Plate Deflection Calculator

Simply Supported Circular Centre Load

A circular plate simply supported around its edge — free to rotate there, but not to deflect vertically — loaded with a concentrated force at its centre, is a common model for a bolted-down cover plate carrying a point load, such as a lifting eye or a mounting boss fitted through the centre of a hatch or access cover. Because the edge is only simply supported (not rigidly fixed), this arrangement deflects and stresses more than the same plate with a fixed edge under the same load.

For the same load and plate rigidly welded or clamped around its edge instead, see our Fixed Circular Centre Load calculator. For a load spread evenly across the plate rather than concentrated at the centre, see Simply Supported Circular Uniform Load.

This calculator calculates the Maximum Deflection and Maximum Stress in a simply supported Circular Plate with a Centre Load.

Enter your values as required and press SOLVE, your results will be displayed. If you change any unit types or values please press SOLVE again.

CLEAR ALL clears all fields.

MATERIAL: Aluminium 2024-T4Aluminium 6061-T6Aluminium 7075-T3BrassCast IronCopperLeadMagnesiumPhosphur BronzeStainless Steel, 304Stainless Steel, 316Steel, S235Steel, S275Steel, S355Steel, 4130Steel, ASTM A36Steel, ASTM A441Titanium, Grade 2Titanium, Grade 5

THICKNESS: (T)

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DIAMETER: (D)

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LOAD DIAMETER: (LD)

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UNIFORM LOAD: (P)

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MAXIMUM DEFLECTION: (ym)

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MAXIMUM STRESS : (sm)

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RELATED PAGES

• Fixed Circular, Centre Load
• Simply Supported Circular, Uniform Load

FREQUENTLY ASKED QUESTIONS

Where does maximum stress occur on a simply supported circular plate under a centre load?

At the centre of the plate, directly under the load, on the underside (tension) face — this is also where maximum deflection occurs.

How much stiffer is a fixed-edge plate compared to simply supported, for the same centre load?

A fixed edge roughly quarters the maximum deflection compared to a simply supported edge, for the same plate and load, since clamping the edge prevents it from rotating and effectively shortens the plate's working span. See our Fixed Circular Centre Load calculator to compare directly.