Composite materials are finding increasing use in many modern structural engineering problems. However, it is well known that these materials are highly susceptible to hidden internal flaws which may occur during the manufacturing process or while the structure is subjected to service loads. Generally speaking, damage tolerant and fail-safe design of both new and ageing aircraft, aerospace and civil structures require a substantial amount of inspection and defects monitoring at regular intervals, adding substantial amounts to their life cycle cost. The main goal of this work is related to the exploitation of the strain data, both for damage detection/ location and for shape monitoring. To reach this aim guided waves are used. Existing algorithms have to be adapted and new ones have to be developed and validated. Stress guided waves in the sonic and ultrasonic regime are acknowledged as a powerful tool to inspect structures in a non-invasive manner. They are strictly related to the section geometry. In this article a test case will be defined: a Z-plate made of a quadratic flat surface (L1 = L2 = 1000 mm; thickness s = 3 mm) with two Z-shaped stringers (H = 100mm; l = 50 mm) will be examined. The influence of the distance between the stringers, as well as of the mechanical properties of the plate and stringers on the elastic response of the system, will be investigated. Guided waves distinctive character is the dispersive behaviour for a given cross-section, well defined by the so-called dispersion curves. Such behaviour, is generally predicted by means of analytical formulations. However, when the geometry of the cross-section complicates, such as in the case of the Z-plate, analytical formulations fail. Here, the computation of the guided waves properties for such a scenario is addressed via a Semi Analytical Finite Element (SAFE) formulation in which the section geometry is modelled at the mesh level. The results could be of interest for inspection and monitoring of particularly cross-sections.
Modellation of composite plates and beams structures in view of experimentally damage identification / A. Marzani; M. Miniaci; E. Viola. - STAMPA. - 1:(2012), pp. 473.1-473.1. (Intervento presentato al convegno International Conference on mechanics of nano, micro and macro composites structures tenutosi a Politecnico di Torino, Italy nel 18-20 June 2012).
Modellation of composite plates and beams structures in view of experimentally damage identification
MARZANI, ALESSANDRO;MINIACI, MARCO;VIOLA, ERASMO
2012
Abstract
Composite materials are finding increasing use in many modern structural engineering problems. However, it is well known that these materials are highly susceptible to hidden internal flaws which may occur during the manufacturing process or while the structure is subjected to service loads. Generally speaking, damage tolerant and fail-safe design of both new and ageing aircraft, aerospace and civil structures require a substantial amount of inspection and defects monitoring at regular intervals, adding substantial amounts to their life cycle cost. The main goal of this work is related to the exploitation of the strain data, both for damage detection/ location and for shape monitoring. To reach this aim guided waves are used. Existing algorithms have to be adapted and new ones have to be developed and validated. Stress guided waves in the sonic and ultrasonic regime are acknowledged as a powerful tool to inspect structures in a non-invasive manner. They are strictly related to the section geometry. In this article a test case will be defined: a Z-plate made of a quadratic flat surface (L1 = L2 = 1000 mm; thickness s = 3 mm) with two Z-shaped stringers (H = 100mm; l = 50 mm) will be examined. The influence of the distance between the stringers, as well as of the mechanical properties of the plate and stringers on the elastic response of the system, will be investigated. Guided waves distinctive character is the dispersive behaviour for a given cross-section, well defined by the so-called dispersion curves. Such behaviour, is generally predicted by means of analytical formulations. However, when the geometry of the cross-section complicates, such as in the case of the Z-plate, analytical formulations fail. Here, the computation of the guided waves properties for such a scenario is addressed via a Semi Analytical Finite Element (SAFE) formulation in which the section geometry is modelled at the mesh level. The results could be of interest for inspection and monitoring of particularly cross-sections.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
