Uniform TitleEffects of geometric nonlinearities and uniform temperature fields on the detachment of patched beam-plates under pressure loading
NameCarabetta, Pamela (author), Bottega, William (chair), Baruh, Haim (internal member), Benaroya, Haym (internal member), Rutgers University, Graduate School - New Brunswick,
SubjectMechanical and Aerospace Engineering,
DescriptionPatched structures have many engineering applications, ranging from aircraft repair to electronic devices and beyond. Delamination growth at the edge of the interface between the substructures may lead to catastrophic results. In the spirit of preventing this, edge delamination failure is studied such that behavior may be predicted as well as characterized for a patched beam-plate structure under different physical conditions. The loading scenario on such structures includes transverse pressure and an applied uniform temperature field. These conditions are intended to mimic possible conditions under which a patched beam-plate may be used. The patched beam-plate consists of two plates: the "patch," which is of shorter length, adhered to the longer "baseplate". This composite structure is examined under various support conditions on the endpoints: hinged-free, clamped-free, hinged-fixed, and clamped-fixed.
The problem is formulated analytically, from first principles, using linear and geometrically nonlinear models. Governing equations are derived using a local force balance on an element of the structure incorporating an appropriate geometrically nonlinear thin structure theory, and can be reduced accordingly to simplify to a corresponding linear model. A Griffith type criterion, is adopted to determine the onset of delamination growth. Exact analytical solutions are obtained for nonlinear as well as linear problems and numerical simulations based on these solutions are performed using MATLAB.
Results are presented in the form of delamination growth paths, which may be interpreted physically to describe the onset, extent, and stability of the delamination growth resulting from each scenario. The effect of various physical parameters on delamination behavior is explored. The results show that a temperature difference has a profound effect on the delamination behavior of the patched plates when subject to transverse pressure, as it significantly alters the delamination growth thresholds. There are scenarios where delamination propagation begins in the absence of transverse pressure, due solely to the applied temperature difference. Conclusions are drawn and physical explanations are given for the behavior of each patched plate system. The nonlinear model reveals different delamination growth thresholds and stabilities than the linear model. It observed that the linear model does not adequately describe the salient behavior in comparison to the nonlinear model.
NoteIncludes bibliographical references (p. 144-146).
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.