title: Stretching instability of helical springs.
abstract: We show that when a gradually increasing tensile force is applied to the ends of a helical spring with sufficiently large ratios of radius to pitch and twist to bending rigidity, the end-to-end distance undergoes a sequence of discontinuous stretching transitions. Subsequent decrease of the force leads to steplike contraction, and hysteresis is observed. For finite helices, the number of these transitions increases with the number of helical turns but only one stretching and one contraction instability survive in the limit of an infinite helix. We calculate the critical line that separates the region of parameters in which the deformation is continuous from that in which stretching instabilities occur.
authors.affiliation: Department of Physics, Bar-Ilan University, Ramat-Gan, Israel.
authors.forename: David A
authors.initials: DA
authors.lastname: Kessler
authors.forename: Yitzhak
authors.initials: Y
authors.lastname: Rabin
mesh_terms: D002784:Cholesterol / Q000737:chemistry; D002843:Chromatin / Q000737:chemistry; D004247:DNA / Q000737:chemistry; D004548:Elasticity; D008956:Models, Chemical; D008962:Models, Theoretical
chemical_list: D002843:Chromatin; D004247:DNA; D002784:Cholesterol