| Grant number: | 18/15671-1 |
| Support Opportunities: | Scholarships in Brazil - Master |
| Start date: | January 01, 2019 |
| End date: | August 31, 2020 |
| Field of knowledge: | Engineering - Mechanical Engineering - Mechanics of Solids |
| Principal Investigator: | Samuel da Silva |
| Grantee: | Jessé Augusto dos Santos Paixão |
| Host Institution: | Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil |
| Associated scholarship(s): | 19/11755-9 - A new baseline-free method using Gaussian process for damage quantification of composite structures, BE.EP.MS |
Abstract The detection of incipient damages in structures of composite material has a strong practical appeal for application in the aerospace and aeronautics industries since the excellent resistance/stiffness/weight ratios have made this type of material increasingly used in new aircraft. However, its structural characteristics and possibilities of having damages initiated by low intensity impact or even invisible internal delamination necessitate the development not only of new and more robust methods for early detection of failures, but also of new methods of quantification and extrapolation of a future structure condition once an incipient damage has been detected, still in the safety margin for use of the component. The question always is: if you have detected any damage, the structure may or may not operate? And how can this damage or its quantification/extension evolve? In this scenario, the present master's degree proposal of the scholarship holder Jessé Paixão is inserted. In general, in order to reach this stage of damage quantification, a physical-mathematical model of the structure to be monitored is usually required, using sophisticated models with approximate numerical solutions by the finite element method or spectral elements. However, once the difficulty of having well-adjusted models of this type in a composite material structure, either due to the need to model well contoured conditions or to perform an effective adjustment of parameters, in the present work proposal we will try to identify them experimentally using autoregressive models with exogenous terms (ARX) to describe the propagation of Lamb waves in the structure. The idea is to bond actuators and piezoelectric sensors and explore the propagation of Lamb waves and correlation of their coefficients to detect and locate damages, as done in a classic way; the quantification proposal will be made using a new identification of ARX models. Once an incipient damage has started, we will gradually increase its intensity in a controlled manner and correlate with the extrapolation of coefficients of new ARX models. For this, we will study and verify in detail how to choose the appropriate orders of the ARX models according to the wave propagation path and verifying their correlation and effect with a change of operating temperature, central frequency range and excitation amplitude of the Lamb waves. The procedure should be robust and be able to differentiate these situations caused by damages from those caused by other variations. In addition, the graded damages will be simulated in an original way and close to real situations of propagation of incipient damages, using a laser cutting technique in the test structures of composites applying laser pulses by a laser welding machine. This will allow obtaining in the laboratory damages with very small and premature intensity, besides not having any microscopic alteration in the region of this fault. This work plan describes in detail all the steps, motivation, objectives, original points and planning for the execution of this research project. (AU) | |
| News published in Agência FAPESP Newsletter about the scholarship: | |
| More itemsLess items | |
| TITULO | |
| Articles published in other media outlets ( ): | |
| More itemsLess items | |
| VEICULO: TITULO (DATA) | |
| VEICULO: TITULO (DATA) | |