Virtual process chain of sheet molding compound: Development, validation and perspectives

A virtual process chain for sheet molding compound (SMC) composites is established and validated by means of experimental investigations on a demonstrator structure. The flow in the compression molding step is simulated via a Coupled-Eulerian-Lagrangian approach using an anisotropic non-Newtonian fluid flow model. Evolution of the fiber orientation distribution (FOD) is described by Jeffery's equation. The predicted FOD is mapped to structural simulations employing a neutral data format. A mean-field anisotropic damage model is used to predict the damage evolution in the demonstrator. Simulated FOD at the end of the compression molding is validated by computer tomography. Structural simulations are validated by means of a cyclic four-point bending test on the demonstrator. The predicted results show increased accuracy with the experiments by transferring FOD data within the virtual process chain. Critical points of high damage concentrations leading to failure agree with the experimental observations

Effective transport properties for periodic multiphase fiber-reinforced composites with complex constituents and parallelogram unit cells

[EN] The two-scale asymptotic homogenization method is used to find closed-form formulas for effective properties of periodic multi-phase fiber-reinforced composites where constituents have complexvalued transport properties and parallelogram unit cells. An antiplane problem relevant to linear elasticity is formulated in the frame of transport properties. The application of the method leads to the need of solving some local problems whose solution is found using potential theory and shear effective coefficients are explicitly obtained for nphase fiber-reinforced composites. Simple formulae are explicitly given for three- and four-phase fiber-reinforced composites. The broad applicability, accuracy and generality of this model is determined through comparison with other methods reported in the literature in relation to shear elastic moduli and several transport problems of multi-phase fiber-reinforced composites in their realm, such as conductivity in a biological context and permittivity leading to gain and loss enhancement of dielectrics. Also, the example of gain enhancement of inertial mass density is looked into. Good agreement with other theoretical approaches is obtained. The formulas may be useful as benchmarks for checking experimental and numerical results.YE gratefully acknowledges the Program of Postdoctoral Scholarships of DGAPA from UNAM, Mexico. RG and RR would like to thank to COIC/STIA/9042 and COIC/STIA/9045/2019. RR thanks the International Research Training Group GRK 2078 "Integrated engineering of continuous-discontinuous long fiber reinforced polymer structures"(CoDiCoFRP) funded by German Research Foundation (DFG) for inviting him as a guest scientist, parts of the manuscript were written during this stay. JB and FJS acknowledge the funding of PAPIIT-DGAPA-UNAM IA100919. TB acknowledges the support by DFG under the grant GRK 2078/2. Thanks to the Department of Mathematics and Mechanics, IIMAS-UNAM, for its support and Ramiro Chavez Tovar and Ana Perez Arteaga for computational assistance.Sabina, FJ.; Guinovart-Díaz, R.; Espinosa-Almeyda, Y.; Rodríguez-Ramos, R.; Bravo-Castillero, J.; López-Realpozo, JC.; Guinovart-Sanjuán, D.... (2020). Effective transport properties for periodic multiphase fiber-reinforced composites with complex constituents and parallelogram unit cells. International Journal of Solids and Structures. 204:96-113. https://doi.org/10.1016/j.ijsolstr.2020.08.001S9611320