The paper considers the issue of residual stresses in 3D-printed plastic models. Most additive technologies create residual stresses in products. Residual stresses occur in the printed material due to its expansion when heated and contraction when cooled. Residual stresses and their intensity depend on the printing technology and technique. The paper discusses the impact of printing techniques and various printing nozzle diameters and model shapes (rectangular, circular) on the occurrence of residual stresses in specimens. As part of the study, in transparent models, residual stresses were detected using a PPU-7 polarization-projection unit. Two series of six specimens each have been printed. The first and second series models had the shape of a parallelepiped and a disk, respectively. The frequency-division multiplexing technology was chosen. In the study, the models were manufactured from a polyethylene terephthalate-glycol plastic filament. This material has a high optical sensitivity. Nozzles of two diameters (0.4 and 1 mm) were used to print specimens. Shell-less and singleand double-shell specimens were printed. The dependence of residual stresses on the specimen shape, the printing nozzle diameter, and the model shell thickness has been estimated. The study is focused on finding a technique for printing models from plastic filament, completely free of residual stresses in the specimen material. This is dictated by the photoelasticity requirements for piezo-optical materials, including some transparent plastics used in 3D printing.
Globalization, which presupposes the strengthening of multifactorial economic, social and other phenomena, needs strategic management, forecasting and foreseeing its impact on every spheres of public life without any exception. Unfortunately, the modern Russian strategic planning system appears to be unbalanced and ineffective; key indicators of the adopted and developed strategies are abstract in nature and are weakly correlated with the practical needs. This is clearly illustrated by the example of such an important branch of the economy as transport. Strategic air transport management in Russia in the context of the digital transformation of the economy, especially the practice of strategic planning and forecasting, has a number of bottlenecks and needs to be improved. A very vulnerable spot in modern strategic management is the occasional use of methods of strategic audit (control). This conclusion is confirmed by the analysis of the draft Transport Strategy for the period up to 2035, submitted for discussion and revision. It is not possible to solve this problem without scientific support and methods of strategizing approved by domestic and foreign practice.
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