Abstract: Pneumatic vibrator, which produces excitation signals, is one of the most important part of repetitive shock machine. In low temperature condition, pneumatic vibrator cannot work as usual. In order to solve this problem, firstly the failure mechanism is studied by theory model. Then the structure of the pneumatic vibrator is ameliorated by the ways of choosing appropriate stuff and dimensions of the cylinder, and minishing the gap in temperature between the inside and outside of the cylinder. The method of controlling temperature is brought forward according to the model. Finally a pneumatic vibrator of cold temperature is made, whose durability of repetitive shock and uniformity and efficiency of calefaction is tested in low temperature conditions, and whose response characteristic of excitation on the roof is tested in low and room temperature condition, respectively. The results show that the working capability in low temperature condition of the newly designed vibrator is much better than that of the primary one, and that it can work normally and continuously in low temperature condition, and that the response characteristics of excitation in low and room temperature condition are accordant, which validates the availability of the new pneumatic vibrator in practice.

Key words: Pneumatic vibrator of cold temperature　Tests in low temperature condition, Repetitive shock machine　Failure mechanism in low temperature condition　Structure improvement