This paper analyses the issues relative to the modelling of tubular (cylindrical) composite structures. This paper aims to describe the design of a multi-layer structure of filament-wound composite pipes where, after loading, the hoop-stress distribution would be as uniform as possible. That would allow the mass of the composite to decrease while maintaining the proper mechanical strength. This publication presents the development of a calculation model dedicated to mono- and multi-layered tubular composite structures. The equations describing the stress pattern were based on the Lamé Problem, whereas to describe the modelled structures, an anisotropy coefficient was introduced and interlayer pressures values were determined. To verify the calculations, experimental studies were performed. The test specimens were fabricated by winding fibre bundles around a steel core (as rings with an internal diameter of 113 mm and a height of 30 mm). For the test, the method of pressing a conical ring into a split ring, which acts on the internal surface of the tested cylindrical sample, was selected. The operation of the test rig (test stand) was simulated using the Finite Element Method (FEM). Measurements with strain gauges were conducted during the experiments.

We report on the application of l,d-poly(lactic acid) (l,d-PLA) with dispersed Single-Walled Carbon Nanotubes (SWCN) as a flexible translucent electrode for organic devices. We used commercially available nanotubes in various weight ratios from 0 to 8% dispersed in chloroform polymeric solution by ultrasonication and were drop cast. The created hybrid materials were investigated by differential scanning calorimetry to determine the influence of SWCN content on the thermal behavior, while polarizing optical microscope was used to find the effect of mechanical deformations on the textures. Drop-cast films were studied by optical transmittance, conductivity, dielectric properties and by thermal imaging under applied potential. Thermal imaging provided evidence of visible voltage-activated conduction. Simple mechanical deformation such as bending with stretching at edge to ca. 90 and elongation test were performed. Moreover, interactions between l,d-poly(lactic acid) and SWCN were investigated by FT-IR and NMR spectroscopy. Finally, we can conclude that the thermographic examination of created films permits fast, simple and inexpensive localization of defects on the surface of l,d-PLA:SWCN film, together with the electrical properties of the films.

We report here the preparation and thermal, electrical and mechanical characterization of binary and ternary films based on l,d-poly(lactic acid) (l,d-PLA) and 4′-pentyl-4-biphenylcarbonitrile (5CB) and Single Walled Carbon Nanotubes (SWCN) with various weight ratio. The transitions for all investigated hybrid compositions detected by differential scanning calorimetry method were shifted to lower temperatures with increasing the concentration of 5CB in the mixture with polymer. Frequency domain dielectric spectroscopy method and thermal imaging together with polarized optical microscope were used to study electric and structural properties of created hybrid compositions. The best electrical conductivity was observed for hybrid composite l,d-PLA:5CB:SWCN with ratio 10:1:0.5 w/w/w - resistance of 41.0 Ω and thermal response up to 160 °C without causing any damages. Films in crystal form are much more inflexible than in amorphous and can be explain by the cold crystallization occurs at heating while the materials changed their physical state. The value of ε′ increases with increasing the 5CB admixture. Moreover, the addition of 5CB to l,d-PLA resulted in increased flexibility of polymeric base films. The best material flexibility and short-term strength were obtained for l,d-PLA sample with 9% 5CB content.

Mechanical and thermal strains in organic photovoltaic layers deposited on poly(ethylene terephthalate) (PET) and glass substrates and the resulting effect on the bandgap energy have been determined for the organic charge-transfer polymer PTB7. Its strong bathochromic shift of the absorption spectra under pressure also depends on the layer preparation method. The effects of different solvents and PTB7 concentrations on agglomerate formation were also studied. A perfect linear dependence of the concentration vs. absorbance was observed up to 1.81 × 10⁻⁷ M for chlorobenzene or o-dichlorobenzene solution. The thermal image monitoring of the current response at an increasing potential showed a linear current-to-voltage tendency, indicating that the conductive behaviour of the polymer depends on the substrate used in PET/ITO/PTB7/Ag/ITO/PET and glass/ITO/PTB7/Ag/ITO/glass devices. The PTB7 layer on the PET/ITO substrate displays superior mechanical properties suitable for flexible photovoltaic panels exposed to strain and deformations.

The paper presents the measurements and the analysis of deformations between lay-ers and the outside surface of a multilayer filament wound composite pipe. The pipe was made through the hoop wrap of roving stripes hence ring-shaped samples were prepared for test purposes. Carbon fibers and glass fibers were used for winding. In the course of their manufacturing, strain gauges and fiber optic sensors were placed be-tween the composite layers. Then, the strength tests were performed. The samples were subjected to the internal pressure of 30 MPa. During the tests peripheral defor-mations were measured on outside surfaces of individual layers of the structure.

This paper presents a strength analysis of a steel container frame fastened to a Jelcz 8x8 chassis with four ISO 1161 corners. As part of the work, optimisation of the structure was performed using the numerical finite element method (FEM) and experimental tests with the use of strain gauges. The results of simulations and tests are summarised in appropriate tables and in the form of the distribution of stress contour lines using the Huber-Mises hypothesis.