Guitar strings - Tensile properties

Tensile properties

Tuning a stringed instrument such as a guitar to pitch puts the strings under a large amount of strain, which indicates the amount of stress inside the string. Stress is relative to the stretch or elongation of the strings. As the string is tuned to a higher pitch, it gets longer and thinner. The instrument can go out of tune because if it has been stretched past its elastic limit, it isn't going to recover its original tension. On a stress vs. strain curve, there is a linear region where stress and strain are related called Young's modulus. When you have a newer set of strings, they are often in a region on the stress vs. strain curve past the Young's Modulus called the plastic region. In the plastic region, plastic deformation occurs?deformation the material cannot recover from. Thus, in the plastic region, the relationship is not linear anymore (Young's Modulus is no longer a constant). The elastic region is where elastic deformation is occurring, or deformation from where the string can recover. The linear (i.e. elastic) region is where musicians want to play their instrument in.