Unformatted text preview: d Section Composite Beam Analysis (Transformed Section Method)
► ► ► The transformed section method requires that the composite beam be transformed into a beam of equal material.
The crosssectional area of one of the materials must be increased or decreased as a ratio of the Young’s Modulii so that the stress distribution varies linearly.
A dimensionless number, transformation factor, n, relates the ratios of E. E1
n=
E2 ► The transformation factor is used to increase (or decrease) the width of the transformed material while keeping the depth of the beam the same. Composite Beam Analysis (Transformed Section Composite Beam Analysis (Transformed Section Method)
► ► ► Once the composite beam has been “transformed” into the new beam made of the same material, the neutral axis is determined (first moment of area calculation).
Next, the moment of inertia is determined for the transformed beam about the NA (parallel axis theorem).
Apply the flexure formula to determine the stress. σ = My I ► Finally, the stress calculated for the transformed material must be multiplied by the transformation factor to account for area change.
σ = nσ ′ σ= My
I Example
Example
► Prob. 6123. Determine maximum bending stress in wood and steel for the composite beam. Ewood = 1600 ksi, Est = 29,000 ksi. Example
Example
► Prob. 6123. Determine maximum bending stress in wood and steel for the composite beam. Ewood = 1600 ksi, Est = 29,000 ksi. Design of Beams and Shafts (Ch. 11)
Design of Beams and Shafts (...
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This note was uploaded on 02/04/2014 for the course MECH 260 taught by Professor Stephenribarits during the Fall '13 term at University of British Columbia.
 Fall '13
 StephenRibarits

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