Low-velocity impact behavior of fiber metal laminates

Abstract

The low-velocity impact response of a range of fiber metal laminate (FML) panels was investigated through testing and finite element simulations. The objective of this study was to understand the impact-damage resistance of these novel composites, so that they can be designed optimally for impact-resistant aircraft applications. The FML panels were made up of aluminum alloy 7475 T761 and unidirectional S2 glass/epoxy oriented in a cross-ply configuration. Experimental tests were performed using a free-fall drop dart testing machine. The plate specimens were constrained on a circular edge by the clamping fixture. The shape and the nature of the damage inflicted by impact were evaluated using both destructive cross-sectional microphotography and nondestructive ultrasonic techniques. The tests showed that FML laminates are capable of absorbing energy through localized plastic deformation and through failure at the interface between the layers. In particular, delaminations occurred in the back face of the aluminum-alloy sheet and its adjacent fiber-reinforced epoxy layer and in between adjacent fiber-reinforced epoxy layer. The finite element code, LS-DYNA3D, was used to perform numerical simulations of low-velocity impact to predict the complex damage propagations. The computed post-impact deformed shapes and damage patterns were found to be fairly close to experimental results.

Low velocity impact response of fibre-metal laminates – A review

“…[39,67] 2011 -Experimental Study was done on glare 5-3/2 specimens to investigate the effects of different specimen geometry and lay-up sequence towards the low velocity impact response. [68] 2011 -Low velocity impact response of glare FML was investigated at different impact velocity and the nature, shape of the damage were quantified through destructive microphotography and non-destructive ultrasonic techniques. [27] 2012 -Impact response of magnesium based FML was determined through experiments.…”

“…-External and internal damage effects on each metal face sheets and embedded composite layers were accurately found by computing absorbed energy on each stacking layers. [68] 2011 LS-DYNA -Glass based multilayered FML was modeled using shell elements and both intra and inter laminar failure was specified using appropriate damage criteria. -Contour plots for different composite failure was able to obtain which helps to quantify the magnitude of damage and its severity.…”

“…Tsartsaris [68] simulated glass based FMLs to investigate its lowvelocity impact response using LSDYNA3D finite element code. Meso-scale approach was utilized to model the FML layers having elastic plastic metal layers and linear elastic GFRP layer with Chang-Chang failure criteria.…”

Modeling Low Velocity Impact Response of Carbon Fiber Reinforced Aluminum Laminates (CARALL)

“…Depending upon the nature of connection, an optional failure criterion can be defined in all tie-break contacts. In this study, an extended form of dycoss discrete crack failure [37][38][39][40][41] criteria which is based on the fracture model defined in a cohesive material that includes a bilinear traction separation law with quadratic mixed mode delamination criterion and a Benzeggagh-Kenane [42] damage propagation formulation was used. The distance between two points initially in contact in the normal and tangential directions corresponds to complete material failure referred as ultimate displacements in the interface cohesive model.…”

The Effects of Debonding on the Low-Velocity Impact Response of Steel-CFRP Fibre Metal Laminates

“…However, debonding affects the load transfer between the metal and composite layers, as well as the interaction between different damage modes during an impact, which makes it important in the damage process [12]. Owing to this, debonding has been implemented in the recent theoretical and finite element models in order to study low-velocity impact behaviour [6,16,[18][19][20]. However, the models have been utilized to simulate the high-energy impact response of FMLs, which includes all the different damage modes.…”