Damage Characteristics of the Logical Chip Module Due to Plasma Created by Hypervelocity Impacts

To researching the damage characteristics of typical logical chip modules in spacecraft due to plasma generated by hypervelocity impacts,we have established a triple Langmuir probe diagnostic system and a logical chips measurement system,which were used to diagnose plasma characteristic parameters and the logical chip module＇s logical state changes due to the plasma created by a 7075 aluminum projectile hypervelocity impact on the 2A12 aluminum target.Three sets of experiments were performed with the collision speeds of 2.85 km/s,3.1 km/s and2.20 km/s,at the same incident angles of 30 degrees and logical chip module＇s positions by using a two-stage light gas gun loading system,a plasma characteristic parameters diagnostic system and a logical chip module＇s logical state measurement system,respectively.Electron temperature and density were measured at given position and azimuth,and damage estimation was performed for the logical chip module by using the data acquisition system.Experimental results showed that temporary damage could be induced on logical chip modules in spacecraft by plasma generated by hypervelocity impacts under the given experimental conditions and the sensors＇ position and azimuth.

Optimization of fused deposition modeling process parameters using a fuzzy inference system coupled with Taguchi philosophy

Fused deposition modeling （FDM） is an additive manufacturing technique used to fabricate intricate parts in 3D, within the shortest possible time without using tools, dies, fixtures, or human intervention. This article empiri- cally reports the effects of the process parameters, i.e., the layer thickness, raster angle, raster width, air gap, part orientation, and their interactions on the accuracy of the length, width, and thicknes, of acrylonitrile-butadiene- styrene （ABSP 400） parts fabricated using the FDM tech- nique. It was found that contraction prevailed along the directions of the length and width, whereas the thickness increased from the desired value of the fabricated part. Optimum parameter settings to minimize the responses, such as the change in length, width, and thickness of the test specimen, have been determined using Taguchi＇s parameter design. Because Taguchi＇s philosophy fails to obtain uniform optimal factor settings for each response, in this study, a fuzzy inference system combined with the Taguchi philosophy has been adopted to generate a single response from three responses, to reach the specific target values with the overall optimum factor level settings. Further, Taguchi and artificial neural network predictive models are also presented in this study for an accuracy evaluation within the dimensions of the FDM fabricated parts, subjected to various operating conditions. The pre- dicted values obtained from both models are in good agreement with the values from the experiment data, with mean absolute percentage errors of 3.16 and 0.15, respectively. Finally, the confirmatory test results showed an improvement in the multi-response performance index of 0.454 when using the optimal FDM parameters over the initial values.