In structural engineering, what does stress refer to?

Stress in structural engineering is defined as the force applied to a material divided by the area over which that force is distributed. This concept is fundamental because it helps engineers determine how materials will behave when subjected to various loads. Stress is crucial for understanding whether a structure can withstand specific loads without yielding or failing.

When loads are applied to structural elements, the way these loads are distributed across the material's surface is vital for analyzing the safety and integrity of the structure. Stress analysis allows engineers to figure out the maximum load a structure can support before it starts to experience deformation or failure.

The other options relate to different concepts in engineering: mass distribution concerns how mass is spread within an object; velocity of load application relates to how quickly a load is applied, which can affect dynamic response but does not equate to stress; and temperature effects refer to how changes in temperature can influence the materials' properties and behavior under load, but they do not define stress itself.