surface description
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Author(s):  
V. Korotkov

The creation of modern high-performance machines often involves design of details with complex surfacese and made with high precision. At the stage of design and preparation of production, project work is carried out using automation tools and modern information and computer technologies. The process of creating a project is accompanied by the preparation of appropriate documentation, sufficient to solve all possible questions, starting with the formation of a design task and disposal of the product at the end of its operation. According to statistics, most details in mechanical engineering are simple in shape, relatively technological in production, and their surfaces are most often described in the drawings by a set of lines and circles (radius of curvature). This approach is economically justified and will ensure the reliable operation of the product during operation. Significant difficulties arise when it is necessary to design parts with surfaces of complex geometric shape, when the geometric parameters are set by coordinate points. The accuracy of surface description depends on the number of such points and the accuracy of numerical data. Typical examples include turbine impellers, parts with aerodynamic surfaces that are used, for example, in the aerospace or rocket industries. The process of manufacturing such parts is accompanied by overcoming specific difficulties in describing complex surfaces at the stages of design and technological preparation, as well as directly in the manufacture of parts on technological equipment, intermediate and final control of geometric accuracy. An option for an effective solution of such problems is to record complex smooth surfaces, predefined by a set of coordinate points, splines. Modern design automation tools make it possible to use this mathematical method for modeling complex geometric objects and use it to calculate the trajectories of the forming tool on CNC machines. On the example of parts from production, which has a complex surface, using computer-aided design systems considered options for making design and technological design decisions for production preparation, equipment design, control the accuracy of shaping when machining on CNC machines.


2021 ◽  
Vol 14 (10) ◽  
pp. 6197-6213
Author(s):  
Lachlan Grose ◽  
Laurent Ailleres ◽  
Gautier Laurent ◽  
Guillaume Caumon ◽  
Mark Jessell ◽  
...  

Abstract. Without properly accounting for both fault kinematics and observations of a faulted surface, it is challenging to create 3D geological models of faulted geological units. Geometries where multiple faults interact, where the faulted surface geometry significantly deviate from a flat plane and where the geological interfaces are poorly characterised by sparse datasets are particular challenges. There are two existing approaches for incorporating faults into geological surface modelling. One approach incorporates the fault displacement into the surface description but does not incorporate fault kinematics and in most cases will produce geologically unexpected results such as shrinking intrusions, fold hinges without offset and layer thickness growth in flat oblique faults. The second approach builds a continuous surface without faulting and then applies a kinematic fault operator to the continuous surface to create the displacement. Both approaches have their strengths; however, neither approach can capture the interaction of faults within complicated fault networks, e.g. fault duplexes, flower structures and listric faults because they either (1) impose an incorrect (not defined by data) fault slip direction or (2) require an over-sampled dataset that describes the faulted surface location. In this study, we integrate the fault kinematics into the implicit surface, by using the fault kinematics to restore observations, and the model domain prior to interpolating the faulted surface. This new approach can build models that are consistent with observations of the faulted surface and fault kinematics. Integrating fault kinematics directly into the implicit surface description allows for complexly faulted stratigraphy and fault–fault interactions to be modelled. Our approach shows significant improvement in capturing faulted surface geometries, especially where the intersection angle between the faulted surface and the fault surface varies (e.g. intrusions, fold series) and when modelling interacting faults (fault duplex).


2021 ◽  
Vol 9 (10) ◽  
pp. 1107
Author(s):  
Diego Villa ◽  
Francesco Furcas ◽  
Jan Oscar Pralits ◽  
Giuliano Vernengo ◽  
Stefano Gaggero

A method for the morphing of surface/volume meshes suitable to be used in hydrodynamic shape optimization is proposed. Built in the OpenFOAM environment, it relies on a Laplace equation that propagates the modifications of the surface boundaries, realized by applying a free-form deformation to a subdivision surface description of the geometry, into the computational volume mesh initially built through a combination of BlockMesh with cfMesh. The feasibility and robustness of this mesh morphing technique, used as a computationally efficient pre-processing tool, is demonstrated in the case of the resistance minimization of the DTC hull. All the hull variations generated within a relatively large design space are efficiently and successfully realized, i.e., without mesh inconsistencies and quality issues, only by deforming the initial mesh of the reference geometry. Coupled with a surrogate model approach, a significant reduction in the calm water resistance, in the extent of 10%, has been achieved in a reasonable computational time.


2021 ◽  
Author(s):  
Lachlan Grose ◽  
Laurent Ailleres ◽  
Gautier Laurent ◽  
Guillaume Caumon ◽  
Mark Jessell ◽  
...  

Abstract. Without properly accounting for both fault kinematics and faulted surface observations, it is challenging to create 3D geological models of faulted geological units that are seen in all tectonic settings. Geometries where multiple faults interact, where the faulted surface geometry significantly deviate from a flat plane and where the geological interfaces are poorly characterised by sparse data sets are particular challenges. There are two existing approaches for incorporating faults into geological surface modelling: one approach incorporates the fault displacement into the surface description but does not incorporate fault kinematics and in most cases will produce geologically unexpected results such as shrinking intrusions, fold hinges without offset and layer thickness growth in flat oblique faults. Another approach builds a continuous surface without faulting and then applies a kinematic fault operator to the continuous surface to create the displacement. Both approaches have their strengths, however neither approach can capture the interaction of faults within complicated fault networks e.g fault duplexes, flower structures and listric faults because they either \\begin{inparaenum}[(1)] \\item impose an incorrect (not defined by data) fault slip direction; or \\item require an over sampled data set that describes the faulted surface location\\end{inparaenum}. In this study we integrate the fault kinematics into the implicit surface by using the fault kinematic model to restore observations and the model domain prior to interpolating the faulted surface. This approach can build models that are consistent with observations of the faulted surface and fault kinematics. Integrating fault kinematics directly into the implicit surface description allows for complex fault stratigraphy and fault-fault interactions to be modelled. Our approaches show significant improvement in capturing faulted surface geometries especially where the intersection angle between the faulted surface geometry and the fault surface varies (e.g. intrusions, fold series) and when modelling interacting faults (fault duplex).


2021 ◽  
Vol 180 ◽  
pp. 107867
Author(s):  
Amita Giri ◽  
Gary P.T. Choi ◽  
Lalan Kumar

2020 ◽  
Author(s):  
Thomas W. Mitchel ◽  
Szymon Rusinkiewicz ◽  
Gregory S. Chirikjian ◽  
Michael Kazhdan

2020 ◽  
Vol 59 (27) ◽  
pp. 8408
Author(s):  
Zhenfeng Zhuang ◽  
Xavier Dallaire ◽  
Jocelyn Parent ◽  
Patrice Roulet ◽  
Simon Thibault

2020 ◽  
Vol 14 (4) ◽  
pp. 154-161 ◽  
Author(s):  
Sheng Ao ◽  
Yulan Guo ◽  
Shangtai Gu ◽  
Jindong Tian ◽  
Dong Li

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