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chris_usyd

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## Homework Statement

A timber beam, with rectangular cross section (h × b) is reinforced with additional full width (b) steel plates. There is a plate of thickness t securely connected on the top and a plate of thickness 2t on the bottom of the timber to ensure composite action in bending. The section is then used as a simply supported beam of length L. The beam is oriented such that the minor principal axis is vertical. It should be taken that ρsteel =7850 kg/m3, ρtimber = 900 kg/m3, Etimber = 12500 MPa and Esteel = 200000 MPa, and that both materials exhibit linear elastic behaviour. The design engineer needs to ensure that the normal bending stress (tension or compression) does not exceed 10 MPa (for the timber) or 275 MPa (for the steel).

Question!: Before the steel plates are connected (ie based on the timber beam only) determine the maximum

bending moment and bending stress in the beam due to self weight only.

## Homework Equations

h (mm)=300 b (mm)=190 t (mm)=3 L (m)=3.6

## The Attempt at a Solution

sorry,i don't know how to do this question? normally, we will get bending moment at somewhere, then draw the stress distribution across the section.

: ( i don't need calculations, just give me some ideas, thank you!

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