Automated processing of results from mechanical experiments on uniaxial compression of cancellous bone

Calculation of mechanical characteristics of spongy bone tissue is an urgent task in orthope-dics, as it allows to assess the risk of loosening of implanted structures during various types of corrective surgeries. Insufficient quality of bone tissue, determined by its mineral density, is one of the possible predictors of instability of fixation of the installed structure. In the literature, there are often articles devoted to the relationship between the strength properties of bone tissue and its density. This paper describes the developed algorithm for automatic processing of the results of ex-periments to determine the mechanical characteristics of spongy bone tissue of the human femoral heads, as well as the knee joint and vertebrae of cattle. For primary data processing, the moving average method was used. Primary processing is necessary to exclude redundant data from the deformation curve. After primary processing, the ultimate strength was determined from the stress-strain diagram as a global maximum, that is, the maximum stress value in MPa. Determining the Young's modulus comes down to finding a linear section of the stress-strain curve. The search is carried out on the section from the first point to the point with the maximum load. The abscissa axis corresponding to this section is divided into N equal segments. The least squares method is used to calculate the slope of the line approximating the curve on each seg-ment. From the resulting set of segments with calculated slope angles, a pair of adjacent ones with the largest sum of angles is selected. The segment from the selected pair, for which the calculated angle is the largest, corresponds to the desired linear section of the curve. Automation made it possible to process a large number of experimental results in a short time, as well as to cluster the results obtained earlier. Regression relationships were obtained for the strength limits and Young's moduli of spongy bone tissue of the femoral heads, as well as the knee joint and vertebrae of cattle, allowing these characteristics to be calculated using Hounsfield units.