Fasteners are subjected to _________ stress when forces are applied on the assembly perpendicular to its axis.

When forces are applied on an assembly perpendicular to the axis of a fastener, the fastener experiences shear stress. This type of stress occurs when an external force causes different portions of a material to slide against one another. In the context of fasteners, such as bolts, rivets, or screws, shear stress is particularly important because it can lead to failure of the fastener when the load exceeds its shear strength.

Understanding shear stress is critical for aerospace assembly mechanics, as components must be securely fastened to withstand operational loads that can change direction and magnitude. By correctly identifying that fasteners are influenced by shear forces when loads are perpendicular, mechanics can ensure that assemblies are designed and maintained to handle these stresses effectively, preventing failure during operation. This underscores the importance of proper material selection and joint design, which must consider the shear forces that fasteners will encounter.