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Elastic smooth-contact screen

Hertzian sphere-on-flat contact

Inputs

Positive compressive normal load; tangential force is excluded.
Nominal radius of the sphere against one locally flat body.
Declared linear-elastic modulus for the spherical body.
Declared isotropic elastic ratio in the range 0 through less than 0.5.
Declared linear-elastic modulus for the locally flat body.
Declared isotropic elastic ratio in the range 0 through less than 0.5.

Results

Reduced elastic modulus

58.605

Contact radius

0.42504

Contact diameter

0.85007

Peak Hertz pressure

1,321.5

Elastic approach

15.055

1/E* = (1−ν₁²)/E₁ + (1−ν₂²)/E₂; a = [3FR/(4E*)]^(1/3); p₀ = 3F/(2πa²)

A first-pass number, not a code check, certification, or approval. Read the method and its limits below. What this is and is not.

Nearby: Axial response · Beam deflection & reactions · Elastic stability · Solid-shaft torsion

Method

Formula, when it applies, and when it does not

Calculate reduced modulus, contact radius, indentation, and peak contact pressure for one elastic sphere-on-flat normal contact.

1/E* = (1−ν₁²)/E₁ + (1−ν₂²)/E₂; a = [3FR/(4E*)]^(1/3); p₀ = 3F/(2πa²)

When

  • Smooth frictionless contact
  • Elastic isotropic homogeneous materials
  • Sphere on flat
  • Normal load only

Don’t

  • This is a smooth, frictionless, elastic, isotropic, homogeneous sphere-on-flat normal-contact screen. It excludes roughness, friction, plasticity, coatings, fatigue, thermal effects, surface finish, material selection, life, safety, and approval.
University of Arizona Hertz-contact tutorial