Article
Computer Science, Interdisciplinary Applications
Oliver Giraldo-Londono, Glaucio H. Paulino
Summary: PolyStress is a Matlab implementation for topology optimization with local stress constraints, which addresses linear and material nonlinear problems. The implementation is based on PolyTop and utilizes a Newton-Raphson scheme and an augmented Lagrangian method to solve nonlinear elasticity and stress-constrained problems consistently.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2021)
Article
Computer Science, Interdisciplinary Applications
Tao Xu, Xiaoshan Lin, Yi Min Xie
Summary: A novel topology optimization method based on the bi-directional evolutionary structural optimization (BESO) method is proposed in this study to increase buckling resistance in structural design. The method uses only two discrete statuses for design variables to alleviate numerical issues associated with pseudo buckling modes. Multiple buckling constraints are aggregated into a differentiable one using the Kreisselmeier-Steinhauser aggregation function. The developed optimization algorithm with buckling constraints significantly improves structural stability with a slight increase in compliance, as shown in numerical results.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2023)
Article
Engineering, Multidisciplinary
Zeshang Li, Lei Wang, Geng Xinyu
Summary: With the diversification of engineering structure performance requirements and the continuous development of structural design refinement, structural design methods are facing more and more factors to be considered. This paper proposes a sensitivity mapping technique for topology optimization based on a gradient optimization algorithm and considers the influence of multi-source uncertainties.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2024)
Article
Computer Science, Artificial Intelligence
Zhanhong Jiang, Chao Liu, Young M. Lee, Chinmay Hegde, Soumik Sarkar, Dongxiang Jiang
Summary: This paper introduces the Stochastic Augmented Lagrangian method (SALM) to address optimization problems in domain adaptation, finding optimal Lagrangian multipliers instead of manually selecting them. Experimental results show that SALM can find feasible points with arbitrary precision in domain adaptation problems with bounded penalty parameters, and approximate stationary infeasibility points with unbounded penalty parameters.
KNOWLEDGE-BASED SYSTEMS
(2022)
Article
Operations Research & Management Science
Christian Kanzow, Andreas B. Raharja, Alexandra Schwartz
Summary: The reformulation of cardinality-constrained optimization problems into continuous nonlinear optimization problems with an orthogonality-type constraint has become popular in recent years. Due to the special structure of the constraints, specialized algorithms are often needed to solve the reformulated problem. However, this study investigates the use of a standard safeguarded multiplier penalty method without problem-tailored modifications, proving global convergence and providing numerical experiments comparing its performance to regularization-based approaches.
JOURNAL OF OPTIMIZATION THEORY AND APPLICATIONS
(2021)
Article
Computer Science, Interdisciplinary Applications
Yuanteng Jiang, Min Zhao
Summary: This paper proposes a topology optimization method based on the parameterized level-set method using radial basis functions, which can handle stress minimization and stress-constraint problems. The method utilizes a p-norm function as a stress aggregation function and an adaptive scaling constraint method to measure the maximum stress. The shape derivative is employed to obtain the normal velocities in the parameterized level-set method, and an augmented Lagrange multiplier is used to ensure stability during the convergence process.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2022)
Article
Computer Science, Interdisciplinary Applications
Zhuo Chen, Kai Long, Chengwan Zhang, Xiaoyu Yang, Feiyu Lu, Rixin Wang, Benliang Zhu, Xianmin Zhang
Summary: This paper proposes a novel methodology for fatigue-resistance topology optimization considering general loads. The independent rainflow counting method is utilized for structural damage estimation, and a damage penalization model is adopted to reduce nonlinearity. Numerical tests validate the effectiveness of the proposed method and further investigation is conducted into the influences of general loads, damage penalization model, and manufacturing error robustness.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2023)
Article
Automation & Control Systems
Alessandro Falsone, Maria Prandini
Summary: This paper proposes a novel Augmented Lagrangian Tracking distributed optimization algorithm for solving multi-agent optimization problems. The algorithm features a constant penalty parameter, the ability to cope with unbounded local constraint sets, and the ability to handle both affine equality and nonlinear inequality coupling constraints.
Article
Engineering, Multidisciplinary
Nouman Saeed, Kai Long, Lixiao Li, Ayesha Saeed, Chengwan Zhang, Zhengkun Cheng
Summary: This article proposes an augmented Lagrangian-based topology optimization approach to minimize the volume fraction subject to multiple nodal displacement constraints. The method transforms the multiple constraint equations into an objective function and solves it through a series of unconstrained optimization problems. The study explains the theoretical aspects of the augmented Lagrangian approach and demonstrates its feasibility and reliability through numerical examples.
ENGINEERING OPTIMIZATION
(2023)
Article
Operations Research & Management Science
Zichong Li, Pin-Yu Chen, Sijia Liu, Songtao Lu, Yangyang Xu
Summary: In this paper, the authors design and analyze stochastic inexact augmented Lagrangian methods (Stoc-iALM) to solve problems involving nonconvex composite objectives and nonconvex smooth functional constraints. By adopting a momentum-based variance-reduced proximal stochastic gradient method (PStorm) and a postprocessing step, they establish an oracle complexity result of O(epsilon(-5)), which is better than the best-known O(epsilon(-6)) result, under certain regularity conditions. Numerical experiments demonstrate the superiority of the proposed method compared to an existing method with the previously best-known complexity result on fairness constrained and Neyman-Pearson classification problems with real data.
COMPUTATIONAL OPTIMIZATION AND APPLICATIONS
(2023)
Article
Computer Science, Artificial Intelligence
Jiayu Huang, Yutian Pang, Yongming Liu, Hao Yan
Summary: Neural Networks (NNs) are widely used in supervised learning for modeling complex nonlinear patterns in high-dimensional data. Traditional NNs lack uncertainty quantification, which can be addressed by Bayesian NNs (BNNS) considering parameter distributions. Incorporating domain knowledge as constraints, a Posterior-Regularized Bayesian Neural Network (PR-BNN) model is proposed, along with an efficient inference method using the augmented Lagrangian method and existing BNN solvers. Simulation and case studies show performance improvement of the proposed model over traditional BNNs without constraints.
KNOWLEDGE-BASED SYSTEMS
(2023)
Article
Mechanics
Nam Nguyen, H. Nguyen-Xuan, Jaehong Lee
Summary: In this paper, we propose an efficient approach based on flexible polygonal meshes for solving stress-constrained topology optimization problems involving both compressible and nearly incompressible materials. The approach tackles volumetric locking phenomena in nearly incompressible material limit and solves topology optimization problems with local stress constraints using an augmented Lagrangian technique. The significant contribution of this work is a unified formulation for stress-constrained topology optimization, valid for various element types, with only displacement field involved and no constraint aggregation technique required. Experimental results demonstrate the distinguishing and intriguing features of the optimized topology for nearly incompressible materials with stress constraints.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2022)
Article
Computer Science, Interdisciplinary Applications
Oliver Giraldo-Londono, Jonathan B. Russ, Miguel A. Aguilo, Glaucio H. Paulino
Summary: This study presents a formulation for topology optimization of structures with constraints on the first principal stress, solved using the augmented Lagrangian method to consider local stress constraints. Numerical examples demonstrate the effectiveness of the framework for practical problems with numerous local constraints, such as the three-dimensional antenna support bracket with over one million constraints.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2022)
Article
Computer Science, Artificial Intelligence
Maocan Song, Lin Cheng
Summary: With the increasing demand for travel and limited transportation resources, traffic congestion remains a challenging problem. This study considers the variability of travel times in vehicle routing optimization by utilizing historical travel time data. A mean-standard deviation based vehicle routing model is developed and solved using an augmented Lagrangian relaxation approach. The proposed method effectively reduces the relative gap between the lower and upper bounds in the solving procedure.
KNOWLEDGE-BASED SYSTEMS
(2022)
Article
Engineering, Multidisciplinary
Gustavo Assis da Silva, Niels Aage, Andre Teofilo Beck, Ole Sigmund
Summary: This research compares local and global stress constraint strategies in topology optimization and finds that local strategies are less sensitive to the continuation procedure, leading to better quality results with fewer iterations compared to global strategies. It is also discovered that global strategies become competitive when using P values larger than 100, but require a slow continuation procedure. The local strategies based on the augmented Lagrangian method provide the best compromise between computational cost and performance.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
(2021)
Article
Engineering, Mechanical
Yuqing Zhou, Tsuyoshi Nomura, Enpei Zhao, Kazuhiro Saitou
Summary: This paper presents a method for designing variable-axial fiber-reinforced composites that allows for customization of fiber orientation and thicknesses. The method addresses computational challenges associated with large-scale 3D anisotropic topology optimization and is applied to designing a heavy-duty drone frame. The paper also discusses the manufacturability gaps between the optimized design and the fabrication-ready design.
JOURNAL OF MECHANICAL DESIGN
(2022)
Article
Mechanics
Taehoon Jung, Jaewook Lee, Tsuyoshi Nomura, Ercan M. Dede
Summary: This paper presents a three-dimensional topology optimization for the inverse design of unidirectional fiber reinforced composite structures, including the co-design of composite macrostructure, spatially-varying fiber size, and orientation. The effectiveness of the proposed design scheme is validated through three design examples for compliance minimization and compliant mechanism problems.
COMPOSITE STRUCTURES
(2022)
Article
Mathematics, Applied
Hao Li, Takayuki Yamada, Pierre Jolivet, Kozo Furuta, Tsuguo Kondoh, Kazuhiro Izui, Shinji Nishiwaki
Summary: The proposed framework is a parallel distributed and open-source framework for full-scale 3D structural topology optimization, which combines parallel computing and mesh adaption techniques using a reaction-diffusion equation based level-set method. The framework can be easily extended to design complex engineering products with optimized structures represented by high-resolution and clear boundaries.
FINITE ELEMENTS IN ANALYSIS AND DESIGN
(2021)
Article
Engineering, Electrical & Electronic
Atsuhiro Takahashi, Katsuya Nomura, Takashi Kojima, Tsuyoshi Nomura
Summary: This article uses topology optimization to design a new magnetic core structure for an EMI filter circuit, resulting in significantly improved performance. By evaluating the noise reduction effects, it was found that the EMI filter with the optimized magnetic core showed about 30 dB higher performance compared to a filter with conventional ring-shaped cores.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2021)
Article
Engineering, Multidisciplinary
Kozo Furuta, Ayami Sato, Kazuhiro Izui, Shinji Nishiwaki
Summary: In this paper, a level-set-based shape optimization method for thermoelectric materials is proposed, which utilizes the phenomenon of temperature jump to analyze the discontinuity effect on material interfaces in nanostructures. The level set function is used to impose boundary effects and optimize the material shape. Numerical examples are computed to validate the effectiveness of the proposed method.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
(2022)
Article
Engineering, Environmental
Yuqing Zhou, Danny J. Lohan, Feng Zhou, Tsuyoshi Nomura, Ercan M. Dede
Summary: In this paper, an inverse design and dehomogenization framework is proposed to discover innovative microreactor flow field designs. Through numerical simulations, trade-offs between reaction performance and fluid flow performance are found for multiple optimized microreactor flow fields. Applying the findings of this study to new reactor flow field designs can enhance performance in biomedical, pharmaceutical, and energy applications.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Mathematics, Applied
Takashi Yodono, Kentaro Yaji, Takayuki Yamada, Kozo Furuta, Kazuhiro Izui, Shinji Nishiwaki
Summary: In this paper, a topology optimization method for isotropic linear elastic body problems using LBM is proposed. The analysis approach of the isotropic linear elastic field using LBM is constructed by incorporating the expansion technique of the governing equations. The design sensitivity is derived using the adjoint lattice Boltzmann method. The validity of the proposed method is demonstrated with numerical examples.
COMPUTERS & MATHEMATICS WITH APPLICATIONS
(2022)
Article
Computer Science, Interdisciplinary Applications
Sunghoon Lim, Ryota Misawa, Kozo Furuta, Shinichi Maruyama, Kazuhiro Izui, Shinji Nishiwaki
Summary: This study applies the topology optimization method to reduce the weight of automobile components by using lightweight materials instead of steel. The design problem is formulated using the level set-based topology optimization concept to determine the precise design candidates of the multi-material structure. The results of benchmark and vehicle component design problems show the effectiveness of the proposed formulation in the 3D design space and present the practical range of the penalty factor value.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2022)
Article
Engineering, Electrical & Electronic
Paul Schmalenberg, Ercan M. Dede, Tsuyoshi Nomura, Shinji Nishiwaki
Summary: This research introduces an optimization method for a vehicular volumetric beam-scanning radar to minimize sidelobe power by determining the placement of array elements. The optimization is achieved using a gradient-based nonlinear programming technique, with the speed accelerated by extending uv-projection planes. Compared to a reference triangular grid array, the optimization method allows for a larger azimuth scanning FOV in typical automotive applications.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2022)
Article
Engineering, Multidisciplinary
Fan Feng, Shiying Xiong, Ziyue Liu, Zangyueyang Xian, Yuqing Zhou, Hiroki Kobayashi, Atsushi Kawamoto, Tsuyoshi Nomura, Bo Zhu
Summary: Cellular structures exhibit remarkable mechanical properties in many biological systems. This paper presents a topology optimization algorithm based on a differentiable and generalized Voronoi representation that allows the continuous evolution of cellular structures. The method uses a hybrid particle-grid representation to encode the discrete Voronoi diagram into a continuous density field. It enables the integration of an effective cellular representation into state-of-the-art topology optimization pipelines.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
(2023)
Article
Computer Science, Interdisciplinary Applications
Yuki Sato, Hiroki Kobayashi, Changyoung Yuhn, Atsushi Kawamoto, Tsuyoshi Nomura, Noboru Kikuchi
Summary: Topology optimization methods are widely used in various industries to provide potential design candidates for mechanical devices. However, their applications are limited to stationary objects due to the difficulties in handling contact and interactions among multiple structures or with boundaries using conventional simulation techniques. In this study, we propose a topology optimization method for moving objects that incorporates the material point method commonly used in computer graphics. Several numerical experiments demonstrate the effectiveness and utility of the proposed method.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2023)
Article
Multidisciplinary Sciences
Masato Tanaka, S. Macrae Montgomery, Liang Yue, Yaochi Wei, Yuyang Song, Tsuyoshi Nomura, H. Jerry Qi
Summary: Turing patterns are used to convert a design with distributed anisotropic materials to a distribution with two materials, which can be fabricated by grayscale digital light processing 3D printing. This study suggests the possibility of applying patterns in biological systems and nature to engineering composites and offers new concepts for future material design.
Article
Engineering, Manufacturing
S. Macrae Montgomery, Liang Yue, Yuyang Song, Tsuyoshi Nomura, Xiaohao Sun, Masato Tanaka, H. Jerry Qi
Summary: Additive manufacturing, also known as 3D printing, can create complex structures that traditional methods cannot. However, current multi-material 3D printing techniques lack accuracy for small-scale property control, making it difficult to print highly anisotropic structures at a small scale. This study proposes a method using grayscale vat photopolymerization to 3D print locally tunable anisotropic patterns, allowing for flexible adjustment of the degree and orientation of anisotropy. This method only requires one resin feedstock, preserving the accuracy and efficiency of vat photopolymerization printing.
ADDITIVE MANUFACTURING
(2023)
Article
Engineering, Mechanical
Naoyuki Ishida, Tsuguo Kondoh, Kozo Furuta, Hao Li, Kazuhiro Izui, Shinji Nishiwaki
Summary: This paper presents a level-set based topology optimization method for maximizing the lowest linear buckling load under a mean compliance constraint in the design of thin-walled structures.
MECHANICAL ENGINEERING JOURNAL
(2022)
Article
Engineering, Mechanical
DoeYoung Hur, Sunghoon Lim, Kazuhiro Izui, Shinji Nishiwaki
Summary: This paper introduces a new structural design framework that integrates topology optimization and genetic algorithms to enhance the manufacturability and structural robustness of the optimal structure. By utilizing the level set function as a topological design variable and considering manufacturing directions and fictitious heat fluxes, the manufacturability of the structure is mathematically defined. The optimization problem aims to find the optimal shape of the structure and the optimal directions of adjustable manufacturing tools.
MECHANICAL ENGINEERING JOURNAL
(2021)