Abstract A tolerancing method highlighting trade-offs against key design variables of mechanical systems is proposed and applied to herringbone-grooved gas journal bearings. Gas bearings typically suffer from a subsynchronous instability, demanding a very tight tolerance on the bearing clearance and groove depth. Classical optimization techniques look for the most stable design, which does not necessarily lead to most robust design against manufacturing deviations. The proposed method uses a normalized multidimensional lookup table of stability score (critical mass), covering a large design space of gas bearings. It then dimensionalizes the table for a specific rotor–bearing system, highlighting regions of the hyperspace where the system is stable. The hyperspace is sliced into 2D maps and a Monte Carlo method creates windows within the stable domain along the two most critical design variables regarding manufacturing: the bearing clearance and the groove depth. Width and length of the windows represent the manufacturing tolerance allowed for the two parameters to remain stable. A Pareto front of optimum windows in the entire hyperspace is then compiled. It displays the trade-off between the tolerance against deviation in clearance and groove depth, allowing the designer to select a nominal geometry tailored to the available manufacturing methods. A test rotor is analyzed with this method and the effects of pressure, speed, viscosity, radius, mass, and centrifugal growth on manufacturing tolerances are investigated, highlighting that the radius and viscosity have the greatest impact on the robustness.

中文翻译：

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沟槽气体轴颈轴承的多目标优化，以提高制造公差的稳健性

摘要 提出了一种突出平衡机械系统关键设计变量的公差方法，并将其应用于人字形槽气体轴颈轴承。气体轴承通常存在次同步不稳定性，要求轴承间隙和凹槽深度的公差非常严格。经典的优化技术寻找最稳定的设计，这不一定会导致最稳健的设计，以应对制造偏差。所提出的方法使用稳定性得分（临界质量）的归一化多维查找表，覆盖了气体轴承的大设计空间。然后对特定转子轴承系统的表格进行维度化，突出显示系统稳定的超空间区域。超空间被分割成 2D 地图，蒙特卡罗方法在稳定域内沿着与制造相关的两个最关键的设计变量创建窗口：轴承间隙和凹槽深度。窗口的宽度和长度代表允许两个参数保持稳定的制造公差。然后编译整个超空间中最佳窗口的帕累托前沿。它显示了公差与间隙偏差和凹槽深度之间的权衡，允许设计人员选择适合可用制造方法的公称几何形状。用这种方法分析了一个测试转子，并研究了压力、速度、粘度、半径、质量和离心增长对制造公差的影响，