Abstract
The random vibration failure of an array power supply for near-space SAR was analyzed. The fracture mechanism and the fracture reason of fracture formation in the specimen were investigated. The results show that antishock MOS pin breaks first, and the power supply is still in the working state during the process of random vibration. This caused dischargings at the tip of the fracture and melting of the tip of the broken pin which form a river-shaped fracture and granular tissue. The plastic fracture with typical dimple morphology of the pins for the resistor tube occurred during the random vibration. The intergranular fracture appeared at the welding part of the electronic components for array power supply, which presented a brittle fracture mechanism. The fracture was dominated by a ductile fracture for components when the stress produced by the vibration was close to the yield strength of the material. The fracture was dominated by a brittle fracture for components when the stress produced by the vibration was far beyond the yield strength of the material. A simulation evaluation system based on the high-confidence model was proposed. The stress of the electronic components for array power supply and its welding was much lower than the allowable strength of the material by the optimization of the structure and the form of the welding for the array power supply. The sample was successfully tested and verified without any further fracture problems.
Highlights
A simulation evaluation system based on the high-confidence model was proposed. e stress of the electronic components for array power supply and its welding was much lower than the allowable strength of the material by the optimization of the structure and the form of the welding for the array power supply. e sample was successfully tested and verified without any further fracture problems
Introduction ere is no influence of meteorological cloud and rain and the air flow is stable in the near-space airspace (20–100 km above the Earth) which is conducive to the movement of high-speed aircraft and floating slow platform [1,2,3]. erefore, with the advantages of higher mobility, shorter preparation period, stronger penetration ability, and richer task modes, near-space vehicles can be used for dynamic observations in specific regions of the world for the purpose of terrestrial environment and disaster monitoring, large-area security surveillance, real-time battlefield monitoring, and accurate strikes [4,5,6,7]
Jiang et al [26] deduced the analytic formulation of dynamic response bounds for both the linear single degree of freedom (SDOF) vibration system and the multiple degree of freedom (MDOF) vibration system which can provide theoretical help for the follow-up research of random vibration analysis
Summary
E natural frequency, mode shape, and other modal parameters of the structure can be obtained by calculation or test analysis. E above equation can be integrated to obtain the mean square acceleration response of the mass to the random vibration input: Gout. E calculation and simulation error are very small when the slope within the resonant frequency range is less than 6 dB/oct According to this theoretical model, the random vibration test and simulation optimization analysis of power supply are carried out. E frequency set in the test is 5–2000 Hz. e square root of the area under the curve still represents the input RMS acceleration level. E specific implementation process is as follows (Figure 6): Firstly, the random vibration acceleration experiment of the first designed power supply is carried out. In case of fracture failure of electronic components, the causes of failure are analyzed and solutions are Structural reliability test
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