Response of Composite Fuselage Sandwich Side Panels Subjected to Internal Pressure and Axial Tension
The results from an experimental and analytical study of two composite sandwich fuselage side panels for a transport aircraft are presented. Each panel has two window cutouts and three frames and utilizes a distinctly different structural concept. These panels have been evaluated with internal pressure loads that generate biaxial tension loading conditions. Design limit load and design ultimate load tests have been performed on both panels. One of the sandwich panels was tested with the middle frame removed to demonstrate the suitability of this two-frame design for supporting the prescribed biaxial loading conditions with twice the initial frame spacing of 20 inches. A damage tolerance study was conducted on the two-frame panel by cutting a notch in the panel that originates at the edge of a cutout and extends in the panel hoop direction through the window-belt area. This panel with a notch was tested in a combined-load condition to demonstrate the structural damage tolerance at the design limit load condition. Both the sandwich panel designs successfully satisfied all desired load requirements in the experimental part of the study, and experimental results from the two-frame panel with and without damage are fully explained by the analytical results. The results of this study suggest that there is potential for using sandwich structural concepts with greater than the usual 20-in.-wide frame spacing to further reduce aircraft fuselage structural weight. in the airframe industry. Structural trade studies for
Dimensionnement d'un fuselage composite réalisé par infusion de résine = Numerical modeling of an aircraft composite fuselage manufactured by Liquid Resin Infusion
Le projet FUSCOMP (FUSelage COMPosite) est un programme de Recherche & Developpement qui a recu la labellisation du pole de competitivite de l'Aerospace Valley. Il menera d'ici 2011 au test d'un demonstrateur de fuselage composite realise par le procede d'infusion de resine LRI (Liquid Resin Infusion). Ce procede utilise une resine liquide infusee dans des tissus secs plutot que des tissus preimpregnes, pour mettre en oeuvre des pieces en materiaux composites hautes performances. L'etude de ce demonstrateur technologique est basee sur la cellule du TBM 850, avion d'affaires pressurise monomoteur a turbopropulseur actuellement fabrique par DAHER-SOCATA. Les resultats concerneront les methodes numeriques et l'analyse par elements finis utilisees pour la modelisation de cette structure de fuselage composite. L'integration des structures composites est un sujet d'actualite dans les projets aeronautiques, puisque de plus en plus de structures (raidisseurs,...) sont integrees dans les revetements de fuselage. En effet les principaux avantages du LRI incluent des gains de temps de fabrication lies a l'integration de fonctions. En particulier l'infusion simultanee des elements de structure et de sous-structure doit permettre de s'affranchir du rivetage. Il est cependant necessaire de valider le dimensionnement de cette aerostructure composite etudiee.
Properties of a monopivot centrifugal blood pump manufactured by 3D printing
An impeller the same geometry as the impeller of a commercial monopivot cardiopulmonary bypass pump was manufactured using 3D printing. The 3D-printed impeller was integrated into the pump casing of the commercially available pump to form a 3D-printed pump model. The surface roughness of the impeller, the hydraulic performance, the axial displacement of the rotating impeller, and the hemolytic properties of the 3D-printed model were measured and compared with those of the commercially available model. Although the surface roughness of the 3D-printed model was significantly larger than that of the commercially available model, the hydraulic performance of the two models almost coincided. The hemolysis level of the 3D-printed model roughly coincided with that of the commercially available model under low-pressure head conditions, but increased greatly under high-pressure head conditions, as a result of the narrow gap between the rotating impeller and the pump casing. The gap became narrow under high-pressure head conditions, because the axial thrust applied to the impeller increased with increasing impeller rotational speed. Moreover, the axial displacement of the rotating impeller was twice that of the commercially available model, confirming that the elastic deformation of the 3D-printed impeller was larger than that of the commercially available impeller. These results suggest that trial models manufactured by 3D printing can reproduce the hydraulic performance of the commercial product. However, both the surface roughness and the deformation of the trial models must be considered to precisely evaluate the hemolytic properties of the model.