What is the main purpose of toughness testing?

The main purpose of toughness testing is indeed to measure the energy absorbed by a material during fracture. Toughness reflects a material's ability to withstand stress without failing, particularly in the presence of flaws or notches. It incorporates both strength and ductility, providing insight into how much energy a material can absorb before it ruptures.

This energy-absorption capacity is crucial in applications where materials are subjected to dynamic loading or impact, as it helps predict how they will perform under such conditions. Thus, toughness is a critical property for materials used in structural applications where failure due to fracturing can lead to significant consequences.

The other choices focus on different material properties. Measuring tensile strength assesses how much force a material can withstand before it breaks, which is distinctly different from measuring toughness. Evaluating thermal resistance involves testing how well a material maintains its properties at varying temperatures, unrelated to the energy absorption of the material. Assessing ductility speaks to a material's ability to deform under tensile stress, which is a component of toughness but does not encompass the entire concept as toughness does.