Review the following mechanical fastening scenarios. Match each scenario to the primary type of stress or characteristic failure mode it is most likely to experience.
- Two overlapping metal plates secured by a single bolt and pulled forcefully in opposite, parallel directions.Single shear stress across the cross-section of the fastener.
- A bolt and nut assembly tightened significantly beyond its recommended torque specification.Excessive tension resulting in fastener stretching or stripped threads.
- A pulley attached to a rotating drive shaft using a square machine key.Torsional shear stress as rotational force is transferred.
- A threaded rod subjected to continuous, alternating bending cycles during machine operation.Metal fatigue leading to progressive cracking and eventual fracture.
Cevap
Overlapping pulled plates experience single shear stress; over-tightened bolts suffer excessive tension; keyed pulleys transfer torsional shear stress; and alternating bending cycles lead to metal fatigue.
Each scenario describes a distinct physical loading condition. Overlapping plates pulled in opposite directions slice across the bolt (single shear). Torquing a nut stretches the bolt shaft along its length (tension). A rotating shaft transferring power through a key creates a twisting sideways force (torsional shear). Continuous bending back and forth causes microscopic damage over time (fatigue).
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Anahtar Kavram
Identifying the specific types of mechanical stress (shear, tension, torsion, fatigue) applied to fasteners in different operating environments.