# engr 244 lab 4.docx - Objective The objective of this...

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Objective:The objective of this experiment is to determine how the stress and strain in a beam are distributed and how they compare to the theoretical values. This experiment will also determine the values of the modulus of elasticity, Poisson’s ration, and the shear modulus.Introduction:Stress analysis on beams allow us to know how much stress a beam can take before it fails. This is particularly important when designing building and bridges so that they are able to handle the stresses of everyday life. Bending occurs when one cross section of a beam/material is in compressive stress while the other in is tensile stress. This can be seen in Figure 1 below.Figure 1 – Beam in tension and compressionIn this experiment we will be considering bending stresses only. When pure bending occurs, there is also a transverse shear that occurs as well. This experiment will consist of applying a load at two separate equidistant locations at the same time. Strain gauges will collect data on the strain that is felt at different positions. Gauges 1-5 will collect strain data in the longitudinal direction, while gauge 6 will collect strain data in the transversal location. From all the data collected from this experiment the moment of inertia (I), bending stresses (σ), modulus of elasticity (E), Poisson’s ratio (υ), and the shear modulus (G) can be calculated using the following formulas.I=bh312Where, I is the moment of inertia (mm4)b is the width of the beam (mm)h is the height of the beam (mm)σexp=M × yIWhere, σ is the experimental bending stress (MPa)M is the moment (Nmm)