Uni-axial tensile response and failure of glass fiber reinforced titanium laminates

Layers of thin metallic sheets and fiber-reinforced composite layers bonded together is known as fiber metal laminates (FMLs). In the current study, titanium Ti-6Al-4V sheets are used with thicknesses 0.2 mm, 0.4 mm and, 0.6 mm along with layers of unidirectional glass-fiber reinforced composite to produce FMLs and the tensile response of these laminates are examined. Four different stacking sequences of FMLs have been considered exhibiting the same thickness for the total metal layer and the hand layup process is used to prepare these laminates. An orthotropic plasticity theory of macro mechanical type and classical laminated plate theory are considered to model the elastic-plastic type of behavior of titanium-based FMLs. A plastic potential function based on three parameters is used to the model the orthotropic plasticity. Behavior with linearly elastic and orthotropic elastic-plastic types is assumed for the layers of glass composite and titanium, respectively in the laminated plate theory. The results show that the initial modulus of FMLs has not been influenced by the sequence of the layup, while this sequence of layup does considerably affect the response of FMLs following ultimate strength. The properties of FMLs such as failure strain and toughness which are important parameters from a design point of view of FMLs can be altered to absorb energy at dissimilar rates, i.e., by insulating the composite layers from each other by metallic layers in case of FMLs 3/2-0.4, 4/3-0.2(O) and 4/3-0.4(O). The model with orthotropic plasticity is found to be precise up to the total strain level of 2.1%, i.e., close to the failure of composite layers within FMLs, when compared with results measured from experiments. The behavior with stress-strain predicted by laminated plate theory also finds realistic up to the total strain of 2.1% to describe the corresponding behavior obtained from experiments. Superscript/Subscript Available