In recent years, woven fabric reinforced composites have been increasingly employed in aerospace and automotive areas due to their high strength and formability as well as low-weight. Recognizing the importance of woven fabric composites, the international corporative benchmark forum has been established to provide valuable information for the material characterization and the forming process design. Through the benchmark works, the material characterization of woven composites has been thoughtfully examined . In order to obtain precise shear properties, bias extension and trellising shear tests have been conducted by many research groups and compared with each other.
As the second stage of the benchmark work, the double dome stretching test has been conducted in order to examine and improve the prediction capability of various numerical tools. In this work, the non-orthogonal constitutive model  was applied to describe the fiber orientation change and the empirical nonlinear friction model  was incorporated. To include temperature dependency in the material property during the thermo-forming, equivalent properties have been utilized according to the contact status between tools and composite blank . As a result, blank draw-in, punch force history and fiber orientation were reported .
Orthogonal Coordinate System and Non-orthogonal Skew Rectilinear Coordinate System
Double Dome Stretching Test
Deformed shape and shear strain distribution
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W. Lee, J. Cao, J. Chen and J. Sherwood, “Numerical Analysis on Double Dome Stretching Tests of Woven Composites” ESAFORM 2007, Accepted.