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Pozycja Local Buckling of Thin-Walled Column of Square Cross-Section Made of In-Plane Coupled Laminate.(Lodz University of Technology. Faculty of Mechanical Engineering. Department Division of Dynamics., 2016) Kołakowski, Zbigniew; Teter, Andrzej; Pasierbiewicz, DamianThe non–symmetric, general laminate exhibits different types of coupling between the extension, shearing, bending and twisting. For practical reasons, the in–plane coupled laminate is a particularly interesting. In this case, the coupling between shearing andextension takes place. Details calculations were performed for a short columns of square cross-section made of in–plane coupled and fully uncoupled laminate under uniform compression. Finite element method (FEM) and analytical–numerical method (ANM) were performed. In FEM analyses, the eigenbuckling problem has been solved using the Lanczos method, whereas the nonlinear buckling analysis were performed using the Newton– Raphson method and the Ritz method. In ANM analyses, the Koiter’s asymptotic theory is applied. The relationship between forces/moments and deformations/curvature were described using classical lamination theory (CLT). The coupling between in–plane shearing and extension has a significant influence on the behavior of thin–walled structures under compression.Pozycja Comparision of Numerical Results with Known Solutions of Buckling Problem of Pressured Shallow Spherical Shells.(Lodz University of Technology. Faculty of Mechanical Engineering. Department Division of Dynamics., 2016) Lykhachova, Olga; Kołakowski, ZbigniewBuckling problem of pressured shallow spherical shells is studied numerically for two types of finite elements: axisymmetric and non–axisymmetric. A very good correspondence of obtained results and known solutions is revealed in the case of clamed and hinged spherical segments for both types of finite elements. The comparison of results also shows that using non–axisymmetric finite element lets one get full pre– and post–buckling equilibrium path in the range of relative deflections w=h.Pozycja Static and dynamic interactive buckling of composite columns.(Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej, 2009) Kołakowski, ZbigniewThe static and dynamic problem of interaction of global buckling modes in compressed columns with complex open and closed cross-sections was considered in the paper. The columns made of laminate composites were assumed to be simply supported at both loaded ends. A plate model was adopted in the analysis. The equations of motion of individual pla- tes (Schokker et al., 1996; Sridharan and Benito, 1984) were obtained from Hamilton’s Principle, taking into account all components of iner- tia forces (Teter and Kołakowski, 2005). Within the frame of the first order nonlinear approximation, the dynamic problem of modal interac- tive buckling was solved by the transition matrix using a perturbation method. Distortions of cross-sections and the shear-lag phenomenon were taken into consideration in the problem solution. A modification of the quasi-bifurcation dynamic Kleiber-Kotula-Saran criterion (Kleiber et al., 1987) was proposed. A comparison of the proposed modification to the Budiansky-Hutchinson criterion (Budiansky and Hutchinson, 1966; Hutchinson and Budiansky, 1966) was presented for a rectangular pulse loading.