Skin–Stiffener Separation in T-Stiffened Composite Specimens in Postbuckling Condition

Optimization of Composite, Stiffened, Imperfect Panels under Combined Loads for Service in the Postbuckling Regime

Local buckling and postbuckling of panels stiffened by stringers and rings and subjected to combined in-plane loads is explored with the use of a single module model that consists of one stringer and a width of panel skin equal to the stringer spacing. The cross-section of the skin-stringer module is discretized and the displacement field is assumed to vary trigonometrically in the axial direct...

Nonlinear Finite Element Formulation for The Postbuckling Analysis of Stiffened Composite Panels with Imperfections

Postbuckling analysis of stiffened laminated composite panels, using a higher-order shear deformation theory

The investigation aims at: (i) constructing a modified higher-order shear deformation theory in which Kirchhoff's hypotheses are relaxed, to allow for shear deformations; (ii) validating the present 5-parameter-smeared-laminate theory by comparing the results with exact solutions; and (iii) applying the theory to a specific problem of the postbuckling behavior of a flat stiffened fiber-reinforc...

Buckling and Postbuckling of Concentrically Stiffened Piezo-Composite Plates on Elastic Foundations

This research presents the modeling and analysis for the buckling and postbuckling behavior of sandwich plates under thermal and mechanical loads. The lay-up configurations of plates are laminated composite with concentric stiffener and surface mounted piezoelectric actuators. The plates are in contact with a three-parameter elastic foundation including softening and/or hardening nonlinearity. ...

Identifying delayed separation in plasma homocysteine specimens.

The delayed separation of plasma from the cellular components of blood can lead to falsely elevated homocysteine results. The incidence of delayed separation in patient specimens was examined by using the ratio of arginine to the sum of arginine plus ornithine [arg/(arg + orn)], a ratio <0.50 being consistent with delayed separation. Two groups were examined: 1) low homocysteine (<10 micromol/L...