Damage analysis of laminated composite beams under bending loads using the layer-wise theory

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dc.contributor.advisor Reddy , J . N . en_US
dc.contributor.committeeMember Hogan , Harry A . en_US
dc.creator Na , Wook Jin en_US
dc.date.accessioned 2010 -01 -15T00 :13 :12Z
dc.date.accessioned 2014 -02 -19T19 :32 :40Z
dc.date.available 2010 -01 -15T00 :13 :12Z
dc.date.available 2014 -02 -19T19 :32 :40Z
dc.date.created 2008 -05 en_US
dc.date.issued 2009 -05 -15 en_US
dc.identifier.uri http : / /hdl .handle .net /1969 .1 /ETD -TAMU -2774
dc.description.abstract A finite element model based on the layer -wise theory and the von K ?rm ?n type nonlinear strains is used to analyze damage in laminated composite beams . In the formulation , the Heaviside step function is employed to express the discontinuous interlaminar displacement field at the delaminated interfaces . Two types of the most common damage modes in composite laminates are investigated for cross -ply laminated beams using a numerical approach . First , a multi -scale analysis approach to determine the influence of transverse cracks on a laminate is proposed . In the meso -scale model , the finite element model based on the classical laminate theory provides the material stiffness reduction in terms of the crack density by computing homogenized material properties of the cracked ply . The multiplication of transverse cracks is predicted in a macro -scale beam model under bending loads . In particular , a damage analysis based on nonlinear strain fields in contrast to the linear case is carried out for a moderately large deformation . Secondly , the effect of delamination in a cross -ply laminated beam under bending loads is studied for various boundary conditions with various cross -ply laminate lay -ups . The crack growth of delamination is predicted through investigating the strain energy release rate . Finally , the interactions of a transverse crack and delamination are considered for beams of different configurations . The relationships between the two different damage modes are described through the density of intralaminar cracks and the length of the interlaminar crack . It is found that geometric nonlinearity plays an important role in progression of interlaminar cracks whereas growth of intralaminar cracks is not significantly influenced . This study also shows that the mixture of fracture mode I and II should be considered for analysis of delamination under bending loads and the fracture mode leading delamination changes as the damage develops . The growth of delamination originated from the tip of the transverse crack is found to strongly depend on the thickness of 90 - degree layers as well as the transverse crack density . Further , the effect of interfacial crack growth on the transverse cracking can be quatitatively determined by the delamination length , the thickness of 90 -degree layers and the transverse crack density . en_US
dc.format.medium electronic en_US
dc.format.mimetype application /pdf en_US
dc.language.iso en _US en_US
dc.subject Damage en_US
dc.title Damage analysis of laminated composite beams under bending loads using the layer -wise theory en_US
dc.type Book en
dc.type.genre Electronic Dissertation en_US
dc.type.material text en_US
dc.format.digitalOrigin born digital en_US

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Damage analysis of laminated composite beams under bending loads using the layer-wise theory. Available electronically from http : / /hdl .handle .net /1969 .1 /ETD -TAMU -2774 .

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