航空液压管道卡箍等效刚度及其影响因素研究

Research on Equivalent Stiffness and Influence Factors of Aero-clamps for Aircraft Hydraulic Pipelines

采用实验方法确定了某型航空液压管道带垫卡箍的等效刚度并研究了管径、温度对刚度的影响。利用带温度箱的电子拉力试验机,测定了不同管径的单点固定带垫卡箍在不同温度(-50℃~125℃)下的等效刚度。研究表明:卡箍Y方向的等效刚度约为X方向等效刚度的1/4;室温环境中,卡箍管径从6 mm增加到12 mm,卡箍X方向等效刚度下降33.6%,卡箍Y方向等效刚度下降了49.6%;卡箍刚度对环境温度十分敏感,随着温度升高,不同管径卡箍刚度均有大幅下降,当温度高于80℃时卡箍夹紧力降低,并出现打滑现象。最后,建立了考虑温度场变化的卡箍细节有限元接触模型,利用该模型计算了不同影响因素下的卡箍刚度,预测结果与试验数据吻合良好。

The equivalent stiffness of the aero-clamps for a certain type aircraft hydraulic pipeline was determined by experiments. The effects of temperature and pipe-diameter on the equivalent stiffness of the clamps were investigated. The tensile experiments of one-point-fixed clamps （containing cushion） with different pipe-diameter were designed. The experiments were carried out by INSTRON 5567 tester with a temperature box. The tested temperature range was -50 ℃ - 125 ℃. The experimental results showed that： I ） The stiffness of the clamps in Y-direction was 25% of that in X-direction approximately; 2） At the room temperature, when the pipe-diameter increased from 6 mm to 12 ram, the equivalent stiffness in X-direction decreased by 33.6%, and the stiffness in Y-direction decreased by 49.6% ; 3） The stiffness of one-point-fixed clamp decreased dramatically with increasing temperature. The clamping force declined when the temperature was greater than 80 ℃ , and the slipping phenomenon was observed. Finally, a FEM model （considering the detailed-contacts between cushion and clamp-strap） for the aero-clamps was established, the numerical predictions are in good agreements with the experimental data.