PSI - Issue 36

Petro Yasniy et al. / Procedia Structural Integrity 36 (2022) 211–216 Yasniy Petro et al./ Structural Integrity Procedia 00 (2021) 000 – 000

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The modification was performed at a temperature of 19 ° C. After the allotted time, the samples were removed and dried at temperature of 18- 21 ° C for 48 hours. The resulting new composite material is environmentally friendly, waterproof, non-flammable and non-toxic. Experimental studies of prisms with a cross-section of 30x30x120 mm were performed on a modern test machine STM-100 (Homon at el. (2020)). The obtained samples were tested by axial compression along the fibers under short-term loading at rigid test mode (by increasing the displacements of the press plate) according to current standards (ANSI / AF & PA: 2012;

ASTM D 143-14: 2014; EN 380: 2008; Eurocode 5: 1995). The extent of experimental studies is given in Table 1.

Table 1. Extent of experimental studies of solid modified wood Wood species Method of modification

Impregnation time, hours Number of samples, pcs

Birch Alder Ash

Surface modification Surface modification Surface modification

12 12 12

6 6 6

3. Results and discussion In our previous research (Yasniy and Homon (2021)) we proposed a model of the actual work of solid, glued and modified wood on compression along the fibers under short- term load, which fully allows to give a real ‘σ с - и с ’ deformation diagram of such materials, both on the ascending and descending branches (Fig.1).

Fig. 1. Complete strain diagram ‘ stress σ c – strain u c ’ of wood and composite materials based on axial tensile along the fibers

According to the above diagram (Fig.1) wood based composite materials also work, which will be confirmed below. Due to the results of experimental studies of twin prisms of hardwood based composite materials and polymer composition ‘ silor ’ with a cross-section of 30x30x120 mm, with the surface modification, the real (complete) diagrams ‘ stress σ s – deformation u c ’ (Fig. 2) were obtained and the main strength and deformability characteristics in all four areas were identified according to (Yasniy and Homon (2021)). The analysis will be performed in comparison with of 60 years old samples that were tested at a standard moisture of 12%. In the first section, the newly formed composite hardwood and ‘ silor ’ based materials (Fig. 2) have the following indicators: for birch wood the stress increases by 6.7% ( σ c1 = 9.5 MPa), and the relative deformations decrease by