УСТАНОВЛЕНИЕ ОГРАНИЧЕНИЙ ПО МАКСИМАЛЬНЫМ СКОРОСТЯМ ДЕСАНТИРОВАНИЯ С УЧЁТОМ ДЕГРАДАЦИИ ПРОЧНОСТНЫХ ХАРАКТЕРИСТИК МАТЕРИАЛОВ КУПОЛА ПАРАШЮТА. СООБЩЕНИЕ 1. ЗАВИСИМОСТЬ ПРОЧНОСТИ ПАРАШЮТОВ ОТ ДЕГРАДАЦИИ ПРОЧНОСТНЫХ ХАРАКТЕРИСТИК КОНСТРУКЦИОННЫХ МАТЕРИАЛОВ

Abstract

It is introduced the concept of the degradation coefficients of the parachute canopy power structure materials strength characteristics. These coefficients are defined as the ratio of destructive loads after long-term operation or storage to the original, taken at the design stage. It is noted revealed the dependence of safety factors on degradation factors. It was determined the condition of safety factors equality after the long-term operation and during the design stage. It was shown that the ratio of maximum permissible loads is equal to the degradation coefficient. It was defined as the method for calculating the load on the parachute during deployment. It was applied to the simplified approach proposed by N. A. Lobanov. The following statement was determined according to this approach: a dynamic coefficient equal to two, a method for determining the dangerous section of the dome when assessing the fabric strength, the dependence of the speed at the moment of full filling of the parachute canopy from the generalized empirical coefficient. Characteristics of the standard atmosphere, depending on the height of throwing the aircraft are given by approximating functions. The movement of the body until the parachute opens is given in the form of differential equations with known initial conditions. The equation allows you to find the falling speed at the initial moment of the parachute opening, depending on the delay time. It is given the speed of steady free fall without the introduction of a parachute into the work and with a stabilizing parachute, the landing speed with the main parachute. The dependences of the maximum permissible loads on the dome at the opening moment on the strength degradation factors for the fabric of the dome, lines, and free ends of the suspension system are established. It was proposed the correlations for the maximum allowable speed at the time of the beginning of the parachute opening on the requirements of strength. This speed determines the maximum allowed landing speed for a particular type of parachute after long-term operation or storage.