Silicones are often used for various types of coatings, but due to their poor mechanical properties, they often require modification to meet specific requirements. At the same time, various production processes throughout the world generate different types of waste, the disposal of which is harmful to the environment. One possible solution is to use production waste as a filler. In this paper, the authors investigated how the use of metallurgical production waste products as fillers changed the mechanical properties of silicone composites prepared by casting. Composite samples were characterized using tensile tests, resilience, pin-on-disc, Schopper–Schlobach abrasion, hardness, and density measurements. Based on the obtained results, the authors assessed the effect of each of the fillers used in different weight proportions. The results showed that the silicone composite filled with 5 wt% zinc dust showed the lowest decrease in tensile strength and Young’s modulus, with a simultaneous significant reduction in abrasion compared with the reference sample. This research shows that zinc waste can be successfully introduced into a silicone matrix in cases where it is important to reduce abrasive wear.

This paper presents the results of research concerning multilayered epoxy composites reinforced with different materials. The strength of multilayered composites depends, to a large extent, on the reinforcing material. The authors decided to compare the low velocity impact response and perform tensile strength tests on several composites, to ascertain the mechanical properties of the prepared composites. Five different reinforcing materials were provided for the research (two fabrics made from aramid fibers, two fabrics made from carbon fibers and one fabric made from polyethylene fibers). The composites were manufactured by the vacuum supported hand laminating method. The low velocity impact response tests were conducted with the use of a pneumatic launcher. Three strikers with different geometry (conical striker, hemispherical striker and ogival striker) were used. A comparison of the resulting damage to the composites after the impact of the strikers was based on the images obtained using an optical microscope; tensile tests were also performed. The experimental investigation showed significant differences in the mechanical properties of the composites, depending on the applied reinforcing material. It was found that, as a result of the impacts, less damage occurred in the composites which were characterized by a lower Young’s modulus and a higher tensile strength.

The promising research on flexible and tactile sensors requires conducting polymer materials and an accurate system for the transduction of pressure into electrical signals. In this paper, the intelligent sensitive mat, based on Velostat, which is a polymeric material impregnated with carbon black, is investigated. Various designs and geometries for home-made sensor mats have been proposed, and their electrical and mechanical properties, including reproducibility, have been studied through the tests performed. The mat pressure sensors have been interfaced with an Arduino microcontroller in order to monitor, read with high precision, and control the variation of the resistance under applied pressure. An approximation method was then developed based on a neural network algorithm to explore the relationship between different mat shapes, the pressure and stresses applied on the mat, the resistance of the conductive Velostat material, and the number of active sensing cells in order to control system input signal management.

The paper presents results obtained by experimental and numerical research focusing on the influence of the strikers’ geometry at the images of the destruction created in hybrid composite panels after applying impact load. In the research, the authors used four strikers with different geometry. The geometries were designed to keep the same weight for each of them. The composite panels used in the experiment were reinforced with aramid and carbon fabrics. An epoxy resin was used as a matrix. The experiments were carried with an impact kinetic energy of 23.5 J. The performed microscopy tests allowed for determination of destruction mechanisms of the panels depending on the geometry of the striker. The numerical calculations were performed using the finite element method. Each reinforcement layer of the composite was modeled as a different part. The bonded connection between the reinforcement layers was modeled using bilateral constraints. That approach enabled engineers to observe the delamination process during the impact. The results obtained from experimental and numerical investigations were compared. The authors present the impact of the striker geometry on damage formed in a composite panel. Formed damage was discussed. On the basis of the results from numerical research, energy absorption of the composite during impact depending on the striker geometry was discussed. It was noted that the size of the delamination area depends on the striker geometry. It was also noted that the diameter of the delamination area is related to the amount of damage in the reinforcing layers.

Waste from large-scale production processes is a growing environmental problem that can potentially be solved by using this waste as fillers in polymeric composites to improve the mechanical and tribological properties of polymeric matrixes. This paper presents research concerning how the introduction of fillers in the form of manganese residue and manganese(II) oxide changes the mechanical and tribological properties of epoxy composites produced by gravity casting. The research was carried out for composites with 2.5 wt.%, 5 wt.%, and 10 wt.% of fillers. Properties such as the density, hardness, resilience, flexural strength, deflection, flexural modulus, tensile strength, elongation at break, and Young’s modulus were determined. Moreover, based on the ball-on-plate test, the wear volume and friction coefficients of the tested materials were determined. Microscopic images of the abrasion profiles were also obtained. The geometry of the wear paths was measured with a profilometer, and the results showed that introducing fillers reduced the abrasive wear of the composites; however, in all cases, the fillers decreased the strength of the tested materials.

In this article, changes in NiTi alloy (Flexinol) electrical resistance during cyclic stretching with small elongation were investigated. A dedicated test stand consisting of motorized vertical test stand, force gauge, and electric resistance measuring device with an accuracy of 0.006 Ω was developed. A dedicated control algorithm was developed using LabVIEW software. Changes in electrical resistance were investigated for the 0.1 mm Flexinol wire with length of 120 mm. Testing was performed in the elongation range between 0.25% and 1.5% in martensite phase. Tested samples were subjected to 30 stretching cycles with a movement speed of 10 mm/min. Obtained results show that the cyclic stretching of Flexinol wire reduces its electrical resistance with each stretching cycle. Moreover, it was noted that changes in Flexinol electrical resistance during cycling stretching depend on the assumed elongation and number of the already performed stretching cycles. The observed electrical resistance change decreases with each stretching cycle. Thus, the observed changes are greater during the first stretching cycles. For elongations exceeding 1%, the Flexinol electrical resistance in the first stretching cycle increases. In each subsequent cycle, electrical resistance decreases, as in the case of the smallest value of assumed elongation. In almost all tested cases (except in the case with 1.5% of assumed elongation), Flexinol electrical resistance after 30 stretching cycles was smaller than before the test.