Young΄s modulus E, is a measure of stiffness of an isotropic elastic material. Its the numerical evaluation of Hooke΄s law. It is defined as the ratio of stress (force per unit area) to corresponding strain (deformation) in a material under tension or compression.
The higher the value of Young’s modulus, the stiffer the material.
Papercete΄s Young΄s Modulus
Papercrete΄s Young΄s modulus has not been established. To make the acoustic calculations I need to define an approximate value.
I studied the values of different materials with similar microstructure (fibrous lightweight concrete, mdf) to make an estimation. Paper and mdf are made from woo
d pulp and have similar densities and directional variation in Young’s modulus. Paper because of stiff cellulose micro-fibres can provide stiffness at relatively low weight.
Until I determine experimentally the Young΄s modulus 1 I w
ill use an approximate value of E=8 GPa.
Many applications require stiff materials, (lie at the top of the chart). Stiff lightweight materials are hard to find – composites appear to offer a good compromise, but they are usually quite expensive