Stability of elastic icosadeltahedral shells under uniform external pressure: application to viruses under osmotic pressure.

We discuss the stability of icosadeltahedral shells subjected to a uniform external load in the form of an isotropic pressure. We demonstrate that there exists a universal critical buckling pressure scaling form that defines a locus of buckling instabilities. The parameter that uniquely determines this scaling form is shown to be the Föppl-von Karman number of nonpressurized shells. Numerical results are interpreted in terms of scaling forms for buckling instabilities of spheres and cylinders under isotropic mechanical pressure, and are applied to the case of viruses under osmotic pressure.