Paper presents comparative analysis of experimental and analytical results of mechanical properties on truss members. Deformations are experimentally determined on the model of plexiglass truss, using six strain gauges. Strain gauges are measuring the deformation of truss members at the pre-defined measuring points. Knowing modulus of the elasticity and Hooke’s law, it is possible to calculate the stress values. The experimental stress values will be compared with the values obtained by the software and the results will be analyzed.

We consider the machinability of the material as a technological feature that expresses the ability of the material to remove the maximum number of shavings from its machined surface in the minimum time with satisfactory processing quality, with as little cutting force as possible and as little tool wear as possible. The aim of the experimental research in this work is to examine the significance of the influential kinematic parameters of the roughness of the machined surface, i.e. of wood density (ρ), feeding speed (s’) and the number of spiral cutting knices (z) in the process of planning massive wood on the roughness of the newly created processing surface, which will vary in 14 trials, of which 6 are repetitions in the central point of the compositional plan, where the roughness parameter Ra is obtained as an output value, and the analysis of experimental data from the point of view of possible achievement of a better quality of the processed surface. The obtained mathematical model is essentially applicable and can be used to optimize the machinability parameters in the planning process of solid wood, and the experimental results can be used in further research into other parameters of the machinability of solid wood in the planning process.

This study investigates the influence of ultraviolet (UV) radiation on the mechanical properties of Fused Deposition Modeling (FDM) 3D printed materials, specifically polycarbonate (PC) and polylactic acid (PLA) specimens. The research involves conducting experiments on five test specimens of each material exposed to UV radiation and comparing their mechanical properties to those of five control specimens that remain unexposed. The results reveal a significant mean difference between the mechanical properties of the control and UV-exposed materials. UV radiation caused a decrease in tensile strength for the PC material, while the PLA material exhibited an increase in tensile strength. The impact of UV radiation on PLA was more substantial compared to PC. Flexural strength testing showed an enhancement in strength for the UV-treated materials, with UV treatment having a greater influence on the flexural strength of PLA compared to PC. The mechanical properties of PLA were more significantly impacted by UV radiation than those of PC. The study findings suggest that PC and PLA materials exhibit different responses to UV exposure, which may have implications for their practical applications. Further research is needed to fully understand the underlying mechanisms governing these divergent responses and to optimize the performance of each material under UV radiation.

This study aims to investigate the influence of thermal modification (TM) on the physical and mechanical properties of wood. For this purpose, the experimental part focused on selected influential parameters, namely temperature, residence time, and density, while the four-point bending strength is obtained as the output parameter. The obtained experimental data are stochastically modeled and compared with the model created by genetic programming (GP). The classical mathematical analysis obtained treatment parameters in relation to the maximum bending strength (T = 187 °C, t = 125 min = 0.780 g/cm3) and compared with the results obtained by genetic algorithm (GA) (T = 208 °C, t = 122 min, and = 0.728 g/cm3). It is possible to obtain models that describe experimental results well with stochastic modeling and evolutionary algorithms.

Sedentary lifestyle and physical inactivity are some of the leading risk factors for cardiovascular diseases and total mortality. The aim of this study was to examine the effects of dosed physical exercise on the nutritional status of recreational athletes. In this study, we included 50 respondents of both sexes between the ages of 18 and 55, who engage in recreational physical exercise, were included in the study. All subjects had their body mass and height measured before the start of exercise and after three months, based on which the body mass index (BMI), waist circumference, and body fat percentage were determined. The exercise was carried out according to the plan 3 times a week for 75 minutes and combined anaerobic training (45 minutes) and aerobic training (30 minutes). The average body weight of all subjects at the beginning of the study was 81.74 kg, while at the end it was 80.16 kg. The average body weight of men at the end of the study was 1.95 kg less than the initial value, while it was 0.71 kg less for women. There is a statistically significant difference in BMI, waist circumference and fat percentage in the total number of respondents at the beginning and at the end of the study. Regular physical activity and exercise have a positive effect on BMI, waist circumference and body fat percentage, showing the importance of exercise in the prevention of obesity and chronic non-communicable diseases.

One of the advantages provided by fused deposition modelling (FDM) 3D printing technology is the manufacturing of product materials with infill structure, which provides advantages such as reduced production time, product weight and even the final price. In this paper, the tensile mechanical properties, tensile strength and elastic modulus, of PLA, Tough PLA and PC FDM 3D printed materials with the infill structure were analysed and compared. Also, the influence of infill pattern on tensile properties was analysed. Material testing were performed according to ISO 527-2 standard. All results are statistically analysed and results showed that infill pattern have influence on tensile mechanical properties for all three materials.

Paper presents the design of experiment and determining mathematical model to calculate roughness parameter of wood planned surface. For design of experiment three different types of solid wood were taken and processed on the planner with three different displacements and three different cutting speeds. After measuring the roughness parameter Rz, experimental results were obtained on the basis of which the central composite plan of the experiment was made. Based on that, a model of roughness parameter Rz was made, which is adequate and with high accuracy. The significance of the model coefficients was determined using the R software and the results were presented using the Design Expert software.

The paper presents the results of modeling the bending strength of wood. During the experimental examination and definition of the model, solid wood was taken, where the bending was performed perpendicular to the grain. The experiment was done with thirteen replications and the input values that varied at three levels were wood density and board thickness. The thirteen-repetition experiment also involved four repetitions in the marginal areas, so two more wood densities and two board thicknesses had to be taken. The experimental measurement was performed in the laboratory of the Technical Faculty Bihać. Based on the experimental results, a sufficiently adequate mathematical model of the breaking force of a solid wood panel perpendicular to the grain is obtained.

One of the advantages of FDM technology is the production of product materials with infill structure. In order to make the most of this advantage, the behaviour of FDM printed material with infill structure under different loads has to be analyzed and understood. Therefore, the goal of this experimental research is to analyze influence of infill density (100%, 80%, 60% and 20%) on tensile mechanical properties (tensile strength and elastic modulus) of PLA antibacterial nanocomposite, tough PLA and ABS-X 3D printed materials.

Widely used additive manufacturing technique for plastic materials is Fused Deposition Modelling (FDM). The FDM technology has gained interest in industry for a wide range of applications, especially today when large number of different materials on the market are available. There are many different manufacturers for the same FDM material where the difference in price goes up to 50%. This experimental study investigates possible difference in strength of the 3D printed PLA material of five different manufacturers. All specimens are 3D printed on Ultimaker S5 printer with the same printing parameters, and they are all the same colour.