Italian Aerospace Research Centre

About: Italian Aerospace Research Centre is a other organization based out in Capua, Campania, Italy. It is known for research contribution in the topics: Aerodynamics & Morphing. The organization has 278 authors who have published 400 publications receiving 3563 citations. The organization is also known as: CIRA & Italian Aerospace Research Center.

Wettability Behavior of Ti6Al4V Electron Beam Melted Surfaces

Abstract: The contribution of the present work is to experimentally evaluate the wettability of Ti6Al4V solid surfaces manufactured via Electron Beam Melting (EBM), an innovative Additive Manufacturing (AM) process. The wettability behavior was quantified via goniometer, measuring the contact angle between a carefully deposited liquid drop (distilled water) and suitable solid surfaces. In order to study the influence of orientation and location in the build chamber on such properties several specimens were EBM manufactured with different growing direction.

Optimal Configuration Model of a Fleet of Unmanned Vehicles for Interoperable Missions

Abstract: It is largely recognized that many missions may be easily performed by unmanned vehicles both in military and in civil domain. Literature shows a large inventory of their applications with operational and logistical challenges. Comparing different types of missions, a multi-vehicle approach is able to guarantee better performances and minimum costs, as long as they are coordinated. Thus, the problem to guarantee the better platform configuration to perform the mission becomes architecting the best fleet. This paper proposes an approach to identify the best fleet to perform an envelope of missions, by transforming the architecting activity in an optimization problem. A classification of unmanned vehicles missions and the formal definition of the problem are proposed.

A Detect and Avoid Concept for Safely Managing Multiple Hazards in Remotely Piloted Aircraft Systems

Abstract: Despite the huge research effort in the development of Detect & Avoid (DAA) systems for remotely piloted aircraft (RPAS), current results are mainly related to systems that only consider air traffic (i.e. other aircraft) hazards. This limitation is currently mitigated by reducing the operation of such DAA systems to an altitude well above the ground and by relying on the remote pilot intervention in case other path constraints can influence correctness of DAA system indications. This paper proposes a new concept of assessing the possible threats for the flight of a RPAS in hazardous scenarios characterized by obstacles of different kinds. Moreover, a strategy for generating an optimal and robust avoidance maneuver that simultaneously considers all such hazards while not causing secondary conflicts is described. Eventually, the proposed DAA system is able to support the remote pilot or perform automatic avoidance maneuvers that take simultaneously into account air traffic, no-fly zones, terrain, bad weather and geo-fencing constraints, thus exceeding current DAA designs. The effectiveness of the proposed algorithm has been demonstrated by means of numerical simulations in several scenarios that are representative of the new features herein described.

Aerodynamic performance analysis of three different vehicle concepts

Abstract: The paper deals with the aerodynamic performance analysis of three reusable and unmanned flying laboratories designed to perform a return flight from low Earth orbit to provide experimental data in the framework of re-entry technologies. Several design approaches, ranging from low-order methods to computational fluid dynamics analyses, have been addressed in this work. In particular, vehicles aerodynamic performances for a wide range of free stream flow conditions, from subsonic to hypersonic regime, including reacting and non-reacting flow and different angles of attack have been provided and in some cases compared. Computational fluid dynamics results confirm that real gas effects seem to be fundamental for the assessment of the concept aerodynamics, especially concerning pitching moment evaluation.

Automatic Differentiation for Solid Mechanics

Abstract: Automatic differentiation (AD) is an ensemble of techniques that allows to evaluate accurate numerical derivatives of a mathematical function expressed in a computer programming language. In this paper we use AD for stating and solving solid mechanics problems. Given a finite element discretization of the domain, we evaluate the free energy of the solid as the integral of its strain energy density, and we make use of AD for directly obtaining the residual force vector and the tangent stiffness matrix of the problem, as the gradient and the Hessian of the free energy respectively. The result is a remarkable simplification in the statement and the solution of complex problems involving non trivial constraints systems and both geometrical and material non linearities. Together with the continuum mechanics theoretical basis, and with a description of the specific AD technique adopted, the paper illustrates the solution of a number of solid mechanics problems, with the aim of presenting a convenient numerical implementation approach, made easily available by recent programming languages, to the solid mechanics community.