Aleksander Muc

Optimal fibre orientation for simply-supported, angle-ply plates under biaxial compression

Abstract Optimum laminate configurations for laminated rectangular plates under uniaxial or biaxial compression are investigated and are obtained under buckling constraints. Complete freedom is permitted in the selection of the ply angle variation through the thickness; however, it is proved that the maximum buckling load occurs when the orientation angle in each of the layers is the same. Three types of optimal angle (directions) are obtained in terms of the material properties, the geometrical properties and the type of buckling mode. They are expressed in closed analytical form.

Transverse shear effects in stability problems of laminated shallow shells

Abstract This paper presents the analysis of the accuracy of the classical shell theory in the prediction of buckling loads of laminated shallow shells of revolution loaded by external pressure or axially compressed. The shells studied are circular cylinders, barrels, inverse barrels and spherical sections. In each case the boundary conditions are simple supports.

On the buckling of composite shells of revolution under external pressure

Abstract The paper deals with the buckling analysis of axisymmetric fully clamped composite shells of revolution such as spherical caps, torispheres and hemispheres. Its first part is devoted to linear buckling analysis in order to determine the appropriate divisors for buckling pressures. Then, the effects of fibre orientation on buckling pressure calculated with the use of the BOSOR4 program are discussed for single-layered (angle-ply), two-layered and quasiisotropic composite shells made of unidirectional glass and carbon/epoxy resin. It is shown that the maximal buckling pressures occur for quasi-isotropic composite shells. The upper and lower bounds of buckling loads for arbitrary fibre orientations of composite torispheres and hemispheres are also proposed.

Methods of Infrared Non-Destructive Techniques: Review and Experimental Studies

The first part of the paper is devoted to presentation and discussion of the capabilities, advantages and limitations of infrared non-destructive techniques (IR NDT). Then, the results of experimental analysis performed by testing several specimens made of woven glass epoxy resin and containing artificial delamination in the form of square PTFE foil are presented.

Application of Composite Materials in Modern Constructions

The paper presents the general review of application of composite materials including the distinction of their specific features. Also short overview of history of composite materials is conducted. The major subject is the explanation, what is advantage of the composites over traditional materials. Additionally, a lot of examples demonstrate in which areas of current industry they are applied.

Numerical and experimental buckling and post - buckling analysis of composite cylindrical panel with delamination

The present work is devoted to the analysis of a buckling behavior of a cylindrical composite panel. The considered structure is subjected to the uniform axial compression. The wall of the panel consists of the 8 layers. In addition, in the geometrical center of the structure there is a square delamination located between the fourth and the fifth layer. The main goal is to determine the buckling and post - buckling behavior as well as the influence of the delamination on the stability of the structure. The nonlinear numerical analysis is carried out with aid of the FEM method. The experimental verification is also performed. The results obtained from numerical and experimental analysis show very similar behavior of the structure.

Design of Particulate-Reinforced Composite Materials

A microstructure-based model is developed to study the effective anisotropic properties (magnetic, dielectric or thermal) of two-phase particle-filled composites. The Green’s function technique and the effective field method are used to theoretically derive the homogenized (averaged) properties for a representative volume element containing isolated inclusion and infinite, chain-structured particles. Those results are compared with the finite element approximations conducted for the assumed representative volume element. In addition, the Maxwell–Garnett model is retrieved as a special case when particle interactions are not considered. We also give some information on the optimal design of the effective anisotropic properties taking into account the shape of magnetic particles.

Modelling of fatigue damage evolution in composite multilayered cylindrical shells

This work presents modelling and numerical analysis of shells with axisymmetric or embedded elliptic delaminations. Numerical studies are conducted including cyclic buckling, contact problems in the post-buckling range and optimisation problems associated with searching from the minimum of the crack growth per one cycle. Finally, the fatigue life is estimated with the use of the fuzzy set approach.

Defects in Single Walled Carbon Nanotubes (SWCNT)

In the paper the stress-strain of pristine and defective single walled carbon nanotubes are investigated. The defects are in the form of point vacancies. The axial deformations of structures are studied only. A special attention is focused on the effects of material and geometrical properties of nanostructures on the results.