# Bradley model of the force applied on a contact area between two spheres

## Description

Contact mechanics is the study of the deformation of solids that touch each other at one or more points. When two solid surfaces are brought into close proximity, they experience attractive van der Waals forces. Bradley’s van der Waals model provides a means of calculating the tensile force between two rigid spheres with perfectly smooth surfaces.

Related formulas## Variables

F_{z} | Total force of adhesion between the two rigid spheres. between the spheres (N) |

π | pi |

γ | Half of the total surface energy of both surfaces per unit area (J/m^{2}) |

R_{1} | Radius of one of the spheres (m) |

R_{2} | Radius of the second sphere (m) |

z_{0} | The equilibrium separation of the two planes (m) |

z | Distance from one sphere to the other (m) |