Yieldtoweight

Yieldtoweight is a material-performance metric used to evaluate how efficiently a material uses weight under load. It compares a material's yield strength to its weight per unit volume (specific weight).

Mathematically, yieldtoweight is defined as YW = sigma_y / gamma, where sigma_y is the yield strength and gamma is the specific weight (gamma = rho g). The units of YW are meters, representing a length scale that indicates how much thickness or span can be supported by the material before yielding, per unit weight.

Yieldtoweight is related to, but distinct from, specific strength (sigma_y / rho) and strength-to-weight ratios used in design. The inclusion of gravity via gamma makes YW particularly relevant for gravity-assisted structures and weight-critical applications.

Applications include aerospace, automotive, and civil engineering, where high YW materials such as carbon fiber composites and some light metals enable weight savings without compromising yield. The metric provides a way to compare the weight efficiency of materials when gravity loading is a key consideration.

Limitations include dependence on temperature, loading direction, and strain rate, as well as the neglect of stiffness, toughness, fatigue, and corrosion properties. Yieldtoweight is best used alongside other material metrics to inform material selection and structural design. See also: specific strength, strength-to-weight ratio, yield strength, specific weight.