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The paper presents numerical and experimental results in the study of composite armour systems for ballistic protection. The modelling of protective structures and simulation methods of experiment as well as the finite elements method were implemented in LS DYNA software. Three armour systems with different thickness of layers were analyzed. Discretization for each option was built with three dimensional elements guaranteeing satisfactory accuracy of the calculations. Two selected armour configurations have been ballistically tested using the armour piercing (AP) 7.62 mm calibre. The composite armour systems were made of Al2O3 ceramics placed on the strike face and high strength steel as a backing material. In case of one ballistic structure system an intermediate ceramic- elastomer layer was applied. Ceramic- elastomer composites were obtained from porous ceramics with porosity gradient using pressure infiltration of porous ceramics by elastomer. The urea-urethane elastomer, as a reactive liquid was introduced into pores. As a result composites, in which two phases were interconnecting three-dimensionally and topologically throughout the microstructure, were obtained. Upon ballistic impact, kinetic energy was dissipated by ceramic body The residual energy was absorbed by intermediate composite layer. Effect of the composite shell application on crack propagation of ceramic body was observed.
This work concentrates on the mathematical analysis of the ceramic admixture influence on the temperature distribution into the polymerizable bone cement. It has been taken the simplified model, which consist in treatment the cement sample as a plate of the definite thickness. It has been determined the temperature field within the plate along the thickness of the sample, during the polymerization process. It was found that Al2O3 admixture added into the bone cement first of all affects on the change of maximal polymerazation temperature through the increase of the temperature condictivity coefficient a for PMMA-Al2O3 composite. Assuming that the coefficient a for the composite is twice higher than for PMMA, the calculated maximal temperature for the polymerizing system decreases to about 30%.
This work concentrates on the developing a method of the contraction and polymerisation temperature testing for the surgical cement. The linear contraction and maximum polymerisation temperature values have been determined for the pure Palacos R cement and for the same cement with Al2O3 admixture. The investigations were performed into metal mould at initial temperature 19 °C and 37 °C. Basing on the examination results it can be stated that on the contraction and polymerisation temperature the following factors have the influence: - temperature of the mould, - kind of the admixture, - a size of the admixture particles.
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