Abstract
The present work aims to experimentally characterize a type of insert used for sandwich panels in space applications.
This thesis was developed during a period of internship at Thales Alenia Space Italia in Turin.
Sandwich structures can be used every time a combination of minimum weight with high mechanical characteristics is required.
A panel so formed, or in general a plate, is not able to withstand concentrated loads in the direction of its thickness. For this reason, the use of rigid fasteners allows a sandwich panel to tolerate concentrated loads along the thickness. So inserts permit to introduce concentrated loads in honeycomb sandwich plate.
This is the main objective of inserts. The studied insert is non-standard.
Therefore a test campaign was needed. In fact this thesis activity started after a first phase of bibliographic investigation on inserts and test methods based on regulations issued by the ECSS (European Cooperation for Space Standardization).
The allowable values were calculated through statistic analysis of tests results. Then a numerical correlation of models allows to have predictive FEM models.
The activity was divided into three phases: Analytical;
Numerical; Experimental.
The analytical part consists of the calculation of standard insert allowable values with the Insert Design Handbook. Moreover samples are designed according to regulations and the non-standard insert is planned according to technical specification.
The numerical phase presents the calculation and the samples modelization with FEM. The FEM models aim to predict allowable values of the insert.
In the experimental part the tests are realized and the obtenined results are elaborated and used to calibrate the FEM models.
Comparing the obtained results with standard insert allowable values it was possible to understand that there were performance increases.
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The document is so structured:
In Chapter 1 sandwich panels and inserts are described in their generality and theory.
In Chapter 2 characterization procedures of structural components are described. Chapter 3 describes the Duoble protruding insert.
This kind of insert presents two heads that remain outwards of the sandwich panel skins.
Chapter 4 describes the Finite Element Method and the modellization of samples used in the test campain.
Chapter 5 is dedicated to experimental tests and data process to obtain design allowable values.
A Conclusive Chapter describes the results of the tests.
Through this thesis, skills in using analysis tools and simulation calculation have been improved:
Altair Hyperworks 12.0 package software. In particular HyperMesh, a pre-processor platform used to model a problem with the Finite Element Method and HyperView for the post-processing part.
MSC/NASTRAN Software package. A solver for the analysis calculation;
Siemens PLM Software package. FEMAP was especially used in the post-processing phase.
