Laszlo M. Szijarto
September 11, 2011
VCU School of Engineering
Department of Mechanical Engineering
Solid Mechanics Lab
EGRM 311 – 004
Lab Report #1
Beam Bending
Introduction
The objective of this experiment was to provide a practical demonstration of the relationship between the vertical shear force and bending moment distributions in a beam. If carried out correctly, this experiment will help to confirm the linear relationship of applied stress on a beam and the resulting strain exhibited in the deformation of the beam. The beam that is being tested will undergo a certain amount of deformation during the test, however, as given by Hooke’s Law, the beam will return to its original configuration as long as the applied stress remains in the elastic range and does not exceed the materials yield strength.
If, after the conclusion of the stress (Equation 1 in Appendix) test some permanent deformation to the beam is evident, one can assume that the material was faulty or more likely too much stress was applied to the beam. The Modulus of Elasticity is a value assigned to materials, in this case aluminum, and will prove to be helpful in determining the shear force that is exerted on the beam during the experiment. This experiment is also helpful in demonstrating the shear force and the bending moment of the beam. When a constant shear force (Equation 2 in Appendix) is measured throughout the beam one can expect to see a linear change in the bending moment. This relationship will be demonstrated with the use of shear and moment diagrams (Figure 1 in Appendix).
Procedures
Inventory of all necessary equipment and materials was taken and verified to be correct. The following equipment was used: Flexor (cantilever flexor frame), two identical 320 mm aluminum bars, one with three strain gages glued into place prior to the experiment, a Model P-3500 Portable Strain Indicator, and a non-digital caliper. Measurements of the blank aluminum bar were...