In this work, the internal geometry measurements of two woven composites are analyzed: cross section of the yarns, fiber volume fraction, crimp, misalignment of the samples, thickness of the plates, nesting value, and so forth. The chosen textile composites are produced using the same resin reinforcement and same architecture, but have different yarn size (3K and 12K). The dispersion of measured geometrical parameters is introduced in a numerical multiscale modeling approach to evaluate the macroscopic stiffness values. A sensitivity analysis is performed for each geometrical parameter and laminate stiffnesses are derived. These are linked to the experimentally obtained elastic properties by tensile tests. Finally, the unit cell size scale effect for measured geometry variability and experimentally obtained elastic properties are evaluated. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

This paper proposes a procedure for obtaining the load distribution in a four contact-point slewing bearing considering the effect of the structure’s elasticity. The uneven stiffness of the rings and the supporting structures creates a variation with respect to the results obtained with a rigid model. It is necessary to evaluate the effect of the elasticity on the increase in the contact forces in order to be able to design the slewing bearing and the structures involved in the connection. Depending on the shape of the structures, the contact force value obtained on the most loaded rolling element is different. The evaluation of this maximum force at extreme loads is essential to design the structures joined to the bearing rings. The new elastic model presented in this paper is highly nonlinear so iterative loops are needed in order to obtain a satisfactory solution. At the same time a finite element model (FEM) has been created for the global model, having also represented the rolling elements and their contact with the raceways. The results obtained using the FEM have been correlated with the results of the new procedure.

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SUMMARYA meso-scale finite element model for static damage in textile composites was established. The impregnated yarn is taken as homogeneous and transverse isotropic material, whose mechanical properties are calculated using Chamis' equations. The damage modes are determined by using the Tsai-Wu criterion and additional criteria. The Murakami damage tensor is used to calculate the post-damage stiffness matrix. The model has been validated using plain weave and twill weave carbon-epoxy composites. The initiation of inter-fibre matrix crack and fibre rupture was analyzed using this meso-FE model.