What describes the maximum stress without permanent deformation upon complete release?

The correct choice pertains to the concept of allowable stress, which is defined as the maximum stress that a material can withstand without experiencing permanent deformation upon complete release. This concept is crucial in engineering design, as it helps ensure that materials are used safely and effectively within their limits.

Allowable stress is derived from the material's yield strength, taking into account a safety factor to provide a margin of safety. This means that even under maximum expected loads, the material should return to its original shape without any lasting changes. In practice, it is essential for preventing structural failure and ensuring that components can handle operational stresses without compromising safety.

In contrast, ultimate stress refers to the maximum stress a material can withstand before failure, which may involve yielding, necking, or rupture. Compressive and tensile stresses relate more to the types of forces acting on the material, denoting the nature of the stresses involved (compression and tension, respectively) but do not encapsulate the concept of stress levels that allow for recovery after unloading.

Understanding allowable stress is fundamental in engineering, as it influences the design and safe operation of equipment and structures.