Increasingly, parts of complex shapes are made using three-dimensional printing. This technique is also used in the design of equipment at the stage of physical modeling of their structures to determine certain properties of the product as a whole and its individual parts (details) on the corresponding models. The necessary conditions for physical modeling are the geometric and physical similarity of the model and kind. The presence of such proportionality makes it possible to recalculate the experimental results obtained for the model in kind by multiplying each of the determined values by a constant multiplier for all values of this dimension – the similarity coefficient. However, to study the physical characteristics of a product, it is necessary to take into account the mechanical properties of the material of its model. From various sources, you can find the main mechanical characteristics of plastic threads or samples made on a 3-D printer. Their values vary greatly depending on the manufacturing technology of models and are determined under conditions of static loading only, which is not enough to study the stress-strain state of parts that are affected by suddenly applied, long-term and dynamic loads during machine operation. This paper presents the results of a study of the physical and mechanical properties of polylactide (PLA) and polyethylene tereflatate (PET-G), which are used in the manufacture of parts by three-dimensional printing. The specific stiffness of polymers was for PLA 1.61…2.18 MPa·m3/kg, for PET-G – 1.15…1.41 MPa·m3/kg. The specific impact strength for PLA is 751.6…774.2 J·m/kg, for PET-G – 571.6…583.0 J·m/kg. The specific endurance for PLA was 1.75…2.76 kPa·m3/kg, for PET-G – 3.0…3.10 kPa·m3/kg.
Asynchronous electric drives hold leading positions in the global structure of electricity consumption. That’s why the development and implementation of an energy-efficient asynchronous electric drive are always economically feasible and important. The aim of this article is to develop an algorithm to minimize losses of asynchronous electric drive power. The article offers methods to optimize the level of losses in the winding of an electric motor, powered in a steady-state mode by a frequency converter with a scalar control. The substitution scheme for an asynchronous electric drive is considered as a consistent set of conductivities for the stator and rotor wirings. The research tasks were solved based on theoretical and experimental methods, including mathematical and physical simulation of studied processes using modern measuring and computation devices as well as statistic treatment of experimental data. The article offers methods to minimize the losses of power in the winding of an electric motor, powered in a steady-state mode by a frequency converter with a scalar control. The offered method is significantly different in that it uses the substitution for an asynchronous electric drive expressed as a consistent set of conductivities for the stator and motor wirings and the use of the energy efficiency ratio which determines the losses of power in an asynchronous drive for assessing the efficiency of a drive. The main principle for optimal frequency control of an asynchronous engine in terms of energy efficiency was formulated. The laboratory bench for studying the modes of frequency-controlled electric drives was built. The tested drive AIR100S4 showed an increase in energy efficiency ratio from 0.59 to 0.67.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.