Article
Computer Science, Interdisciplinary Applications
Xuanpei Rong, Jing Zheng, Chao Jiang
Summary: In this paper, an efficient topology optimization method is proposed for bi-modulus structures considering displacement constraints. A new smooth elastic modulus matrix is constructed to approximate the discontinuous modulus matrix for bi-modulus materials. The topology optimization model for structures under both single and multiple load cases is built to minimize structural compliance with volume and displacement constraints. The sensitivities of the objective function and constraints are explicitly achieved based on the adjoint method, and the gradient-based method of moving asymptotes algorithm is employed to update the topological design variables. The proposed method has been shown to be efficient and applicable to problems with multiple load cases and constraints through several numerical examples.
COMPUTERS & STRUCTURES
(2023)
Article
Computer Science, Interdisciplinary Applications
Otavio Augusto Alves da Silveira, Lucas Farias Palma
Summary: This paper proposes modified material and cost models for ordered solid isotropic material with penalization (SIMP) interpolation, addressing the unusual behavior observed when using the original material model equations. The new ordered SIMP presents the desired interpolation characteristics and is suitable for non-monotonic properties, using density filtering and threshold projection to remove checkerboard patterns and reduce the presence of intermediate densities. A comparative analysis of the original interpolation with the modified one is conducted through various numerical examples, identifying some issues related to the filtering techniques and boundary effects on an ordered SIMP.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2022)
Article
Computer Science, Software Engineering
Aaditya Chandrasekhar, Krishnan Suresh
Summary: This paper presents a neural network-based method for multi-material topology optimization, which can achieve the distribution of multiple materials within the topology and solve some challenges encountered when using mesh-based methods.
COMPUTER-AIDED DESIGN
(2021)
Article
Mechanics
Zhengtong Han, Zhonggang Wang, Kai Wei
Summary: By assembling metamaterials with different characteristics, the applicability of shape morphing structures can be effectively enlarged. Numerical simulations show that these designs can accurately present the desired deformation behavior under various loadings. These approaches open new avenues for the extensive applications of shape morphing structures in aerospace, electric, and biomedical domains.
COMPOSITE STRUCTURES
(2022)
Article
Computer Science, Interdisciplinary Applications
Tejeswar Yarlagadda, Zixin Zhang, Liming Jiang, Pradeep Bhargava, Asif Usmani
Summary: This paper presents a new topology optimization scheme called SIMTP, which uses 2.5D elements and introduces nodal thickness variables. It transforms the 2D problem into a 3D problem and demonstrates its effectiveness and advantages in solving classical optimization problems. The implementation is simple, with high resolution and reduced computational efforts.
COMPUTERS & STRUCTURES
(2022)
Article
Engineering, Multidisciplinary
Jingyu Hu, Yang Liu, Yunfeng Luo, Huixin Huang, Shutian Liu
Summary: Topology optimization for multi-material structures is a significant and popular research topic due to their potential applications in modern industries. However, existing methods often assume perfectly bonded interfaces or overlook strength differences between different interfaces. In this study, a multi-material topology optimization method considering tension/compression-asymmetric interface stress constraint is proposed to improve interface strengths of multi-material structures.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Computer Science, Interdisciplinary Applications
Masatoshi Shimoda, Hirotaka Nakayama, Shota Suzaki, Ryo Tsutsumi
Summary: This paper proposes a simultaneous shape and topology optimization method for designing multi-material structures. The method effectively combines shape and topology optimization by using shape along with fictitious homogenized-density variations as design variables. The proposed method allows for obtaining an optimal multi-material laminated shell structure without the need for design parameterization, eliminating numerical instabilities such as checkerboard pattern and zigzag shape problems.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2021)
Article
Computer Science, Interdisciplinary Applications
Stephen W. K. Roper, Haksung Lee, Mongyoung Huh, Il Yong Kim
Summary: The aerospace industry is constantly seeking breakthroughs in lightweight design by integrating advanced materials and manufacturing methods. This paper presents practical examples of multi-material topology optimization in aerospace, including the first simultaneous application of isotropic and orthotropic material models.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2021)
Article
Computer Science, Interdisciplinary Applications
Rubens Bohrer, Il Yong Kim
Summary: This paper introduces an improved multi-material topology optimization method that avoids the element stacking process and considers a mixture of isotropic and anisotropic materials in commercial finite element engines. By enhancing the element duplication method, it improves numerical efficiency and serves as an alternative for computing sensitivities in discrete material optimization schemes.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2021)
Article
Construction & Building Technology
Minh-Ngoc Nguyen, Dongkyu Lee, Joowon Kang, Soomi Shin
Summary: This research presents a multi-material topology optimization method for functionally graded materials (FGM) and non-FGM with elastic buckling criteria. It utilizes a Jacobi scheme and a Method of Moving Asymptotes (MMA) for revising the design variables. Mathematical expressions for modified interpolation materials in the buckling framework are provided. The effectiveness of the approach is demonstrated through structural design features.
STEEL AND COMPOSITE STRUCTURES
(2023)
Article
Engineering, Multidisciplinary
Shuzhi Xu, Jikai Liu, Bin Zou, Quhao Li, Yongsheng Ma
Summary: A novel solution to the stress-constrained multi-material topology optimization (SMMTO) problem is proposed based on the ordered SIMP method. The approach utilizes a new interpolation function and scaling of stress measure to effectively address the SMMTO problem.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2021)
Article
Engineering, Multidisciplinary
Yi Wu, Julien Yvonnet, Pengfei Li, Zhi-Cheng He
Summary: This paper proposes a topology optimization framework to improve the dynamic fracture resistance of structures. By combining the phase field method for fracture with Solid Isotropic Material with Penalization (SIMP) topology optimization, the fracture energy is minimized during the entire dynamic loading process, reducing the risk of fracture for the structure.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Computer Science, Interdisciplinary Applications
Shanshan Zhang, Houmin Li, Yicang Huang
Summary: An improved topology optimization model is proposed for optimizing continuum structures with self-weight loading conditions. The objectives include minimizing the total strain energy of the design domain and minimizing the total displacement of the fixed domain. The model is validated under two-dimensional models and it is found that the optimal structural topology is affected by the ratio of external force to self-weight.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2021)
Article
Mechanics
M. R. Costa, A. Sohouli, A. Suleman
Summary: This study presents a computationally efficient topology optimization approach for lattice structures, while increasing design flexibility. The proposed two-scale concurrent optimization method achieves optimal topologies by simultaneously optimizing the macro-scale structure and the underlying material micro-structures. Surrogate models and an energy-based homogenization method combined with voxelization are used to represent material and geometrical properties. The optimized graded lattice structure outperforms the uniform lattice structure in terms of performance.
COMPOSITE STRUCTURES
(2022)
Article
Materials Science, Multidisciplinary
Ali Radhi, Vincent Iacobellis, Kamran Behdinan
Summary: This paper presents a combined approach of topology optimization and graphic statics for generating lightweight structures and meeting predefined structural/load constraints. By coupling these two methods, it is possible to manipulate structures without breaking the global equilibrium state. Optimized structures demonstrate uniform load distribution and reduced member loads.
MATERIALS & DESIGN
(2021)
Article
Biochemistry & Molecular Biology
Pan Zheng, Wugui Jiang, Qinghua Qin, Duosheng Li
Summary: In this study, the molecular dynamics method was used to investigate the influence of helium on the dynamic behavior of a heterogeneous rotation transmission nano-system built on carbon nanotubes and boron nitride nanotube. The results show that gas density and system temperature are the two main factors affecting the RTS transmission behavior, with higher temperature and lower motor input frequency leading to a larger critical working helium density range.
Article
Engineering, Civil
Minghui Zhang, Chao Hu, Chengzhen Yin, Qing-Hua Qin, Jianshan Wang
Summary: In this paper, a quantitative local resonance analysis scheme is proposed for efficient design of three-dimensional (3D) latticed EMMs with broad and complete wave attenuation band at low frequency. This analysis scheme and the EMM structure facilitate the development of structure designs for elastic wave attenuation.
THIN-WALLED STRUCTURES
(2021)
Article
Biochemistry & Molecular Biology
Jiao Shi, Weihua Yu, Chunwei Hu, Haiyan Duan, Jiaxing Ji, Yuanyuan Kang, Kun Cai
Summary: In this study, the fracture properties and crack propagation path of pre-cracked graphene during tearing process were evaluated using molecular dynamics simulation. The results showed that loading speed, temperature, and loading direction significantly affected the crack propagation path. Tearing graphene can be achieved by changing the loading direction and conducting out-of-plane tearing.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Chemistry, Physical
Miao Zou, Wu-Gui Jiang, Qing-Hua Qin, Yu-Cheng Liu, Mao-Lin Li
Summary: This study developed an optimized XGBoost model to predict the density of SLMed Ti-6Al-4V parts and found that with the reduction of dataset size, the prediction accuracy decreases but overall accuracy remains high. Additionally, the optimized XGBoost model outperformed ANN and SVR models in evaluation indicators.
Article
Polymer Science
Quanyan He, Miaojing Wang, Yitao Du, Qinghua Qin, Wei Qiu
Summary: This study used the photoelastic method to investigate the stress-optical properties of PET films. A self-built bidirectional photoelasticity measurement system was developed and used to measure the stress-optical coefficients and isoclinic angles of PET films with different stretching angles. The linear combinations of the photoelastic tensor components and refractive-index-related parameters were determined by fitting the analytical relationship between the stress-optical coefficients and isoclinic angles.
Article
Physics, Applied
Shaohua Yan, Zheng Zhong, Qing. H. Qin
Summary: This paper investigates the mechanical properties of nanotwined copper at micro/nanoscales. The influence of vertical twin-boundary spacing and orientation on the deformation behavior of micropillars is explored through experiments, simulations, and theoretical analysis. The results show that decreasing twin-boundary spacing leads to increased yield stress, and micropillars with slanted twin boundaries at a spacing of 15.5 nm exhibit the highest strength.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Nanoscience & Nanotechnology
Bo Song, Kun Cai, Jiao Shi, Qing-Hua Qin
Summary: This study reveals the feasibility of fabricating graphene nanotubes (GNTs) by self-assembling a monolayer graphene ribbon on a carbon nanotube (CNT) and explores the mechanism of temperature dependence in the self-assembly process. Different types, lengths, and radii of GNTs can be obtained by controlling the geometry of the graphene ribbon and temperature.
Article
Engineering, Civil
Chengzhen Yin, Yi Xiao, Di Zhu, Jianshan Wang, Qing-Hua Qin
Summary: This paper investigates the dynamic characteristics of a one-dimensional phononic crystal with compression-twist coupling effect, and explores its starting frequency, bandwidth, and attenuation performance through analytical and numerical methods.
THIN-WALLED STRUCTURES
(2022)
Article
Materials Science, Multidisciplinary
Kun Cai, Puwei Wu, Qing-Hua Qin
Summary: In this study, the interaction between the bladed rotor and water in a rotation transmission nanosystem is investigated using molecular dynamics simulation. Several important conclusions are drawn for the design of nanomachines, including the ability to control rotation transmission efficiency by adjusting the height of the blades.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2022)
Article
Biochemistry & Molecular Biology
Jiao Shi, Xin Zhou, Pan Jia, Kun Cai
Summary: We propose a CNT-based concentric twin tube (CTT) as nanochannels for water purification and ion separation at the nanoscale. In this model, a source reservoir connects three containers via the CTT with three subchannels for mass transfer. The solution in the separating zone forms three layers by applying a charged capacitor with the two electrodes parallel to the flow direction. Under an electric field, the CTT subchannels enable stable configurations for ion separation and water purification. The model's physical properties, such as water purification speed, are analyzed considering the effects of electric field, CTT size, and solute concentration.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Mechanics
Minghui Zhang, Yi Xiao, Qing-Hua Qin
Summary: Engineering topological structures in unit cells provides elastic metamaterials (EMMs) with exceptional wave attenuation capabilities. However, practical metastructures, which are truncated versions of infinite EMMs, may significantly reduce wave attenuation capabilities. To address this, a novel modal-based method (MM) is proposed for evaluating the wave attenuation of 3D metastructures. By characterizing dominant eigenmodes developed in metastructures, the opening and closing of stopbands are evaluated, and the influence of different mechanisms on wave attenuation performance is investigated. Additionally, a modal-based design framework is introduced to modify metastructures for improved applicability in various engineering disciplines.
INTERNATIONAL JOURNAL OF APPLIED MECHANICS
(2023)
Article
Chemistry, Multidisciplinary
Shaohua Yan, Thomas D. Bennett, Weipeng Feng, Zhongyin Zhu, Dingcheng Yang, Zheng Zhong, Qing H. Qin
Summary: Metal-organic framework (MOF) glasses, a new type of glass, have the potential to solve greenhouse effects, energy storage and conversion. However, the mechanical behavior of MOF glasses is not well understood. Through experiments and simulations, we found that a specific type of MOF glass can achieve both high strength and large ductility at the nanoscale. The insights gained from this study can guide the manufacturing of ultra-strong and ductile MOF glasses for real-world applications.
Article
Chemistry, Physical
Kun Cai, Xin Li, Zheng Zhong, Jiao Shi, Qing-Hua Qin
Summary: A method for designing tunable chiral nano-networks using partly hydrogenated graphene ribbons and carbon nanotubes (CNTs) is proposed in this study. Molecular-dynamics simulations reveal that the network reaches a stable state when the shrinkage reaches 70% of the two in-plane dimensions.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Ning Wei, Zhen Li, Zhi-Hui Li, Chao Zhang, Chunlei Wang, Junhua Zhao, Kun Cai
Summary: The study presents a sensor based on knitted graphene sheet for fast and accurate localization of heat or force points with nanoscale precision under thermal or mechanical loadings. Results show that the sensor can efficiently locate and evaluate the positions and sizes of heat/force sources with high accuracy.
