Papers by Author: F.J. Doblas

Abstract: This work presents a project of teaching innovation on the subject Technology of Manufacturing that has been developed for the last five years. The objective is to stimulate students for training through a self-evaluation system based on e-learning tools, in agreement with the guidelines of the European Higher Education Area (EHEA). The system includes a methodology to perform a series of evaluations about theoretical and practical knowledge which allows the student self-learning. The data obtained with the proposed system are analyzed and the effect on student results is discussed. The evolution in time of the student grades, their involvement and satisfaction with the project, and its influence in their final score are presented.

Abstract: In this paper, the evolution of plastic strain and hydrostatic pressure evolutions in incremental sheet forming (ISF) processes to postpone fracture of the metal sheet is analyzed. A finite element (FE) model of an incremental forming operation and a conventional stretch-bending operation is performed. Experimental results of stretching tests are used as reference. The local evolution of the straining and the distribution of hydrostatic pressure are studied in detail. Different step downs and friction coefficients are simulated and their results are discussed.

Abstract: This paper presents a numerical analysis of the influence on the fatigue life of hybrid metal/CFRP bolted joints of some deviations in certain assembly parameters. Two types of hybrid joints typically used in aircraft are analyzed, the Ti-6Al-4V/CFRP and the Al-2024-T3/CFRP, riveted with blind bolts. The parameters analyzed are: the thickness of sealant between metal sheet and composite laminate, the angle of countersunk and the adjustment or chamfer at the countersunk-drill zone. The analysis highlights critical areas for fatigue failure and the relative influence of these parameters on the fatigue resistance of the joint.