Mechanical Properties and Strength Reliability of Impregnated Wood after High Temperature Conditions

Research on the Durability and Reliability of Industrial Layered Coatings on Metal Substrate Due to Abrasive Wear

This paper discusses the issue of evaluating the durability and reliability of organic coatings applied on the outer surfaces of roofing sheets. Two sheets, i.e., ZA200 and S220GD, were selected as research objects. Metal surfaces of these sheets are protected with multilayer organic coatings to protect them against weather conditions, assembly, and operational damages. The durability of these coatings was tested by evaluating their resistance to tribological wear using the ball-on-disc method. The testing was conducted in reversible gear according to a sinuous trajectory at a 3 Hz frequency. The test load was 5 N. When the coating was scratched, the metallic counter sample touched the metallic surface of the roofing sheet, which indicated a significant drop in electrical resistance. It is assumed that the number of performed cycles specifies the durability of the coating. Weibull analysis was applied to examine the findings. The reliability of the tested coatings was evaluated. The tests have confirmed that the structure of the coating is essential for the durability and reliability of products. The research and analysis included in this paper present important findings.

Adhesive Bonding of Scots Pine Wood from the Szczecinek Forest District for the Production of Garden Equipment: An Experimental Investigation

This work aimed to determine the gluability of pressure-impregnated pine wood with two protection agents used in production technologies for garden equipment and their effect on the strength, water resistance and thermal resistance of joints, as well as their susceptibility to aging. The tests were carried out on Scots pine wood (Pinus sylvestris L.) purchased from the forest districts of the Regional Directorate of State Forests in Szczecinek town, Poland. For the impregnation, two commercial protection agents were used. The pressure impregnation of the elements and gluing with the PUR adhesive were carried out by a garden furniture manufacturer. The strength and durability after aging tests of glued joints were performed in accordance with the procedure described in Technical Approval No. AT-15-2948/00 and the PN-EN ISO 9142 standard. The collected experimental data can be used in technological solutions, mainly for processes which involve gluing wood after impregnation.

Wood Preservation Practices and Future Outlook: Perspectives of Experts from Finland

This paper examined wood preservation practices and outlook considering climate change from the perspective of Finnish experts through interviews. Key findings highlighted that: (1) pressure impregnated wood will continually evolve and secure its market, and it seems worthy of developing modified wood products, especially with the increasing attention to recyclability and lifecycle concepts; (2) demand for highly processed surface treatment products is high; (3) opportunities for more sustainable and environmentally friendly wood preservation methods, and thus production volume will increase in the future; (4) increasing mold problems in Finland due to climate change make surface treatment more important than ever; (5) demands for fire protection treatments are increasing, but fire testing fees and processes have slowed product development; (6) although the possibility of the spread of termites triggered by global warming to Finland seems to be a future scenario, this issue needs to be considered in products exported to hot countries; and (7) preservatives have become more critical to protect untreated wood from the adverse effects of climate change. It is believed that this study will help accelerate the transition of innovative and environmentally friendly wood treatments on the Finnish market, thereby promoting the use of wood in the building construction industry.

Influence of Thermal Shocks on Residual Static Strength, Impact Strength and Elasticity of Polymer-Composite Materials Used in Firefighting Helmets

The article presents results of experimental studies on mechanical properties of the polymer-composite material used in manufacturing firefighting helmets. Conducted studies included static and impact strength tests, as well as a shock absorption test of glass fiber-reinforced polyamide 66 (PA66) samples and firefighting helmets. Samples were subject to the impact of thermal shocks before or during being placed under a mechanical load. A significant influence of thermal shocks on mechanical properties of glass fiber-reinforced PA66 was shown. The decrease in strength and elastic properties after cyclic heat shocks ranged from a few to several dozen percent. The average bending strength and modulus during the 170 degree Celsius shock dropped to several dozen percent from the room temperature strength. Under these thermal conditions, the impact strength was lost, and the lateral deflection of the helmet shells increased by approximately 300%. Moreover, while forcing a thermal shock occurring during the heat load, it was noticed that the character of a composite damage changes from the elasto-brittle type into the elasto-plastic one. It was also proved that changes in mechanical and elastic properties of the material used in a helmet shell can affect the protective abilities of a helmet.