Numerical-Experimental Assessment of a Hybrid FE-MB Model of an Aircraft Seat Sled Test

This paper deals with the development of an established hybrid finite element multibody (FE-MB) model for the simulation of an experimental sled test of a single row of a double passenger seat placed in front of a fuselage bulkhead, by considering a single anthropomorphic Hybrid II 50th dummy arranged on one of the seat places. The numerical investigation has been carried out by focusing on the passenger passive safety. Specifically, the occupant injury assessment has been quantitatively monitored by means of the head injury criterion (HIC), which, based on the average value of the dummy head acceleration during a crash event, should not exceed, according to the standards, the value of 1000. Numerical results provided by the hybrid model have been compared with the experimental ones provided by the Geven S.p.A. company and with the results carried out by a full FE model. The hybrid model simulates with a good level of accuracy the experimental test and allows reducing significantly the computing time with respect to the full FE one

Design of Composite Stanchions for the Cargo Subfloor Structure of a Civil Aircraft

Abstract The present work was performed in the frame of a national research program focused on the development of analysis method able to improve the structural response of civil aircraft subject to crash event. In particular, the aim of the program is to demonstrate the energy absorption capability of the lower lobe section of the fuselage aircraft. One of principal substructures, which is able to absorb the impact energy in a crash event, is the cargo subfloor. In this work, the results obtained by an experimental test campaign on cargo subfloor elements are presented. The test case consists in a full scale composite stanchion. The experimental results were used to provide information useful to set the numerical models. Indeed, setting and calibrating the numerical models is an important point in order to have useful tools able to improve the absorption energy capability by means of optimization analyses. The stanchion was tested under static and dynamic load conditions, at different impact energy levels

fuselage crashworthiness lower lobe dynamic test

Abstract The focus of this paper is to demonstrate the energy absorption capability of the lower lobe section of the aircraft, and to provide test data in support of validation of the LS-DYNA numerical model. Following a national research program, a full scale drop test, of an airliner composite sub cargo floor fuselage, has been performed by the Italian Aerospace Research Center (CIRA) at their LISA (Laboratory for Impact testing of Structures in Aerospace field) facility. The ultimate aims of research are design, size and evaluation of the crash behaviour of a specific concept of composite aircraft fuselage section linked to the full scale tests. The results are based on pre-test simulations performed on coupon including representative elements devoted to the absorbption of the crash energy, and finally with the final drop test results and the corresponding post-test simulations. Test provides validation of LS-DYNA analysis, and using the simulation tools it is possible to quantify different parameters as energy distribution, accelerations, dynamic structural efficiency, and structural deformations throughout the crash event, but above all the importance to define the real conditions of the constraints and loads in the attempt to reproduce the behaviour of the full scale aircraft fuselage, or section of it, during an emergency landing condition, partially reduced to the full scale subfloor. Then the simulation allows to develop geometries and size of the structures with stanchions and other structural elements in order to reduce the energy absorbing capabilities of the cargo subfloor. Test data indicates the cargo subfloor can absorb an impact velocity of 22 feet/sec with typical payload, and the certification requirements about the emergency landing as satisfied. Finally, the decelerations and deformations are restricted in a survivable space for the passenger compartment

EVOLUTION OF THE (AERO)SPACE ENGINEERING STUDIES IN ITALY IN THE PAST 20 YEARS

The paper presents the evolution and trends in the Master studies in aerospace engineering in Italy, looking at the last 20 years. In the year 2000, a major reform of the higher education in engineering took place in Italy, with the introduction of the so-called “Bologna system” and the clear separation of Bachelor and Master studies. With this reform, a relatively high flexibility was given to universities to define their program structures. The ministerial rules defined only broad subject areas within which courses and credits should be allocated. This reform allowed to diversify the educational profile within each University and, even more relevant, allowed to create mobility across the country between Bachelor and Master study programs. The paper will show the basic facts and figures in the 6 Italian Universities participating in the PEGASUS network (Politecnico di Milano, Politecnico di Torino, Università di Pisa, Università degli Studi di Napoli “Federico II”, Sapienza Università di Roma, Alma Mater Studiorum - Università di Bologna), elaborating on the impact of the potential workforce for the sector

Noise, emissions and costs trade factors for regional jet platforms using a new software for aircraft preliminary design

A multidisciplinary analysis approach plays a very important role in the development of future transport aircraft, being able to interconnect all aircraft-related subjects and suppliers. A major issue, which has prevented aircraft manufacturers from implementing efficient and cost-effective design processes, is the loose integration of engine models into iterative aircraft design workflows. The continuous improvement of computer calculation capabilities over years has allowed the growth of a large family of software dedicated to aircraft preliminary design activities concerning also multi-disciplinary analyses, and optimizations. In this context, a new software for aircraft preliminary design, multi-disciplinary analyses and optimizations named JPAD (Java toolchain of Programs for Aircraft Design) has been developed at the University of Naples Federico II. The main purpose of this paper is to show the capabilities of the JPAD software applied to typical preliminary design problems. Thus, results of the activities carried out by means of JPAD in the scope of the Work Package 2 (WP2) of the European CleanSky2 project ADORNO will be shown. Those will concern trade factors and response surfaces related to environmental noise, DOC, and pollutant emissions (linked to the design mission block fuel) for a Rear-Mounted engines (RM) reference 2014 aircraft configuration

At the crossroads of Architecture and Landscape: Preservation Strategies of Historic Military Systems: a Comparison between Italy and the Netherlands

In the context of rapid urban transformations, this thesis explores the possible preservation strategies for historic military systems that used to be embedded in extra-urban settings, but that now are absorbed in the development dynamics of complex metropolitan areas. The research stems from the main peculiarity of these heritage systems: namely, the coexistence of cultural and natural values, and their being at the crossroads of the architecture and landscape domains. Although the need to address nature-culture interlinkages has become a topical issue in the field of heritage preservation, military landscapes have been almost completely left out of this debate. Moreover, the lack of inter-scale strategies in current preservation practices for historic military systems further complicates the way nature-culture interlinkages are addressed. The development of a conceptual framework on this topic has required considering the diversity of existing approaches to landscape, architectural heritage and their interconnection. Italy and the Netherlands were selected as relevant contexts in Western Europe for comparison on this topic. Linking archival research, interviews and field observations, Italian and Dutch contemporary experiences with the revitalization and reuse of historic military systems (NL: New Dutch Waterline; IT: Entrenched Field of Mestre) were compared. Both national and international initiatives promoted in the frame of the World Heritage Convention were analysed. To understand the historical roots of the recent approaches, the evolution of landscape protection in the two contexts has been investigated, highlighting the different influences played by the national discourse on architectural heritage and spatial planning. This historical background, together with the cross-reading of the case studies, has led to the definition of a transnational conceptual framework on the possible preservation strategies for historic military systems with an inter-scale approach. Taking into account the peculiarities of each context, it provides a tool for facilitating the decision-making process, bringing historic military systems into the international discussion on nature-culture interlinkages. Ultimately, it can serve as a reference for other historic landscape systems sharing similar characteristics and preservation issues.A+BE | Architecture and the Built Environment. No. 22 (2022)Heritage & Value

Introduction to Ship Acoustics

Some basic concepts involved in the ship acoustics are reported in the lesson. The main noise sources on board are briefly overviewed as well as the typical transmission paths along which noise can be transmitted to a receiving position. The peculiarities of the ship context with respect to other industrial environments are outlined. Some problems connected with the characterization of the various sources strength are presented. The basic concepts of noise reduction (absorption, damping, isolation) are overviewed together with some quantities commonly used to describe the effectiveness of different counter-measures adooted on board