Coupled twoscale analysis of fiber reinforced composite structures with microscopic damage evolution

Abstract

a b s t r a c tThe simultaneous twoscale analysis of unidirectionally fiber reinforced composite structures with attention to damage evolution is the objective of the contribution. The heterogeneous microstructure of the composite represents the microscale, whereas the laminate or the structural component are addressed as the macroscale. The macroscale is conventionally discretized by the finite element method (FEM). The generalized method of cells (GMC) in its efficient stress based formulation serves as the discrete microscale model. The stiff and brittle fibers behave linearly elastic. The epoxy resin is described by the nonlinear-elastic model of Ramberg-Osgood. By introducing microcrack models, the damage of the epoxy matrix under combined tensile and shear loading is taken into account. The cell boundaries of the micromodel are used to locate microscopic cracks deterministically. Interface models for the representation of damage in the matrix phase as well as for the weakening of the fiber-matrix-bond are used. This approach circumvents the need for the regularization, as it would be necessary for continuum damage models with softening characteristics. Hence, the micromodel is numerically stable and convergent. The GMC allows to obtain the consistently linearized constitutive tensor in the case of nonlinear material behavior in a simple and straight forward manner which is easily implemented in comparison to micromodels based on the finite element technique. The damage evolution on the microscale manifests itself macroscopically in the degradation of the homogenized stiffnesses.

Evaluation of carbon fiber/epoxy interfacial strength in transverse fiber bundle composite: Experiment and multiscale failure modeling

“…Two limitations may exist in both FE models: (1) the failure load of the TFB test was directly assigned to the TFB sample in the FE models and no failure initiation or damage propagation was simulated; (2) the fiber and matrix were assumed to be perfectly bonded due to the complexity of applying any interface elements. Two-or multi-scale approaches based on the solution of microscale boundary condition problems are very efficient and suitable for characterizing the effective constitutive behavior of micro-heterogeneous materials [7]. The multiscale approach can overcome the limitations mentioned above.…”

Multi-Scale Analysis for Assessing the Impact of Material Composition and Weave on the Ultimate Strength of GFRP Stiffened Panels

“…The fibre-reinforced composites combine two materials, and the reinforcing phase, i.e., fibres, is embedded in the matrix phase. Their failure behaviours at the micro-, mesoand macro-scale have been investigated by the multi-scale finite element analysis using representative volume element (RVE) models [5][6][7][8][9][10]. The reasonable progressive damage model has to be established to obtain accurate results in the multi-scale analysis [11][12][13][14][15].…”

Inverse determine the interfacial strength and surface geometry effects concerning carbon fiber reinforced epoxy composites by experiment aided FFT‐based spectral analysis

“…The finite element (FE) models comprised of macro-interphase-micro information are usually established to figure out the relation between measured results in TFBT and actual interface strength. [25,26] However, some limitations may exist in these models: the fiber/matrix interface is assumed to be perfectly bonded, the detail damage propagation is ignored, the input stiffness of the interphase is constant, and the interfacial geometric characteristics are ideal. These factors may seriously affect the calculated interfacial strength.…”