Tensile Strength is defined as which of the following?

• A. The onset of plastic deformation
• B. The stiffness of a material
• C. The maximum strain a material can withstand before failing
• D. The maximum stress that a material can withstand before failing

Answer: (D)

Tensile strength is the maximum stress a material can withstand in tension. It comes from a tensile test as the peak engineering stress on the stress–strain curve just before failure (often called the ultimate tensile strength). This is a stress-based property, unlike stiffness (which is the elastic modulus) or the onset of plastic deformation (which is the yield point). It’s also not the maximum strain the material can endure (that would be fracture strain or elongation at break). So, the defining idea is the greatest stress the material can sustain before it breaks.