Pub Date : 2025-01-28DOI: 10.1016/j.compstruc.2025.107655
Xiang Zhao, My Ha Dao
Component Modal Synthesis (CMS) is a reduced order modelling method widely used for large-scale complex systems. It can effectively approximate system-level models through component synthesis, in which the repetitive geometrical components are modelled once and synthesised together. However, the conventional CMS only applies to systems with stationary components connected by strictly compatible ports, limiting it from modelling systems with moving components. This paper presents an adaptive port (AP) technique to extend CMS approaches for modelling parametric systems with rotational parts. To demonstrate the capability of the AP technique, we apply it to the Static Condensation Reduced Basis Element (SCRBE), one widely used variant of CMS approaches. The AP-based SCRBE (AP-SCRBE) can enforce the synthesis of rotational-stationary components over a shared adaptive port when the connecting surfaces of two components are discretisation-wise incompatible, which happens when one component moves relative to the others. Numerical experiments on the NREL 5 MW wind turbine show that, in the context of rotational-stationary component synthesis, the AP-SCRBE can accurately and efficiently model the rotating rotor with pitch rotation of blades. It can produce almost identical results to a high-fidelity finite element model at two to three orders faster speeds.
{"title":"An adaptive port technique for synthesising rotational components in component modal synthesis approaches","authors":"Xiang Zhao, My Ha Dao","doi":"10.1016/j.compstruc.2025.107655","DOIUrl":"https://doi.org/10.1016/j.compstruc.2025.107655","url":null,"abstract":"Component Modal Synthesis (CMS) is a reduced order modelling method widely used for large-scale complex systems. It can effectively approximate system-level models through component synthesis, in which the repetitive geometrical components are modelled once and synthesised together. However, the conventional CMS only applies to systems with stationary components connected by strictly compatible ports, limiting it from modelling systems with moving components. This paper presents an adaptive port (AP) technique to extend CMS approaches for modelling parametric systems with rotational parts. To demonstrate the capability of the AP technique, we apply it to the Static Condensation Reduced Basis Element (SCRBE), one widely used variant of CMS approaches. The AP-based SCRBE (AP-SCRBE) can enforce the synthesis of rotational-stationary components over a shared adaptive port when the connecting surfaces of two components are discretisation-wise incompatible, which happens when one component moves relative to the others. Numerical experiments on the NREL 5 MW wind turbine show that, in the context of rotational-stationary component synthesis, the AP-SCRBE can accurately and efficiently model the rotating rotor with pitch rotation of blades. It can produce almost identical results to a high-fidelity finite element model at two to three orders faster speeds.","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"40 1","pages":""},"PeriodicalIF":4.7,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-27DOI: 10.1016/j.compstruc.2025.107657
F. Kazemi, A. Ӧzyüksel Çiftçioğlu, T. Shafighfard, N. Asgarkhani, R. Jankowski
The utilization of advanced structural materials, such as preplaced aggregate concrete (PAC), fiber-reinforced concrete (FRC), and FRC beams has revolutionized the field of civil engineering. These materials exhibit enhanced mechanical properties compared to traditional construction materials, offering engineers unprecedented opportunities to optimize the design, construction, and performance of structures and infrastructures. This formal description elucidates the inherent mechanical properties of PAC, FRC, and FRC beams, explores their diverse applications in civil engineering projects. This research aims to propose a surrogate multi-subject ensemble machine-learning (ML) method (named RAGN-R) for estimating mechanical properties of aforementioned advanced materials. The proposed learning approach, RAGN-R, integrates Random forest, Adaptive boosting, and GradieNt boosting techniques, employing a Ridge regression framework for stacking the ensemble. For this purpose, three experimental dataset have been prepared to determine the capability of RAGN-R and the results of the study have been compared with six well-known ML models. It is noteworthy that the proposed RAGN-R has the ability of self-optimizing the hyperparameters, which facilitate the adoptability of the model with engineering problems. Moreover, three datasets have been investigated to show the ability of the RAGN-R for diverse problems. Different performance evaluation metrics have been conducted to present results and compare ML models, which confirms the highest performance of RAGN-R (i.e., 97.7% accuracy) in handling complex relationships and improving overall prediction accuracy.
{"title":"RAGN-R: A multi-subject ensemble machine-learning method for estimating mechanical properties of advanced structural materials","authors":"F. Kazemi, A. Ӧzyüksel Çiftçioğlu, T. Shafighfard, N. Asgarkhani, R. Jankowski","doi":"10.1016/j.compstruc.2025.107657","DOIUrl":"https://doi.org/10.1016/j.compstruc.2025.107657","url":null,"abstract":"The utilization of advanced structural materials, such as preplaced aggregate concrete (PAC), fiber-reinforced concrete (FRC), and FRC beams has revolutionized the field of civil engineering. These materials exhibit enhanced mechanical properties compared to traditional construction materials, offering engineers unprecedented opportunities to optimize the design, construction, and performance of structures and infrastructures. This formal description elucidates the inherent mechanical properties of PAC, FRC, and FRC beams, explores their diverse applications in civil engineering projects. This research aims to propose a surrogate multi-subject ensemble machine-learning (ML) method (named RAGN-R) for estimating mechanical properties of aforementioned advanced materials. The proposed learning approach, RAGN-R, integrates Random forest, Adaptive boosting, and GradieNt boosting techniques, employing a Ridge regression framework for stacking the ensemble. For this purpose, three experimental dataset have been prepared to determine the capability of RAGN-R and the results of the study have been compared with six well-known ML models. It is noteworthy that the proposed RAGN-R has the ability of self-optimizing the hyperparameters, which facilitate the adoptability of the model with engineering problems. Moreover, three datasets have been investigated to show the ability of the RAGN-R for diverse problems. Different performance evaluation metrics have been conducted to present results and compare ML models, which confirms the highest performance of RAGN-R (i.e., 97.7% accuracy) in handling complex relationships and improving overall prediction accuracy.","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"52 1","pages":""},"PeriodicalIF":4.7,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-24DOI: 10.1016/j.compstruc.2025.107651
Raj Kiran, Krishana Choudhary, Nhon Nguyen-Thanh
Phase-field modeling, owing to the regularized representation of discrete crack topologies, provides an efficient and robust framework for simulating complex fracture mechanisms in brittle materials. This study proposes an adaptive isogeometric-based approach to comprehend the fracture behaviour of polycrystalline materials under different thermo-mechanical loadings. The model considers anisotropy in the fracture resistance to examine intergranular and transgranular fracture mechanisms in polycrystalline materials. The individual grains in the morphology are modelled as anisotropic linear elastic domains possessing random preferential cleavage orientations. The present adaptive isogeometric framework uses polynomial splines over hierarchical T-meshes which offers an efficient adaptive mesh refinement scheme employing the phase-field parameter as an error indicator. Additionally, a hybrid-staggered scheme is implemented where the displacement field is computed using an isotropic model (no tension–compression splitting), while the phase-field parameter is evaluated based on an anisotropic model (with tension–compression splitting). The effect of thermo-mechanical coupling is examined on the fracture loads, and it is observed that the effects of temperature on the fracture loads are insignificant, however, it may accelerate or delay the fracture process. A series of numerical examples dealing with the fracture behaviour of single crystal, bicrystals, and polycrystalline domains are presented to showcase the robustness and capability of the present adaptive isogeometric framework.
{"title":"Phase-field modeling of brittle anisotropic fracture in polycrystalline materials under combined thermo-mechanical loadings","authors":"Raj Kiran, Krishana Choudhary, Nhon Nguyen-Thanh","doi":"10.1016/j.compstruc.2025.107651","DOIUrl":"https://doi.org/10.1016/j.compstruc.2025.107651","url":null,"abstract":"Phase-field modeling, owing to the regularized representation of discrete crack topologies, provides an efficient and robust framework for simulating complex fracture mechanisms in brittle materials. This study proposes an adaptive isogeometric-based approach to comprehend the fracture behaviour of polycrystalline materials under different thermo-mechanical loadings. The model considers anisotropy in the fracture resistance to examine intergranular and transgranular fracture mechanisms in polycrystalline materials. The individual grains in the morphology are modelled as anisotropic linear elastic domains possessing random preferential cleavage orientations. The present adaptive isogeometric framework uses polynomial splines over hierarchical T-meshes which offers an efficient adaptive mesh refinement scheme employing the phase-field parameter as an error indicator. Additionally, a hybrid-staggered scheme is implemented where the displacement field is computed using an isotropic model (no tension–compression splitting), while the phase-field parameter is evaluated based on an anisotropic model (with tension–compression splitting). The effect of thermo-mechanical coupling is examined on the fracture loads, and it is observed that the effects of temperature on the fracture loads are insignificant, however, it may accelerate or delay the fracture process. A series of numerical examples dealing with the fracture behaviour of single crystal, bicrystals, and polycrystalline domains are presented to showcase the robustness and capability of the present adaptive isogeometric framework.","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"26 1","pages":""},"PeriodicalIF":4.7,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Multi-scale lattice structures are celebrated for their superior mechanical properties and have been widely adopted across various engineering disciplines. Traditional periodic multi-scale lattice structures, however, often struggle with maintaining the fidelity of the original model's boundaries, encounter complex geometric modeling processes, and require extensive optimization times. This paper introduces a conformal optimization design framework for three-dimensional lattice structures that can be efficiently and conveniently applied to design domains with complex or irregular boundaries. The framework capitalizes on the unique properties of Stochastic Lattice Structures (SLS), which provide greater design flexibility and reduced sensitivity to defects compared to periodic counterparts. We present the Three-dimensional Functionally Graded Stochastic Lattice Structures (3D-FGSLS) design framework, which includes four main components: a database for optimization and geometric modeling that links microstructure's relative density with its geometric parameters and mechanical properties; a homogenization-based optimization design method; a novel vertex-based density mapping approach; and a advanced software kernel for lattice geometric modeling. The effectiveness of this framework is validated through several cases, showcasing its practical applicability.
{"title":"A conformal optimization framework for lightweight design of complex components using stochastic lattice structures","authors":"Zhuangyu Li, Hui Liu, Changri Xiong, Wenlei Xiao, Shulin Chen, Ziteng Zhu, Gang Zhao","doi":"10.1016/j.compstruc.2025.107646","DOIUrl":"https://doi.org/10.1016/j.compstruc.2025.107646","url":null,"abstract":"Multi-scale lattice structures are celebrated for their superior mechanical properties and have been widely adopted across various engineering disciplines. Traditional periodic multi-scale lattice structures, however, often struggle with maintaining the fidelity of the original model's boundaries, encounter complex geometric modeling processes, and require extensive optimization times. This paper introduces a conformal optimization design framework for three-dimensional lattice structures that can be efficiently and conveniently applied to design domains with complex or irregular boundaries. The framework capitalizes on the unique properties of Stochastic Lattice Structures (SLS), which provide greater design flexibility and reduced sensitivity to defects compared to periodic counterparts. We present the Three-dimensional Functionally Graded Stochastic Lattice Structures (3D-FGSLS) design framework, which includes four main components: a database for optimization and geometric modeling that links microstructure's relative density with its geometric parameters and mechanical properties; a homogenization-based optimization design method; a novel vertex-based density mapping approach; and a advanced software kernel for lattice geometric modeling. The effectiveness of this framework is validated through several cases, showcasing its practical applicability.","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"120 1","pages":""},"PeriodicalIF":4.7,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-20DOI: 10.1016/j.compstruc.2025.107643
Mojtaba Aliasghar-Mamaghani, Ioannis Koutromanos, Carin Roberts-Wollmann, Matthew Hebdon
This paper presents a computational scheme describing the formation and evolution of cracks in concrete structures due to chloride-induced corrosion in reinforcing or prestressing steel. The scheme accounts for coupled heat, moisture and chloride transport, while phenomenologically describing the kinetics of the electrochemical corrosion reaction in steel, formation of expansive corrosion products, and subsequent formation of stresses and cracks in concrete. Advective and diffusive chloride transport mechanisms are considered. The increase in concrete permeability against moisture and chloride transport due to cracking is considered in the constitutive laws. Novel equations are proposed to accurately describe the expansion of corrosion products. The scheme is calibrated using data from small-scale tests in the literature. Subsequently, it is applied to the simulation of real-life prestressed concrete bridge beams that exhibited corrosion-induced cracking after decades of service. The boundary conditions represent the ambient climate data, obtained from weather stations near the bridges. The analyses reproduce the observed cracking damage and enable the investigation of the validity of modeling assumptions commonly adopted in analytical studies for concrete infrastructure durability. The results also emphasize the significance of cracking on the evolution and spatial distribution of chloride content and on the extent of corrosion.
{"title":"Multiphysics Modeling of Chloride-Induced Corrosion Damage in Concrete Structures","authors":"Mojtaba Aliasghar-Mamaghani, Ioannis Koutromanos, Carin Roberts-Wollmann, Matthew Hebdon","doi":"10.1016/j.compstruc.2025.107643","DOIUrl":"https://doi.org/10.1016/j.compstruc.2025.107643","url":null,"abstract":"This paper presents a computational scheme describing the formation and evolution of cracks in concrete structures due to chloride-induced corrosion in reinforcing or prestressing steel. The scheme accounts for coupled heat, moisture and chloride transport, while phenomenologically describing the kinetics of the electrochemical corrosion reaction in steel, formation of expansive corrosion products, and subsequent formation of stresses and cracks in concrete. Advective and diffusive chloride transport mechanisms are considered. The increase in concrete permeability against moisture and chloride transport due to cracking is considered in the constitutive laws. Novel equations are proposed to accurately describe the expansion of corrosion products. The scheme is calibrated using data from small-scale tests in the literature. Subsequently, it is applied to the simulation of real-life prestressed concrete bridge beams that exhibited corrosion-induced cracking after decades of service. The boundary conditions represent the ambient climate data, obtained from weather stations near the bridges. The analyses reproduce the observed cracking damage and enable the investigation of the validity of modeling assumptions commonly adopted in analytical studies for concrete infrastructure durability. The results also emphasize the significance of cracking on the evolution and spatial distribution of chloride content and on the extent of corrosion.","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"11 1","pages":""},"PeriodicalIF":4.7,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-20DOI: 10.1016/j.compstruc.2025.107645
Carlos M. Patlán, Hugo Hernández-Barrios, Iván F. Huergo, Francisco Domínguez-Mota
In this study, a method for the integration of the equation of motion for the inelastic analysis of structures utilizing the Force Analogy Method (FAM) and nonlinear control systems is proposed. The method is implicit, unconditionally stable, one-step scheme, multi-stage, with second-order precision, self-start capability, and high-frequency response filtering, exhibiting low overshooting. It enables consideration of sources of nonlinearity from the inelastic behavior of materials and the incorporation of control systems in structures. Four numerical examples are used to validate the proposed method, encompassing a diverse range of application scenarios, including varying numerical stiffness, dynamic load sources, and nonlinearity sources. The obtained results demonstrate excellent agreement with expected solutions, highlighting the method capacity to suppress high-frequency responses while maintaining solution accuracy. Our study suggests that the proposed method holds significant potential as a dynamic integration tool in analyzing complex systems. Its application in structures with nonlinear control systems and material nonlinearity represents a substantial contribution to the field, providing a robust and efficient solution for understanding structural response to dynamic actions.
{"title":"Time integration scheme for nonlinear structural dynamics, FAM, including structural vibration control","authors":"Carlos M. Patlán, Hugo Hernández-Barrios, Iván F. Huergo, Francisco Domínguez-Mota","doi":"10.1016/j.compstruc.2025.107645","DOIUrl":"https://doi.org/10.1016/j.compstruc.2025.107645","url":null,"abstract":"In this study, a method for the integration of the equation of motion for the inelastic analysis of structures utilizing the Force Analogy Method (FAM) and nonlinear control systems is proposed. The method is implicit, unconditionally stable, one-step scheme, multi-stage, with second-order precision, self-start capability, and high-frequency response filtering, exhibiting low overshooting. It enables consideration of sources of nonlinearity from the inelastic behavior of materials and the incorporation of control systems in structures. Four numerical examples are used to validate the proposed method, encompassing a diverse range of application scenarios, including varying numerical stiffness, dynamic load sources, and nonlinearity sources. The obtained results demonstrate excellent agreement with expected solutions, highlighting the method capacity to suppress high-frequency responses while maintaining solution accuracy. Our study suggests that the proposed method holds significant potential as a dynamic integration tool in analyzing complex systems. Its application in structures with nonlinear control systems and material nonlinearity represents a substantial contribution to the field, providing a robust and efficient solution for understanding structural response to dynamic actions.","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"38 1","pages":""},"PeriodicalIF":4.7,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.compstruc.2024.107597
Hao Yu, Pizhong Qiao
Significance of structural components with local abnormality in buckling analysis has drawn considerable interest from researchers. A versatile and effective non-uniform spline finite strip method (N-u SFSM) is developed to allow for mesh refinement in local zones, enabling a comprehensive analysis of buckling characteristics of structures with local abnormality. The inclusion of non-uniform spline functions facilitates the precise modeling and refinement of localized abnormal (e.g., damage or geometric change) regions, leading to more accurate forecasts of fluctuations in buckling modes compared to the original finite strip method. The convergence and validation studies confirm the capability of N-u SFSM to accurately predict buckling behaviors in structures with local abnormality. The computational efficiency is significantly enhanced through the spline knot reduction achieved by optimizing the spline interpolation points, resulting in time and resource savings. The versatility of the N-u SFSM is demonstrated through the successful applications in various scenarios involving the locally-damaged channels, plates, and cylinders with differing damage sizes, types, locations, degrees, numbers, and shapes. The results confirm that the developed N-u SFSM, as a highly efficient and practical numerical technique, can accurately predict the buckling behaviors of both intact and damaged structures exhibiting local abnormalities, thereby providing valuable insights for structural analysis and design.
{"title":"Buckling analysis of structures with local abnormality using non-uniform spline finite strip method","authors":"Hao Yu, Pizhong Qiao","doi":"10.1016/j.compstruc.2024.107597","DOIUrl":"10.1016/j.compstruc.2024.107597","url":null,"abstract":"<div><div>Significance of structural components with local abnormality in buckling analysis has drawn considerable interest from researchers. A versatile and effective non-uniform spline finite strip method (N-u SFSM) is developed to allow for mesh refinement in local zones, enabling a comprehensive analysis of buckling characteristics of structures with local abnormality. The inclusion of non-uniform spline functions facilitates the precise modeling and refinement of localized abnormal (e.g., damage or geometric change) regions, leading to more accurate forecasts of fluctuations in buckling modes compared to the original finite strip method. The convergence and validation studies confirm the capability of N-u SFSM to accurately predict buckling behaviors in structures with local abnormality. The computational efficiency is significantly enhanced through the spline knot reduction achieved by optimizing the spline interpolation points, resulting in time and resource savings. The versatility of the N-u SFSM is demonstrated through the successful applications in various scenarios involving the locally-damaged channels, plates, and cylinders with differing damage sizes, types, locations, degrees, numbers, and shapes. The results confirm that the developed N-u SFSM, as a highly efficient and practical numerical technique, can accurately predict the buckling behaviors of both intact and damaged structures exhibiting local abnormalities, thereby providing valuable insights for structural analysis and design.</div></div>","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"307 ","pages":"Article 107597"},"PeriodicalIF":4.4,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142804465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.compstruc.2024.107600
Shuya Onodera , Takayuki Yamada
This study presents a topology optimization method for thermal actuators that accounts for boundary conditions influenced by variables such as thermal convection and pressure load. Thermal actuators with gripper-like designs are essential for handling hot and brittle materials. The objective of this study is to design actuator shapes that achieve an optimal balance between flexibility and stiffness in high-temperature environments. Unlike previous studies that consider load conditions imposed on fixed boundaries within the design domain, this research introduces a high-temperature fluid as the driving source and employs a novel approach to boundary condition setting by integrating fictitious physical problems. This approach allows for the precise specification of various boundary conditions across multiple domains. A weighted-sum method is applied to optimize three objective functions related to deformability, stiffness, and thermal diffusibility of the actuators. To address the issue of excessively thin structures compromising deformability and the poor convergence of the optimization process, stress constraints based on the optimization history are introduced. The proposed method is validated through numerical examples, demonstrating improvements in structural deformability while controlling deformation on the target surface plane. The numerical results confirm that the objective function decreases and stress is suppressed, verifying the effectiveness of the proposed approach.
{"title":"Design of compliant thermal actuators using topology optimization involving design-dependent thermal convection and pressure load","authors":"Shuya Onodera , Takayuki Yamada","doi":"10.1016/j.compstruc.2024.107600","DOIUrl":"10.1016/j.compstruc.2024.107600","url":null,"abstract":"<div><div>This study presents a topology optimization method for thermal actuators that accounts for boundary conditions influenced by variables such as thermal convection and pressure load. Thermal actuators with gripper-like designs are essential for handling hot and brittle materials. The objective of this study is to design actuator shapes that achieve an optimal balance between flexibility and stiffness in high-temperature environments. Unlike previous studies that consider load conditions imposed on fixed boundaries within the design domain, this research introduces a high-temperature fluid as the driving source and employs a novel approach to boundary condition setting by integrating fictitious physical problems. This approach allows for the precise specification of various boundary conditions across multiple domains. A weighted-sum method is applied to optimize three objective functions related to deformability, stiffness, and thermal diffusibility of the actuators. To address the issue of excessively thin structures compromising deformability and the poor convergence of the optimization process, stress constraints based on the optimization history are introduced. The proposed method is validated through numerical examples, demonstrating improvements in structural deformability while controlling deformation on the target surface plane. The numerical results confirm that the objective function decreases and stress is suppressed, verifying the effectiveness of the proposed approach.</div></div>","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"307 ","pages":"Article 107600"},"PeriodicalIF":4.4,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142804466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.compstruc.2024.107615
Christopher Nahed , Jacques de Lamare
The role of dimensionless ratios in engineering and physics is ubiquitous; but their utility in the multiphysics community is sometimes overlooked. Notably, in the multiphysics modelling community, coupling methods are often discussed and developed without an explicit monitoring of the various dimensionless ratios of the various inter-physics coupling terms. However, it is evident that the varying strengths of the coupling terms in a multiphysics model of k physics solvers/modules will influence either the convergence rate, the stability of the coupling scheme and the program execution speed. In fact, it is well known that the “ordering” of the predictor physics modules is primordial to the performance characteristics of a multiphysics coupling scheme. However, the question of “how to order” (who came first, the chicken or the egg?) the k physics modules remains vaguely discussed. In fact, physics ordering is generally based on the scientist's experience or on problem specific stability analyses performed on academic computational configurations. In the case of generic multiphysics coupling, where volume, interface and/or surface coupling terms can manifest, the optimal ordering of the physics modules may strongly vary along simulation time (for the same application) and/or across applications. Motivated to find an approximate measure that does not resort to cumbersome and problem specific stability analyses, we borrow the concept of dimensionless numbers from physics and apply it to the algebraic systems that manifest in multiphysics computational models. The “chicken-egg” algorithm is based on a dimensionless methodology that serves to “reorder” the Jacobian matrix of an exact Newton-Raphson implicit scheme. The method poses a dimensionless preconditioner that estimates the different strengths of the various coupling terms found in the multiphysics application. The chicken-egg algorithm estimates at every given time step the order of magnitude of coupling terms and correspondingly orders the k partitioned physics solvers automatically. This algorithm is tested for the first time on a thermo-hygro-corrosive multiphysics model and shows promising results. Benchmarking against monolithic and diagonalised calculation strategies, the first numerical tests show a significant reduction in iterations before convergence and thus over a 1.7-fold improvement in program execution time.
无量纲比率在工程学和物理学中的作用无处不在，但它们在多物理场中的作用有时会被忽视。值得注意的是，在多物理场建模领域，耦合方法的讨论和开发往往没有明确监测各种物理场间耦合项的各种无量纲比率。然而，很明显，由 k 个物理求解器/模块组成的多物理场模型中耦合项的不同强度会影响收敛速度、耦合方案的稳定性和程序执行速度。事实上，众所周知，预测物理模块的 "排序 "对于多物理场耦合方案的性能特征至关重要。然而，关于 K 物理模块 "如何排序"（先有鸡还是先有蛋？事实上，物理排序通常基于科学家的经验或在学术计算配置上进行的特定问题稳定性分析。在一般的多物理场耦合情况下，体积、界面和/或表面耦合项都可能出现，物理模块的最佳排序可能会随着仿真时间（同一应用）和/或不同应用而发生很大变化。为了找到一种近似的测量方法，而不诉诸繁琐的、针对具体问题的稳定性分析，我们借用了物理学中的无量纲数概念，并将其应用于多物理场计算模型中的代数系统。鸡-蛋 "算法基于无量纲方法，用于 "重排 "精确牛顿-拉斐森隐式方案的雅各布矩阵。该方法采用了一个无量纲预处理器，用于估算多物理应用中各种耦合项的不同强度。鸡-蛋算法在每个给定的时间步估计耦合项的数量级，并相应地自动对 k 个分区物理求解器进行排序。该算法首次在热腐蚀多物理场模型上进行了测试，结果令人满意。首次数值测试显示，收敛前的迭代次数显著减少，因此程序执行时间缩短了 1.7 倍以上。
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Pub Date : 2025-01-15DOI: 10.1016/j.compstruc.2024.107630
Marek Tyburec , Martin Doškář , Michael Somr , Martin Kružík , Jan Zeman
Modular designs have gained popularity because they can generally address manufacturing efficiency, reusability, and sustainability concerns. Here, we contribute to the growing field by proposing a fully automatic design method for modules utilized in several products. Our manufacturing-aware procedure is composed of three consecutive steps: (i) free-material optimization for obtaining the optimal spatially distributed elasticity tensors, (ii) hierarchical clustering of the stiffness tensors directly into a given number of modules while allowing for their flipping, and (iii) single-scale topology optimization with manufacturing aspects to design the final topology of mechanically compatible modules. These aspects include connectivity constraints to ensure the integrity of all modules and the three-field projection to account for manufacturing inaccuracies. We illustrate the entire procedure with the design and fabrication of eight different reusable modules assembled into well-functioning modular inverter and gripper mechanisms. These mechanisms were 3D printed and subjected to mechanical testing using an in-house testing machine and digital image correlation. The experimental results show excellent agreement between the predicted and observed behavior and highlight the potential of the method for scalable additive manufacturing.
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