When employing end milling for the thin-walled elements, in particular aircraft gas-turbine engines, it is possible to observe their forced vibrations due to the machining discontinuity. The authors present the calculation method for determining the best performance of discontinuous milling of the given elements, which minimizes the forced vibrations’ level and provides the required quality of the machined surface. The proposed method is based on the modeling of machining, considering the differences between the end milling and standard milling. The main difference lies in the discontinuity in the process of machining. The authors developed a model for determining the milling force with the considered type of machining of thin-walled elements. A dissipative system with one degree of freedom is chosen as the calculation model to investigate the forced vibrations. The experimental investigations are performed on the specially designed facilities to study the vibrations in the thin-walled structural elements in their end milling. The paper provides the calculation results, which are compared with the experimental data in the wide range of rotational spindle frequency. A satisfactory coincidence between the rotational spindle frequencies with the largest and smallest vibration amplitudes is demonstrated. The reduced analysis of roughness of the machined surface shows an evident dependence of the given parameter on the vibration amplitude. Therefore, the smallest vibration amplitude denotes the highest quality of machining. The spectrum analysis of the deviation element signal implies the presence of beats when the natural element frequency is close to the excitation frequency of its vibrations, which is the main source of their amplitude increase and degradation of the machined surface. Here the smallest vibration amplitudes are observed with the frequencies of their excitation between the resonance peaks. Thus, the analysis of the motion law of the thin-walled element during milling confirms the accuracy of modeling of the considered process and determination of its vibration stability modes.

中文翻译：

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薄壁构件抗振性的计算方法

当对薄壁元件，特别是飞机燃气涡轮发动机采用端铣削时，由于加工的不连续性，有可能观察到它们的强制振动。作者介绍了一种用于确定给定元素的不连续铣削最佳性能的计算方法，该方法可以最大程度地减小强迫振动的水平，并提供所需的加工表面质量。所提出的方法基于加工建模，考虑了立铣和标准铣之间的差异。主要区别在于加工过程中的不连续性。作者开发了一种模型，用于确定考虑了薄壁元件加工类型的铣削力。选择具有一个自由度的耗散系统作为计算模型来研究强迫振动。在专门设计的设备上进行了实验研究，以研究端铣削中薄壁结构元件的振动。本文提供了计算结果，并将其与广泛的旋转主轴频率范围内的实验数据进行了比较。在最大和最小振动幅度的旋转主轴频率之间显示出令人满意的一致性。加工表面粗糙度的减少分析表明，给定参数明显取决于振动幅度。因此，最小的振动幅度表示最高的加工质量。偏差元素信号的频谱分析表明，当自然元素频率接近其振动的激发频率时，会出现拍子，这是其振幅增加和加工表面退化的主要来源。在此观察到最小的振动幅度，以及它们在共振峰之间的激发频率。因此，在铣削过程中对薄壁元件运动规律的分析证实了所考虑过程建模的准确性以及确定其振动稳定模式的准确性。在此，观察到最小的振动振幅以及它们在共振峰之间的激发频率。因此，在铣削过程中对薄壁元件运动规律的分析证实了所考虑过程建模的准确性以及确定其振动稳定模式的准确性。在此，观察到最小的振动振幅以及它们在共振峰之间的激发频率。因此，在铣削过程中对薄壁元件运动规律的分析证实了所考虑过程建模的准确性以及确定其振动稳定模式的准确性。