Modeling of degraded composite beam due to moisture absorption for wave based detection

Abstract

In this paper, wave propagation is studied in degraded composite beam due to moisture absorption. The obtained wave responses are then used for diagnosis of the degraded zone. Moisture absorption causes an irreversible hygrothermal deterioration of the material. The change in temperature and moisture absorption changes the mechanical properties. Thus this affects the structure in dimensional stability as well as material degradation due to reduction in mechanical properties. Here, the composite beam is modeled as Timoshenko beam using wavelet based spectral finite element (WSFE) method. The WSFE technique is especially tailored for simulation of wave propagation. It involves Daubechies scaling function approximation in time and spectral finite element approach. The simulated wave responses are then used as surrogate experimental results to predict degradation using a measure called damage force indicator (DFI). Numerical experiments are presented for moisture absorbed composite beam due to modulated sinusoidal excitation. The responses are studied for different environmental conditions in term of relative humidity and at a temperature.