A generalized multilength scale nonlinear composite plate theory with delamination

A new type of plate theory for the nonlinear analysis of laminated plates in the presence of delaminations and other history!dependent e}ects is presented[ The formulation is based on a generalized two length scale displacement _eld obtained from a superposition of global and local displacement e}ects[ The functional forms of global and local displacement _elds are arbitrary[ The theoretical framework introduces a unique coupling between the length scales and represents a novel two length scale or local!global approach to plate analysis[ Appropriate specialization of the displacement _eld can be used to reduce the theory to any currently available\ variationally derived\ displacement based "discrete layer\ {smeared|\ or {zig!zag|# plate theory[ The theory incorporates delamination and:or nonlinear elastic or inelastic interfacial behavior in a uni_ed fashion through the use of interfacial constitutive "cohesive# relations[ Arbitrary interfacial constitutive relations can be incorporated into the theory without the need for reformulation of the governing equations[ The theory is su.ciently general that any material constitutive model can be implemented within the theoretical framework[ The theory accounts for geometric nonlinearities to allow for the analysis of buckling behavior[ The theory represents a comprehensive framework for developing any order and type of displacement based plate theory in the presence of delamination\ buckling\ and:or nonlinear material behavior as well as the interactions between these e}ects[ The linear form of the theory is validated by comparison with exact solutions for the behavior of perfectly bonded and delaminated laminates in cylindrical bending[ The theory shows excellent correlation with the exact solutions for both the inplane and out!of!plane e}ects and the displacement jumps due to delamination[ The theory can accurately predict the through!the!thickness distributions of the transverse stresses without the need to integrate the pointwise equilibrium equations[ The use of a low order of the general theory\ i[e[ use of both global and local displacement _elds\ reduces the computational expense compared to a purely discrete layer approach to the analysis of laminated plates without loss of accuracy[ The increased e.ciencycompared to a solely discrete layer theory\ is due to the coupling introduced in the theory between the global and local displacement _elds[