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In various applications, it is common to use thin beam-like structures, made of plastic or fibre-reinforced materials, as well as components such as cables. They are flexible, and the most common form of deformation is bending, but they can also be stretched or torqued. Due to their structural composition, a coupling between the different loading directions exists. This is especially pronounced for cables, where the different components interact with each other and the kinematics of each component are different. Thus, to characterise these materials, it is necessary to consider tension, torsion, bending, and a coupling of the three load cases. In this work, such characterisations are performed for a polyvinyl chloride rod, a carbon fibre-reinforced rod, and a coaxial cable. The three materials represent the isotropic and anisotropic material classes and include homogeneous and non-homogeneous cross-sections. An anisotropic elasto-plastic material model is implemented in the finite element method to model the behaviour of such structures. The material model includes anisotropic plasticity so that the structural effects can also be modelled for large deformations. Thin structures are discretised with higher-order elements, and a comparison of the experimental and the simulation results is presented.

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Polyamide exhibits hygroscopic nature and can absorb up to 10% of moisture relative to its dry weight. The absorbed moisture increases the mobility of the molecular chains and causes a reduction in the glass transition temperature. Thus, depending on the moisture distribution, a polyamide component can show different stiffness and relaxation times. Moreover, the moisture distribution also depends on the mechanical loading of the material as the volumetric deformation results in a change of the available free volume for the moisture. Thus, a strongly coupled model is required to describe the material behaviour. In this work, a thermodynamically consistent coupled model within the framework of mixture theory is developed. The mechanical deformation of polyamide 6 (PA6) is based on a linear viscoelastic material model, and the moisture transport is based on a nonlinear diffusion model. The stiffness and the relaxation time of the viscoelastic model change with the moisture concentration. Furthermore, the moisture transport is affected by the pressure gradient generated by the mechanical loading of the material. This strongly coupled model has been implemented using the finite element method, and simulation results are presented for a three-point bending experiment.

This article presents a two-dimensional (2D) numerical study on hydrodynamics and thermal transport in the presence of superimposed thermal buoyancy in a rectangular channel with staggered ribs mounted on both walls. This study is carried out for the Newtonian fluid at moderate Reynolds number. The Reynolds number is considered within the range (50 Re 120) with constant Prandtl number Pr ¼ 0.7, and mixed convective heat transfer is studied for Richardson number range 0 Ri 2. The unsteady 2D governing equations are solved using the lattice Boltzmann method. The computational strategy is applied in various test cases and validated with the results reported in the literatures. The flow and heat transfer characteristics are analyzed with the streamlines and isotherm patterns at various Reynolds and Richardson numbers. The effects of superimposed thermal buoyancy on flow and isotherm patterns, drag coefficient, local Nusselt number distribution, and time-and surface-average Nusselt number are presented and discussed.