What physical process describes stress relaxation ___________________?
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Answer: C. in which deformation tends to loosen the joint and produces a stress reduced
Explanation
Stress relaxation involves a gradual reduction of internal stress while total strain remains constant. Deformation over time can cause bolted or mechanical joints to loosen significantly. This joint loosening directly produces a notable reduction in the sustained internal stress level. Materials under constant deformation exhibit time-dependent viscoelastic or plastic flow behaviors. High operating temperatures often accelerate the rate at which stress relaxation occurs. Bolts tightened to specific preloads can lose clamping force due to this internal phenomenon.
Engineers must regularly re-tighten industrial flanges and high-temperature pipe joints to combat relaxation. Flange leaks in power plants often stem from progressive gasket stress relaxation over time. Designing bolted connections requires accounting for long-term load loss in operational machinery. Creep is the continuous increase in strain under a constant applied mechanical stress level. Elastic recovery describes the immediate return of material dimensions upon removing loads. Plastic deformation introduces permanent structural changes that do not reverse automatically.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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