Papers by Author: Pawel Kudela

Abstract: The goal of this paper is to develop a new method of filtering and processing of guided wavefield images acquired by the laser vibrometers. The concept is tested on both numerical results and experimental data obtained from measurements of aluminium alloy plate which notch cuts. Results were compared with RMS based maps for different excitation frequencies.

Abstract: The aim of this paper is development of an algorithm for damage localisation in composite plates based on wave propagation signals registered by sensors. It is proposed to distribute the sensors uniformly over the area of a plate-like structure performing triangulation. Next the registered signals are processed and a damage influence map is created in each triangle separately in order to avoid problems connected with reflections from boundaries of the structure. The proposed procedure has been verified on numerical signals as well as experimental signals.

Abstract: The paper presents results of numerical simulation for transverse elastic waves corresponding to A0 mode of Lamb waves propagating in a composite plate. This problem is solved by using the Spectral Finite Element Method. Spectral plate elements with 36 nodes defined at Gauss-Lobatto-Legendre points are used. As a consequence of selecting Lagrange polynomials discrete orthogonality guaranteed leading to a diagonal mass matrix. This results in a crucial reduction of numerical operations required for a chosen time integration scheme. Numerical calculations have been carried out for various orientations of reinforcing fibres within the plate as well as for various fibre volumes fractions. The paper shows that the velocities of transverse elastic waves in composite materials are functions of the fibre orientation and the fibre volume fraction.

Abstract: The aim of this paper is to investigate the influence of temperature fields on wave propagation in composite plates (A0 mode of the Lamb wave has been used). This phenomenon is modelled by the Spectral Element Method. For this purpose a spectral composite plate element, which enables one to take into account thermal effects, has been developed. Different temperature fields have been considered. Results of numerical simulations have been used as input data for a special damage location algorithm. The proposed damage location algorithm utilises signals registered by a clock-like sensor array. In the next step the results from crack location for different temperature fields have been compared.