What does the term 'stress' refer to in fabrication?

In the context of fabrication, the term 'stress' specifically refers to the internal forces that develop within materials when they are subject to external loads. Stress is quantified as the force exerted per unit area, typically measured in units like Pascals (Pa) or pounds per square inch (psi). When external loads are applied to a material, they induce a reaction within the material's structure, leading to either deformation or failure depending on the amount and nature of the load.

Understanding this concept of internal forces is crucial for metal fabricators, as it influences their choices in material selection, design, and processing techniques. For example, knowing the stress limits of various materials allows fabricators to ensure that components will perform adequately under anticipated loads, thereby minimizing the risk of failure during service.

The other options present important concepts in material science and engineering, but they do not accurately represent the definition of 'stress.' External forces are relevant, as they cause stress, but they do not define it. Temperature changes and the weight of materials also play roles in material behavior but are not direct definitions of stress itself.