动车组车体模态频率贡献度和改进方法研究

Research on the frequency contribution and improvement method for car body modes of high-speed train

针对高速列车车体低阶模态频率提升过程中,传统灵敏度分析方法存在的设计变量繁多和难以识别出优先改进部件的难题,提出了一种新颖的车体模态频率贡献度评估与结构改进方法。重点分析了铝合金车体板件厚度与模态频率的灵敏度关系,并在此基础上提出了部件模态贡献度概念,推导和建立了描述部件模态频率灵敏度与贡献度的数学模型。通过对动车组车体中各铝型材的贡献度进行计算,详细分析了车顶、侧墙、底架等六大部件对前3阶模态频率的影响。研究揭示,部件模态贡献度表示了局部部件对整体结构模态影响的大小,呈现了灵敏度无法显示的全局量化指标。车顶部件对车体前3阶模态的贡献度最大,侧墙和底架居中,底架边梁、端墙和牵枕缓最小。车顶与侧墙、侧墙与底架连接处的型材对低阶模态产生了显著影响。通过增加内外板厚度并适度降低内部筋板厚度的策略,可提升1阶垂弯模态频率。应用所提出的方法,基于车体54个部件模态贡献度,成功甄别出车顶和连接处型材等优先优化部件并进行了改进,实现了1阶垂弯模态频率从9.5 Hz提升至10.2 Hz,同时将车体重量增加控制在43 kg以内,验证了方法的有效性和高效性,为车体模态频率的优化提供了清晰的路径。该方法具有广泛的适用性,可推广应用于其他领域的结构模态改进。

In order to solve the difficulties of traditional sensitivity analysis by identifying prioritized improvement components in the process of enhancing low-order modal frequencies of high-speed train car bodies,a novel method for evaluating modal frequency contribution and improving car body structure was proposed.The study analyzed the relationship between the thickness of aluminum alloy body panels and the sensitivity of modal frequency.Additionally,the concept of component modal contribution was proposed,and a mathematical model describing the sensitivity and contribution of component modal frequency was derived and established.By calculating the contribution of each aluminum profile in the rolling stock body,the influence of six major components,such as the roof,sidewalls,and underframe,on the first three orders of modal frequencies was analyzed in detail.The component modal contribution reveals the extent to which each local component affects the overall structural modes,providing a global quantitative index that cannot be shown by sensitivity.The roof components have the greatest contribution on the first three body modes,followed by the sidewalls and chassis.The chassis edge beams,end walls,and traction buffer have the least contribution.The profiles at the junctions between the roof and sidewall,as well as the sidewall and chassis,have a significant effect on the body modes.To enhance the first-order droop-bend modal frequency,the thickness of the inner and outer panels can be increased while moderately reducing the thickness of the inner fascia.By applying the proposed method,we successfully screened and improved priority optimization components such as roof and joint profiles based on the modal contributions of 54 vehicle body components.As a result,the 1st-order droop-bend modal frequency improved from 9.5 Hz to 10.2 Hz while controlling the increase in vehicle body weight to less than 43 kg.This verifies the validity and high efficiency of the method and provides a clear path for optimizing the modal frequency of the vehicle body.The method is widely applicable and can be generalized to improve structural modes in other fields.