Randeffekte an Kreislöchern in Faserverbund-Laminaten
Zusammenfassung der Projektergebnisse
In the current project, several reliable and practical calculation methods have been developed and examined. Here, the focus was on the free-edge effects at the edges of holes in composite laminates and thus a representative of thin composite laminates with a central and small hole was considered as an example. The uniaxial, biaxial, in-plane shear, cylindrical bending and pure temperature change problems were investigated. For the load case of the biaxial tension and its combination with temperature change a computationally efficient closed-analytical solution was developed based on Lekhnitskii’s theory of 2D anisotropic elasticity adopted with CLPT. It has been shown that the present semi-analytical method is capable of predicting peeling and shear interlaminar stresses surrounding the hole in composite laminates which are thin, and the radius of their holes are small enough in comparison to the overall dimensions of the laminate. The layup optimization of composite plates with a central hole was investigated to obtain the optimum orientation angles to minimize the interlaminar peeling stress around the free edge of the hole. Furthermore, failure strength around the hole based on Hashin’s failure criteria was considered as constraint. Finally, the effect of varying the material properties, the radius of the hole and the initial guess applied for the pattern search solution on the optimal layup sequence were studied.
Projektbezogene Publikationen (Auswahl)
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"Reduction of free-edge effects around a hole of a composite plate using a numerical layup optimization ", ICCS25: 25th Int. Conf. on Composite Structures, 19-22 July 2022, Porto, Portugal.
Kharghani, Navid & Mittelstedt, Christian
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Free-Edge Effects in Composite Laminates—A Review of Recent Developments 2005–2020. Applied Mechanics Reviews, 74(1).
Mittelstedt, Christian; Becker, Wilfried; Kappel, Andreas & Kharghani, Navid
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Reduction of free-edge effects around a hole of a composite plate using a numerical layup optimization. Composite Structures, 284, 115139.
Kharghani, Navid & Mittelstedt, Christian
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Free-edge effects at circular holes in composite laminates under hygrothermomechanical load. Journal of Composite Materials, 57(25), 3991-4007.
Kharghani, Navid & Mittelstedt, Christian
