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61.
航天结构的约束阻尼振动抑制优选方案研究 总被引:3,自引:0,他引:3
约束阻尼结构的高可靠性和良好的阻尼性能使得它在航天振动控制工程中得到了越来越广泛的应用。但是为实现约束阻尼结构的减重增效 ,需要寻找其优选的方案。本文通过典型的一种耦合结构约束阻尼振动抑制方案研究 ,得到了其优选的振动抑制方案。仿真结果表明 ,约束层和粘弹层相等面积铺设的方案比较保守 ;可以通过合理布置粘弹层而不改变约束层面积的方案来代替 ,实现约束阻尼结构的减重增效。该方案可为约束阻尼振动抑制设计提供参考 相似文献
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China manned space station is designed to operate for over ten years. Long-term and sustainable research on space science and technology will be conducted during its operation. The application payloads must meet the ‘‘long life and high reliability" mission requirement. Gearbox machinery is one of the essential devices in an aerospace utilization system, failure of which may lead to downtime loss even during some disastrous catastrophes. A fault diagnosis of gearbox has attracted attentions for its significance in preventing catastrophic accidents and guaranteeing sufficient maintenance. A novel fault diagnosis method based on the Ensemble Multi-Fault Features Indexing(EMFFI) approach is proposed for the condition monitoring of gearboxes. Different from traditional methods of signal analysis in the one-dimensional space, this study employs a supervised learning method to determine the faults of a gearbox in a two-dimensional space using the classification model established by training the features extracted automatically from diagnostic vibration signals captured. The proposed method mainly includes the following steps. First, the vibration signals are transformed into a bi-spectrum contour map utilizing bi-spectrum technology,which provides a basis for the following image-based feature extraction. Then, Speeded-Up Robustness Feature(SURF) is applied to automatically extract the image feature points of the bi-spectrum contour map using a multi-fault features indexing theory, and the feature dimension is reduced by Linear Discriminant Analysis(LDA). Finally, Random Forest(RF) is introduced to identify the fault types of the gearbox. The test results verify that the proposed method based on the multi-fault features indexing approach achieves the target of high diagnostic accuracy and can serve as a highly effective technique to discover faults in a gearbox machinery such as a two-stage one. 相似文献
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黄烈德 《中国空间科学技术》1989,9(4):40-47
本文是考虑化学火箭发动机燃烧理论的数学模型、疲劳断裂传播的随机模型以及复杂航天飞机运动动力学方程和解题方法。 相似文献
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基于屏蔽数据的航空电源系统可靠性分析 总被引:3,自引:0,他引:3
当航空电源系统具有屏蔽寿命数据时,研究逆Weibull型部件可靠性的估计问题.利用Bayes方法和极大似然方法,给出了逆Weibull型部件可靠性的Bayes估计和极大似然估计.利用随机模拟方法对两种估计的结果进行了比较. 相似文献
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某产品的电池在地面试验中由于振动响应过大而出现故障.本文采有限元分析的方法对电池支架进行约束阻尼处理的优化设计,并进行试验验证.结果表明,采用约束阻尼技术后,电池的功率谱密度共振峰值放大倍数由未处理前的28倍下降到14倍,电池故障完全排除,验证了约束阻尼减振技术对此类板和薄壳等结构进行减振的有效性. 相似文献
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The utilization of pressure vessels in aerospace applications is manifold.In this work,fnite element analysis(FEA)has been carried out using ANSYS software package with 2D axisymmetric model to access the failure pressure of cylindrical pressure vessel made of ASTM A36 carbon steel having weld-induced residual stresses.To fnd out the effect of residual stresses on failure pressure,frst an elasto-plastic analysis is performed to fnd out the failure pressure of pressure vessel not having residual stresses.Then a thermo-mechanical fnite element analysis is performed to assess the residual stresses developed in the pressure vessel during welding.Finally one more elasto-plastic analysis is performed to assess the effect of residual stresses on failure pressure of the pressure vessel having residual stresses.This analysis indicates reduction in the failure pressure due to unfavorable residual stresses. 相似文献