Design and Research Sowing Devices for Aerial Sowing of Forest Seeds with UAVs

Modern unmanned aerial vehicles (UAV) can be effectively used for aerial sowing of forests. A feature of aerial sowing is the possibility of rapid reforestation at low costs, which is extremely important in the current environmental situation. The purpose of this study is to develop a set of sowing devices intended for use with UAVs. For this, the metering devices and seed distribution devices were analyzed, used on the UAV or having prospects for such use. The existing studies of metering devices, implemented by numerical methods, are analyzed. Further, the synthesis of eight different designs of sowing devices in the 3D CAD was carried out and their comparative assessment was completed in terms of mass and a set of technological parameters. Based on its results, a sowing device was selected that is most suitable for a specific given technology. Discrete Element Method (DEM) was used to simulate the workflow: imitation of loading of the sowing device, study of work in various modes, study of the process of impact interaction of seeds with the soil environment. The complex of developed sowing devices can provide sowing of almost any type of forest seeds within the framework of various technologies and soil climatic conditions.

Investigation of the impact interaction of pelleted seeds with the soil environment

The issues of studying the impact interaction of seeds with the soil environment by the method of discrete elements are considered. The main parameters of the used virtual stand are described and a brief description of the interaction model is given. As a result of the study, the depth of penetration of the seed, its displacement in the horizontal plane and the greatest depth of the crater were obtained. Analysis of the data showed that on unbound and loosely bound soils, a penetration rate of 50 m/s is sufficient for almost 100% penetration into the surface layer without noticeable displacement of the pelleted seed. On medium cohesive soils at a speed of 50 m/s, stable seed penetration is not ensured. The probability of its release is about 10%. At speeds of 75 m/s, almost 100% penetration into the surface layer is provided without noticeable displacement of the coated seed. On cohesive soils at speeds of 25 m/s, the seed is always ejected from the crater over a considerable distance. At a speed of 50 m/s, the probability of seed ejection is reduced to 30% and at 75 m/s to 10%.

Setting mode for precision systems of impact and laser engraving under conditions of uncertainty of characteristics

The Hertz impact interaction formula is extended to rigid bodies, the real physical characteristics of which a priori have a significant scatter and cannot be specified exactly. Fuzzy-functions are determined that characterize a micro-impact under conditions of indistinctly specified strength properties of the material of the processed halfspace and the geometry of the impact tool. It is shown that an effective solution of applied problems of precision engraving in conditions of this kind of uncertainty of parameters is the use of adaptive IT-technology based on the interactive pre-launch setting of the system. Keywords; impact engraving technology, micro impact, fuzzy parameters, critical parameters, fuzzy surfaces, gradation scale of shades.

Research on the dynamics of impact of elastic-plastic cylindrical rod against an absolutely rigid barrier

В статье рассматривается один из аспектов ударного взаимодействия сталкивающихся объектов, который может реализовываться при экстремальных и аварийных ситуациях с судами и морскими инженерными сооружениями. Решается задача об ударе деформируемого цилиндрического стержня об абсолютно жесткую преграду. Построены уравнения для моделей удара, основанные на подходе Г. Тейлора и уравнениях динамики упругопластического стержня, учтены изменения поперечных сечений кругового цилиндра в процессе пластического деформирования. Разработаны алгоритмы расчета упругопластического деформирования круговых цилиндров для исследования динамического процесса удара об абсолютно жесткую преграду. Результаты расчетных исследований по рассматриваемым моделям сопоставляются между собой и сравниваются с имеющимися экспериментальными данными. Проанализированы конечные формы пластического деформирования цилиндров. Предложенная уточненная модель Г. Тейлора дает результаты, которые близки результатам решения уравнений динамики упругопластических стержней при ударе, а также хорошо согласуются с экспериментальными данными. The article considers one of the aspects of impact interaction of colliding objects, which can be implemented in extreme and emergency situations with ships and offshore structures. The problem of impact of deformable cylindrical rod against absolutely rigid barrier is solved. Equations for impact models are built based on the approach of G. Taylor and the equations of the dynamics of the elastoplastic rod, changes in the cross sections of the circular cylinder during plastic deformation are taken into account. Algorithms have been developed for calculating elastoplastic deformation of cylindrical rod to study the dynamic process of impact on an absolutely rigid barrier. The results of the calculated studies on the models in question are compared with each other and compared with the available experimental data. Final modes of plastic deformation of cylinders are analyzed. The proposed refined model of G. Taylor gives results that are close to the results of solving the equations of dynamics of elastoplastic rods during impact, and are also well consistent with experimental data.