脉冲风洞测力系统结构动力学特性

Structural Dynamic Characteristics of Force-Measurement System for Impulse Wind Tunnel

脉冲风洞试验过程时,试验气流引起测力系统强烈振动对测试结果产生严重干扰.为解决测力系统振动对测力结果干扰的问题,首先根据测力系统结构特点建立了相应的动力学模型;其次,对其进行了虚拟标定和模态分析;第三,对测力系统进行了瞬态分析和惯性补偿,获得了相应的瞬态输出;最后,对测力系统进行了风洞试验,分别获得了相应的弹性输出结果和惯性输出结果.分析和试验结果表明:惯性补偿后,测力系统均值测量精度略有提高,瞬态测量精度大幅提高;惯性补偿后瞬态测量精度最低为87.4%,出现在测力系统共振时,其他状态下,瞬态测量精度超过91%;惯性补偿后的测力系统输出结果振动基本消失,说明惯性补偿方法能够消除振动对输出结果的干扰.

During testing in impulse wind tunnel,vibrations of the force-measurement system(FMS) caused by airflow will greatly tamper measurement results. To solve this issue,firstly the dynamic model of the FMS was constructed according to its structural characteristics. Then, the virtual calibration and modal analysis were carried out. Thirdly,the transient analysis and inertia compensation were processed to obtain the response of the FMS. Finally,the force measurement tests was conducted in the impulse wind tunnel,and both the elastic and inertia outputs were obtained in tests. Results show that after inertia compensation, the mean measurement accuracy were improved,and the transient measurement accuracy were improved significantly. When there was resonance,the lowest transient measurement accuracy was 87.4% after inertia compensation. In the other cases,the transient measurement accuracy exceeded 91%. Vibrations on the output curves of the FMS were virtually smoothed after inertia compensation,demonstrating that inertia compensation can eliminate the disturbance in the outputs.