How is "stress" defined in materials used in aviation?

In the context of materials used in aviation, "stress" is defined as the internal resistance offered by a material to an external force. This concept is crucial in understanding how materials respond when subjected to loads, which is a common occurrence in aircraft structures during both operation and landing.

When an external force is applied to a material, it induces internal forces within the material as it attempts to maintain its shape and resist deformation. This internal resistance is quantified as "stress," which is typically expressed in units of force per unit area, such as pascals (Pa). Understanding stress is fundamental for aviation structural mechanics because it helps engineers and mechanics evaluate whether materials can withstand the forces they encounter during flight.

The other options do not accurately reflect the definition of stress. While bending without breaking refers to ductility or flexibility, the state of distortion pertains to strain rather than stress, and overall strength relates to a material’s ability to withstand loads without failing but does not encapsulate the specific concept of internal resistance to external forces. This distinction highlights the critical nature of stress in assessing material performance in aviation applications.