Article
Acoustics
Tyler Wiest, Carolyn Conner Seepersad, Michael R. Haberman
Summary: Advancements in additive manufacturing technology show great potential in the field of acoustic materials. This research focuses on the design of an acoustic metasurface with Willis constitutive behavior, which utilizes precise arrangements of multi-material inclusions embedded in an elastomeric matrix to achieve asymmetric acoustic absorption. Finite element models demonstrate the sensitivity of the absorption to the asymmetry in material distribution and small changes in inclusion geometry. A classifier-based metamodel is used to support efficient Monte Carlo simulations and evaluate the sensitivity of the design performance to manufacturing variability. This study explores material choices and dimensional accuracies to guide the selection of additive manufacturing methods for fabricating acoustic material structures.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2022)
Article
Engineering, Aerospace
Italo Antonio Aranda, Gustavo Perez-Zunez
Summary: In this article, a method is proposed to filter out glint noise in target tracking and provide robustness for nonlinear tracking. Numerical simulations comparing the proposed solution to other state-of-the-art methods were conducted, showing promising results.
IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS
(2022)
Article
Computer Science, Information Systems
Ian McLane, Dimitra Emmanouilidou, James E. West, Mounya Elhilali
Summary: This study introduces an advanced electronic stethoscope, which significantly reduces external noise contamination through hardware redesign and real-time signal processing, improving diagnostic capability in noisy environments.
IEEE JOURNAL OF BIOMEDICAL AND HEALTH INFORMATICS
(2021)
Article
Engineering, Electrical & Electronic
Tao Yu, Wenqi Li, Yi Yu, Rodrigo C. de Lamare
Summary: This paper introduces a novel SAF-LHC-MNAG algorithm for nonlinear system identification under impulsive noise environments, which combines LHC cost function and MNAG learning method to improve robustness and accelerate convergence speed.
Article
Engineering, Multidisciplinary
Shuai Dong, Jia Ma, Zhilong Su, Chuanxi Li
Summary: In this work, a homomorphic filtering-gray weighted centroid method (HF-GWCM) is proposed to improve the localization accuracy of circular markers under non-uniform illumination conditions. Simulation examples and experimental tests show that HF-GWCM can resist the interference of uneven lighting and enhance the positioning accuracy and stability of circular markers.
Article
Engineering, Electrical & Electronic
Xingkang He, Karl Henrik Johansson, Haitao Fang
Summary: In this study, a distributed robust Kalman filter with stochastic gains for uncertain systems over corrupted communication channels is proposed. A robust collective observability condition is introduced to ensure an upper bound on the mean square error of the distributed filter when the network is strongly connected. The filter is further improved with a switching fusion scheme based on a sliding window to provide a smaller upper bound on the conditional mean square error, as validated through numerical simulations showing scalability to large networks.
IEEE TRANSACTIONS ON SIGNAL PROCESSING
(2021)
Article
Physics, Multidisciplinary
Angel Arturo Rendon-Castro, Dante Mujica-Vargas, Antonio Luna-Alvarez, Jean Marie Vianney Kinani
Summary: In this paper, an efficient method is proposed to remove noise in image processing using redescending M-estimators within the framework of Wiener estimation. This method effectively suppresses impulsive, additive, and multiplicative noise at various densities and works on grayscale and color images.
Article
Engineering, Mechanical
Jie Gao, Mi Xiao, Zhi Yan, Liang Gao, Hao Li
Summary: This paper proposes a robust isogeometric topology optimization (RITO) method for the design of piezoelectric actuators. The method effectively removes the critical issue caused by one-node connected hinges and maintains uniform manufacturability in the optimized topologies. Isogeometric analysis is used to compute the unknown electro elastic fields, and an erode-dilate operator is introduced for constructing the density distribution functions of the topology. Several numerical examples are presented to demonstrate the effectiveness and efficiency of the proposed RITO method.
FRONTIERS OF MECHANICAL ENGINEERING
(2022)
Article
Computer Science, Artificial Intelligence
Kai-fa Hui, Xiang-jun Shen, Stanley Ebhohimhen Abhadiomhen, Yong-zhao Zhan
Summary: This paper proposes a robust low-rank representation method via residual projection, which learns the structure of residues to find robust features for dimensionality reduction and noise suppression. Experimental results demonstrate that this method achieves higher classification accuracy than state-of-the-art methods in image classification tasks, especially on corrupted datasets.
KNOWLEDGE-BASED SYSTEMS
(2022)
Article
Critical Care Medicine
Oystein Tronstad, Dylan Flaws, Sue Patterson, Robert Holdsworth, John F. Fraser
Summary: Two innovative ICU bedspaces were redesigned and implemented in this project, addressing issues such as noise reduction, optimizing lighting, access to nature through digital solutions, and improving patient connectivity and engagement. The early evaluation shows improved lighting and acoustic environment. The impact on patient outcomes needs to be further evaluated.
Article
Engineering, Electrical & Electronic
L. Ben Saad, B. Beferull-Lozano, Elvin Isufi
Summary: This paper analyzes how quantization affects distributed graph filtering over both time-invariant and time-varying graphs, providing insights on the quantization effects for the two most common graph filters. The study includes theoretical performance guarantees on the filter performance with fixed or dynamically changing quantization stepsizes, showing that dynamic quantization can reduce quantization noise for FIR filters and decrease it to zero for ARMA filters at steady-state. Additionally, robust filter design strategies are proposed to minimize quantization noise for both types of networks.
IEEE TRANSACTIONS ON SIGNAL PROCESSING
(2022)
Article
Acoustics
O. Scussel, A. Secgin, M. J. Brennan, J. M. Muggleton, F. C. L. Almeida
Summary: This paper develops a stochastic model of the speed of leak noise propagation in plastic water distribution pipes, taking uncertainties into account and providing confidence limits for the estimate. The model is based on the mean and standard deviation of pipe geometry and material properties. Numerical examples and Monte Carlo simulations are used to validate the model.
JOURNAL OF SOUND AND VIBRATION
(2021)
Article
Engineering, Electrical & Electronic
Soheila Amiri Roshan, Mehdi Rahmani
Summary: In this article, a consensus-based robust filter is proposed for sensor networks with weighted and unweighted topologies, and communication delays. The consensus protocol ensures an agreement between the estimates of all sensors, and optimization problems are solved to achieve a suitable filter with considerations for time-varying delays. The robust performance and efficiency of the proposed filters have been investigated in simulation experiments.
IEEE SENSORS JOURNAL
(2023)
Article
Mathematics
Qiming Bai, Hongyi Li, Shixian Zhang, Jiezhong Tian
Summary: This paper investigates the issue of design efficiency for asymmetric minimum projection uniform designs. The uniformity of the designs with mixed levels is defined based on the centered L2 discrepancy, which measures the projection uniformity of the designs. An analytical relationship between the uniformity pattern and the design efficiency is established for mixed-level orthogonal arrays with a strength of two, and a tight lower bound of the uniformity pattern is presented. This research is relevant in the field of experimental design, providing a theoretical basis for constructing the minimum number of projection uniform designs with a high design efficiency under a certain condition. The theoretical results are verified by numerical examples.
Article
Engineering, Electrical & Electronic
Xingli Zhou, Guoliang Li, Ziyi Wang, Gang Wang, Hongbin Zhang
Summary: A novel hybrid affine projection algorithm (H-APA) is proposed as a derivation of the affine projection sign algorithm (APSA). The proposed algorithm incorporates the robust mixed-norm algorithm (RMNA) to handle impulsive noise. Simulation results demonstrate that the proposed algorithm is robust to impulsive noise and achieves fast convergence under colored input conditions. Additionally, a simplified version of H-APA (SH-APA) is derived to reduce algorithm complexity, and numerical simulations show that the proposed algorithms outperform existing AP-type algorithms in terms of convergence speed.
Article
Engineering, Multidisciplinary
Peter Dorffler Ladegaard Jensen, Ole Sigmund, Jeroen P. Groen
Summary: This work presents an extension of the de-homogenization method to obtain high-resolution, near-optimal 2D topologies optimized for minimum compliance under multiple load cases. The design is regularized using a material indicator field to avoid thin microstructure features and the orientations of the microstructures are further regularized to avoid singularities. A single-scale interpretation of the designs is derived using de-homogenization, eliminating the need for costly postprocessing analysis. The approach consistently delivers structural performance values close to density-based large-scale solutions with a significant reduction in CPU time.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Engineering, Multidisciplinary
Gustavo Assis da Silva, Andre Teofilo Beck, Ole Sigmund
Summary: This paper discusses the concept of predetermined breaking points in topology optimization and proposes a novel formulation for designing optimized structures. The formulation allows for controlling the location of failure in case of overload and ensures that the structure remains functional after removing the damaged part.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Mechanics
Morten N. Andersen, Yiqiang Wang, Fengwen Wang, Ole Sigmund
Summary: This study investigates the buckling strength of stretch-dominated lattice structures using local member analysis and proposes a new isotropic plate lattice configuration with enhanced buckling strength isotropy.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2022)
Article
Chemistry, Multidisciplinary
Fengwen Wang, Marie Brons, Ole Sigmund
Summary: Stretch-dominated truss and plate microstructures are competing in the development of highly rigid and strong architected materials. Although closed-cell isotropic plate microstructures meet theoretical upper bounds on stiffness, they have low buckling strength, whereas open-cell truss microstructures have high buckling strength but reduced stiffness. Hollow truss lattice and hierarchical microstructures outperform both in terms of buckling strength, but are challenging to build. In this study, single-scale non-hierarchical microstructures are designed, built, and tested, surpassing the buckling strength of hollow truss lattice and plate microstructures. The microstructures are realized with 3D printing and both experiments and numerical modeling validate the theoretical predictions.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Optics
Rasmus E. Christiansen, Philip Trost Kristensen, Jesper Mork, Ole Sigmund
Summary: Using topology optimization, compact wavelength-sized devices are designed to study the effect of optimizing geometries for enhancing different optical processes. The findings show that different field distributions lead to maximization of different processes, emphasizing the importance of targeting the appropriate metric when designing photonic components for optimal performance.
Article
Engineering, Multidisciplinary
Yafeng Wang, Ole Sigmund
Summary: This study aims to optimize the buckling capacity of mechanical structures subjected to thermal and mechanical loading through a density-based topology optimization scheme. By decoupling the effects of mechanical and thermal loadings, the buckling aspects induced by each loading can be separately analyzed and optimized. The study also employs a multi-material topology optimization scheme to optimize the buckling capacity of active structures and prestressed structures.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Erik A. Traff, Anton Rydahl, Sven Karlsson, Ole Sigmund, Niels Aage
Summary: This work presents three-dimensional linear elastic compliance minimisation using topology optimisation implementations accelerated by Graphics Processing Units (GPUs). Two GPU-accelerated implementations, based on OpenMP 4.5 and the Futhark language, are presented. Both implementations utilize high level GPU frameworks, avoiding the need for expertise knowledge of CUDA or OpenCL. Additionally, a vectorised and multi-threaded CPU code is included for reference. The results show that the GPU accelerated codes are able to solve large-scale topology optimisation problems faster than the reference CPU code, and they can also handle nonlinear problems.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Christoffer Fyllgraf Christensen, Fengwen Wang, Ole Sigmund
Summary: Topology optimization has been used for maximizing stiffness or minimizing compliance in multiscale structures. This study focuses on optimizing buckling stability of multiscale structures with isotropic porous infill, by considering both local and global instability.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Federico Ferrari, Ole Sigmund
Summary: In this study, a strategy is introduced to prevent the occurrence of spurious modes in the spectrum computed by linearized buckling analysis in the context of topology optimization. Spurious buckling modes commonly appear in low density regions, but this study also highlights the occurrence of localized modes in solid areas due to the limitations of linearized buckling analysis. The proposed remedy involves using filtering and erosion operations on the stress field, helping to mitigate the occurrence of spurious modes and improve the optimization process towards high performance designs.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
(2023)
Article
Computer Science, Interdisciplinary Applications
Lukas C. Hoghoj, Cian Conlan-Smith, Ole Sigmund, Casper Schousboe Andreasen
Summary: This paper presents a method for simultaneous optimization of the outer shape and internal topology of aircraft wings, with the objective of minimizing drag subject to lift and compliance constraints for multiple load cases. The physics are evaluated by the means of a source-doublet panel method for the aerodynamic response and linear elastic finite elements for the structural response, which are one-way coupled. Wings of small fixed-wing airplanes both with and without a stiffening strut are optimized. The resulting wings show internal topologies with struts and wall-truss combinations, depending on the design freedom of the shape optimization. The lift distributions of the optimized wings show patterns like the ones obtained when performing optimization of wing shapes with constraints on the bending moment at the root.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2023)
Article
Multidisciplinary Sciences
Corey A. Richards, Christian R. Ocier, Dajie Xie, Haibo Gao, Taylor Robertson, Lynford L. Goddard, Rasmus E. Christiansen, David G. Cahill, Paul V. Braun
Summary: In this study, the authors used subsurface 3D printing to fabricate compact and high-performance achromatic imaging micro-optics. These micro-optics, which integrate refractive and diffractive elements, demonstrate high focusing efficiencies, high numerical apertures, and low chromatic focusing errors, offering a promising pathway towards achromatic micro-optical systems.
NATURE COMMUNICATIONS
(2023)
Article
Mathematics, Interdisciplinary Applications
Andreas Henrik Frederiksen, Ole Sigmund, Konstantinos Poulios
Summary: This paper addresses the limitations of incorporating contact in topology optimization and proposes a new method for topology optimization problems with internal contact. The method ensures stability and robustness of the optimized designs by introducing a tangent stiffness requirement and penalizing small features. The examples demonstrate the effectiveness of the method in topology optimization under large deformations.
COMPUTATIONAL MECHANICS
(2023)
Article
Engineering, Multidisciplinary
Weichen Li, Yingqi Jia, Fengwen Wang, Ole Sigmund, Xiaojia Shelly Zhang
Summary: This study systematically investigates several precisely programmed nonlinear extreme responses in 3D structures under finite deformations through multimaterial inverse design by topology optimization. Unique complex 3D geometries with deformation capabilities are discovered and utilized to deliver the target responses. The optimized structure is accurately fabricated through a proposed hybrid fabrication method and the design's programmed behavior is validated.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2023)
Article
Multidisciplinary Sciences
Felipe Gomez-Lozada, Carlos Andres del Valle, Julian David Jimenez-Paz, Boyan S. Lazarov, Juan Galvis
Summary: In this study, a mathematical model is developed to describe the phenomenon of brinicles. The model is able to capture the general behavior of the physical system, generating structures similar to brinicles and recovering dendrite composition in alignment with previous experimental results.
ROYAL SOCIETY OPEN SCIENCE
(2023)
Article
Engineering, Multidisciplinary
Rebekka Woldseth, J. Andreas Baerentzen, Ole Sigmund
Summary: This paper presents an alternative approach to dehomogenisation of elastic Rank-N laminate structures based on the computer graphics discipline of phasor noise. The proposed methodology offers an improvement of existing methods, where high-quality single-scale designs can be obtained efficiently without the utilisation of any least-squares problem or pre-trained models. Numerical tests verifies the performance of the proposed methodology compared to state-of-the-art alternatives, and the dehomogenised designs achieve structural performance within a few percentages of the optimised homogenised solution.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2024)
