论文部分内容阅读
在兰利研究中心进行了确定美国空军F-4战斗机主起落架30×11.5-14.5/26PR斜交轮胎和子午线轮胎的准静态和动态反应特性的研究。通过采用垂直载荷、侧向载荷和前后向载荷试验测定了轮胎的性能。还获得了质量惯性矩数据。研究结果包括准静态负荷变形曲线、自由振动随时间变化的曲线图、能量损失与滞后损失的关系、刚性和阻尼特性、印痕几何形状以及两种轮胎的惯性。给出了斜交轮胎和子午线轮胎的差异,还提出了两种轮胎设计的优缺点。介绍了表征粘性、结构和库仑摩擦的三种简单的阻尼模型并比较了实验数据。讨论的结论包括一个试验观测总结。本研究结果表明,子午线轮胎的垂直刚性值与斜交轮胎的刚性相当,在飞机上采用子午线轮胎不会影响飞机着陆的动态性能。子午线轮胎会降低横向刚性和前后向刚性,这样有可能会增加轮胎的颤动并产生轮胎与现有防滑刹车系统的兼容性问题。自由振动试验与准静态试验相比,自由振动试验的横向和前后向阻尼增加。这表明不仅存在假定的结构阻尼,而且还存在粘性阻尼。用原来的试验不能试验库仑摩擦特性。印痕几何形状数据说明,印痕纵横比影响可能会对与这种子午线轮胎有关的已改进的防水滑性不利。子午线轮胎的充气压力比斜交轮胎的高。子午线轮胎的惯性矩值比斜交轮胎的低,较低的惯性矩值表明在转动操作中需要较少的能量,可以减少子午线轮胎的胎面磨耗。
A study was conducted at Langley Research Center to determine the quasi-static and dynamic response of the main landing gear 30 × 11.5-14.5 / 26PR bias tires and radial tires of the USAF F-4 fighter. Tire performance was measured by vertical load, lateral load and forward and backward load tests. Also obtained mass moment of inertia data. The results of the study include quasi-static load deformation curves, free vibration curves over time, energy loss versus hysteresis loss, stiffness and damping characteristics, imprint geometry, and inertia of both tires. The differences between bias tires and radial tires are given, and the advantages and disadvantages of two kinds of tire designs are also proposed. Three simple damping models that characterize the viscosity, structure and Coulomb friction are introduced and the experimental data are compared. The conclusions of the discussion include a summary of the experimental observations. The results of this study show that the vertical stiffness of radial tires is comparable to that of bias tires. The use of radial tires on aircraft does not affect the dynamic performance of aircraft landing. Radial tires reduce lateral rigidity and stiffness in the anteroposterior direction, which may increase tire chatter and create compatibility issues with existing anti-skid brakes. Free vibration test Compared with the quasi-static test, the free vibration test increases the lateral and longitudinal damping. This shows not only the assumed structural damping, but also the viscous damping. Coulomb friction characteristics can not be tested with the original test. Imprint geometry data indicates that the effect of print aspect ratio may be detrimental to the improved slip resistance associated with such radial tires. The radial pressure of a radial tire is higher than that of a bias tire. The radial moment of inertia of a radial tire is lower than that of a bias tire, and the lower value of moment of inertia indicates that less energy is required in the turning operation and the tread wear of the radial tire can be reduced.