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Title: Piezoelectric actuators for delamination control in composite plates subjected to low velocity impact
Author: Shaik Dawood, Mohamed Sultan Ibrahim
ISNI:       0000 0004 2696 9717
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2011
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The potential of MFC actuator as a tool for reducing low velocity impact induced delamination has been investigated using LS-DYNA explicit code. For this purpose, three different piezoelectric actuation models were implemented through its user defined material subroutine, namely, the linear strain model, electric field dependent model and induced strain model. The induced strain model was found to provide the best match with experimental results for actuation strain prediction, hence used in impact investigations. In predicting the delamination, a newly formulated damage model was used as it was found that the existing damage models in LS-DYNA are simplistic and rate sensitive. An independent three-dimensional piezoelectric finite element code was developed and used to study the effects of design and actuation parameters on the actuation characteristics of the MFC. The parametric study was meant to determine a laminate-actuator system that would allow sufficient presence of the piezoelectric effects in it. A selected laminate-actuator system was later used to investigate the effects of piezoelectric control actions on the impact force and displacement for purely elastic impact cases. For simply supported laminate it was found that the peak impact force and displacement could be reduced by applying a counter moment to the incoming impact load, whereas for clamped laminate the same was achieved by regulating the laminate stiffness at the impact point. The technique of impact force reduction confirmed that delamination could be reduced. However, this concept could not be experimentally verified as the design requirements could not be practically implemented. The actuator required voltages beyond its operating range to reduce delamination even in the case of very low energy impact. This is something not achievable with the existing piezoelectric materials. Assuming powerful piezoelectric actuators are not impossible in near future, this study could provide useful information for an attempt to validate this concept.
Supervisor: Greenhalgh, Emile ; Iannucci, Lorenzo Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral