Shear Force and Bending Moment Objectives: The purpose of doing this experiment was to determine the bending moment and shear force at any section through different cases which involve concentrated load, symmetrical load and unsymmetrical load. Besides, it also helps to establish the relationship between bending moment and shear force at any section.
Beams have numerous other applications in case of bridges, automobiles or in mechanical systems. In this article we will see how we can do strength analysis of a beam. Following article gives detailed description of the video lecture. What is a Beam? In a beam transverse load is acted, which in fact comes from the slabs to the column or walls.
It is clear from following figure that, beams are integral part of of building structure.
In all of the beams load acted is transverse, as shown. This way we can determine external load acting on individual beams. After determining load acting on individual beam, beam can be separated out from beam column system for further analysis.
So axial strain developed in a beam will be very small compared to shear strain, or strain induced due to bending. This is shown in figure below. Both shear force and bending moment are induced in beam in order to balance external load acting on it.
We will go through details of it separately.
Shear Force Shear force is the internal resistance created in beam cross sections, in order to balance transverse external load acting on beam. Consider following beam, it does not matter from where you take a section, when you add forces acting on it, it should be in equilibrium.
Shear force is induced exactly for this purpose, to bring the section to equilibrium in vertical direction. It acts parallel to cross section. Usual sign convention of the shear force is as follows.
Bending Moment But balance of transverse forces alone does not guarantee equilibrium of a section. There is another possibility of beam rotation, if moment acting on it is not balanced. If this is the case a bending moment will be induced in cross section of beam, to arrest this rotation.
It will be induced as normal forces acting on fiber cross section as shown. So we can calculate moment induced at any cross section by balancing the external moment acting on the free body diagram.
Sign convention of bending moment is as follows.Shear force and bending moment experiment for symmetrical load The 2 edge supports is set up on the base of the structural test frame at a distance of mm from the edge to edge.
The shear force apparatus is placed on the support. The beam . Draw the Shear Force and Bending Moment diagrams and calculate the position and magnitude of the maximum B.M.
(U.L.) The Total Load on the beam (i.e. the load plus the mean rate of loading of 1/2 tons/ft) is given by.
Below the moment diagram are the stepwise functions for the shear force and bending moment with the functions expanded to show the effects of each load on the shear and bending functions. The example is illustrated using United States customary units.
Shear Forces occurs when two parallel forces act out of alignment with each other. For example, in a large boiler made from sections of sheet metal plate riveted together, there is an equal and opposite force exerted on the rivets, owing to the expansion and contraction of the plates.
Shear Force and Bending Moment in Beams Beam Loads The way a part is loaded determines whether it is called a tensile or compressive member, a torsional shaft, or a beam. If a uniformly distributed load is not symmetrical, then we need to convert the distributed load into a point load equivalent to the total load W=wL 1 where L.
THEORY Defination: Shear influence line is defined as a line representing the changes in shear force at a section of a beam when a unit load moves on the beam Part 1: This Experiment examines how shear force varies at a cut section as a unit load moves from one end to another (see Figure 1).5/5(47).