Plate Deflection Calculator

Fixed Annulus Uniform Load

An annulus (or annular) plate is a flat, ring-shaped plate with a hole through its centre — think of a large flat washer, a flange blank, or a bearing housing end cover with a shaft passing through the middle. This calculator covers an annulus plate rigidly fixed around its outer edge, with the inner edge (around the hole) left free and unsupported, carrying a load spread uniformly across the ring-shaped surface — a common model for a flange cover plate under evenly distributed pressure, with a shaft or pipe passing through a clearance hole in the middle that doesn't touch or support the plate.

If the inner edge is guided (constrained to stay level but able to move up and down, as with a sliding collar or piston guide) rather than left completely free, see our Fixed Annulus Guided Uniform Load calculator instead.

This calculator calculates the Maximum Deflection and Maximum Stress in a Fixed Edge Annulus Plate with a Uniform 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)

MillimetresCentimetresMetresInches

OUTER DIAMETER: (OD)

MillimetresCentimetresMetresInches

INNER DIAMETER: (ID)

MillimetresCentimetresMetresInches

UNIFORM LOAD: (P)

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MAXIMUM DEFLECTION :(ym)

MetresCentimetresMillimetresMicrometresInches

MAXIMUM STRESS : (sm)

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RELATED PAGES

• Fixed Annulus, Guided, Uniform Load
• Fixed Annulus, Load at Hole
• Simple Annulus, Uniform Load

FREQUENTLY ASKED QUESTIONS

What does "free inner edge" mean for this calculator?

It means the material around the central hole isn't supported, guided, or restrained in any way — it's simply the edge of an unsupported hole, free to deflect and rotate as the surrounding plate bends under load. This is the case for a plain clearance hole with nothing touching its edge.

How does the size of the central hole affect deflection?

A larger hole (relative to the outer diameter) generally increases maximum deflection and stress for the same load and outer support condition, since there's less material available to carry the load and the plate's effective span increases.