火箭推进

振动试验是液体火箭发动机结构可靠性评估和力学环境适应性验证的重要内容。相比单轴振动试验,三轴向振动试验能够更加真实地模拟产品的实际受力状态。开展三轴向虚拟振动试验研究,对于预示发动机动态响应,指导结构设计优化,以及研究修改单轴向振动试验输入谱以适用于三轴向振动试验都具有重要的研究价值。针对液体火箭发动机的振动问题,利用三轴向振动台的控制方法和有限元仿真技术,逆向构建了某三轴向振动台的虚拟振动试验系统。基于Patran有限元平台将某型号产品和振动台模型进行联合仿真动力学建模,以发动机正弦振动和随机振动试验条件作为动力学响应分析的载荷边界,利用Nastran进行三轴向振动问题求解。通过与实际的振动试验结果的对比和修正,获得精确的三轴向振动台和产品仿真模型、精确控制方法等,为液体火箭发动机结构振动响应预示、薄弱环节识别提供虚拟试验技术手段。

The vibration test is an important part for the structure reliability evaluation and force enviorment adaption verification of the liquid rocket engine. In comparison with the uniaxial vibration test, the three-axial vibration test is more realistic to simulate the actual stress of the product. The study on the virtual three-axial vibration test is worth significantly on predicting the dynamic response of a liquid rocket engine, guiding design optimization for the structure, and modifying the unialxial vibration test input spectrum for three-axial vibration test. Aimed at the vibration problem of the liquid rocket engine, a virtual vibration testing system for three-axial vibration table was built up by the control method and finite element simulation technology of the three-axial vibration table. The joint simulation dynamics modeling combining with a certain product and vibration table model was conducted on the basis of the Patran finite element platform. The test conditions of sine vibration and random vibration test were taken as loading boundary for dynamics response analysis to solve the three-axial vibration using Nastran software. By comparison and modification with the actual vibration test results, the accurate models of the three-axial vibration table and the product as well as accuracy control method were obtained, which can provide a virtual test method for the structural vibration response prediction and weekness identification of the liquid rocket engine.

引言
1 电动振动台工作原理
2 三轴向电动振动台建模技术
3 三轴向虚拟振动试验算例
4 结论

图1 三轴向振动台几何模型<br/>Fig.1 Geometrical model of three-axial vibration test bench

图1 三轴向振动台几何模型
Fig.1 Geometrical model of three-axial vibration test bench

图2 三轴向电动振动台有限元模型<br/>Fig.2 Finite element model of three-axial electric shaker

图2 三轴向电动振动台有限元模型
Fig.2 Finite element model of three-axial electric shaker

图3 正弦响应计算原理框图<br/>Fig.3 Block diagram for calculation principle of sine response

图3 正弦响应计算原理框图
Fig.3 Block diagram for calculation principle of sine response

图4 随机响应计算原理框图<br/>Fig.4 Block diagram for calculation principle of random response

图4 随机响应计算原理框图
Fig.4 Block diagram for calculation principle of random response

图5 控制点加速度曲线<br/>Fig.5 Acceleration curve of reference control point

图5 控制点加速度曲线
Fig.5 Acceleration curve of reference control point

图6 试验件与三轴向振动台有限元模型<br/>Fig.6 Finite element model of specimen and three-axial shaker

图6 试验件与三轴向振动台有限元模型
Fig.6 Finite element model of specimen and three-axial shaker

图7 氧化剂导管中部加速度幅值曲线<br/>Fig.7 Acceleration amplitude curves in middle of the oxidant tube

图7 氧化剂导管中部加速度幅值曲线
Fig.7 Acceleration amplitude curves in middle of the oxidant tube

表1 窄带随机振动激励条件<br/>Tab.1 Excitation conditions of narrow-band random vibration

表1 窄带随机振动激励条件
Tab.1 Excitation conditions of narrow-band random vibration

图8 应力Mises云图<br/>Fig.8 Mises nephogram of stress

图8 应力Mises云图
Fig.8 Mises nephogram of stress

表2 仿真结果与试验结果应力值对比<br/>Tab.2 Comparison between stress values of simulation results and test results

表2 仿真结果与试验结果应力值对比
Tab.2 Comparison between stress values of simulation results and test results

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备注

引言

1 电动振动台工作原理

2 三轴向电动振动台建模技术

3 三轴向虚拟振动试验算例

4 结论

期刊信息