ECTS - University of Pisa
| Modules | Area | Type | Hours | Teacher(s) | |
| SPACECRAFT STRUCTURES AND MECHANISMS | ING-IND/04 | LEZIONI | 120 |
|
The student who successfully completes the course will be able to demonstrate a good knowledge of both mechanical and technological aspects that refer to the space structures and to the mechanisms; will be aware of fatigue and fracture mechanics of metallic materials; will be able to solve problems of mechanics and will be able to prepare a technical report at the end of a project exercise. The evaluation is based for a 50% on the verification executed during the examination (written and oral). The other 50% is based on the evaluation of the project report that a single student or a group of students will produce at the end of the course before the examination phase.
The evaluation is based primarily on the verification of the basic knowledge necessary for the design of aerospace structures and mechanisms (strenght analysis, fatigue, fracture mechanics, joints, bearings, gears). The uncertainty of these skills is not allowed. The student must demonstrate the ability to put into practice and to execute, with critical awareness, the design methods and the verification procedures illustrated during the course. For this reason the discussion of the project report will take an important part of the examination phase.
The examination is based on the solution of written exercises and on a subsequent discussion of the results.
Course Contents
( I ) October-December
Notes about the design process of a spacecraft.
The launch phase: preliminary examination of acoustic and vibration loading conditions
Random vibrations analysis.
Vibro-acoustic Response Analysis.
Reliability of components and structures: basic definitions and applications.
Strength analysis: definition of the limit loading condition and ultimate loading condition (yielding and collapse of structures).
( II ) February-April
Computer Lab (ANSYS Workbench)
Welded joints.
Fastened joints.
Fatigue.
S-N curves.
The Goodman diagram for ductile materials.
Effect of the stress concentration.
Fatigue crack growth: basic notes on fracture mechanics.
( III ) May
Computer Lab (ANSYS Workbench)
Contact stresses: discussion of results of the Hertz theory.
Springs (basic notes)
Bearings.
Spur gears.
Gear trains (basic notes)
Rotating shaft dynamics: critical speeds computation.
Theoretical lessons and, in the second period, use of personal computer for the preparation of Finite Element models by Ansys Workbench environment.
Recommended reading includes the following books and/or technical documentation:
T.P. Sarafin "Spacecraft Structures and Mechanisms - From Concept to Launch"
R.C. Juvinall & K.M. Marshek "Fundamentals of Machine Component Design"
ESA Spacecraft mechanical loads analysis handbook - ECSS-E-HB-32-26A, 19 February 2013
ESA Buckling - ECSS-HB-32-24A, 24 March 2010
NASA TM-X-73305 - Astronautic Structures Manual - Vol I - Vol II - Vol III, 1975
NASA-HDBK-7008 - SPACECRAFT DYNAMIC ENVIRONMENTS TESTING, 2014
Jacob Job Wijker - Spacecraft Structures, Springer, 2008
Lectures of Spacecraft Structures and Mechanisms (notes) - M. Chiarelli (e-learning)
Please visit the website www.ecss.nl to consult all the technical documentation produced by ESA
