Fibre Bragg Gratings (FBGs) are optical strain gages manufactured directly inside the fiber core.... more Fibre Bragg Gratings (FBGs) are optical strain gages manufactured directly inside the fiber core. They provide several advantages with respect to conventional strain gages. In particular it is possible to put several FBGs along the same fibre (multiplexing), they are immune to corrosive environments and to electromagnetic interferences. They can be embedded in almost all types of materials and are very useful in Structural Health Monitoring. An innovative approach for testing specimens in this area is reported in this work. An aluminium alloy 2024-T3 CT specimen has been manufactured with one small feed-through hole and a superficial groove. Two FBG sensors, multiplexed on the same fibre, have been glued one inside the hole and one inside the groove. Fatigue test has been carried out monitoring the crack length both with standard measure system and with the FBG strain sensors placed in front of the crack tip.
56th International Astronautical Congress of the International Astronautical Federation, the International Academy of Astronautics, and the International Institute of Space Law, 2005
The architectural artwork “Cubierta de Oviedo” is located in the Buenavista building complex, it ... more The architectural artwork “Cubierta de Oviedo” is located in the Buenavista building complex, it being the movable roof of the City of Oviedo (Asturie, Spain) conference centre. The original design and realization was by the archistar Santiago Calatrava (2004-11). The structure is made in steel. Since the testing of the structure, it was not possible to open the roof. From this occurrence, the idea to design the cubierta in structural aluminum seemed to be a challenge, due to the lowest weight of aluminum as respect to steel. In this perspective, the study focuses on the design of the main beam, spanning 134m total length, with 110m cantilever length, in the most unfavorable condition of open roof. The more appropriate aluminum alloy 7075 has been selected, according to the required mechanical properties. Considering the large height (4.20m) of the cross section, which is a special welded box section, for connecting the component elements, the Friction Stir Welding innovative techni...
ABSTRACT. The present paper describes the failure analysis of an aircraft component subjected to ... more ABSTRACT. The present paper describes the failure analysis of an aircraft component subjected to several episodes of in service failure, resulted in loss of the aircraft safety. Modern aircrafts are provided with mechanical systems which have the task to open not pressurized hatches during landing. The components of such systems are subject to considerable mechanical stresses in harsh environment (presence of moisture and pollutants, significant and sudden temperature variations). The system is constituted by a sliding piston, a related nipple and by a locking system consisting of 4 steel spheres which are forced into a countersink machined on the piston when the hatches is open. The whole system is activated by a preloaded spring. The machined parts, nipple and piston, are made of EN3358 steel (X3CrNiMo13-8-2), a precipitation hardening stainless steel with very low content of carbon often used in the aerospace. The samples provided by the manufacturer present different types of da...
Fibre Bragg Gratings (FBGs) are optical strain gages manufactured directly inside the fiber core.... more Fibre Bragg Gratings (FBGs) are optical strain gages manufactured directly inside the fiber core. They provide several advantages with respect to conventional strain gages. In particular it is possible to put several FBGs along the same fibre (multiplexing), they are immune to corrosive environments and to electromagnetic interferences. They can be embedded in almost all types of materials and are very useful in Structural Health Monitoring. An innovative approach for testing specimens in this area is reported in this work. An aluminium alloy 2024-T3 CT specimen has been manufactured with one small feed-through hole and a superficial groove. Two FBG sensors, multiplexed on the same fibre, have been glued one inside the hole and one inside the groove. Fatigue test has been carried out monitoring the crack length both with standard measure system and with the FBG strain sensors placed in front of the crack tip.
56th International Astronautical Congress of the International Astronautical Federation, the International Academy of Astronautics, and the International Institute of Space Law, 2005
The architectural artwork “Cubierta de Oviedo” is located in the Buenavista building complex, it ... more The architectural artwork “Cubierta de Oviedo” is located in the Buenavista building complex, it being the movable roof of the City of Oviedo (Asturie, Spain) conference centre. The original design and realization was by the archistar Santiago Calatrava (2004-11). The structure is made in steel. Since the testing of the structure, it was not possible to open the roof. From this occurrence, the idea to design the cubierta in structural aluminum seemed to be a challenge, due to the lowest weight of aluminum as respect to steel. In this perspective, the study focuses on the design of the main beam, spanning 134m total length, with 110m cantilever length, in the most unfavorable condition of open roof. The more appropriate aluminum alloy 7075 has been selected, according to the required mechanical properties. Considering the large height (4.20m) of the cross section, which is a special welded box section, for connecting the component elements, the Friction Stir Welding innovative techni...
ABSTRACT. The present paper describes the failure analysis of an aircraft component subjected to ... more ABSTRACT. The present paper describes the failure analysis of an aircraft component subjected to several episodes of in service failure, resulted in loss of the aircraft safety. Modern aircrafts are provided with mechanical systems which have the task to open not pressurized hatches during landing. The components of such systems are subject to considerable mechanical stresses in harsh environment (presence of moisture and pollutants, significant and sudden temperature variations). The system is constituted by a sliding piston, a related nipple and by a locking system consisting of 4 steel spheres which are forced into a countersink machined on the piston when the hatches is open. The whole system is activated by a preloaded spring. The machined parts, nipple and piston, are made of EN3358 steel (X3CrNiMo13-8-2), a precipitation hardening stainless steel with very low content of carbon often used in the aerospace. The samples provided by the manufacturer present different types of da...
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Papers by Francesco Passeggio