English to Russian Tech/Engineering Aerospace / Aviation / Space standard

Добрый день!
Помогите, пожалуйста, перевести feed preparation length в следующем контексте:

Plastic-deformation theory is employed to investigate the plastic deformation in pipe and tube bending. The major contribution of this
paper is that it provides solutions to seven common tube-bending questions. In this paper, some practical formulae are developed to explain
the phenomena in tube bending and their magnitudes are also derived. These are: (1) stresses in the bend; (2) wall thickness change; (3)
shrinking rate at the tube section; (4) deviation of neutral axis; (5) feed preparation length of the bend; (6) bending moment, and (7) flattening.

The feed preparation length of a bend is shorter than the geometric centroid axis arc length (Fig. 7). Its infuence factors are: (1) The sector of constant deviation of neutral axis. Within this sector all sections are finally formed, calculate the length of this sector, which is by the arc length of neutral axis. (2) Transitional sector, it is between the section of constant deviation of neutral axis and the section of straight tube. This transitional sector behavior of the cross-section, which from a straight tube gradually varied to the final deformation dimensions. These dimensions include wall thickness, diameter shrinking and neutral axis deviation. Therefore, for calculating the length of this sector, only half of the deviation value is used. From Fig. 7 the distribution of the neutral axis can be seen.

Заранее спасибо!