Drawing potential of fiber metal laminates in hydromechanical forming: A numerical and experimental study

Abstract

It is known that fiber metal laminates as one of hybrid materials with thin metal sheets and fiber/resin layers have limited formability in conventional forming methods. This paper presents an experimental and numerical study for drawability of glass fiber-reinforced aluminum laminates under hydromechanical drawing technique. Fiber metal laminates comprised of a layer of woven glass fiber-reinforced prepreg, sandwiched between two layers of aluminum alloy. In order to produce fiber metal laminates, the laminates were subjected to a sufficient squeezing pressure under a controlled heating time and temperature by using a hydraulic hot press. A hydromechanical tooling equipped with blank-holder force and fluid pressure control system was used to form the initial circular fiber metal laminate blank. Finally, the effect of parameters such as pre-bulging pressure, final chamber pressure, and drawing ratio on process variables was evaluated. Also, the characteristic curve of hydromechanical drawing of fiber metal laminate i.e. chamber pressure in terms of drawing ratio was achieved by means of experimental tests and numerical simulations. The results showed that the maximum drawing ratio of defect-free fiber metal laminates, namely without any tearing, wrinkling, and delamination was obtained at pre-bulging and chamber pressure of 35 and 80 bar, respectively.

Permeability and fabric compaction in forming of fiber metal laminates

“…However, Blala et al applied shell elements to model the glass fabric, implying that compaction was neglected. Comparable approaches are also presented by Li et al 41 and Saadatfard et al 42 These approaches aim to predict deformation and stresses during the deep drawing of FML using cup-shaped geometries. Going beyond a cup shape, Werner et al 44,43 presented the first approaches for simulating the hybrid in situ FML process presented by Mennecart et al 14 Their approaches aim to include metal sheets in the traditional forming simulation approach for CoFRPs.…”

New Advances and Future Possibilities in Forming Technology of Hybrid Metal–Polymer Composites Used in Aerospace Applications

“…The forming process can be isothermal or non-isothermal [390]. The comparison of the forming behaviour of FMLs with the conventional deep drawing process leads to the conclusion that early fracture of the laminate arises without achieving a significant depth [391][392][393][394]. FMLs must usually undergo preprocessing in terms of heating and stacking before being properly formed.…”

Creep Age Forming of Fiber Metal Laminates: Effects of Process Time and Temperature and Stacking Sequence of Core Material

“…Blala et al [3], using variable blank holder force, improved the drawability of FMLs in fabrication of cylindrical surfaces with the deep drawing process. Saadatfard et al [4] studied the drawability of FMLs in the hydromechanical drawing (HMD) process, concluding that necking happens at the lower metal sheet near the pole of the drawn part. Hahn et al [5] predicted the forces in the stamping process of FMLs at thermoforming temperature with an analytical model.…”