Fundamental assumption used in the design of riveted joints Which of the following is a standard assumption when analysing riveted joints in bearing-type connections?
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ABending stress in rivets is explicitly accounted for in capacity
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BThe rivet hole is assumed to be completely filled by the rivet (bearing contact)
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CPlate stress is non-uniform and taken with a large gradient
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DFriction between plates is the primary load-transfer mechanism
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ENone of these
Answer
Correct Answer: The rivet hole is assumed to be completely filled by the rivet (bearing contact)
Explanation
Introduction / Context:Traditional riveted connections (similar logic applies to bearing-type bolted joints) transfer load primarily by bearing of the fastener shank against the hole and by fastener shear. The classic analysis adopts simplifying assumptions.
Given Data / Assumptions:
- Riveted, bearing-type joint is considered (not friction-grip).
- Load is transferred by bearing and shear.
- Elastic distribution and minor bending of rivets are neglected in capacity equations.
Concept / Approach:The standard idealization treats the rivet as snugly filling the hole such that bearing develops over an effective projected area, while the rivet shank resists shear. This yields simple formulae for plate tearing, rivet shear, and bearing.
Step-by-Step Solution:
Identify load-transfer mechanism → bearing and shear in bearing-type joints.Apply simplifying assumption → rivet fills the hole sufficiently to mobilize bearing.Use standard strength checks (rivet shear, plate bearing, and plate net-section tension).Verification / Alternative check:Design texts support the assumption that bending in rivets is usually neglected and that friction is not relied upon for capacity in bearing-type joints (unlike friction-grip bolts).
Why Other Options Are Wrong:Bending stress explicitly is not counted in basic rivet design; non-uniform plate stress is not modelled in simple formulas; friction primary is characteristic of HSFG bolted joints, not riveted bearing joints.
Common Pitfalls:Assuming friction capacity without proof of pretension; ignoring net-section reduction due to holes.
Final Answer:The rivet hole is assumed to be completely filled by the rivet (bearing contact)