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Fibre-Reinforced Polymers and Steel for the Reinforcement of Wooden Elements - Experimental and Numerical Analysis
These elements are innovative and of interest to many researchers for the reinforcement of wooden elements. For the reinforced beam elements, the effect of the reinforcement factor, FRP and steel elastic modulus or FRP and steel arrangement of the reinforcement on the performance of the flexural elements was determined, followed by reading the load-displacement diagram of the reinforced beam elements. The finite element model was then developed and verified with the experimental results, which was mainly related to the fact that the general theory took into account the typical tensile failure mode, which can be used to predict the flexural strength of reinforced timber beams. From the tests, it was determined that reinforced timber beam elements had relatively ductile flexural strengths up to brittle tension for unreinforced elements. As for the reinforcements of FRP, the highest increase in load-bearing capacity was for carbon mats at 52.47%, with a reinforcement grade of 0.43%, while the lowest was for glass mats at 16.62% with a reinforcement grade of 0.22%. Basalt bars achieved the highest stiffness, followed by glass mats. Taking into account all the reinforcements used, the highest stiffness was demonstrated by the tests of the effectiveness of the reinforcement using 3 mm thick steel plates. For this configuration with a reinforcement percentage of 10%, this increase in load capacity was 79.48% and stiffness was 31.08%. The difference between the experimental and numerical results was within 3.62–27.36%, respectively.
Qualitative and Strength Analysis of Pine (Pinus Sylvestris L.) Wood Materials - Study of Pallet Elements
The manufacture of packaging products requires determining the strength requirements of the components that make up the structural elements of pallets, crates and other packaging. Wood, as a renewable material, is the basic raw material for manufacturing wooden pallets. The premise of the research is that the strength of pallets is derived from the characteristics of the components of the subassemblies. Strength tests of lumber were carried out, which determine the evaluation of the suitability of sawn materials. Verification of raw material properties determines the adaptation of individual assemblies to static and dynamic force loads. Pine (Pinus sylvestris L.) lumber was verified, taking into account the origin of the cross-sectional area and the presence of anatomical structure features. The results of the study confirm the influence of wood origin on the suitability of pine wood for wood packaging. The influence of a certain origin from the log can translate into changes in strength properties. It was found that wood density is not a critical parameter for evaluating the strength of lumber and product. Tests of separated structural lumber for wood packaging indicate significant differences in the condition of the wood and the magnitude of the strength parameter.