The influence of the type of loading on the asymptotic behavior of slender elastic rings

We study the influence of the type of loading on the asymptotic behavior of linearly elastic, isotropic and homogeneous slender circular rings. By using formal asymptotic expansions, we obtain three families of models depending on the properties of the loads. If the loads expend work in inextensional displacements, then we find the classical model where the leading term of the energy corresponds to the bending-torsion energy of inextensional displacements. If the loads do no work in inextensional displacements, the model must be refined and we obtain two other types of models. In these other models, which depend on the type of loading, the leading term of the energy contains additional terms such as, for the second class, an extension energy due to the circumferential stretching of the ring, and even, for the third class, specific load-dependent contributions. This classification is illustrated in several examples.