Agnieszka Sabik

Modeling of Composite Shells in 6–Parameter Nonlinear Theory with Drilling Degree of Freedom

Within the framework of a 6-parameter nonlinear shell theory, with strain measures of Cosserat type, constitutive relations are proposed for thin elastic composite shells. The material law is expressed in terms of five engineering constants of classical anisotropic continuum plus an additional parameter accounting for drilling stiffness. The theory allows for unlimited displacements and rotations. A number of examples are presented to show the correctness of the proposed model.

Linear analysis of laminated multilayered plates with the application of zig-zag function

An Equivalent Single Layer Model for linear static analysis of multilayered plates is considered in the paper. The displacements field of the First Order Shear Deformation Theory is supplemented with the Murakamis function to emulate the zig-zag effect. The applied Reissners Mixed Variational Theorem allows to assume an independent shear stress field of parabolic distribution in each layer and to satisfy the equilibrium conditions at the layer interfaces. The Finite Element implementation of the model is based on the application of the 9-node Lagrangian element with a selective reduced integration. Two numerical examples of symmetrically laminated plates are presented to illustrate the accuracy of presented approach.

Stability analysis of multilayered composite shells with cut-outs

A numerical stability analysis of an axially compressed multilayered composite shell is presented. The authors examine how the stability performance of a panel can be influenced by a centrally located square cut-out. The computations are performed within FEM computer program NX-Nastran (ver. 6.0). The stability is investigated by means of a linearized buckling analysis as well as of a non-linear large deformations incremental analysis . To get more insight into the performance of the layered structure, the failure index according to Tsai–Wu criterion is monitored in the study.

MONITORING OF CONCRETE CURING IN EXTRADOSED BRIDGE SUPPORTED BY NUMERICAL SIMULATION

The paper describes a mathematical model of concrete curing taking into account kinetics of setting reactions. The numerical model is implemented in the author’s program that was used to monitor thermal effects recorded in the concrete bottom plate of the extradosed bridge. Numerical approach was verified by experimental measurements and used for assessment of the current compressive strength due to degree of hydration of fresh concrete.