IHEORYMECHANICS优Electronic teaching planChapter2 Planar Concurrent ForceSystem and Plane CouplesCollege of Mechanicaland Vehicle Engineering王晓君
College of Mechanical and Vehicle Engineering 王晓君 THEORY MECHANICS Electronic teaching plan
Chapter2PlanarConcurrentForce System andPlane CouplesIntroductionForce system is divided into:planar force system ;space force system@Planar concurrentplanarforce systemPlane specialforce②Plane Couplesforce systemPlanarparallelforcesystemsystem@Plane general forceCoplanar forcesystemsystemPlanar ConcurrentForce System:A force system in which the lines of action of all forces are in thesame plane and converge at a point。Example:CranehookResearch methods:Geometric methodT2analytical method
Planar Concurrent Force System ： A force system in which the lines of action of all forces are in the same plane and converge at a point。 Introduction Research methods: Geometric method, analytical method. Example：Crane hook Force system is divided into :planar force system ;space force system ①Planar concurrent force system ②Plane Couples ③Planar parallel force system ④Plane general force system planar force system Plane special force system Coplanar force system Chapter2 Planar Concurrent Force System and Plane Couples
Chapter2PlanarConcurrentForce System and Plane Couples≥ 2.1 Resultant and Equilibrium Condition ofPlanar Concurrent Force Systems> 2.2 Concept and Calculation of the Moment ofForce about a Co-planarPoint> 2.3Plane Couples
Ø 2.1 Resultant and Equilibrium Condition of Planar Concurrent Force Systems Ø 2.2 Concept and Calculation of the Moment of Force about a Co-planar Point Ø 2.3 Plane Couples Chapter2 Planar Concurrent Force System and Plane Couples
2.1 ResultantandEquilibriumCondition of Planar Concurrent ForceSystems,GeometricalMethod1.ResultantThetriangleruleofforceFRRFAabFFTriangle abc is called force triangle; The above drawingmethod is called trianglerule offorce
The triangle rule of force Triangle abc is called force triangle; The above drawing method is called triangle rule of force. a b F1 c F2 R 一. Geometrical Method A F1 F2 2.1 Resultant and Equilibrium Condition of Planar Concurrent Force Systems 1.Resultant R
2.1 Resultant and Equilibrium Condition of Planar Concurrent ForceSystemsPolygonal ruleofforceFdF2Fc1E2RF4baThe polygon formed by each force vector and the resultant force vector is called aforce polygon. The drawing rule for finding the resultant force by force polygon iscalled the polygon rule of force. The edge representing the resultant force vector inthe force polygon is called the closed edge of the force polygonConclusion:The final result of planar concurrent force system resultantis aforce (called resultant force). Its action line passes through the concurrent pointof force system, and its size and direction are determined by the closed edge offorce polygon, which is equal to the vector sum of each force vector. Expressed asavector:R=F+F,+...+F,=ZF
Polygonal rule of force A F1 F2 F3 F4 R a b F1 c F2 d F3 4 e F The polygon formed by each force vector and the resultant force vector is called a force polygon. The drawing rule for finding the resultant force by force polygon is called the polygon rule of force. The edge representing the resultant force vector in the force polygon is called the closed edge of the force polygon. Conclusion: The final result of planar concurrent force system resultant is a force (called resultant force). Its action line passes through the concurrent point of force system, and its size and direction are determined by the closed edge of force polygon, which is equal to the vector sum of each force vector. Expressed as a vector： R F F Fn F 1 2 2.1 Resultant and Equilibrium Condition of Planar Concurrent Force Systems