Preloaded-joint separation calculator

Linear bolt/member stiffness partition; no gasket nonlinearities.

fasteners-joint-separation.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	boltLoadN	clampReserveN
	5600	2600
	4600	1600

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

joint stays clamped2600.00 N✓ passes

BASELINE INPUTS

preload5000 Nexternal3000 NboltFraction0.2

CALCULATED

boltLoad5600 N

clampReserve2600 N

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Preloaded-joint separation
# Scope: Linear bolt/member stiffness partition; no gasket nonlinearities.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

preload = 5000 N
external = 3000 N
boltFraction = 0.2

boltLoad := preload+boltFraction*external [N]
clampReserve := preload-(1-boltFraction)*external [N]

check joint stays clamped: clampReserve > 0 N

scenario alternative: preload = 4000 N

Calculated from your source · not saved

Baseline · Baseline

joint stays clamped2600.00 N ✓ passes

alternative · alternative

joint stays clamped1600.00 N ✓ passes

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

bolt load: boltLoad = preload+boltFraction*external [N]
clamp reserve: clampReserve = preload-(1-boltFraction)*external [N]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

preload: 5000 N
external: 3000 N
bolt fraction: 0.2

Calculated

bolt load: 5600 N
clamp reserve: 2600 N

Assumptions and limits

Linear bolt/member stiffness partition; no gasket nonlinearities.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Preloaded-joint separation. Inputs: preload; external load; bolt/joint stiffness. Outputs: remaining clamp load; separation threshold. Model scope: Explicit load paths, preload uncertainty and joint stiffness. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: preload, external load, bolt/joint stiffness
Outputs: remaining clamp load, separation threshold
Modes: calculate, compare, sweep
Drawing: Joint load diagram

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS