, there are no forces acting in the vertical direction in this problem either. ...Does that mean the vertical reaction force is also 0? ...No. If the reaction force is 0, this moment load (the force that rotates an object) will cause the simple beam to spin around. This moment must be stopped. So, how do we do this? Actually, we can solve this using a topic we've already learned about. It's... It's "couple"! Do you remember? If you've forgotten, you can read the article at the link below. In this problem, the moment load is rotating clockwise with a force of 15 kN･m. To stop it, we need to use couple and apply a force of 15 kN･m counterclockwise. Now, let's plug this into the couple formula. The couple formula is below. Formula for Couple Moment M = PL [N m, kN m, etc.] P... Magnitude of one force [N, kN, etc.] L... Perpendicular distance between the two forces [mm, m, etc.] This means... M = 15 kN m L = 5 m Therefore, 15 = 5 × P P = 3 kN . If we set this to create a counterclockwise couple... VA = -3 kN VB = 3 kN . Additional Note: Notes on Moment Load Reaction Force Moment loads may not come up in many questions. So, be sure to remember these points. Notes on moment loads are... The location where the moment load is applied has no effect on the reaction force. Moment loads are forces that rotate an object. So, regardless of where they are applied, they have a force that tends to rotate the entire object. See the diagram below. And the reaction force to this moment load is often referred to as "couple." Make sure you remember this. #Architecture #StructuralMechanics #ReactionForce #SimpleBeam #MomentLoad Website: "Net Architecture School" https://kentikukozosekkei.com/ Twitter   / kenchiku_juku   BGM Sound sources from several people, including @Khaim, are used.