The effect of thermal shock, in an accelerated-corrosion environment spectrum, on the fatigue and corrosion behavior of 7B04-T6 aluminum alloy, was determined. The environment spectrum consists of two modules, namely...The effect of thermal shock, in an accelerated-corrosion environment spectrum, on the fatigue and corrosion behavior of 7B04-T6 aluminum alloy, was determined. The environment spectrum consists of two modules, namely： salt-spray corrosion and thermal shock. The effect of thermal shock on the mechanical properties was determined via tensile tests; SEM, DCS, and XRD were used to determine the effect of thermal shock on the corrosion products. In addition, the corrosion resistance of the products was ascertained through electrochemical testing. The results show that the mechanical properties and fatigue life of the aluminum alloy will decline with prolonged thermal shock time. The thermal shock process may result in denser surface corrosion products than those formed on the no thermal shock specimens, and transformation of some Al（OH）_3 into Al OOH. Al OOH may have resulted in improved corrosion resistance and hence a lower decrease in the fatigue life after corrosion, compared with that of the no thermal shock specimen. Repeated corrosion/thermal shock may have delayed further decease in the fatigue life. Therefore, selection of an appropriate equivalent thermal shock temperature and time was essential for designing the environmental spectrum.展开更多
The shock loads generated by spacecraft during docking can cause functional failure and structural damage to aerospace electronic equipment and even lead to catastrophic flight accidents.There is currently a lack of s...The shock loads generated by spacecraft during docking can cause functional failure and structural damage to aerospace electronic equipment and even lead to catastrophic flight accidents.There is currently a lack of systematic and comprehensive research on the shock environment of spacecraft electronic equipment due to the diversity and complexity of the shock environment.In this paper,the validity of the finite element model is verified based on the sinusoidal vibration experiment results of the spacecraft reentry capsule.The method of shock dynamic response analysis is used to obtain the shock environment of electronic equipment under different shock loads.The shock response spectrum is used to describe the shock environment of aerospace electronic equipment.The results show that the resonance frequency error between the sinusoidal vibration experiment and the model is less than 4.06%.When the docking relative speed of the reentry capsule is 2 m/s,the shock response spectrum values of one of the equipment are 30 m2/s,0.67 m/s,and 0.059 m,respectively.The wire rope spring on the mating surface can provide vibration isolation and shock resistance.An increase in spring damping coefficient results in a decrease in the amplitude and time of the vibration generated.An increase in spring stiffness reduces the input of shock load within a certain range.These research results can provide guidance for the design and evaluation of shock environmental adaptability of aerospace electronic equipment.展开更多
文摘The effect of thermal shock, in an accelerated-corrosion environment spectrum, on the fatigue and corrosion behavior of 7B04-T6 aluminum alloy, was determined. The environment spectrum consists of two modules, namely： salt-spray corrosion and thermal shock. The effect of thermal shock on the mechanical properties was determined via tensile tests; SEM, DCS, and XRD were used to determine the effect of thermal shock on the corrosion products. In addition, the corrosion resistance of the products was ascertained through electrochemical testing. The results show that the mechanical properties and fatigue life of the aluminum alloy will decline with prolonged thermal shock time. The thermal shock process may result in denser surface corrosion products than those formed on the no thermal shock specimens, and transformation of some Al（OH）_3 into Al OOH. Al OOH may have resulted in improved corrosion resistance and hence a lower decrease in the fatigue life after corrosion, compared with that of the no thermal shock specimen. Repeated corrosion/thermal shock may have delayed further decease in the fatigue life. Therefore, selection of an appropriate equivalent thermal shock temperature and time was essential for designing the environmental spectrum.
文摘The shock loads generated by spacecraft during docking can cause functional failure and structural damage to aerospace electronic equipment and even lead to catastrophic flight accidents.There is currently a lack of systematic and comprehensive research on the shock environment of spacecraft electronic equipment due to the diversity and complexity of the shock environment.In this paper,the validity of the finite element model is verified based on the sinusoidal vibration experiment results of the spacecraft reentry capsule.The method of shock dynamic response analysis is used to obtain the shock environment of electronic equipment under different shock loads.The shock response spectrum is used to describe the shock environment of aerospace electronic equipment.The results show that the resonance frequency error between the sinusoidal vibration experiment and the model is less than 4.06%.When the docking relative speed of the reentry capsule is 2 m/s,the shock response spectrum values of one of the equipment are 30 m2/s,0.67 m/s,and 0.059 m,respectively.The wire rope spring on the mating surface can provide vibration isolation and shock resistance.An increase in spring damping coefficient results in a decrease in the amplitude and time of the vibration generated.An increase in spring stiffness reduces the input of shock load within a certain range.These research results can provide guidance for the design and evaluation of shock environmental adaptability of aerospace electronic equipment.
