“Measurement of bending moment and shear forces for structural analysis”
Azamat Omarov
ID201102658
1.Theory and background
1.1 Summary
That performed laboratory session on bending moments and shear forces requires good understanding and sufficient knowledge of axial forces. Bending is defined as a behavior of any structural element that undergoes the external load, which is applied perpendicularly to longitudinal axis. That experiment helps us to find the maximum load that can be applied to the beam with rectangular cross section. Moments are calculated by using statics theory, or multiplying perpendicularly directed load by the respective distance to the pivot point.
1.2 Objective
The main objective of that laboratory is to provide students with basic experience and thus, the comparison between calculated and measured values (software) should be demonstrated to show the ability to apply statics theory from applied mechanics module.
1.3 Theory
Shear forces
The shearing force at any section of a beam is the algebraic sum of the lateral components of the forces acting on either side of the section. F is the resultant reaction on the left of AA. As the beam is in equilibrium then resultant reaction on the right of AA must be downwards.
Figure1. Shear forces diagram Equilibrium state ∑Fx=0N; ∑Fy=0N; ∑Mo=0N.m (1) In our case we use AA as a reference point to calculate the bending moment
Bending Moment
Bending Moment at AA is defined as the algebraic sum of the moments about the section of all forces acting on either side of the section. Bending moment is considered to be positive when the total moment on the right of AA is clockwise, whereas moment to the right of AA is anticlockwise. That type of behavior of bending moment is called sagging since it makes the beam to become concave upward. The opposite of sagging is called hogging.
Figure 2. Bending moment (sagging) diagram
2.