Composite Beams

examples

bimetallic		plastic coated steel pipe
wood reinforced with steel plate		sandwich - plastic core
sandwich - corrugated core		sandwich - honeycomb core
reinforced concrete

CE 120 specimens

 

stress and strain

Moment-curvature relationship for a composite beam

Flexure formulas for a composite beam

 

Transformed-Section Method

This method is an alternative to the preceding section.  It provides a convenient way to visualize the calculations.

steps

1. Transform the cross section of a composite beam into an equivalent cross section (called the transformed section) of an imaginary beam composed of only one material.
2. Analyze the transformed section as customary for a beam of one material.
3. Convert the stresses back to the original beam.

 

modular ratio

To transform the beam into material 1:

The dimensions of area 1 remain unchanged, and the width of area 2 is multiplied by n. (all dimensions perpendicular to the neutral axis remain the same)

A similar procedure can be used to transform the beam into material 2 or a completely different material. One can also extend this technique to cover beams of more than two materials.

 

flexure formulas