Mesoscopic scale simulation and wear investigation of self-lubricating fabric liner based on representative volume element

As the self-lubricating layer of self-lubricating spherical plain bearings, fabric liner shows obvious heterogeneous anisotropic characteristics, so it is a technical difficulty to predict its wear properties. In this paper, the continuous wear of self-lubricating fabric liner was simulated based on the mesoscopic scale wear model. The macroscopic wear properties of the fabric liner were characterized by establishing a representative volume element (RVE), and subsequently imposing periodic boundary restrictions (PBCs) on periodic surfaces. In order to avoid excessive mesh distortion, voxel grids meshing method was used, and then continuous wear of the heterogeneous material was realized by adjusting node coordinates and combining nodes. Detailed comparison between simulation prediction results and wear test data of fabric liner was made. The good correlation of the results confirmed that the mesoscopic scale wear model could be used in accurately predict the tribological performance of fabric composite.

Representative Volume Element (RVE) Analysis for Mechanical Characterization of Fused Deposition Modeled Components

Additive manufacturing processes have evolved considerably in the past years, growing into a wide range of products through the use of different materials depending on its application sectors. Nevertheless, the fused deposition modelling (FDM) technique has proven to be an economically feasible process turning additive manufacture technologies from consumer production into a mainstream manufacturing technique. Current advances in the finite element method (FEM) and the computer-aided engineering (CAE) technology are unable to study three-dimensional (3D) printed models, since the final result is highly dependent on processing and environment parameters. Because of that, an in-depth understanding of the printed geometrical mesostructure is needed to extend FEM applications. This study aims to generate a homogeneous structural element that accurately represents the behavior of FDM-processed materials, by means of a representative volume element (RVE). The homogenization summarizes the main mechanical characteristics of the actual 3D printed structure, opening new analysis and optimization procedures. Moreover, the linear RVE results can be used to further analyze the in-deep behavior of the FDM unit cell. Therefore, industries could perform a feasible engineering analysis of the final printed elements, allowing the FDM technology to become a mainstream, low-cost manufacturing process in the near future.

Electrical and mechanical behaviour of metal thin films with deformation-induced cracks predicted by computational homogenisation

Motivated by advances in flexible electronic technologies and by the endeavour to develop non-destructive testing methods, this article analyses the capability of computational multiscale formulations to predict the influence of microscale cracks on effective macroscopic electrical and mechanical material properties. To this end, thin metal films under mechanical load are experimentally analysed by using in-situ confocal laser scanning microscopy (CLSM) and in-situ four point probe resistance measurements. Image processing techniques are then used to generate representative volume elements from the laser intensity images. These discrete representations of the crack pattern at the microscale serve as the basis for the calculation of effective macroscopic electrical conductivity and mechanical stiffness tensors by means of computational homogenisation approaches. A comparison of simulation results with experimental electrical resistance measurements and a detailed study of fundamental numerical properties demonstrates the applicability of the proposed approach. In particular, the (numerical) errors that are induced by the representative volume element size and by the finite element discretisation are studied, and the influence of the filter that is used in the generation process of the representative volume element is analysed.