- #1

- 3

- 0

**I am constructing a glutamine beam as part of a project and need to estimate the load at which the beam fails in bending and the load that will give deflection of length/200.**

I have been allowed to do a none destructive test on each piece of timber to be used in my beam. This has given me a range of natural frequencies from 1335Hz to 1532Hz, and have been given to equations to get modulus of elasticity (v=2*f*l, where f=frequency and l=length of sample, and E=v^2*d where v=velocity and d=density), I have looked into these and they don't seem completely accurate as the moe equation is missing the poissons ratio parts. I have learned that if I use cm for the units my moe gives me dynes/cm^2 which I have got 16204.9kN/m^2 for the specimen with 1523Hz that has l=180.8cm t=2.01cm and b=9.32cm (l=length, t=thickness and b=breadth) and weight of 1.8kg.

I was wondering if there is a link between modulus of elasticity and bending strength of timber, as the equations for the failure of a beam in bending in eurocode 5 uses the bending strength characteristic, is this conversion possible as I guess this is how timber grading machines work but can't seem to find anything on it.

v=2*f*l

v=2*1523*180.8

v=550716.8m/s

E=v^2*d

E=550716.8^2*0.000558(kg/cm^3)

E=169,235,258.5dynes/cm^2

Therfore,

E=169,235,258.5*0.0001

E=16923.5kN/m^2

Can I get to bending strength with what I already have.