Phenomenological modeling of DNA overstretching
  A phenomenological model based on the three-dimensional theory of nonlinear elasticity is developed to describe the phenomenon of overstretching in the force-extension curve for dsDNA. By using the concept of a material with multiple reference configurations a single formula is obtained to fit the force-extension curve. 
Ray W. Ogden (Department of Mathematics, University of Glasgow,   Scotland, UK), Giuseppe Saccomandi (Dipartimento di Ingegn...