Riveted joint detailing – Minimum edge distance (margin)\nTo avoid tearing at the plate edge, what should be the minimum distance from the centre of a rivet hole to the nearest edge (margin), in terms of hole diameter d (in mm)?

Introduction / Context:
Proper detailing of riveted joints ensures that plates do not tear at the edges under load. The minimum edge distance (margin) is a standard proportion in machine design and fabrication practice.

Given Data / Assumptions:

• Unwelded, riveted lap or butt joint plate.
• Hole diameter d (mm) after drilling or punching.
• Need to prevent edge tearing and maintain manufacturability.

Concept / Approach:
If the rivet hole is placed too close to the edge, the ligament is weak and may tear. Empirical and codal recommendations prescribe a minimum margin to ensure adequate strength and avoid local failures.

Step-by-Step Reasoning:
Tearing strength along the edge ligament must exceed the force transferred by shear of rivets.A commonly adopted minimum margin for general machine design is 1.5 d, balancing strength and plate economy.Larger margins (2 d or more) may be used for thicker plates or severe service, but 1.5 d is the accepted minimum.

Verification / Alternative check:
Design handbooks and fabrication guides list 1.5 d as the minimum edge distance to prevent edge tearing and facilitate hole making without distortion.

Why Other Options Are Wrong:
d is too small and risks tearing; 2 d, 2.5 d, 3 d are conservative but not the minimum standard requirement for typical joints.

Common Pitfalls:
Confusing pitch/spacing with margin; using bolt diameter instead of hole diameter; not accounting for plate tolerance and hole drift.

Final Answer:
1.5 d