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CALCULATORS / BEAMS, PLATES AND STRUCTURAL SCREENING

Panel stiffness versus thickness calculator

Equivalent panel strip as a simply supported beam; no two-way plate action.

structures-panel-stiffness.napkin / editable
✓ checks pass

SCENARIO COMPARISON

Compare the numbers.

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

Scenarioinertiamm^4deflectionmm
2250.724638
2250.371014

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.

deflection budget0.72 mm✓ passes

BASELINE INPUTS

CALCULATED

inertia225 mm^4
deflection0.72464 mm

Edits change the baseline source.

Calculated from your source · not saved
Baseline · Baseline
deflection budget0.72 mm ✓ passes
alternative · alternative
deflection budget0.37 mm ✓ 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.

inertia
inertia = width*thickness^3/12 [mm^4]
deflection
deflection = load*span^3/(48*modulus*inertia) [mm]

Original worked example

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

Given

span
300 mm
width
100 mm
thickness
3 mm
modulus
69 GPa
load
20 N

Calculated

inertia
225 mm^4
deflection
0.724638 mm

Assumptions and limits

Equivalent panel strip as a simply supported beam; no two-way plate action.

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: Panel stiffness versus thickness. Inputs: panel geometry; material; thickness range. Outputs: stiffness and mass tradeoff. Model scope: Linear elastic idealizations and stated boundary conditions. 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: panel geometry, material, thickness range
  • Outputs: stiffness and mass tradeoff
  • Modes: calculate, compare, sweep
  • Drawing: Deflection and stress diagram

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

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