Analytical study of modular cutting tools dynamic properties

The paper studies a comparative evaluation method for the modular cutting tools dynamic properties under the cutting forces loading with the help of the finite element numerical method. The method allows forecasting the modular cutting tool dynamic properties with identification of the confidence bounds for its exploitation in compliance with its intended use and reference operating conditions. The conducted modeling describes the modular cutting tool structure as a ranked set of structural components, such as a frame, a cassette, a cutting insert, etc., oriented towards a certain direction with some surfaces being contiguous and thus making contact interactions. The analytical model is represented by a multi-mass system in the form of elastic rods connected at elastic and damping joints. The research examined different tool structural component layout options, including those equipped/not equipped with a shim, having a radial/tangential (face or peripheral) location type of cutting components. The dynamic compliance values and vibrational modes at the natural frequencies were calculated for all structural component layout options. The calculation results showed an acceptable level of model convergence with the existing experimental data on the cutting tool condition express diagnostics

Influence of Substituent in Conjugated Chain of Molecules on Nanocomponents Composition of Polymethine Dye Films

Molecular layers of polymethine dye long conjugation chain on glass contain several types of molecular nanocomponents. The number and type of the components depend on the thickness of a layer. In thin layers, only monomolecular components (all-trans-stereoisomers and cis-isomers) are present. We studied a series of four dicarbocyanines and determined the steric structure of the nanocomponents of the layers. The layers of less than 1 monolayer thick contain up to 4 monomeric components. For monocis- and dicisisomers of the dyes studied, which are obtained from the all-trans form upon rotation of fragments of a molecule around different bonds in the conjugated chain, the steric models were constructed. It was shown that in the series of polymethine molecules differing in the substituents and their positions in the chain there is a correlation between the intensity of the absorption bands of the certain components and the steric hindrance of molecular isomers. The above correlation may be used for the determination of the steric structure of monomeric components of the layer. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3489

Experimental research into impact of kinematic and design parameters of a spiral potato separator on quality of plant residues and soil separation

Saabunud / Received 08.10.2020 ; Aktsepteeritud / Accepted 15.12.2020 ; Avaldatud veebis / Published online 31.12.2020 ; Vastutav autor / Corresponding author: Jüri Olt [email protected] experimental investigations carried out in field production conditions have proved that the process of cleaning potato tubers from extraneous material with the use of a spiral separator takes place due to the active conveyance of the heap by the turns of the cantilever mounted cleaning spiral springs. The cleaning spiral springs not only rotate at the set angular velocity, but simultaneously their cantilevered ends perform oscillatory motion, which arises due to the deflection of their longitudinal axes under the action of the weight of the potato heap fed into the work zone of the separator. The results obtained in the process of the field experiment investigations carried out by the authors have provided for obtaining the relations that enable selecting the optimum design and kinematic parameters of the spiral-type potato cleaning devices for the targeted separation rate and, accordingly, estimating their impact on the quality of the performed work process

Analytical study of modular cutting tools dynamic properties

The paper studies a comparative evaluation method for the modular cutting tools dynamic properties under the cutting forces loading with the help of the finite element numerical method. The method allows forecasting the modular cutting tool dynamic properties with identification of the confidence bounds for its exploitation in compliance with its intended use and reference operating conditions. The conducted modeling describes the modular cutting tool structure as a ranked set of structural components, such as a frame, a cassette, a cutting insert, etc., oriented towards a certain direction with some surfaces being contiguous and thus making contact interactions. The analytical model is represented by a multi-mass system in the form of elastic rods connected at elastic and damping joints. The research examined different tool structural component layout options, including those equipped/not equipped with a shim, having a radial/tangential (face or peripheral) location type of cutting components. The dynamic compliance values and vibrational modes at the natural frequencies were calculated for all structural component layout options. The calculation results showed an acceptable level of model convergence with the existing experimental data on the cutting tool condition express diagnostics

Designing spline broaches of optimal structure

Methods of designing spline broaches of optimal structure according to smallest length of body are described. Multitude of broach designs may be explained by summation of geometric, structural and operating parameters of working and tail parts. In order to evaluate the efficiency of spline broaches, a system of functions characterizing length of broach, round and chamfer parts in accordance with the cutting pattern is introduced. A system of structural and technological limitations over basic features of broaches is supported. Mathematical optimization model of a broach consisting of a sum of target functions and constraint system is put together. Choice of optimal solution is based on implementation of linear programming algorithms. Optimal methods of designing spline broaches are determined using MS Excel. The developed design method is applicable for comparative evaluation of spline broaches of various designs with various cutting and cut-off patterns and allows to form the entire sum of broach designs according to set input parameters and to choose the most efficient one which would correspond to minimal length of the tool

Designing spline broaches of optimal structure

Methods of designing spline broaches of optimal structure according to smallest length of body are described. Multitude of broach designs may be explained by summation of geometric, structural and operating parameters of working and tail parts. In order to evaluate the efficiency of spline broaches, a system of functions characterizing length of broach, round and chamfer parts in accordance with the cutting pattern is introduced. A system of structural and technological limitations over basic features of broaches is supported. Mathematical optimization model of a broach consisting of a sum of target functions and constraint system is put together. Choice of optimal solution is based on implementation of linear programming algorithms. Optimal methods of designing spline broaches are determined using MS Excel. The developed design method is applicable for comparative evaluation of spline broaches of various designs with various cutting and cut-off patterns and allows to form the entire sum of broach designs according to set input parameters and to choose the most efficient one which would correspond to minimal length of the tool

Numerical Approach Based on Solving 3D Navier–Stokes Equations for Simulation of the Marine Propeller Flow Problems

The report presents the approach implemented in the Russian LOGOS software package for the numerical simulation of the marine propeller flow problems using unstructured computational meshes automatically generated by the mesh generator. This approach includes a computational model based on the Navier–Stokes equation system and written with respect to the physical process: the turbulent nature of flow with transient points is accounted using the Reynolds Averaged Navier–Stokes method and the k–ω SST model of turbulence by Menter along with the γ–Reθ (Gamma Re Theta) laminar-turbulent transition model; the Volume of Fluid method supplemented with the Schnerr–Sauer cavitation model is used to simulate the cavitation processes; a rotating propeller is simulated by a moving computational mesh and the GGI method to provide conformity of the solutions on adjacent boundaries of arbitrarily-shaped unstructured meshes of the two domains. The specific features of the numerical algorithms in use are described. The method validation results are given; they were obtained because of the problems of finding the performance curves of model-scale propellers in open water, namely the problems of finding the performance of propellers KP505 and IB without consideration of cavitation and the performance of propellers VP1304 and C5 under cavitation conditions. The paper demonstrates that the numerical simulation method presented allows for obtaining sufficiently accurate results to predict the main hydrodynamic characteristics for most modes of operation of the propellers