Types Of Three-dimensional Models Research Articles

Features of modeling the system of turbine unit with a variable contact zone of its stator parts

Modeling of stator parts of power units of thermal and nuclear power plants is carried out according to several standard schemes. Common methods of modeling systems with non-uniform and non-stationary contact of stator elements lead to significant errors in calculating the amplitudes of forced vibration displacement at a given external load. The object of this paper is to analyze errors in calculating the displacement amplitudes of forced oscillations in different modeling schemes according to the standard approach and developing a method for constructing a quasi-dynamic model taking into account the time-varying contact of the system’s stator parts as well as other factors. To do this, the author has developed a series of models with different degrees of sampling and considering different system factors. Particular attention is paid to the impact of factors arising from the long operation of the power plant (subsidence of foundation). The modeling was carried out taking into account the calculation method. The finite element method was used to perform calculations. The results of the calculation of forced oscillation displacement amplitudes are available to show the areas of application of different types of three-dimensional models of the steam power unit. The results of research conducted on the developed models show the impossibility of using standard simulation schemes for systems with a variable contact between its stator elements, as shown by the example of a power unit with steam turbine. The efficiency of using the models taking into account the variable contact between the stator parts and other factors to calculate the displacement amplitudes of the forced oscillations with high accuracy is likewise presented. Every specialist should be aware of the factors that influence the research results. This paper is concerned with assessment of the influence of a number of factors on the results of calculating the vibrations of a complex mechanical system.

PECULIARITIES OF THREE-DIMENSIONAL METRIC MODEL CONSTRUCTION FROM LASER SCANNING DATA

Three-dimensional metric models of real physical objects are actively used when solving various tasks in the process of a person's professional activity. In the construction industry, 3D modeling helps to capture all life cycles of buildings from engineering surveys to design, operation and demolition work. Three-dimensional models allow quickly performing all the necessary measurements in a computer environment, provide the ability to build two-dimensional drawings and make changes to design documentation. Among all types of three-dimensional models, there are separately those that allow storing various attributive information about an object in addition to geometric information, significantly automate the process of many engineering calculations using a three-dimensional model and provide the ability to automatically create various types of documentation. These types of three-dimensional models are called building information models (BIM). The most appropriate method is laser scanning as a data source for creating BIM. The technique of three-dimensional modeling based on laser scanning data is discussed. The advantages of BIM over simple three-dimensional models created in specialized software for processing laser scanning data and computer-aided design systems are analyzed.

Dynamic analysis of the tokamak support system in ITER

The ITER tokamak machine has a relatively flexible support structure against horizontal loads as from an earthquake. Modal analyses and modal transient analyses have been carried out by using the finite element analysis code NASTRAN to assess the response of the tokamak driven by a horizontal seismic load with the ITER design response spectra. Two types of three-dimensional models and a simplified mass/spring model have been used as structural models. The three-dimensional models have been used for modal analyses and modal transient analyses. The simplified mass/spring model has been used for parameter surveying of the transient response. It has been shown in the analyses that the lowest natural frequency of the tokamak is about 2 cycles s −1 and that the maximum relative response displacement between the magnet and the vacuum vessel is about 14 mm.

Some Models of Interest in Meteorological Thermodynamics

Techniques of construction and examples of application of several types of three-dimensional models depicting important thermodynamic functions are discussed, with special emphasis on models useful in the teaching of thermodynamics as related to cloud physics.