Stiffness to Weight Ratio
<p><b>Specific modulus</b> is a <a href="/wiki/Materials_property" class="mw-redirect" title="Materials property">materials property</a> consisting of the <a href="/wiki/Elastic_modulus" title="Elastic modulus">elastic modulus</a> per mass <a href="/wiki/Density" title="Density">density</a> of a material. It is also known as the <b>stiffness to weight ratio</b> or <b>specific stiffness</b>. High specific modulus materials find wide application in <a href="/wiki/Aerospace" title="Aerospace">aerospace</a> applications where minimum structural <a href="/wiki/Weight" title="Weight">weight</a> is required. The <a href="/wiki/Dimensional_analysis" title="Dimensional analysis">dimensional analysis</a> yields units of distance squared per time squared.</p>
Applicable units are those of quantitykind:SpecificModulus
https://en.wikipedia.org/wiki/Specific_modulus
http://dbpedia.org/resource/Specific_modulus
$specific modulus = E/\rho$, where $E$ is elastic modulus and $\rho$ is density.