Papers by Author: Francis Collombet

Abstract: Drilling of multimaterails is a challenge to manufacturing engineers. Many combinations of multimaterial stacks are possible, they are CFRP/Ti, CFRP/Al, CFRP/Ti/Al etc. The thrust force and surface roughness measured during drilling using plain carbide drill (K20) with drill parameters in drilling carbon fibre reinforced plastic (CFRP) laminate/aluminium (Grade 2024) stack and CFRP/Ti were experimentally investigated in this study.

Abstract: This paper presents experimental and analytical investigation on drilling of carbon fibre reinforced plastic and aluminium stacks. The experimental results conducted as per full factorial experimental design reveal that drill diameter and feed rate have significant effects in reducing thrust force and torque while spindle speed has the least effect. The analytical study is based on artificial neural network (ANN) training using feed-forward back propagation network. The correlations obtained by multi-variable regression analysis and ANN, indicate that ANN is more effective than regression analysis.

Abstract: This paper describes a technique to fabricate instrumented composite cylinders made by the filament winding process and based on the insertion of Bragg grating sensors contained in an optical fiber, so that real time monitoring of the temperature and strain response can be made. The main advantage of this method is that, for the first time, the strain response of the wound layers as a function of time and temperature can be monitored during fabrication without alteration of the composite structure, since the sensor is a filament itself. The sensor data reveals the existence of several phenomena related to the manufacturing process and material response. The results show that during the curing stage of the fabrication of the composite cylinders there is a dimensional contraction without change in temperature which indicates that a material transformation occurs, and also that at the last stage there is a residual compressive strain which may affect the in-service behavior of the composite cylinder.