FE Analysis of the Influence of Fiber Orientation to Shearing and Wrinkling of Fiber Reinforced Thermoplastic Parts

Abstract

This work presents the influence of deviations of fiber orientations of warp and weft yarns to the shear stress vs. shear angle behavior and the formation of wrinkles of fabric reinforced thermoplastics. FE results of bias-extension tests and the forming of a double dome part will be investigated with angular misalignment of the yarns and/or deviations of the blank to its loading direction. The prepregs or organic sheets may have imperfections like fiber misalignment or the prepregs of multilayered sheets are twisted against each other. Furthermore, there may be deviations to the idealized orientation caused by the operator or cutting machine for example.

The Influence of the Sample Size of Bias Extension Tests on the Results of Forming Simulations of Fiber-Reinforced Thermoplastics

“…The forming simulations are performed with Abaqus/ Explicit. The FE model in this work bases on the unit cell and a checkerboard mesh (Chck) introduced in prior studies [5,6,7]. It consists of membrane elements with *Fabric material card of Abaqus for in-plane properties (tensile, compression, fabric shear) and beam elements to represent the out-of-plane bending behavior.…”

Sensitivity Study of Material Input Data on FE Forming Results for Wrinkling and Shearing of Fiber Reinforced Thermoplastic Parts

“…Picture Frame Test. The results of the picture-frame-test are discussed in [3,5]. They show the test results for dry fabrics with several fixtures of the test specimen, pins and clamps.…”

“…Using clamps results in higher shear forces. [5] explain that fiber misalignment and inaccuracies due to handling and cutting process may lead to tensile stresses in fibers if they are not exactly parallel to the frame edges. Fixing the dry fabric with pins leads to decreasing shear forces.…”

Measurement of fiber wrinkles and shear angles of double dome forming parts

“…In prior studies [4,5] an FE sensitivity study of forming of a Double Dome part also showed the interaction between shear and bending behavior as well as compression and bending behavior for the FE model of bidirectional fabrics. The results were assessed qualitatively.…”

“…Several material tests are necessary to characterize the forming behavior over the melting temperature of the thermoplastic matrices for validation of FE models. They were investigated in prior studies [1][2][3][4][5].…”