凹底平车是铁路长大货车中最常见的一种车型。凹底平车的凹底架为变断面曲梁,对于这种结构的强度和刚度研究,特别是弯头部分应力的计算方法,弯头的上下缘过渡形式(圆弧过渡或折线过渡)对弯头应力的影响,弯头倾角对车架的挠度和应力分布的影响,等等,都是当前车辆设计和制造工作 Concave flat car is the railway growing up in the most common car models. The concave chassis of the concave flat car is a variable cross section curved beam. For the study of the strength and rigidity of this structure, especially the calculation method of the elbow part stress, the upper and lower edge transition forms of the elbow (arc transition or polyline transition) The impact of elbow stress, the effect of elbows on the deflection and stress distribution of the frame, and so on, are all current vehicle design and manufacturing efforts