In this paper, coupled axial and torsional large deformation of an incompressible isotropic functionally graded nonlinearly elastic solid cylinder is investigated. Utilizing stretch-based constitutive models, where the deformation tensor is non-diagonal is complex. Hence, an analytical approach is presented for combined extension and torsion of functionally graded hyperelastic cylinder. Also, finite element analysis is carried out to verify the proposed analytical solutions. The Ogden model is employed to predict the mechanical behavior of hyperelastic materials whose material parameters are function of radius in an exponential fashion. Both finite element and analytical results are in good agreement and reveal that for positive values of exponential power in material variation function, stress decreases and the rate of stress variation intensifies near the outer surface. A transition point for the hoop stress is identified, where the distribution plots regardless of the value of stretch or twist, intersect and the hoop stress alters from compressive to tensile. For the Ogden model, the torsion induced force is always compressive which means the total axial force starts from being tensile and then eventually becomes compressive i.e., the cylinder always tends to elongate on twisting.

No abstract

This work introduces a combined experimental finite element method (FEM) to calculate J‐integral and Q parameter for centre‐crack tension of high‐density polyethylene specimens. In the majority of the studies to date, mostly a pure FEM has been used. However, the several simplified assumptions that are included in such models could result in imperfect predictions. This study aims to overcome this issue by suggesting a novel method that privileges from the displacement fields on specimens' surface that is provided for our finite element model. The method introduced in this work has a merit in presenting Q results for a softening material. The results of our proposed method were in a satisfactory agreement with the pure FEM results of similar models, and thereby validating our approach. Using this model, the effects of parameters like crack length and thickness were also investigated. This method could be utilized in health monitoring of structures.

No abstract