Aeronautical engineering

1. Backgrounds in the theory of measurements: fundamental measuring quantities, measuring system, metrological characteristics of the measuring systems, measurement blocks (range, accuracy, dynamic response, precision). Error propagation and "3-sigma" analysis. 2. Working principles on strain gauges, accelerometers, load cells, excitation systems such as hammers and shakers. 3. Static measurements: experimental set up for trasmissibility matrix and correlation with numerical models. 4. Dynamic measurements with deterministic inputs: wide frequency band input (hammer) and narrow frequency band input (shaker with periodic input). Static model updating. 5. Problems in signal analysis: discrete Fourier Transform, aliasing, leakage, windowing. Auto-Cross correlation functions: Wiener Theorem. 6. Estimates of the modal parameters: a) from FRFs data using single- and multi-degree of freedom methods; b) direct modal appropriation; c) time domain methods. 7. Dynamic measurements with random inputs: Correlation functions and power spectral densities PSD. 8. Correlation between experimental and F.E. numerical models. Fundamentals on structural F.E. updating. 9. Dynamic measurement techniques for flying aircraft; free-free structure model simulations. Reference to EASA and FAA international regulations. 10. Techniques for the measurements of the dynamic response of satellites during environmental testing. Launch qualification, sine, random and shock testing.

Knowledge of Aerospace Design, Aeronautical or Space Structures.

1) Course notes. 2) Ewins, D.J., Modal Testing: Theory, Practice and Application, Research study press LTD, John 2000. 3) He, J., Fu, Z., Modal Analysis, Butterworth Heinemann, 2001. 4) Inmann, D.J., Vibration with Control, John Wiley & Sons, 2006. 5) Bendat, J.S., Piersol, A.G., Random Data, John Wiley & Sons, 1986. 6) Shin, K., Hammond, J., Fundamentals of signal Processing for Sound and Vibration Engineers, John Wiley & Sons, 2008.

The course considers both classroom-taught lectures, laboratory activities on case studies (using scientific instrumentations available at the Structural Dynamic Laboratory), and specific seminars. Laboratory activities are based on previous theoretical classes and are periodically carried out. Through reports on the laboratory activities, students can assess the comprehension of the course topics while they are taught. Course attendance is not mandatory but strongly recommended.

Course attendance is not mandatory but strongly recommended.

The objective of the final exam is to assess the learning on how to apply methods for the experimental investigations in both static and dynamic testing of aerospace structures aimed at validation and safety certification. For a discussion on the laboratory reports concerning the experimental activities and the assessment of the theoretical background considered during the lectures will be considered during the final exam. The evaluation of the learning is based on the assessment of the reasoning skills and autonomous study demonstrated in the reports regarding the laboratory activities and on the skill to process transverse competencies: these are needed skills for fruitful professional interactions with civil aviation authority and/or aero-mechanical structure design/analysis working group. A positive evaluation is given to a) passing an intermediate test (written, taken at about course half-time); b) passing of the laboratory reports, and c) prove the ability to move within the topics covered in the second half of the course. Because the course attendance is not mandatory, the previous evaluation items will be substituted by an oral examination when the student is not able to attend the intermediate test nor the laboratory activities. The final exam schedule will follow the calendar given by the "Facoltà di Ingegneria Civile e Industriale" starting from the end of the semester in which the course is taught.

The course considers both classroom-taught lectures, laboratory activities on case studies (using scientific instrumentations available at the Structural Dynamic Laboratory), and specific seminars. Laboratory activities are based on previous theoretical classes and are periodically carried out. Through reports on the laboratory activities, students can assess the comprehension of the course topics while they are taught. Course attendance is not mandatory but strongly recommended.