scholarly journals Generalized Geometry Projection: A Unified Approach for Geometric Feature Based Topology Optimization

2019 ◽  
Vol 27 (5) ◽  
pp. 1573-1610 ◽  
Author(s):  
Simone Coniglio ◽  
Joseph Morlier ◽  
Christian Gogu ◽  
Rémi Amargier
Author(s):  
Tim E. Westhoven ◽  
C. L. Philip Chen ◽  
Yoh-Han Pao ◽  
Steven R. LeClair

Process planning is the function that converts an engineering design into a manufacturing plan. One of the problems in feature-based process planning is the sequencing of features. Features must be given an order for removal. This order, or sequence, is partially dependent on the geometric relationships between the features. If the geometric relationships between features are such that they dictate a particular sequence, the features are said to have an interaction. Identifying these interactions is an important first step in creating the process plan. An approach to solve this problem using constructive solid geometry operations and the Episodal Associative Memory (EAM) is demonstrated. The EAM is an associative memory that integrates dynamic memory organization and neural computing techniques. The geometric feature relationships can be represented by a pattern. This pattern captures very qualitative information about the geometric positions fo the features. The EAM can organize these patterns into groups of similar geometric relationships. A method for dealing with exceptions, and for retrieving and storing general machining problems associated with interacting features will be described. The system implemented is shown to correctly sequence several types of feature interactions.


2016 ◽  
Vol 54 (5) ◽  
pp. 1173-1190 ◽  
Author(s):  
Shanglong Zhang ◽  
Julián A. Norato ◽  
Arun L. Gain ◽  
Naesung Lyu

Author(s):  
Zafer Leylek ◽  
A. J. Neely

This paper will present an enhanced parametric modeling technique for gas turbine stator and rotor blades. The enhanced blade parametric modeling system has been developed as part of a wider research program into global surrogate modeling of compressor and turbine aerodynamic performance using Design and Analysis of Computer Experiments (DACE) based techniques. The proposed method is based on a hybrid of geometric feature and Non-uniform Rational B-Spline (NURBS) based techniques. A base-line geometry is defined using the physical parameters and represented using NURBS curves and surfaces. A number of constraints are then imposed on the parametric model to ensure that DACE techniques can be effectively utilized. This is accomplished by mapping the geometric feature based parameters from the physical space to an alternative parametric space so that all feasible and numerically stable blade configurations can be represented using a unit hyper-cube. This method ensures a one-to-one mapping between the parametric sub-space and the geometric feature based system. The mapping is geometrically and numerically stable and does not produce ill-conditioned and unrealistic blade geometries. The development of the blade parametric modeling process allows the application of the complete suit of DACE tools and techniques. The method is valid for all axial blade profiles which include compressor and turbine stator and rotor blades.


Author(s):  
Hollis Smith ◽  
Julian Norato

Abstract This work introduces a topology optimization method for the design of structures composed of rectangular plates each of which is made of a predetermined anisotropic material. This work builds upon the geometry projection method with two notable additions. First, a novel geometric parameterization of plates represented by offset surfaces is formulated that is simpler than the one used in previous works. Second, the formulation presented herein adds support to the geometry projection method for geometric components with general anisotropic material properties. A design-generation framework is formulated that produces optimal designs composed exclusively of rectangular plates that may be made of a predetermined, generally anisotropic material. The efficacy of the proposed method is demonstrated with a numerical example comparing optimal cantilever beam designs obtained using isotropic- and orthotropic-material plates. For this example, we maximize the stiffness of the structure for a fixed amount of material. The example reveals the importance of considering material anisotropy in the design of plate structures. Moreover, it is demonstrated that an optimally stiff design for plates made of an isotropic material can exhibit detrimental performance if the plates are naively replaced with an anisotropic material. Although the example given in this work is in the context of orthotropic plates, since the formulation presented in this work supports arbitrary anisotropic materials, it may be readily extended to support the design of each component’s material anisotropy as a part of the optimization routine.


2006 ◽  
Vol 54 (7) ◽  
pp. 546-558 ◽  
Author(s):  
Diego Rodriguez-Losada ◽  
Fernando Matia ◽  
Ramon Galan

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