The study assessed the quality of pine lumber by marking the modulus of elasticity in the horizontal system. The research material was a plank with the following dimensions: 137 mm wide × 39.50 mm thick × 3485 mm long. The pine wood was obtained by sawing timber in the form of logs with round cross sections and originating from the Forest Division Olesno (50°52′30″ N, 18°25′00″ E). Each long log was sawn to provide four logs of about 3.5 m, which were marked as butt-end logs (O), middle logs (S)—2 items, and top logs (W). The origin of the logs from the trunk (Pinus sylvestris L.) has a significant impact on the physical and mechanical properties of the wood from which they are made. Only butt-end logs (log type O) allows for the production of high-quality timber elements. The pine timber that was evaluated in this paper had a high density of about 570 kg/m3 and a high percentage of timber items were assigned to class C24 and higher (above 50%). The adopted horizontal model of evaluation of the modulus of elasticity gave similar results to those obtained in an evaluation according to the EN-408.

The paper assessed the feasibility of manufacturing glued structural elements made of pine wood after grading it mechanically in a horizontal arrangement. It was assumed that the pine wood was not free of defects and that the outer lamellas would also be visually inspected. This would result in only rejecting items with large, rotten knots. Beams of the assumed grades GL32c, GL28c and GL24c were made of the examined pine wood. Our study indicated that the expected modulus of elasticity in bending was largely maintained by the designed beam models but that their strength was connected with the quality of the respective lamellas, rather than with their modulus of elasticity. On average, the bending strength of the beams was 44.6 MPa. The cause of their destruction was the individual technical quality of a given item of timber, which was loosely related to its modulus of elasticity, assessed in a bending test. Although the modulus of elasticity of the manufactured beam types differed quite significantly (11.45–14.08 kN/mm2), the bending strength for all types was similar. Significant differences occurred only during a more detailed analysis because lower classes were characterized by a greater variation of the bending strength. In this case, beams with a strength of 24 MPa to 50 MPa appeared.

Different kind of foams, usually made from polymers, metals, ceramics, glass, etc. have been widely used in various branches of civil engineering since the 80s. The most common are polyurethane foams. Since their role in construction nowadays is not only to act as a thermal barrier but also to take some of loads, the engineers need to know also their mechanical properties. This implies that manufacturers or designers must perform a number of laboratory tests in order to find a set of substantial parameters of this particular material. Due to noticeable orthotropic behavior of foams, one needs to carry out several laboratory tests to identify elastic properties only. Here, an enhanced testing methodology is proposed to reduce the number of tests required for characterization of elastic orthotropic properties of foams. By combining the advanced measurement techniques, non-traditional experimental setup, numerical modeling and inverse analysis one can capture all nine elastic properties from just two or three tests. In the paper, full experimental and numerical procedures are presented and validated by noisy pseudo-experimental data.

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Abstract. Sandwich panels with thin metal sheets and a thick, anisotropic foam core are considered in the paper. While the experiments show a large anisotropy of core's material, this factor is usually neglected due to elementary assemble of sandwich panels and basically simple boundary conditions. In this paper the problem of rectangular openings is considered. Thus, the influence of two main factors on the response of modelled panels are analysed, mainly: the material model of the PU foam core and openings existing in the panel. Sensitivity analysis with respect to these factors is presented. In the final part of the paper, the conclusions are formulated.