A Study on Topological Optimization of Structure Using Cantor Function As Teaching Function

Author(s):  
Masao Arakawa ◽  
Naoto Ohkubo ◽  
Hiroshi Yamakawa

Abstract In order to obtain better structural designs, it is important to carry out optimization from primary parts of those designs. Especially, designs of topologies of structures were depended on intuition of the designers and they were not always best fitted to the requirements of the structure. These days, designs of topologies of the structures become important to meet those purposes. In this study, we will propose a new method to obtain optimum topology of the structure to satisfy their requirements by growth and degeneration tutored by Cantor function as teaching function. Cantor function is the one which is very famous as an introduction of the fractal. By operating its order, it is very easy to manipulate its division among 0 and 1. We set skipping and restarting rules of growth and degeneration, and criteria of convergence. We applied the proposed method to the problem similar to the one well-known as Mitchell truss problem to compare the results obtained by the proposed method. From these numerical examples, we can obtain quite similar topological results to the homogenization method in small number of iteration. There, the proposed method has advantages in computational time, cost and memory. More over, we can see the growth of the topology. Although we demonstrate the proposed method in a few examples, we can say that the proposed method can derive optimum oriented topology even with this simple scheme efficiently.

2020 ◽  
Vol 998 ◽  
pp. 221-226
Author(s):  
Diaa Emad ◽  
Mohamed A. Fanni ◽  
Abdelfatah M. Mohamed

A lot of interest to simulate piezocomposite actuators with finite element method has been increased recently. However, there are still open questions regarding the modeling methodology, accuracy, and computational time cost. In this work, a new technique for modeling macro fiber composite piezoelectric actuator by finite element analysis is proposed. The presented technique models the piezocomposite actuator as a simple monolithic piezoceramic material with just two electrodes along its longitudinal extremes instead of using the actual large number of electrodes which results in very fine finite element mesh with high computational time cost. The proposed technique is validated successfully by comparing its results with those of the actual detailed model as well as with the published experimental results and manufacturer’s data.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Wenfa Hu ◽  
Xinhua He

The time, quality, and cost are three important but contradictive objectives in a building construction project. It is a tough challenge for project managers to optimize them since they are different parameters. This paper presents a time-cost-quality optimization model that enables managers to optimize multiobjectives. The model is from the project breakdown structure method where task resources in a construction project are divided into a series of activities and further into construction labors, materials, equipment, and administration. The resources utilized in a construction activity would eventually determine its construction time, cost, and quality, and a complex time-cost-quality trade-off model is finally generated based on correlations between construction activities. A genetic algorithm tool is applied in the model to solve the comprehensive nonlinear time-cost-quality problems. Building of a three-storey house is an example to illustrate the implementation of the model, demonstrate its advantages in optimizing trade-off of construction time, cost, and quality, and help make a winning decision in construction practices. The computational time-cost-quality curves in visual graphics from the case study prove traditional cost-time assumptions reasonable and also prove this time-cost-quality trade-off model sophisticated.


2017 ◽  
Vol 7 (1.2) ◽  
pp. 117
Author(s):  
Sirisati Ranga Swamy ◽  
Sridhar Mandapati

The cloud computing is the one that deals with the trading of the resources efficiently in accordance to the user’s need. A Job scheduling is the choice of an ideal resource for any job to be executed with regard to waiting time, cost or turnaround time. A cloud job scheduling will be an NP-hard problem that contains n jobs and m machines and every job is processed with each of these m machines to minimize the make span. The security here is one of the top most concerns in the cloud. In order to calculate the value of fitness the fuzzy inference system makes use of the membership function for determining the degree up to which the input parameters that belong to every fuzzy set is relevant. Here the fuzzy is used for the purpose of scheduling energy as well as security in the cloud computing.


RBRH ◽  
2018 ◽  
Vol 23 (0) ◽  
Author(s):  
Alice César Fassoni-Andrade ◽  
Fernando Mainardi Fan ◽  
Walter Collischonn ◽  
Artur César Fassoni ◽  
Rodrigo Cauduro Dias de Paiva

ABSTRACT The one-dimensional flow routing inertial model, formulated as an explicit solution, has advantages over other explicit models used in hydrological models that simplify the Saint-Venant equations. The main advantage is a simple formulation with good results. However, the inertial model is restricted to a small time step to avoid numerical instability. This paper proposes six numerical schemes that modify the one-dimensional inertial model in order to increase the numerical stability of the solution. The proposed numerical schemes were compared to the original scheme in four situations of river’s slope (normal, low, high and very high) and in two situations where the river is subject to downstream effects (dam backwater and tides). The results are discussed in terms of stability, peak flow, processing time, volume conservation error and RMSE (Root Mean Square Error). In general, the schemes showed improvement relative to each type of application. In particular, the numerical scheme here called Prog Q(k+1)xQ(k+1) stood out presenting advantages with greater numerical stability in relation to the original scheme. However, this scheme was not successful in the tide simulation situation. In addition, it was observed that the inclusion of the hydraulic radius calculation without simplification in the numerical schemes improved the results without increasing the computational time.


Author(s):  
Robert R. Mayer ◽  
Noboru Kikuchl ◽  
Richard A. Scott

Abstract The topological optimization of components to maximize crash energy absorption for a given volume is considered. The crash analysis is performed using a DYNA3D finite element analysis. The original solid elements are replaced by ones with holes, the hole size being characterized by a so-called density (measure of the reduced volume). A homogenization method is used to find elastic moduli as a function of this density. Simpler approximations were developed to find plastic moduli and yield stress as functions of density. Optimality criteria were derived from an optimization statement using densities as the design variables. A resizing algorithm was constructed so that the optimality criteria are approximately satisfied. A novel feature is the introduction of an objective function based on strain energies weighted at specified times. Each different choice of weighting factors leads to a different structure, allowing a range of design possibilities to be explored. The method was applied to an automotive body rear rail. The original design and a new design of equal volume with holes were compared for energy absorption.


Author(s):  
Shijia Zhao ◽  
Linxia Gu

The structural topological optimization method is an effective way to find the optimal topology of stents, which could be tailored for targeted stent performance, such as scaffolding ability, foreshortening, potential restenosis rate, etc. The radial stiffness is one of the major characteristics about stent performance. In this work, the homogenization method was utilized for the optimization of stent designs with the objective of maximizing the scaffolding ability of stent, i.e. its radial stiffness. A few design choices were presented by changing the number and distribution of strut connectors while keeping the void volume as 80%. The obtained optimal topology illustrated that the material distribution was mainly determined by the radial stress applied onto the stent. The optimal topology design in this work paves the way for the following dimension design, which can be targeted to the customized stent design for patient-specific lesions.


Entropy ◽  
2022 ◽  
Vol 24 (1) ◽  
pp. 78
Author(s):  
William Graham Hoover ◽  
Carol Griswold Hoover ◽  
Edward Ronald Smith

Time-reversible dynamical simulations of nonequilibrium systems exemplify both Loschmidt’s and Zermélo’s paradoxes. That is, computational time-reversible simulations invariably produce solutions consistent with the irreversible Second Law of Thermodynamics (Loschmidt’s) as well as periodic in the time (Zermélo’s, illustrating Poincaré recurrence). Understanding these paradoxical aspects of time-reversible systems is enhanced here by studying the simplest pair of such model systems. The first is time-reversible, but nevertheless dissipative and periodic, the piecewise-linear compressible Baker Map. The fractal properties of that two-dimensional map are mirrored by an even simpler example, the one-dimensional random walk, confined to the unit interval. As a further puzzle the two models yield ambiguities in determining the fractals’ information dimensions. These puzzles, including the classical paradoxes, are reviewed and explored here.


Author(s):  
Débora Isabel Ramos Torres

The Sustainable Development Goals (SDGs) have become entrenched in higher education institutions (HEIs) for their commitment to training people with relevant key competencies to address them. The article examines how teaching has been configured as the dimension with the greatest potential to incorporate sustainable development and how, together with research, it is considered one of the main areas of contribution to the achievement of the SDGs, concretized in the integration of these objectives to the study plans of the official degrees that, as a training action, are carried out. From the review of the Report of the Second World Survey of the International Association of Universities on Higher Education, Research and Sustainable Development, the annual Report of the Agreement on the SDGs of the Global Alliance and the Dossier of the Spanish Network for Development Sustainable, each SDG analyzes the relevant actions of integration of these Global Objectives in the teaching function and references to experiences as case studies. The analysis of the results shows a high variability between the universities regarding the degree of approach of each of the SDGs and the tendency to identify as well-established work, the one carried out with SDG 4, as a priority from teaching. The case studies analyzed show a significant differentiation regarding the types of actions they carry out and their trends. The use of surveys such as those analyzed are insufficient to observe the development of integration in the curricula, more experiences such as that developed by REDS are needed, as well as online platforms in which teachers present their experiences of curricular redesigns and incorporation from the SDGs to the curricula and mapping of the new degrees that are emerging.   


2012 ◽  
Vol 11 (5) ◽  
pp. 1591-1617 ◽  
Author(s):  
Marta M. Betcke ◽  
Heinrich Voss

AbstractIn this work the one-band effective Hamiltonian governing the electronic states of a quantum dot/ring in a homogenous magnetic field is used to derive a pair/quadruple of nonlinear eigenvalue problems corresponding to different spin orientations and in case of rotational symmetry additionally to quantum number -L•i. We show, that each of those pair/quadruple of nonlinear problems allows for the min-max characterization of its eigenvalues under certain conditions, which are satisfied for our examples and the common InAs/GaAs heterojunction. Exploiting the minmax property we devise efficient iterative projection methods simultaneously handling the pair/quadruple of nonlinear problems and thereby saving up to 40% of the computational time as compared to the nonlinear Arnoldi method applied to each of the problems separately.


DYNA ◽  
2020 ◽  
Vol 87 (212) ◽  
pp. 155-162
Author(s):  
Ageu Araujo Machado ◽  
João Carlos Zayatz ◽  
Marcos Meurer Da Silva ◽  
Guilherme Melluzzi Neto ◽  
Gislaine Camila Lapasini Leal ◽  
...  

This study aims to optimize the one-dimensional cutting process of aluminum bars for the production of aluminum doors. Reducing the use of bars and the amount of material that becomes scrap is a key factor in process efficiency, reducing the need for raw material procurement. The mathematical model used considers the size of the bar, the number and size of cuts, the size of the leftovers that can be used and the size of the leftovers that are considered scrap. Based on real data from a company in the aluminum frame segment, the mathematical model was used to simulate three different scenarios. Three different objective functions were used in the simulations, and the results obtained in each scenario were described in order to indicate the advantages and disadvantages of using each objective function. For the instance sizes studied, the model is able to obtain optimal solutions with little computational time.


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