Structural Engineering & Statics
where the load goes
Generator

The slip-curve generator

Rendered here at the parameters it defaults to, with every essay that calls it — which is the same list as the blast radius of changing it.
A preloaded joint, before and after it slipsTwo preloaded bolts at 172 kN each, on one friction face at μ = 0.5. The joint carries 172 kN by friction with the bolts in tension and not in shear at all; past that it slips into bearing and carries 250 kN with the bolts now in shear. Two different mechanisms, one joint.00.511.522.533.544.55050100150200250displacement, mmload, kNfriction 172 kNbearing 250 kNslipthe rising branch is drawn, not solved: it is elastic shear of the plates

2 essays call slip-curve. The drawing above is what it returns with no arguments at all; every call below passes it something, because a placement that passes nothing draws whichever member of the family the generator happens to default to rather than the one its essay argues about.

Where it is called

Changing this generator changes every one of these figures.

020406080100120140160180200050100150200end distance, mmbearing capacity, kN40 mm → 52.12 kNcorner at 165 mmplate crushesbolt tears out Connections

The hole that goes oval, and the one that tears to the edge

A bolt pressing on the side of its hole either crushes the plate in front of it or shoves a channel of metal out to the end. Which one happens is decided entirely by a distance that is usually set by a minimum in a table.

 00.511.522.533.544.55050100150200displacement, mmload, kNfriction 137 kNbearing 188 kNslipthe rising branch is drawn, not solved: it is elastic shear of the plates Connections

The joint that carries nothing until it slips

Tighten the bolts hard enough and the plates are clamped together with a force nothing applied. The joint then carries shear by friction, the bolts are in tension and not in shear at all, and the load path has nothing in common with the joint it looks identical to.

The library, page 3 of 4 — where slip-curve sits