Triple correlation for detection of damage-related nonlinearities in composite structures

Abstract

Nonlinear effects in vibration responses are investigated for the undamaged composite plate and the composite plate with a delamination. The analysis is focused on higher harmonic generation in vibration responses for various excitation amplitude levels. This effect is investigated using the triple correlation technique. The dynamics of composite plate was modelled using two-dimensional finite elements and the classical lamination theory. The doubled-node approach was used to model delamination area. Mode shapes and natural frequencies were estimated based on numerical models. Next, the delamination divergence analysis was used to obtain relative displacements for delaminated plies. Experimental modal analysis test was carried out to verify the numerical models. The two strongest vibration modes as well as two vibration modes with the smallest and largest motion level of delaminated plies were selected for nonlinear vibration test. The Fisher criterion was employed to verify The results show that the method can be used not only to reveal nonlinearities, but also to reliably detect impact damage in composites. These results are confirmed using the statistical analysis.

Modal Triggered Nonlinearities for Damage Localization in Thin Walled FRC Structures – A Numerical Study

“…Taking into account that for the method proposed in this paper many time integration steps (for every mode) over a quite long period of time (essential to obtain a sufficient frequency resolution) need to be calculated, this phenomenon is therefore not feasible here. Whereas the state-dependent impedance mismatch, caused by a slight local stiffness reduction in the case of an open-state delamination, can be easily modeled with a lumped parameter model [31,32].…”

Analysis of Wave Propagation in a Discrete Chain of Bilinear Oscillators

“…We focus on a conservative system; for the effects of damping in bilinear oscillators see (Shaw and Holmes, 1983;Natsiavas, 1990aNatsiavas, , 1990bLiu et al, 2015;Dyskin et al, 2012;Klepka et al, 2015, Guzek et al, 2016.…”

Analysis of wave propagation in a discrete chain of bilinear oscillators

“…However, a general case of a discrete chain of bilinear oscillators has never been studied with respect to the mechanical wave propagation, which is why it has been decided to numerically investigate the response of the bilinear system that could represent a continuous bimodular medium. We focus on a conservative system; for the effects of damping in bilinear oscillators see Holmes (1983), Natsiavas (1990a, b), Liu et al (2015), Dyskin et al (2012), Klepka et al (2015), or Guzek et al (2016).…”