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The degradation behavior of the solder joint under constant vibration loading is discussed, the voltage value at both sides of the solder joint is taken as the degradation characteristic. Considering the heteroskedasticity of characteristic signal under the vibration loading, the general time series model cannot describe heteroskedasticity, a Generalized Autoregressive Conditional Heteroskedastic...
Atmospheric icing is one of the main threats to overhead transmission lines in cold regions. The ice related loads may cause mechanical incidents, such as wire breakage, cable rupture, clamp slipping, cross-arm deformation and even tower collapse. Ice shedding may lead to dramatic vibration of lines and cause flashover or short circuit among ground wires, conductors and the earth. Therefore, to obtain...
In recent years the turbine blades of air cycle machine in MA60 often damaged. In order to analyze the fatigue life of the turbine blade in the high speed rotating air cycle machine, we establish the fluid-solid coupling model of turbine blades. Through the FSI module in ANSYS workbench, the result of fluid field is introduced into the solid domain, by the simulation analysis of solid domain getting...
Considering the problem of blind source separation without known number of sources for complicated mechanical system, this paper proposes a novel blind source separation (BSS) algorithm based on parallel factor analysis (PARAFAC). In the proposed method, the centralized sensor data are firstly divided into non-overlapping range blocks of fixed size, and single time-delay covariance matrices of each...
Satellite telemetry data is the only basis for the experts to obtain the working status and the health status of the in-orbit satellite. The pattern mining and extraction of satellite telemetry data are of high significance for automatic judgment and anomaly detection. Clustering, as an important time series data mining method, can achieve automatic and intelligent analysis of satellite telemetry...
Astronautically Phased Mission System (APMS) has the characteristics of sophisticated system structure, complex mission profile and varied system working modes and states. For these characteristics, this paper analyses the mission profile and reliability features (sequential, correlate and dynamic) of APMS, and proposes a method of reliability synthetic modeling considering multi-feature for APMS...
With the development of long life and high reliability satellite, the radiation resistance ability of aerospace components has been put forward higher requirements. If the radiation resistance ability of components doesn't satisfy the requirement, it will need to be hardened by radiation shielding. However, there is a great deal of redundancy in the radiation shield hardening method used in satellite...
Model-based fault diagnosis approach has been widely studied and applied because of high accuracy, strong adaptability and other advantages. However, as the complexity of the structure and function of the satellite systems increase, online reasoning of model based fault diagnosis method is greatly challenged by the low time efficiency. Offline compilation technology compiles the system model into...
The increasing IoT technology provides large volume of data from various industrial applications, but the gap between the conventional automatic management system and the industry 4.0 system is how to convert the data to information, and then how to use the information to better assist the decision support and optimization in various aspects, including scheduling, planning, supply chain optimization,...
Since the complex industrial processes' fault data overlap each other, Fisher Discriminant Analysis (FDA) and its improved algorithm are widely used to solve the problems relying on the advantage of reducing dimension. Although many improved FDA algorithms have been proposed in recent decades, generally, it is difficult to obtain entire classified information. In order to extract more useful information,...
Artificial intelligence theory is extensively employed in fault diagnosis, as the frequently used technologies, expert system and neural network, have their inherent disadvantages that have poor expansibility and unknown blackbox structure. Genetic Programming (GP), an improved evolution algorithm based on Genetic Algorithm (GA), could offset these insufficient for its explicit structure. Combining...
The paper investigates the problem of degenerative model of board-level solder joint subjected to harmonic vibration load with the constant frequency fixed amplitude. Based on the experimental monitoring signal, square root amplitude, waveform factor and kurtosis factor can be used as the degradation quantity by analyzing ten amplitude domain statistics' correlation and significance. Square root amplitude...
There are of great importance to monitor the working condition of hydraulic equipment in industry. Some abnormal wear can be discovered from content and character of metal debris in lubricant. Detecting the debris can prognosticate failures in time and reduce losses. In this paper, the authors design a micro detecting system of lubricant debris based on LC resonance to improve the measuring accuracy...
As industrial control systems are operating in the long run, the performance of their components will inevitably degenerate, which might ultimately lead to the systems failure. Compared with the single-component systems, the output of control systems may remain satisfactory tracking on the reference output due to the distinctive structure of closed-loop feedback, even if the structural parameters...
This paper presents a method of fault detection based on the stacked auto-encoder (SAE) and support vector data description (SVDD) for rotating rectifier of brushless ac synchronous generator. The rotating rectifier (RR) is a key component of synchronous generator, and its health state needs to be monitored to ensure the safety of the generator. The method is composed of three steps. In the first...
Gas turbine engine blades are subjected to severe fatigue which is caused by complex in-service environment. In fact, blade crack is one of the costliest sources of damage in gas turbine. Detection of cracks of blades is important to ensure safe and reliable operation of gas turbine engine. A vibration-based damage-detection methodology is presented in this paper to monitor the health condition of...
First of all, this paper briefly introduces the current management and use of telemetry data, remote control information, satellite test environment data, space environment data after orbit and so on, which most are produced by satellite test and on-orbit management. Then the software platform for application of the satellite data accessing and monitoring based on the distributed large data management...
The paper has analyzed the problems discovered in the application validation of a certain NOR FLASH for aerospace use, and clarified that the failure of this FLASH belongs to bit interference caused by over-erase. At the same time, the failure mechanism has also been analyzed, which is found to be discreteness of chip manufacturing process and incomplete coverage of the test; additionally, evasion...
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