The subject of the article is the analysis of the array of experimental data of loading and elongation at break of the slings of the main parachute landing parachute systems D-5 series 2 1973 and 1974 years of manufacture after long-term storage with zero (inexhaustible) resource. The current article attempts to determine the ratio of external factors related to the natural factors of aging of polymers, and internal, due to errors in the measurement process, based on statistical analysis of measurement results. Objective: to determine the degree of influence of internal and external factors on the process and result of measuring indicators. The following methods and equipment were used. An improved method of spot sampling of the samples under study of landing parachute systems D-5 series 2 for laboratory studies to determine the load at break and elongation at break of the slings of the main parachute. Measurements were performed on a machine of bursting brand ИР 5047-50M2C, accuracy class - 0.5 for the measurement range from 0.5 kN to 5 kN. The volume of the party was 25 parachute systems, only 250 elementary tests. The array of empirical data was processed by mathematical and statistical methods of the software package Descriptive statistics on the add-on of MS EXCEL Analysis Package. The following results were obtained. The relative error of the results of load measurement when breaking the slings of the domes of parachutes of 1973 production was ± 5.0%, for parachutes of 1974 production - ± 3.8%. The relative error of the results of measuring the elongation at the break of the slings of the domes of parachutes of 1973 manufacture was ± 2.9%, for parachutes of 1974 manufacture ± 3.3%. Given that the measuring instrument has an error of ± 0.29% in the passport, which can be considered systematic, the overall level of uncertainty is acceptable for conventional measurements in engineering. Conclusions. The main factors of accidental errors in the process of measuring the load at break and elongation at break of the slings of the main parachute are external factors due to the state of the cord structure and changes in the internal structure of the polymer.
Experimental determination of the state of textile materials of the D-5 series 2 aircraft parachute system after long-term storage. Message 2. Statistical characteristics of the results of measuring the indexes of the main parachute lines
2021
Article (Journal)
Electronic Resource
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