为更好地指导跳汰机大型化过程中的机体设计并检验当前设计的合理性，以现30 m²三段跳汰机为研究对象，通过理论计算得出机体空气小庙内的低压风风压以及机体的许用疲劳应力，并以此为基础进行了有限元分析。结果表明：考虑安全系数，空气小庙内的低压风风压为35 427.6 Pa，机体许用弯曲疲劳应力为214 MPa；此条件下，当跳汰机机体钢板厚度为8 mm，且间隔750 mm加设筋板时，机体最大等效应力为69.7 MPa，最大变形为0.9 mm，机体结构安全，满足强度和刚度要求；若跳汰机大型化过程中，机体受到的空气压力变化较小，那么只要间隔一定距离加设筋板，机体就可以满足强度和刚度要求。研究结果为跳汰机进一步大型化提供了一定的理论支撑。

In order to offer a better instruction to the design of the body of a large-size jigging machine and verify the rationality of the design currently, the 30 m² 3-compartment jigging machine is taken as the object to explore the low-pressure air pressure inside the small air chest and the permissible fatigue stress inside the machine body through theoretical calculation. Finite-element analysis is then made based on the calculated result. As indicated by result of analysis, in consideration of the margin of safety, the air pressure in the chest and the permissible fatigue stress of the machine body should be rated at 35 427.6 Pa and 214 Mpa, respectively. In this instance, for a machine body formed up using 8 mm-thick steel plates and reinforced with steel ribs set at an interval of 750 mm, the machine body is subjected to an equivalent stress of 69.7 MPa and a maximum strain of 0.9 mm, indicating that the body can meet the safety and rigidity requirements. For the design of a large-size jigging machine, if its body is subjected to an air pressure without too much fluctuation, and the reinforcing ribs are set at a certain interval, the body can surely attain the strength and rigidity as required. The work made in the paper provides a certain theoretical basis for the design of large-size jigging machine.