# Changes

,  16:31, 21 April 2010
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</ref> Moisture content, as bales need to be dry to prevent rotting. Dry density determines the strength of bales. The equation for density, <nowiki>[kg/m</nowiki><sup>3</sup><nowiki>]</nowiki> is found here:

</ref> Moisture content, as bales need to be dry to prevent rotting. Dry density determines the strength of bales. The equation for density, <nowiki>[kg/m</nowiki><sup>3</sup><nowiki>]</nowiki> is found here:
−
$\rho\ = frac{m}{V}$
+
$\rho\ = {m}/{V}$

The density of a bale is based on the compressibility of the material and the stress exerted by the piston. Studies have shown that when laid flat, bales with a higher density fail at a higher ultimate load. <ref>Bou-Ali, G. Straw Bales and Straw Bale Wall Systems. M.Sc. Thesis,Tucson: University of Arizona, 1993</ref> Further studies have shown a correlation between density and modulus of bales, but orientation has a larger effect on mechanical properties. <ref>Tattersall, Graeme H. EFFECTS OF DENSITY ON MECHANICAL PROPERTIES OF STRAW BALES. Thesis, Kingston: Queen's University, 2010.</ref> Straw bales are used to form a composite wall with plaster on either side of the bales. When these plastered walls are subjected to a concentric compressive load it acts like a column with the plaster taking the majority of the load. The straw primarily provides lateral bracing for the plaster skins, while taking a small part of the compressive load. If lateral bracing is insufficient, local buckling of the thin plaster layer will cause failure. Straw bales also provide insulation in these composite systems.<ref>

The density of a bale is based on the compressibility of the material and the stress exerted by the piston. Studies have shown that when laid flat, bales with a higher density fail at a higher ultimate load. <ref>Bou-Ali, G. Straw Bales and Straw Bale Wall Systems. M.Sc. Thesis,Tucson: University of Arizona, 1993</ref> Further studies have shown a correlation between density and modulus of bales, but orientation has a larger effect on mechanical properties. <ref>Tattersall, Graeme H. EFFECTS OF DENSITY ON MECHANICAL PROPERTIES OF STRAW BALES. Thesis, Kingston: Queen's University, 2010.</ref> Straw bales are used to form a composite wall with plaster on either side of the bales. When these plastered walls are subjected to a concentric compressive load it acts like a column with the plaster taking the majority of the load. The straw primarily provides lateral bracing for the plaster skins, while taking a small part of the compressive load. If lateral bracing is insufficient, local buckling of the thin plaster layer will cause failure. Straw bales also provide insulation in these composite systems.<ref>
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