1. Enhancing sustainability of building foundations with efficient open-end pile optimizationPrimož Jelušič, 2024, original scientific article Abstract: Optimizing open-end piles is crucial for sustainability as it minimizes material consumption
and reduces environmental impact. By improving construction efficiency, less steel is needed, reducing the carbon footprint associated with production and transportation. Improved pile performance
also results in more durable structures that require less frequent replacement and maintenance, which
in turn saves resources and energy. This paper presents a parametric study on optimal designs for
open-ended piles in sand, presenting a novel approach to directly compute optimal pile designs
using CPT results. It addresses challenges posed by soil variability and layered conditions, with
the optimization model accounting for interdependencies among pile length, diameter, wall thickness and soil properties, including the pile–soil plug system. A mixed-integer optimization model
OPEN-Pile was developed, consisting of an objective function for pile mass and CO2 emissions. The
objective function was constrained by a set of design and geotechnical conditions that corresponded
to current codes of practice and recommendations. The efficiency of the developed optimization
model is illustrated by two case studies. In the case of Blessington sand, the calculation results show
that it is more economical and environmentally friendly to increase the pile diameter and pile wall
thickness than the pile length. In efficient design, the ratio between diameter and wall thickness is
calculated at the upper limit. For the optimum design of piles in Blessington sand, the optimum
ratios of pile length to diameter, diameter to wall thickness and length to wall thickness are 5, 50 and
250, respectively. In a layered soil profile, the decision of where to place the pile base depends on the
resistance of the cone tip and the thickness of the individual layers. To determine in which layer the
pile base should be placed, we need to perform an optimization for the given design data.
Keywords: open-ended pile, computational modeling, structural optimization
Published in DKUM: 03.09.2024; Views: 49; Downloads: 5
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2. Structural topology optimization of the wheel's spokes of NASA's perseverance rover using advanced discretization techniques : magistrsko deloJure Trdin, 2023, master's thesis Abstract: In the space industry, the continuous effort to reduce the weight of structural components is of utmost importance due to the high cost of launching mass into space. Structural analyses and optimizations with numerical methods play a crucial role in achieving this goal by minimizing material usage while ensuring structural integrity. The objective of this dissertation is to implement and demonstrate the accuracy and effectiveness of meshless methods in numerical studies compared to the Finite Element Method (FEM), focusing on designing cost-effective and lightweight components. Through benchmark examples and extensive research on optimal parameters, the accuracy and effectiveness of these methods are established. Furthermore, practical application is demonstrated by optimizing the spoke of NASA's Rover Perseverance wheel, resulting in more optimized structures with significantly reduced mass and lower mechanical stresses. Additionally, analysis of different materials for the wheel's spoke is performed with the aim of further reducing mass and increasing performance. By utilizing structural optimization, this work not only highlights the diverse applications and benefits of integrating structural optimization in the product design phase but also contributes to the ongoing efforts in the space industry to reduce material mass and enhance performance, addressing the challenges associated with launching mass into space while ensuring the adequate structural resistance. Furthermore, this thesis also contributes to the development of the meshless methods in structural optimization, showcasing its effectiveness and potentials.
Keywords: Space technology, Mars Rover, Structural Optimization, Meshless Methods
Published in DKUM: 08.11.2023; Views: 376; Downloads: 33
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3. Discrete optimization with fuzzy constraintsPrimož Jelušič, Bojan Žlender, 2017, original scientific article Abstract: The primary benefit of fuzzy systems theory is to approximate system behavior where analytic functions or numerical relations do not exist. In this paper, heuristic fuzzy rules were used with the intention of improving the performance of optimization models, introducing experiential rules acquired from experts and utilizing recommendations. The aim of this paper was to define soft constraints using an adaptive network-based fuzzy inference system (ANFIS). This newly-developed soft constraint was applied to discrete optimization for obtaining optimal solutions. Even though the computational model is based on advanced computational technologies including fuzzy logic, neural networks and discrete optimization, it can be used to solve real-world problems of great interest for design engineers. The proposed computational model was used to find the minimum weight solutions for simply-supported laterally-restrained beams.
Keywords: uncertainty, discrete optimization, neuro-fuzzy technique, structural optimization
Published in DKUM: 09.08.2017; Views: 1474; Downloads: 373
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4. Optimiranje oblike konstrukcij: tristranični projektni elementMarko Kegl, 2002, original scientific article Abstract: Prispevek obravnava izpeljavo tristraničnega projektnega elementa za uporabo pri optimalnem projektiranju oblike konstrukcij. Osnova za izpeljavo novega elementa je tristranična Bézierjeva ploskev, ki je običajno parameterizirana z uporabo težiščnih koordinat. V prispevku je uporabljena drugačna parameterizacija, ki je bolj prilagojena postopkom optimizacije oblike. Na podlagi te ploskve je definiran projektni element-Bézierjevo telo, katerega mreža nadzornih točk ima v tipološkem pomenu obliko tristranične prizme. Uporaba izpeljanega elementa je ponazorjena na dveh številčnih zgledih.
Keywords: structural design, shape optimization, element design
Published in DKUM: 10.07.2015; Views: 1582; Downloads: 35
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5. The multilevel MINLP optimization approach to structural synthesis: the simultaneous topology, material, standard and rounded dimension optimizationStojan Kravanja, Simon Šilih, Zdravko Kravanja, 2005, original scientific article Abstract: The paper describes the simultaneous topology, material, standard and rounded dimension optimization of mechanical structures, performed by the Mixed-Integer Non-linear Programming (MINLP) approach. Beside the generation of an MINLP mechanical superstructure, the development of a general multilevel MINLP formulation for a mechanical superstructure is presented. The consideration of the discrete materials as well as standard and particularly rounded dimensions in structural synthesis significantly increases the combinatorics of the discrete optimization, which as a result may become too difficult to solve. A Linked Multilevel Hierarchical Strategy (LMHS) has been introduced for the solving of such large combinatorial problems. In order to decrease the effect of non-convexities, the Modified Outer-Approximation/Equality-Relaxation (OA/ER) algorithm has been applied. Four numerical examples of different complexities are presented to illustrate the proposed multilevel MINLP optimization approach: the optimization of two steel trusses, a composite I beam and a hydraulic steel roller gate Intake gate, erected in Aswan II, Egypt.
Keywords: structural optimization, structural synthesis, MINLP, topology opitmization, material optimization, discrete variable optimization, multilevel MINLP strategy, truss, composite beam, roller gate
Published in DKUM: 01.06.2012; Views: 2803; Downloads: 107
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