Torsion refers to the twisting action on a material when a force is applied to rotate an element around its axis. Timber’s response to torsional forces is significantly influenced by grain direction. When torsional forces are applied parallel to the grain, timber elements are more vulnerable to failure, as the fibers are more likely to twist apart.
Proper design and detailing must account for the grain direction to ensure timber elements can resist torsional stresses effectively.