AEROSPACE STRUCTURE TESTING Understanding of the main issues related to the modelling of aerospace structures, the design and execution of tests, development of the ability to analyze the experimental measurements in order to derive their basic features. AEROSPACE MANIFACTURING TECHNOLOGY AND PROCESS Starting from the aerospace structure requirements, students shall be able to decide the most appropriate manufacturing process and to choose the most appropriate material for that technological process.

AEROSPACE STRUCTURE TESTING Content of the courses such as Aerospace Construction and Aerospace Structures. AEROSPACE MANIFACTURING TECHNOLOGY AND PROCESS The course makes reference to concepts, notions and methodologies from the courses of engineering drawing, aircraft structures, jet propulsion, design of aerospace vehicles.

AEROSPACE STRUCTURE TESTING (40 h) Introduction to the Course. Design flows and related tests (development, qualification, acceptance). Legislation dealing with structures. Criteria for structural verification, monitoring and design. Design loads level and verification load level. Importance of analytical/numerical and experimental models in structural design. References to Model theory and Similarity. Processing of the experimental data using statistical techniques. Standard components for laboratory tests: strain-gage and Wheatstone bridge arrangement of strain-gage load in special cases, Interferometry. Aerospace materials and their characterization: tensile test, compression test, shear test, elements of characterization at high strain rates; Influence of the statistical properties in structural design. Compression test on thin/stiffened panels. Buckling and post-buckling tests. Experimental methods for the determination of compressed rod/panel critical points. Southwell method . Experimental procedure for fracture toughness in metals. Identification and updating of numerical models by experimental test results. Techniques for real-time monitoring of structural behavior. Introduction of specific models for static analysis of typical aerospace components (beams in reinforced-shell, sandwich structures, junctions) and design of relevant experimental tests. Design and FEM analysis of typical thin-walleb structures and correlations with tests Lab results. Conclusions. AEROSPACE MANIFACTURING TECHNOLOGY AND PROCESS Introduction: development of aerospace structures, materials and manufacturing processes. State-of-art and prospective. Criteria and merit index for the best choose of materials and technologies. Classification and comparison of main structural aerospace materials (Al, Ti, Mg and steel alloys, composite materials); mechanical and physical characteristics. Materials selection principles: relation between material properties and aeronautical applications, multi-property analyses. Aerospace applications requirements and quality standards. Metallic materials: Solid structure and deformation; elasto-plastic behaviour. Manufacturing characteristics, thermal treatment, alloy and temper designation systems; alloy development. Coatings and protection systems. Environmental deterioration: Material corrosion, typologies, causes and prevention methods. Standard test methods for material mechanical and physical proprieties. Processes-products qualification. Non Destructive Inspection and Tests and Structural Health management systems Conventional manufacturing processes. Casting processes; hot and cold metal forming (forging, rolling, drawing, extrusion, etc.); machining processes (lathe, drilling, milling, broaching, sawing, etc.); CAD-CAE-CAM; Machining centres, advanced machining concepts and structures, and machining economics, Abrasive machining and finishing operations. Introduction to Additive manufacturing and 3D-print. Non conventional manufacturing processes: water-jet; chemical milling, Super Plastic Forming-Diffusion Bonding. Welding and joining processes: Riveting, welding, bonding. Arc-welding processes, shielded metal arc welding, gas metal arc welding, electro-gas welding, electrodes, non consumable electrode, Gas tungsten arc welding, plasma arc welding, basics of Laser welding. Sheet Metal Folding Other processes: Spot welding, Brazing and soldering. Laser beam, electron beam, friction-stir-welding. Final assembly of aerospace structures. Fatigue: S-N curves, residual stresses, fatigue strength, stress concentration. Factors influencing the fatigue behaviour of metallic materials: geometric discontinuities, surface finishing, working temperature, pre-load, roll and cold-working, manufacturing processes, etc. Fracture mechanics. Composite Materials: aircraft structures in composite materials; innovative composite materials, processes. Materials: Carbon, glass, aramide and boron fibres production; thermosetting and thermoplastic composite for structural applications; resin properties: FST (Fire, Smoke, Toxic) requirements, flow, gel time, and Tg. Characteristic and requirements of composite materials for aeronautical applications. Comparison of static, fatigue, environmental behaviour with metallic materials; CTE and CME, composite structure lightning protection Production Processes: Basic principles (materials storage – layup - vacuum bag - cure cycle – NDI - trimming ; in-coming & process control specimens; facilities characteristics & certification). SMC (Sheet Moulding Compound); resin infiltration technologies. Multi-layers structure production. Tape and filament winding. Poltrusion, Braiding, Injection moulding, co-bonding e co-curing of primary structures, automatic deposition technology, Thermal expansion Moulding, composites repair processes, lightning for composite materials. Post autoclave processes: trimming – drilling – fastening – painting. Others: Production of aeronautical structures. Structural adhesives & foam adhesives. Sandwich structures. Metal Matrix composites; Ceramic composite. Several examples of aircraft structures shall be shown. Thermal Protection System for Space structures.

AEROSPACE STRUCTURE TESTING (20 h) The first part of the course sees the presence of 2-3 guided experimental exercises at the LAQ AERMEC "Structural Aeromechanical Systems" of the Department and numerical activity at the university's computer laboratories in order to directly verify the notions presented in class. A summary report is expected to be prepared. In the second part, the preparation, organization, simulation and possibly experimental execution (based on availability) on a component defined at the beginning of the course will be addressed by groups. This activity will conclude with the preparation of a final report. Attendance to laboratory exercises is mandatory. Computer lab exercises: • Analysis by FEM method of selected components for identification and numerical / experimental correlation both in the case of intact configurations and in the presence of defects / anomalies. Guided experimental laboratory exercises (2-3 of the following subject to availability): • Mechanical characterization of typical aerospace materials • Bending tests on sandwich beam • Stress test on components available in the laboratory (perforated plate, isotropic C beam, damaged and repaired C beam, composite C beam). Evaluation and estimation of stiffnesses. Experimental laboratory exercise set up for groups on an agreed topic associated with the second part of the activity. Visit to DIMEAS laboratories during experimental tests on aerospace structures or components (based on ongoing research). AEROSPACE MANIFACTURING TECHNOLOGY AND PROCESS Introduction to riveting; failure modes of a riveted joint and dimensioning. Bonded joints, modeling and dimensioning of joints with single and double lap, linear/nonlinear adhesive model, peel stresses. Elements of probability theory: Definitions of probability, random variables and distributions, characteristics of a distribution, limit theorems, probability of structural failure. Elements of Statistics: Analysis of frequencies, moments of a sample, sampling distributions, estimation theory, least square method, montecarlo method; AEROSPACE STRUCTURES LABORATORY: aeronautical structures: Examples of Aircraft Structures made of carbon fiber. Unmanned aerial vehicles (UAVs). Stiffened panels. Technological procedures for the assembly of an aircraft or space structures. Visits to industries and laboratories of Turin Area.

SPERIMENTAZIONE SU STRUTTURE AEROSPAZIALI Didactical material from the portal . Schematic presentation for the experiments developed during the course ( numerical/experimental). Material useful for the testing activity. Reference books: a) slides from lessons established by the reference teacher. b) Bray, Vicentini, Meccanica sperimentale. Levrotto & Bella Torino. 1975. c) J. Singer, J. Arbocz, T. Weller, Buckling Experiments: Experimental Methods in Buckling of Thin-Walled Structures. Vol I, II. d) Ewins, Modal testing: theory and practice. Wiley, 1994. TECNOLOGIE AEROSPAZIALI a) G. Romeo: Appunti per il corso di "Tecnologie Aerospaziali". Politeko Ed. b) for further informations: -F.C. Campbell "Manufacturing Technology for Aerospace Structural Materials" Elsevier 2006 -D.F. Horne: "Aircraft Production Technology", Cambridge Univ Press, 1986. -M. Marchetti, Felli: "Tecnologie Aeronautiche", Editrice ESA, Milano -D.H. Middleton: "Composite Materials in Aircraft Structures", Longman S.&T., UK, 1990 -Lubin: "Handbook of Composites", Van Nostrand, New York -Schwartz: "Composite Materials Handbook", McGraw-Hill Book Co., New York -M. Marchetti, D. Cutolo: "Tecnologie dei Materiali Compositi", Editrice ESA, Milano, 1991 -Noor: "Structures Technology for Future Aerospace Systems", AIAA Vol.188, Reston -J. Delmonte, Tecnology of Carbon and Graphite Fiber Composites, Van Nostrand Reihnold, 1981.

Exam: Compulsory oral exam; Paper-based written test with video surveillance of the teaching staff;

The exam consists in : 1) the written part ( 3 hours) with 3-4 questions on the aerospace testing ( maximum mark =27/30 inclusive of max 5 pt related to the final report) and 3-4-questions on the Technology ( maximum mark = 30/30). 2) for the aerospace testing there is an oral part for those students who have passed the written one with not less than 15/30 ( maximum mark =3/30) . During the oral part the candidate has to deliver the reports of the testing guided exercises performed during the course and the oral discussion will be on at least one question on these reports plus other two on the arguments of the course. The final mark will be a combination of the Aerospace testing final mark and Technology final mark. The exam has been considered passed if the final mark will be not less than 18/30. The oral part has to be passed within the same session of the written part.

Exam: Written test; Compulsory oral exam; Paper-based written test with video surveillance of the teaching staff;

The exam consists in : 1) the written part ( 3 hours) with 3-4 questions on the aerospace testing ( maximum mark =27/30 inclusive of max 5 pt related to the final report) and 3-4-questions on the Technology ( maximum mark = 30/30). 2) for the aerospace testing there is an oral part for those students who have passed the written one with not less than 15/30 ( maximum mark =3/30) . During the oral part the candidate has to deliver the reports of the testing guided exercises performed during the course and the oral discussion will be on at least one question on these reports plus other two on the arguments of the course. The final mark will be a combination of the Aerospace testing final mark and Technology final mark. The exam has been considered passed if the final mark will be not less than 18/30. The oral part has to be passed within the same session of the written part.