Bolt tensile stress calculator

Average tensile stress on supplied tensile stress area.

fasteners-bolt-tension.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

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

Scenario	stressMPa	factor
	248.756	1.608
	199.005	2.01

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.

tensile factor target1.61 ✓ passes

BASELINE INPUTS

force5000 NstressArea20.1 mm^2allowable400 MPa

CALCULATED

stress248.76 MPa

factor1.608

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Bolt tensile stress
# Scope: Average tensile stress on supplied tensile stress area.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

force = 5000 N
stressArea = 20.1 mm^2
allowable = 400 MPa

stress := force/stressArea [MPa]
factor := allowable/stress

check tensile factor target: factor >= 1.5

scenario alternative: force = 4000 N

Calculated from your source · not saved

Baseline · Baseline

tensile factor target1.61 ✓ passes

alternative · alternative

tensile factor target2.01 ✓ 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.

stress: stress = force/stressArea [MPa]
factor: factor = allowable/stress

Original worked example

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

Given

force: 5000 N
stress area: 20.1 mm^2
allowable: 400 MPa

Calculated

stress: 248.756 MPa
factor: 1.608

Assumptions and limits

Average tensile stress on supplied tensile stress area.

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: Bolt tensile stress. Inputs: axial load; thread stress area; preload. Outputs: tensile stress; utilization screening. 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: axial load, thread stress area, preload
Outputs: tensile stress, utilization screening
Modes: calculate, compare, sweep
Drawing: Joint load diagram

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