面向航空关键部件性能测试的多维力加载装置

A Multi-Axis Loading Device for Testing Key Components of Aircrafts

航空关键部件多数工作在受力复杂的环境中,承受由拉(压)力、弯矩和扭矩组成的多维力载荷,其性能直接影响系统整体的表现,所以需在接近实际工况载荷下测试关键部件的力学性能和疲劳寿命,保障其安全高效的服役。以直升机弹性轴承为应用对象,基于6–SPS并联机构研制多维力加载装置,可模拟其真实受力工况,对弹性轴承进行压力、弯矩和扭矩的组合加载并测试其刚度特性。设计了加载装置的几何参数和构件结构,开展弹性轴承压缩、弯曲和扭转刚度测试,相较于传统测试方法所得结果,压缩刚度和扭转刚度的吻合度较好,弯曲刚度存在偏差,因为传统方法在施加弯矩时不能排除轴向力的影响。试验验证了并联机构的多维力加载能力,并初步探索了弹性轴承在压力–扭矩组合加载下的刚度特性变化规律。最后讨论了并联机构在多维力加载材料试验机和多维力随动加载装置中的应用,形成面向工程材料、关键部件和运动系统的多维力加载理论体系。

Most of the key components of aircrafts work in a complex loading environment that they are loaded by multi-axis force composed of tension or compression, bending moment and torque. The mechanical properties and fatigue life of key components have direct influence on the overall performance of the aeronautical system. Ensuring their safe and efficient service, it is necessary to test these properties under the load that close to the actual working conditions. In this paper, the elastomeric spheric thrust bearing (ESTB) is employed as the test object. Based on a 6–SPS parallel mechanism, a multi-axis loading device which is expected to simulate the ESTB’s actual working condition is developed. This device can load the ESTB with combined loading of pressure, bending moment and torque, and test the stiffness of the ESTB. The geometric parameters of the loading device were designed and its prototype was presented. Tests for compression, bending and torsional stiffness were conducted by the multi-axis loading device. Compared with the results obtained by traditional testing methods, the compression and torsional stiffness are in good agreement, but the bending stiffness is deviated because the traditional method didn’t eliminate the influence of axial force while applying bending moment. The tests prove multi-axis loading ability of the parallel mechanism. In addition, the stiffness characteristics of the ESTB under combined pressure-torque is initially explored. Finally, the applications of the parallel mechanism in material tests and loading moving targets are discussed, and a multi-axis loading theory system for material, component and system could be formed.