Assessing the effects of delamination on the damped dynamic response of composite beams with piezoelectric actuators and sensors

Abstract

Experimental and analytical studies are presented investigating the effect of delamination cracks on the low-frequency dynamic response of composite beam specimens with surface attached piezoelectric actuators and sensors. Frequency response functions of laminated beams with piezoceramic actuators and piezoelectric sensors having single delamination cracks of various sizes are measured. Comparisons with mechanical actuation-accelerometer sensor configurations illustrate the sufficiency and advantages of piezoelectric actuator-sensor pairs in self-monitoring the effects of delamination on the dynamic response. Modal frequencies and damping values of the beams are also measured and their dependence on delamination size is studied. Comparisons with analytically predicted results are shown. Finally, the sensitivity of damage indices based on changes in modal frequency, modal damping, and modal peak density to the crack size is quantified.

Generalized layerwise mechanics for the static and modal response of delaminated composite beams with active piezoelectric sensors

“…The accuracy of the developed mechanics is first validated for the case of pristine beams with previous models. Predicted modal frequencies of delaminated beams are also compared with previously contacted experimental results (Chrysochoidis and Saravanos, 2004). All applications were focused on composite Gr/Epoxy T300/934 beams with quasi-isotropic laminations [0/90/45/À45] s , 0.127 mm nominal ply thickness, 280 mm long and 25 mm wide.…”

“…Di Sciuva and Librescu (2000) presented a geometrically non-linear theory of multilayered composite plates and shells with damaged interfaces, Luo and Hanagud (2000) presented a model for describing the static, modal and dynamic response of delaminated beams using a nonlinear approach based on piecewise linear spring models between the delaminated sublaminates; Thornburgh and Chattopadhyay (2001) used a higher-order theory to model matrix cracking and delamination in laminated composite structures; Hu et al (2002) analyzed the vibration response of delaminated composite beams using a higher-order finite element with a C 0 type finite element materials; and Diaz Valdes and Soutis (1999) presented experimental work on the detection of delaminations in composite beams using piezoelectric actuator and sensor. Chrysochoidis and Saravanos (2004) investigated mainly experimentally effects of delamination on the modal parameters and frequency response functions of artificially delaminated composite beams obtained via attached piezoceramic actuators and sensors pairs and demonstrated the potential of the latter compared to other traditional sensors. Chattopadhyay et al (1999) studied the dynamics of delaminated composite plates with piezoelectric actuators using a third-order shear theory and more recently (Chattopadhyay et al, 2004) reported a refined layerwise theory for the prediction of the vibration of delaminated plates considering the crack faces interface contact using a system of nonlinear springs.…”

Model based defect detection for free stator of ultrasonic motor

“…Also it can be observed in Table I that 1 C is increased which means the stiffness of the composite is decreased. Many literatures [17]- [19] propose that these phenomena occur because of delamination in case of multilayer composites. Furthermore, Zou et al in [20] states that delamination increases the damping of the structure.…”

“…Furthermore, Zou et al in [20] states that delamination increases the damping of the structure. Also Chrysochoidis et al [19] presents that the damping in the delaminated specimen changes because of variations in effective damping and stiffness properties in the delaminated sub-laminates, and friction and impacts between the crack faces. But both literatures agree that the behavior of damping is more sophisticated and is a challenging subject of research.…”

Application of Piezoelectric Materials on Repair of Delaminated Structures

“…Such damage when left unattended can grow at alarming rate due to the singularity of the stress and strain in the vicinity of the damage. This can lead to an increase in vibration level, reduction in load carrying capacity, deterioration in the normal performance of the component, and even catastrophic failure [1][2][3]. Delamination in composites has been a topic of concern and this has been extensively reviewed [4].…”