动车组车下设备对舒适度的影响分析

为研究车下设备对动车组舒适度的影响，建立考虑车体弹性和多个车下设备的高速动车组垂向动力学模型，实现设备的质量参数、结构参数和悬挂参数等参数化建模，基于频域分析法推导系统加速度频响函数表达式，采用随机轨道不平顺激励功率谱和舒适度滤波函数计算舒适度指标，基于最优同调理论设计设备的最优悬挂频率和阻尼比并进行数值验证。结果表明，车体垂弯频率越高、设备质量越大且越靠近车体中心安装，舒适度指标越小，车辆乘坐舒适性越好，建议将大质量设备（4 t及以上）悬挂在距车体中心5 m以内；设备质心纵向偏心导致其吊挂点的作用力力臂改变和转动惯量增加，造成舒适度指标略有增加；在优化设备悬挂参数时，可以忽略车体结构阻尼的影响；设备质量越大，最优悬挂频率越低、最优悬挂阻尼比越大，且应当基于加速度响应设计最优悬挂阻尼比，最优同调条件为车体和设备的相位差接近π/2；针对所述车辆，设备最优悬挂频率和阻尼比分别为7 Hz和0.2~0.3，车体加速度功率谱中的弹性振动主频得到充分抑制。

Influence of Car Body-suspended Equipment on the Ride Comfort of High-speed Railway Vehicles

A parametric vertical dynamic model of a high-speed railway vehicle with a flexible car body and car body-suspended equipment is built to study the influence of suspension parameters of equipment on the ride comfort, in which the equipment mass, geometry and suspension parameters are represented by variable quantities. The frequency response function of car body acceleration is derived through frequency domain analysis method, and the ride comfort index is calculated using random track irregularity spectrum and ride comfort filtering function, and numerical simulation verifies the proposed optimal suspension frequency and damping ratio of the equipment obtained from the optimal homology theory. It shows that the comfort index gets smaller with a higher first bending frequency of car body, a larger mass of the equipment or a closer equipment installation position to the center of the car body. Thus, the equipment which has a mass more than 4 t should be suspended no further than 5 m away from the car body center for good ride comfort. The longitude eccentricity of the equipment changes the force arms of the suspension points, and increases its inertia as well, resulting in a small increment of the ride comfort index. The structural damping of the car body has almost no effect on the optimal suspension parameters. The larger the mass of equipment, the lower the optimal suspension frequency and the larger the optimal suspension ratio. In addition, the optimal suspension parameters relies on the acceleration response rather than the displacement response. The optimal homology requires that the phase difference between the car body and equipment accelerations is close to π/2. For the specific vehicle in this work, the optimal suspension frequency of the equipment is 7 Hz with an optimized ratio of 0.2-0.3, which significantly restrains the power spectrum peak of acceleration on the car body.