Analysis of vibro-impact pressing of plant mass with clarification of the mathematical model of the process
Authors: Yeremenko O. I. , Subota S. V. 
Published: May 2022

Annotation
Purpose. Improving the technical level of design of briquette presses through the analysis of the theory of vibro-impact pressing and refinement of the mathematical descriptive model of the process.
Methods. The method of dynamic similarity is used to select the mass and stiffness of the model, when the frequencies of the model and the medium are the same. A set of differential equations of motion for solving a dynamic system of vibratory impact briquetting. Mathematical modeling, which assumes the dependence of the degree of compression of the plant mass on the magnitude of the impact load (pulse) and reveals the nonlinear nature of the resistance of the deformation medium.
Results. The analysis of studies of dynamic compaction of plant materials for briquettes allowed identifying significant differences in research results. The process of briquetting plant mass under dynamic action is insufficiently studied. The limited scientific basis of vibro-impact briquetting of plant materials has a negative impact on the effectiveness of design developments.
According to the results of comparative analysis with the use of certain research methods, a refined mathematical model of the process of vibratory impact briquetting in the form of a system of differential equations is obtained. This model takes into account the most important factors that determine the effectiveness of the vibrating shock press. Solving the equations of the obtained model assumes that the deformation of the material is influenced not only by inertial effects, but also by the rheological properties of the briquetted plant mass.
Conclusions
1. Models of static pressing of crushed plant materials are based on the assumption that the processing speed has no significant effect on compaction performance. This assumption is not true in all cases, because the deformation of the material is affected not only by inertial effects, which in the case of static pressing can rightly be neglected, but also the rheological properties of the briquetted raw material.
2. According to the results of the analysis it is established that briquettes with a density of more than 1000 kg/m3 are formed under the pressure of the working body of the press more than 100 MPa. In general, the influence of dynamic (shock and vibration) loads on crushed plant materials at constant values of the parameters characterizing the deformation is considered. A fundamental difference from studies on the static effect on plant mass is the consideration of speeds and accelerations of the working body in the process of briquette formation, as well as caused by its influence of additional dynamic stresses in the plant mass.
3. The analysis of experimental data shows that the coefficient of viscous resistance for plant material is not a constant and varies depending on the density of briquettes. This confirms the need to take into account nonlinear models of briquetted plant material.
Keywords: vibro-shock pressing, plant mass, dynamic loading, briquetting, research, analysis, models.