Interface Behavior When Drilling GFRP/Al-Based Composites: Temperature Analysis

This attempt focuses on the effects of temperature generation at interfaces when drilling composite stacks associating unidirectional glass fiber-reinforced polymer (UD-GFRP) and aluminum alloy (Al). The thermomechanical properties of GFRP phase combined with disparate properties of isotropic Al phase present several issues for controlling material removal process of such composites. GFRP/Al/GFRP and Al/GFRP/Al stacking sequences were specially considered in drilling tests. The tool geometry and drilling conditions were kept constants during machining. The thrust force, and cutting temperature within both the composite stacks and tool were measured in real machining time. Specially, temperature recordings were ensured using thermocouples TCs preinstalled surrounding the hole to be drilled within the composite stack and within the axis of the drill as well. Thrust force plots obtained within the composite stacks reveal different machining stages to be distinguished by severe discontinuities at interface region between phases regardless the stacking sequence. Unexpectedly, the peak temperature values captured in the tool when drilling Al/GFRP/Al was found more critical than those recorded when drilling GFRP/Al/GFRP while no significant difference was outlined over the thrust force when comparing phase to phase singly. However, temperature history captured within the composite shows increasing flow directed from top to bottom layer regardless the stacking sequence.