Orthotropic Materials Stiness Identication by MNET based on Modal Analyis

Orthotropic Materials Stiness Identication by MNET based on Modal Analyis

Volpe, E.

Kaminski, M.L. (mentor)

Mechanical, Maritime and Materials Engineering

Marine and Transport Technology

Ship Hydromechanics and Structures

2016-05-24

The work focuses on the use of mixed numerical experimental techniques (MNETs) to identify the stiness material properties of a ship deck section demonstrator for naval shipbuilding application. The project arose from the resolution of Damen Schelde Naval Shipbuilding to develop a protocol to identify the material properties of bre reinforced composites by non-destructive methodologies in order to validate nite element models of real scaled structural components. The requirements set-up for this protocol were conceived to create a feasible user friendly system, applicable mostly using in-house equipments and software. MNETs combine experimental global results with numerical simulation results in order to obtain priori unknown characteristics or parameters minimizing the distance between the experimental and numerical outputs. The results obtained in the last 25 years have proved modal analysis to be a great experimental technique for this application. The structural parts of the deck used in the analysis consisted in two Carbon/Epoxy sandwich panels and one monolithic E-Glass girder. All of them were subjected to modal vibration tests (EMA) and numerical simulation by nite element methods (FEA). The two sets of results made up of numerical and experimental natural frequencies and mode shapes obtained respectively from the experimental modal analysis and the nite element analysis were correlated in pairs matching each numerical couple of natural frequency and mode shape to the equivalent experimental couple. These data set together with the stiness parameters to update are implemented in the material identication routine to computed the new updated stiness parameters. The parameters were input in the FE-model of the original deck section and compared with the test results to check if the new parameters generated a numerical simulation closer to the reality. This thesis demonstrated that the MNET based on modal analysis for composites sti- ness parameters identication can be successfully applied within the shipbuilding environment with low initial impact of investment. Further research will be necessary to improve the protocol and to back-check the results evaluating the update FE-model performance static simulations focused on stresses and strains. Investigation of the same procedure applied to the identication of other structural parameters such as: damping, damage etc. would be high interesting projects.

composites
MNETs
EMA
material identification
non destructive test

http://resolver.tudelft.nl/uuid:ecfac639-b4e3-44bd-b103-18d17e7800ad

2016-10-01

Student theses

master thesis

(c) 2016 Volpe, E.