On Evaluation of Adaptive Mask Overlay Topology Synthesis Method Using Different Mask Shapes

2010 ◽  
Author(s):  
Pranay Sharma ◽  
Anupam Saxena
Keyword(s):  
Design Space ◽  
Resource Constraints ◽  
Synthesis Method ◽  
Closed Curves ◽  
Unique Minimum ◽  
Compliance Minimization ◽  
Topological Features ◽  
Fair Comparison ◽  
Mean Compliance ◽  
Material Layout

Previous versions of the Material Mask Overlay Strategy (MMOS) for topology synthesis have primarily employed circular masks to simulate voids within the design region. MMOS operates on the photolithographic principle by appropriately positioning and sizing a group of negative masks to create voids within the design region and thus iteratively improve the material layout to meet the desired objective. The fundamental notion has been that a group of circular masks can represent a local void of any shape. Thus, circular masks, as opposed to those modeled using simple, non-intersecting, closed curves of generic shapes, have been employed. This paper investigates whether employing masks of more general shapes (e.g., any two-dimensional polygon) offers significant enhancements in efficiently attaining the appropriate topological features in a continuum. Here, performance of two other mask shapes, namely, elliptical and rectangular are compared with that of the circular masks. For fair comparison, two mean compliance minimization examples under resource constraints are solved as each design space is known to contain a unique minimum.

Are Circular Shaped Masks Adequate in Adaptive Mask Overlay Topology Synthesis Method?

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Anupam Saxena
Keyword(s):  
Resource Constraints ◽  
Synthesis Method ◽  
Design Procedure ◽  
Topology Design ◽  
Two Dimensional ◽  
Closed Curves ◽  
Compliance Minimization ◽  
Topological Features ◽  
Mean Compliance ◽  
Material Layout

Previous versions of the material mask overlay strategy (MMOS) for topology synthesis primarily employ circular masks to simulate voids within the design region. MMOS operates on the photolithographic principle by appropriately positioning and sizing a group of negative masks and thus iteratively improves the material layout to meet the desired objective. The fundamental notion is that a group of circular masks can represent a local void of any shape. The question whether masks of more general shapes (e.g., any two-dimensional closed, nonself intersecting polygon) would offer significant enhancements in efficiently attaining the appropriate topological features in a continuum remains. This paper investigates the performance of two other mask types; elliptical and rectangular masks are compared with that of the circular ones. These are the respective modest representatives of closed curves and their polygonal approximations. First, two mean compliance minimization examples under resource constraints are solved. Thereafter, compliant pliers are synthesized using the three mask types. It is observed that the use of elliptical or rectangular masks do not offer significant advantages over the use of circular ones. On the contrary, the examples suggest that less number of circular masks are adequate to model the topology design procedure more efficiently. Thus, it is postulated that using generic simple closed curves or polygonal masks will not introduce significant benefits over circular ones in the MMOS based topology design algorithms.

Modal Methodology for the Simulation and Optimisation of the Free-Layer Damping Treatment of a Car Body

2006 ◽  
Author(s):  
Marco Danti ◽  
Davide Vige` ◽  
Guido Vincent Nierop
Keyword(s):  
Weight Reduction ◽  
Design Space ◽  
Computation Time ◽  
Software Tool ◽  
Automotive Applications ◽  
Free Layer ◽  
Acoustic Performance ◽  
Damping Material ◽  
The Cost ◽  
Material Layout

The cost and weight reduction requirements in automotive applications are very important targets in the design of a new car. For this reason all the components of the vehicle have to be optimised, and the design of the damping material layout has to be deeply analysed in order to have a good NVH performance with the minimum of weight and cost. A tool for the optimisation of the damping material layout has been implemented and tested; the need to explore the entire design space with a big number of variables suggested the use of a genetic multi-objective algorithm for the optimisation. These algorithms require a large number of calculations and the solution of the complete NVH model would be too expensive in terms of computation time. For this reason, a new software tool has been developed based on the simulation of the damping material treatments by means of an auxiliary mass and stiffness matrix to be added to the baseline modal base; using this procedure the required time for the simulation of each damping material layout configuration is reduced to a few minutes, allowing to exploit the genetic algorithm capability to efficiently explore the design space. As a result, some configurations with an important weight reduction or a much better acoustic performance have been found. This method has been verified on a simple Aluminium box in order to verify all the assumptions and to test the effectiveness in predicting the vibration levels of plates with free layer damping added to it.

scholarly journals Shape Optimization of Thermoelastic Fields for Mean Compliance Minimization

2011 ◽  
Vol 77 (783) ◽  
pp. 4015-4023 ◽  
Author(s):  
Eiji KATAMINE ◽  
Hiroki YOSHIOKA ◽  
Kousuke MATSUURA ◽  
Hideyuki AZEGAMI
Keyword(s):  
Shape Optimization ◽  
Compliance Minimization ◽  
Mean Compliance

scholarly journals DOUBLY PERIODIC TEXTILE STRUCTURES

2009 ◽  
Vol 18 (12) ◽  
pp. 1597-1622 ◽  
Author(s):  
HUGH R. MORTON ◽  
SERGEI GRISHANOV
Keyword(s):  
Periodic Structures ◽  
Original Structure ◽  
Closed Curves ◽  
Polynomial Invariants ◽  
Topological Features ◽  
Algebraic Properties ◽  
Full Symmetry ◽  
Thickened Torus ◽  
Traditional Structures ◽  
Woven Textile

Knitted and woven textile structures are examples of doubly periodic structures in a thickened plane made out of intertwining strands of yarn. Factoring out the group of translation symmetries of such a structure gives rise to a link diagram in a thickened torus, as in [2]. Such a diagram on a standard torus in S3 is converted into a classical link by including two auxiliary components which form the cores of the complementary solid tori. The resulting link, called a kernel for the structure, is determined by a choice of generators u, v for the group of symmetries. A normalized form of the multi-variable Alexander polynomial of a kernel is used to provide polynomial invariants of the original structure which are essentially independent of the choice of generators u and v. It gives immediate information about the existence of closed curves and other topological features in the original textile structure. Because of its natural algebraic properties under coverings we can recover the polynomial for kernels based on a proper subgroup from the polynomial derived from the full symmetry group of the structure. This enables two structures to be compared at similar scales, even when one has a much smaller minimal repeating cell than the other. Examples of simple traditional structures are given, and their Alexander data polynomials are presented to illustrate the techniques and results.

Comparative study of 3.4 micron band features from carbon dust analogues obtained in pulsed plasmas

2019 ◽  
Vol 15 (S350) ◽  
pp. 237-240
Author(s):  
Ioana Cristina Gerber ◽  
Alina Chiper ◽  
Valentin Pohoata ◽  
Ilarion Mihaila ◽  
Ionut Topala
Keyword(s):  
Atmospheric Pressure ◽  
Barrier Discharge ◽  
Synthesis Method ◽  
Laboratory Astrophysics ◽  
Rf Discharge ◽  
Graphite Target ◽  
Saturated Hydrocarbons ◽  
Dielectric Barrier ◽  
Topological Features ◽  
Experimental Parameters

AbstractSyntheses of carbon dust analogues are key experiments in laboratory astrophysics, as an approach to study some chemical and topological features of interplanetary and interstellar carbon dust. We report a comparative experimental study for carbon dust analogues obtained in (1) an atmospheric pressure dielectric barrier discharge (DBD), fed with helium – saturated hydrocarbons gas mixtures, (2) a low pressure radio frequency (RF) discharge and (3) a pulsed laser deposition (PLD) experiment with a Nd:YAG laser and a graphite target. The aliphatic –C–H stretching band, known as the 3.4 micron feature, as well as the CH2/CH3 ratio, the H/C ratio value and the physical appearance at microscopic scale, show a variability that is influenced by the synthesis method and the experimental parameters of each specific technique.

2106 Shape Optimization of Thermoelastic Fields for Mean Compliance Minimization

2010 ◽  
Vol 2010.20 (0) ◽  
pp. _2106-1_-_2106-5_
Author(s):  
Eiji KATAMINE ◽  
Kousuke MATSUURA ◽  
Hideyuki AZEGAMI
Keyword(s):  
Shape Optimization ◽  
Compliance Minimization ◽  
Mean Compliance

Synthesis of Gear-Linkage Mechanisms by Topology Optimization

2018 ◽  
Author(s):  
Neung Hwan Yim ◽  
Seok Won Kang ◽  
Yoon Young Kim
Keyword(s):  
Topology Optimization ◽  
Design Space ◽  
Synthesis Method ◽  
Variable Stiffness ◽  
Optimization Methods ◽  
Optimization Method ◽  
Planar Mechanisms ◽  
Gear Design ◽  
Linkage Design ◽  
Gradient Based

This work is concerned with a new mechanism synthesis method for the simultaneous determination of the type, number and dimension of mechanisms by topology optimization. Earlier topology optimization methods can synthesize linkage mechanisms that consist only of links and joints. The proposed synthesis method is a gradient-based topology optimization method useful for the synthesis of planar mechanisms consisting of linkages and gears. To formulate the topology optimization based method, we propose two superposed design spaces as a ground structure: the linkage and gear design spaces. The gear design space is discretized by newly proposed gear blocks while the linkage design space by rigid blocks. The zero-length springs with variable stiffness are used to control the connectivity of blocks, which in turns determines the configuration of the synthesized mechanism. After the proposed topology-optimization-based synthesis formulation is presented, its effectiveness and validity are checked with various synthesis examples.

Sign in / Sign up

Export Citation Format

Share Document