THE ELASTOPLASTIC PROPERTIES OF THE TRABECULAR BONE TISSUE

: The trabecular bone tissue is a natural composite material with the developed hierarchical structure. The detailed study of its mechanical properties is important both for understanding the mechanism of injury production and for developing the optimal designs for osteosynthesis, prosthetics, and replacement of bone defects. The study of mechanical behavior of the trabecular bone under the cyclic loading is fundamental for the formation of current approaches to the prevention, as well as to the conservative and surgical treatment of fractures, as the bone tissue has different strength in different parts of the skeleton. The authors studied the uniaxial compression deformation behavior using five cylindrical specimens made from fragments of the trabecular bone tissue of lateral condyle of the tibia. The ratios of elastic and nonreversible deformations in the trabecular bone tissue of the subchondral area of the tibia under the uniaxial compression were investigated depending on the magnitude of the applied load and the total deformation. The authors carried out phased loading with the step of 0.5 % to 10 % of deformation and then with the step of 1 % to 15 % of deformation. The study showed that the trabecular bone is deformable both elastically and plastically. The elastic properties of bone tissue slightly decrease only with the appearance of macroscopic cracks in the sample. Thanks to the high porosity (30–90 %) and organic components, the trabecular bone is significantly deformable. The deformation of less than ~3 % is elastic and, therefore, does not lead to nonreversible changes in the trabecular bone tissue. With deformations exceeding 3 %, the nonreversible changes in the microstructure causing a depressed fracture of the limb bones take place in the bone tissue.