Handling bolted joint connections in structural FEA — bonded contact vs. modeling real preload?

I’m analyzing a bolted assembly and trying to decide how much detail the bolted connections actually need for a trustworthy structural result. The simplifications range from very crude to very expensive, and I’d like to hear how others draw the line.

The options I’m weighing:

  • Bonded/rigid connections — fast and stable, but they ignore slip, separation, and the real load path through the joint. Fine for a rough stiffness check, but I’m unsure how far to trust the stresses.

  • Simplified bolt representations (beam or spring elements with preload) — a middle ground, but how well does this capture the clamped region and load transfer?

  • Full contact with modeled preload — most realistic, captures separation and slip, but expensive and can be tricky to converge.

A few questions:

  • For a general strength/stiffness assessment, when is bonded contact “good enough” and when does it seriously mislead?

  • When you do model preload, how are you applying it, and does it change your results meaningfully vs. the simplified approach?

  • Any practical tips for getting contact-based bolted joints to converge without blowing up solve time?

Trying to match the modeling effort to what the result actually needs, rather than over-modeling every bolt.