The long-term strength of rods under tension in an aggressive environment is investigated. We consider rods of various shapes of a single-cell cross-section (circle, square, and rectangles with different aspect ratios), provided that the areas of these cross-sections are equal. To determine the level of inclusions from aggressive environment into the rod at different time moments, approximate diffusion equations based on the motion of diffusion fronts from the rod surface are used. The high accuracy of the obtained approximation is shown. To assess the influence of an aggressive environment on long-term strength, the Yu. N. Rabotnov kinetic theory with two structural parameters (material damage and concentration of environment elements in the rod material) is used. The dependence of the time to rupture for the rods with various cross-section shapes under the same level of tensile stress is obtained. It is shown that the time to rupture for a rod with square cross-section under the indicated conditions exceeds the time to rupture for a rod with circular cross-section. In the case of rods with the same cross-section shape, the relation of the cross-section perimeter to time to rupture for the rod is considered. The minimum time to rupture for the considered rods is observed for rods of rectangular cross-section with the smallest thickness

中文翻译：

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侵略性环境下受拉杆蠕变断裂寿命与单细胞截面形状的关系

研究了在腐蚀性环境中受拉杆的长期强度。我们考虑各种形状的单细胞横截面的杆（具有不同长宽比的圆形，正方形和矩形），前提是这些横截面的面积相等。为了确定在不同时刻从侵蚀性环境进入棒中的夹杂物含量，使用了基于从棒表面扩散前沿运动的近似扩散方程。显示了获得的近似值的高精度。为了评估侵略性环境对长期力量的影响，喻。N. Rabotnov动力学理论具有两个结构参数（材料损坏和棒材中环境元素的浓度）。对于在相同水平的拉应力下具有各种横截面形状的杆，其破裂时间的依赖性得以获得。结果表明，在所示条件下，具有正方形横截面的杆的断裂时间超过了具有圆形横截面的杆的断裂时间。在具有相同横截面形状的棒的情况下，考虑到棒的横截面周长与破裂时间的关系。对于厚度最小的矩形截面的杆，观察到的杆断裂的最短时间 在具有相同横截面形状的棒的情况下，考虑到棒的横截面周长与破裂时间的关系。对于厚度最小的矩形截面的杆，观察到的杆断裂的最短时间 在具有相同横截面形状的棒的情况下，考虑到棒的横截面周长与破裂时间的关系。对于厚度最小的矩形截面的杆，观察到的杆断裂的最短时间