Generative design (GD) techniques have been proposed to generate numerous designs at early design stages for ideation and exploration purposes. Previous research on GD using deep neural networks required tedious iterations between the neural network and design optimization, as well as post-processing to generate functional designs. Additionally, design constraints such as volume fraction could not be enforced. In this paper, a two-stage non-iterative formulation is proposed to overcome these limitations. In the first stage, a conditional generative adversarial network (cGAN) is utilized to control design parameters. In the second stage, topology optimization (TO) is embedded into cGAN (cGAN+TO) to ensure that desired functionality is achieved. Tests on different combinations of loss terms and different parameter settings within topology optimization demonstrated the diversity of generated designs. Further study showed that cGAN+TO can be extended to different load and boundary conditions by modifying these parameters in the second stage of training without having to retrain the first stage. Results demonstrate that GD can be realized efficiently and robustly by cGAN+TO.
{"title":"Generative Design by Embedding Topology Optimization into Conditional Generative Adversarial Network","authors":"Zhichao Wang, S. Melkote, David Rosen","doi":"10.1115/1.4062980","DOIUrl":"https://doi.org/10.1115/1.4062980","url":null,"abstract":"\u0000 Generative design (GD) techniques have been proposed to generate numerous designs at early design stages for ideation and exploration purposes. Previous research on GD using deep neural networks required tedious iterations between the neural network and design optimization, as well as post-processing to generate functional designs. Additionally, design constraints such as volume fraction could not be enforced. In this paper, a two-stage non-iterative formulation is proposed to overcome these limitations. In the first stage, a conditional generative adversarial network (cGAN) is utilized to control design parameters. In the second stage, topology optimization (TO) is embedded into cGAN (cGAN+TO) to ensure that desired functionality is achieved. Tests on different combinations of loss terms and different parameter settings within topology optimization demonstrated the diversity of generated designs. Further study showed that cGAN+TO can be extended to different load and boundary conditions by modifying these parameters in the second stage of training without having to retrain the first stage. Results demonstrate that GD can be realized efficiently and robustly by cGAN+TO.","PeriodicalId":50137,"journal":{"name":"Journal of Mechanical Design","volume":"4 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86609933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pengwei Liang, Shuai Zhang, Yonglin Pang, Jianji Li, Xueguan Song
The ensemble of surrogate models is commonly used to replace computationally expensive simulations due to their superior prediction accuracy and robustness compared to individual models. This paper proposes a new pointwise ensemble of surrogate models, namely, a Pointwise-optimal ensemble of surrogate models (POEM). To address the limitations of the cross-validation (CV) error in evaluating the performance of regression surrogate models, this paper introduces the compensated cross-validation (CCV) error, which is more reliable in selecting better individual surrogate models and improving the accuracy of surrogate model ensembles. To overcome the limitations of CV error in calculating pointwise weight factors, this paper designs and solves an optimization problem at training points to obtain corresponding pointwise weight factors. Additionally, this paper proposes two weight calculation methods to be applied in the interpolation and extrapolation regions, respectively, to reduce the instability of ensembles caused by extrapolation. Thirty test functions are employed to investigate the appropriate hyperparameters of POEM and the Friedman test is used to verify the rationality of the a value. The thirty test functions are also used to examine the performance of POEM and compare it with state-of-the-art ensemble surrogate models. Furthermore, POEM is applied to a large-aperture mirror holder optimization case to verify its superiority. The results demonstrate that POEM presents better accuracy and robustness than individual surrogates and other compared ensembles of surrogate models.
{"title":"A Pointwise-optimal Ensemble of Surrogate Models","authors":"Pengwei Liang, Shuai Zhang, Yonglin Pang, Jianji Li, Xueguan Song","doi":"10.1115/1.4062979","DOIUrl":"https://doi.org/10.1115/1.4062979","url":null,"abstract":"\u0000 The ensemble of surrogate models is commonly used to replace computationally expensive simulations due to their superior prediction accuracy and robustness compared to individual models. This paper proposes a new pointwise ensemble of surrogate models, namely, a Pointwise-optimal ensemble of surrogate models (POEM). To address the limitations of the cross-validation (CV) error in evaluating the performance of regression surrogate models, this paper introduces the compensated cross-validation (CCV) error, which is more reliable in selecting better individual surrogate models and improving the accuracy of surrogate model ensembles. To overcome the limitations of CV error in calculating pointwise weight factors, this paper designs and solves an optimization problem at training points to obtain corresponding pointwise weight factors. Additionally, this paper proposes two weight calculation methods to be applied in the interpolation and extrapolation regions, respectively, to reduce the instability of ensembles caused by extrapolation. Thirty test functions are employed to investigate the appropriate hyperparameters of POEM and the Friedman test is used to verify the rationality of the a value. The thirty test functions are also used to examine the performance of POEM and compare it with state-of-the-art ensemble surrogate models. Furthermore, POEM is applied to a large-aperture mirror holder optimization case to verify its superiority. The results demonstrate that POEM presents better accuracy and robustness than individual surrogates and other compared ensembles of surrogate models.","PeriodicalId":50137,"journal":{"name":"Journal of Mechanical Design","volume":"5 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74866322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There are numerous design possibilities for vibration-suppression systems considering components from multiple domains (e.g., mechanical, hydraulic, pneumatic, electrical). Traditional vibration absorber design approach could only explore limited possibilities, of which the performance is away from optimal. Since the 2000s, network-synthesis-based approach has been applied. It allows identification of optimal absorber properties represented by networks consisting of modelling elements (stiffness, damping, inertance), providing significant theoretical performance improvements. However, such improvements have not yet been realised in industry. This is because the following questions have not been answered: (1) what are the network-represented properties of the conventional absorber? (2) how can the optimal network-represented properties be realised considering multidomain physical components? This paper provides a method for answering these questions by proposing a novel multidomain synthesis technique, allowing bi-directional transformation between networks and multidomain components. Building on this technique, a vibration-absorber design methodology is proposed, which can construct physical realisations of optimal absorbers considering multidomain components. Another contribution of this work is to propose a novel component, providing a hydraulic realization of compliance ‘embedded’ in a hydraulic network. This methodology is demonstrated using an automotive case study, where the constructed optimal hydraulic suspension provides 23% ride comfort enhancement over the conventional one.
{"title":"Multidomain synthesis of optimal vibration suppression systems","authors":"Yuan Li, J. Z. Jiang, S. Neild, B. Titurus","doi":"10.1115/1.4062981","DOIUrl":"https://doi.org/10.1115/1.4062981","url":null,"abstract":"\u0000 There are numerous design possibilities for vibration-suppression systems considering components from multiple domains (e.g., mechanical, hydraulic, pneumatic, electrical). Traditional vibration absorber design approach could only explore limited possibilities, of which the performance is away from optimal. Since the 2000s, network-synthesis-based approach has been applied. It allows identification of optimal absorber properties represented by networks consisting of modelling elements (stiffness, damping, inertance), providing significant theoretical performance improvements. However, such improvements have not yet been realised in industry. This is because the following questions have not been answered: (1) what are the network-represented properties of the conventional absorber? (2) how can the optimal network-represented properties be realised considering multidomain physical components? This paper provides a method for answering these questions by proposing a novel multidomain synthesis technique, allowing bi-directional transformation between networks and multidomain components. Building on this technique, a vibration-absorber design methodology is proposed, which can construct physical realisations of optimal absorbers considering multidomain components. Another contribution of this work is to propose a novel component, providing a hydraulic realization of compliance ‘embedded’ in a hydraulic network. This methodology is demonstrated using an automotive case study, where the constructed optimal hydraulic suspension provides 23% ride comfort enhancement over the conventional one.","PeriodicalId":50137,"journal":{"name":"Journal of Mechanical Design","volume":"6 8 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83841323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Prior work has demonstrated that design tasks can be cognitively demanding, due to the inherent ambiguity and complexity of design problems. Few studies, however, have examined the evolution of cognitive load during the engineering design process and the linkages between sub-dimensions of cognitive load and design task outcomes. To address this gap, the current work investigates the evolution of cognitive load across two distinct design tasks: ideation and prototyping, and the relationship between cognitive load and design task outcomes. Results suggest that there is a significant difference in cognitive load experienced by the designer during ideation and prototyping. Additionally, findings suggest that cognitive load during ideation is positively correlated with the uniqueness, usefulness, and elegance of ideas.
{"title":"The Cognitive Costs of Design Tasks: Examining Cognitive Load Through Verbal and Physical Indicators","authors":"Nicole Calpin, Jessica Menold","doi":"10.1115/1.4062976","DOIUrl":"https://doi.org/10.1115/1.4062976","url":null,"abstract":"\u0000 Prior work has demonstrated that design tasks can be cognitively demanding, due to the inherent ambiguity and complexity of design problems. Few studies, however, have examined the evolution of cognitive load during the engineering design process and the linkages between sub-dimensions of cognitive load and design task outcomes. To address this gap, the current work investigates the evolution of cognitive load across two distinct design tasks: ideation and prototyping, and the relationship between cognitive load and design task outcomes. Results suggest that there is a significant difference in cognitive load experienced by the designer during ideation and prototyping. Additionally, findings suggest that cognitive load during ideation is positively correlated with the uniqueness, usefulness, and elegance of ideas.","PeriodicalId":50137,"journal":{"name":"Journal of Mechanical Design","volume":"86 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72911602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jianji Li, Shuai Zhang, Pengwei Liang, Xiaonan Lai, Xueguan Song
Along with the development of surrogate models, there is a growing need to use surrogate models instead of computationally intensive simulations to estimate real system responses. Compared with individual surrogate models, the ensemble of surrogate models is gradually drawing more attention due to its better applicability and robustness. Thus, this paper proposes an adaptive median-based ensemble of surrogate models (MID-ESM). At first, construct a reference model using the median of the predicted values of several surrogate models. Then an adaptive weight ensemble strategy is proposed based on the reference model to integrate global trends and local features. Thirty test functions and a practical engineering case are used to evaluate the model performance. In addition, this paper investigates the effect of homoscedasticity noise and test functions of different dimensions on the proposed model. The results demonstrate that MID-ESM has higher accuracy and robustness than individual surrogate models and other ensembles of surrogate models, offering better applicability in engineering problems.
{"title":"MID-ESM: An Adaptive Median-Based Ensemble of Surrogate Models","authors":"Jianji Li, Shuai Zhang, Pengwei Liang, Xiaonan Lai, Xueguan Song","doi":"10.1115/1.4062977","DOIUrl":"https://doi.org/10.1115/1.4062977","url":null,"abstract":"\u0000 Along with the development of surrogate models, there is a growing need to use surrogate models instead of computationally intensive simulations to estimate real system responses. Compared with individual surrogate models, the ensemble of surrogate models is gradually drawing more attention due to its better applicability and robustness. Thus, this paper proposes an adaptive median-based ensemble of surrogate models (MID-ESM). At first, construct a reference model using the median of the predicted values of several surrogate models. Then an adaptive weight ensemble strategy is proposed based on the reference model to integrate global trends and local features. Thirty test functions and a practical engineering case are used to evaluate the model performance. In addition, this paper investigates the effect of homoscedasticity noise and test functions of different dimensions on the proposed model. The results demonstrate that MID-ESM has higher accuracy and robustness than individual surrogate models and other ensembles of surrogate models, offering better applicability in engineering problems.","PeriodicalId":50137,"journal":{"name":"Journal of Mechanical Design","volume":"6 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83395008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Deployable structures composed of hinge joints (revolute joints) with inclined axis have a potential to realize a rich variety of deformation with a small number of members, which enables it to be lightweight with low-risk of failure. In this paper, a systematic method is proposed to obtain new hinge-jointed structures which have N-dihedral symmetry and can be folded into a straightly bundled shape. The proposed structure, which we call N-MLSRL, is composed of some layers. Each layer is an assemblage of 2N bars and 2N inclined hinges, which can be deformed from a regular 2N-gonal frame into an entirely straight rod shape, which is a generalization of a 4-bar Bennett linkage. For the case N is less than or equal to 3, the N-MLSRL has a single degree of freedom. For an application to design of deployable structures, a method is introduced to generate the structure expanded to a predefined target surface of revolution. For designing the realistic detail considering the finite sizes of the joints, a technique called hinge offsets is used. The proposed method is applied to a horn-shaped structure, a ball-shaped structure and a dome-shaped structure as its numerical examples. The validity of the proposed method is confirmed by a physical model of a dome-shaped structure including hinge offsets.
{"title":"N-gonal multilayer symmetric revolute linkage deployed from bundle to surface of revolution","authors":"Ryo Watada, M. Ohsaki","doi":"10.1115/1.4062945","DOIUrl":"https://doi.org/10.1115/1.4062945","url":null,"abstract":"\u0000 Deployable structures composed of hinge joints (revolute joints) with inclined axis have a potential to realize a rich variety of deformation with a small number of members, which enables it to be lightweight with low-risk of failure. In this paper, a systematic method is proposed to obtain new hinge-jointed structures which have N-dihedral symmetry and can be folded into a straightly bundled shape. The proposed structure, which we call N-MLSRL, is composed of some layers. Each layer is an assemblage of 2N bars and 2N inclined hinges, which can be deformed from a regular 2N-gonal frame into an entirely straight rod shape, which is a generalization of a 4-bar Bennett linkage. For the case N is less than or equal to 3, the N-MLSRL has a single degree of freedom. For an application to design of deployable structures, a method is introduced to generate the structure expanded to a predefined target surface of revolution. For designing the realistic detail considering the finite sizes of the joints, a technique called hinge offsets is used. The proposed method is applied to a horn-shaped structure, a ball-shaped structure and a dome-shaped structure as its numerical examples. The validity of the proposed method is confirmed by a physical model of a dome-shaped structure including hinge offsets.","PeriodicalId":50137,"journal":{"name":"Journal of Mechanical Design","volume":"117 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90539777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bryan J. Stringham, Christopher A. Mattson, P. Jenkins, E. Dahlin, Immaculate Okware
Remotely measuring social impact indicators of products in developing countries can enable researchers and practitioners to make informed decisions relative to the design of products, improvement of products, or social interventions that can help improve the lives of individuals. Collecting data for determining social impact indicators for long-term periods through manual methods can be cost prohibitive and preclude collection of data that could provide valuable insights. Using in-situ sensors remotely deployed and paired with deep learning can enable practitioners to collect long-term data that provides insights that can be as beneficial as data collected through manual observation but with the cost and continuity made possible by sensor devices. Postulates related to successfully developing and deploying this approach have been identified and their usefulness demonstrated through an example application related to a water hand pump in Uganda in which sensor data was collected over a five month span. Following these postulates can help researchers and practitioners avoid potential issues that could be encountered without them.
{"title":"Enabling Insights by Long-Term Evaluation of Social Impact Indicators of Engineered Products for Global Development using In-Situ Sensors and Deep Learning","authors":"Bryan J. Stringham, Christopher A. Mattson, P. Jenkins, E. Dahlin, Immaculate Okware","doi":"10.1115/1.4062944","DOIUrl":"https://doi.org/10.1115/1.4062944","url":null,"abstract":"\u0000 Remotely measuring social impact indicators of products in developing countries can enable researchers and practitioners to make informed decisions relative to the design of products, improvement of products, or social interventions that can help improve the lives of individuals. Collecting data for determining social impact indicators for long-term periods through manual methods can be cost prohibitive and preclude collection of data that could provide valuable insights. Using in-situ sensors remotely deployed and paired with deep learning can enable practitioners to collect long-term data that provides insights that can be as beneficial as data collected through manual observation but with the cost and continuity made possible by sensor devices. Postulates related to successfully developing and deploying this approach have been identified and their usefulness demonstrated through an example application related to a water hand pump in Uganda in which sensor data was collected over a five month span. Following these postulates can help researchers and practitioners avoid potential issues that could be encountered without them.","PeriodicalId":50137,"journal":{"name":"Journal of Mechanical Design","volume":"20 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81932861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. S. Yousaf, D. Detwiler, F. Duddeck, S. Menzel, Satchit Ramnath, Nathan Zurbrugg, M. Bujny
Topology Optimization (TO) is used in the initial design phase to optimize certain objective functions under given boundary conditions by finding suitable material distributions in a specified design domain. Currently available methods in industry work very efficiently to get topologically-optimized design concepts under static and dynamic load cases. However, conventional methods do not address the designer's preferences about the final material layout in the optimized design. In practice, the final design might be required to have a certain degree of local or global structural similarity with an already present good reference design because of economic, manufacturing and assembly limitations or the desire to re-use parts in different systems. In this article, a heuristic Energy Scaling Method (ESM) for similarity-driven TO under static as well as dynamic loading conditions is presented and thoroughly evaluated. A 2D cantilever beam under static point load is used to show that the proposed method can be coupled with gradient-based and also heuristic, non-gradient methods to get designs of varying similarity w.r.t. a reference design. Further testing of the proposed method for similarity-driven TO on a 2D crash test case and a large-scale 3D hood model of a car body indicates the effectiveness of the method for a wide range of problems in the industry. Finally, the application of similarity-driven TO is further extended to show that ESM also has the potential for sensitivity analysis of performance w.r.t. the extension of design domain.
{"title":"Similarity-driven Topology Optimization for Statics and Crash via Energy Scaling Method","authors":"M. S. Yousaf, D. Detwiler, F. Duddeck, S. Menzel, Satchit Ramnath, Nathan Zurbrugg, M. Bujny","doi":"10.1115/1.4062943","DOIUrl":"https://doi.org/10.1115/1.4062943","url":null,"abstract":"\u0000 Topology Optimization (TO) is used in the initial design phase to optimize certain objective functions under given boundary conditions by finding suitable material distributions in a specified design domain. Currently available methods in industry work very efficiently to get topologically-optimized design concepts under static and dynamic load cases. However, conventional methods do not address the designer's preferences about the final material layout in the optimized design. In practice, the final design might be required to have a certain degree of local or global structural similarity with an already present good reference design because of economic, manufacturing and assembly limitations or the desire to re-use parts in different systems. In this article, a heuristic Energy Scaling Method (ESM) for similarity-driven TO under static as well as dynamic loading conditions is presented and thoroughly evaluated. A 2D cantilever beam under static point load is used to show that the proposed method can be coupled with gradient-based and also heuristic, non-gradient methods to get designs of varying similarity w.r.t. a reference design. Further testing of the proposed method for similarity-driven TO on a 2D crash test case and a large-scale 3D hood model of a car body indicates the effectiveness of the method for a wide range of problems in the industry. Finally, the application of similarity-driven TO is further extended to show that ESM also has the potential for sensitivity analysis of performance w.r.t. the extension of design domain.","PeriodicalId":50137,"journal":{"name":"Journal of Mechanical Design","volume":"94 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90520044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daniel Giraldo Guzman, C. Lissenden, P. Shokouhi, M. Frecker
In this paper, we present a design methodology for resonant structures exhibiting particular dynamic responses by combining an eigenfrequency matching approach and a harmonic analysis-informed eigenmode identification strategy. This systematic design methodology, based on topology optimization, introduces a novel computationally efficient approach for 3D dynamic problems requiring antiresonances at specific target frequencies subject to specific harmonic loads. The optimization's objective function minimizes the error between target antiresonance frequencies and the actual structure's antiresonance eigenfrequencies, while the harmonic analysis-informed identification strategy compares harmonic displacement responses against eigenvectors using a modal assurance criterion, therefore ensuring an accurate recognition and selection of appropriate antiresonance eigenmodes used during the optimization process. At the same time, this method effectively prevents well-known problems in topology optimization of eigenfrequencies such as localized eigenmodes in low-density regions, eigenmodes switching order, and repeated eigenfrequencies. Additionally, our proposed localized eigenmode identification approach completely removes the spurious eigenmodes from the optimization problem by analyzing the eigenvectors' response in low-density regions compared to high-density regions. The topology optimization problem is formulated with a density-based parametrization and solved with a gradient-based sequential linear programming method, including material interpolation models and topological filters. Two case studies demonstrate that the proposed design methodology successfully generates antiresonances at the desired target frequency subject to different harmonic loads, design domain dimensions, mesh discretization, or material properties.
{"title":"Topology optimization design of resonant structures based on antiresonance eigenfrequency matching informed by harmonic analysis","authors":"Daniel Giraldo Guzman, C. Lissenden, P. Shokouhi, M. Frecker","doi":"10.1115/1.4062882","DOIUrl":"https://doi.org/10.1115/1.4062882","url":null,"abstract":"\u0000 In this paper, we present a design methodology for resonant structures exhibiting particular dynamic responses by combining an eigenfrequency matching approach and a harmonic analysis-informed eigenmode identification strategy. This systematic design methodology, based on topology optimization, introduces a novel computationally efficient approach for 3D dynamic problems requiring antiresonances at specific target frequencies subject to specific harmonic loads. The optimization's objective function minimizes the error between target antiresonance frequencies and the actual structure's antiresonance eigenfrequencies, while the harmonic analysis-informed identification strategy compares harmonic displacement responses against eigenvectors using a modal assurance criterion, therefore ensuring an accurate recognition and selection of appropriate antiresonance eigenmodes used during the optimization process. At the same time, this method effectively prevents well-known problems in topology optimization of eigenfrequencies such as localized eigenmodes in low-density regions, eigenmodes switching order, and repeated eigenfrequencies. Additionally, our proposed localized eigenmode identification approach completely removes the spurious eigenmodes from the optimization problem by analyzing the eigenvectors' response in low-density regions compared to high-density regions. The topology optimization problem is formulated with a density-based parametrization and solved with a gradient-based sequential linear programming method, including material interpolation models and topological filters. Two case studies demonstrate that the proposed design methodology successfully generates antiresonances at the desired target frequency subject to different harmonic loads, design domain dimensions, mesh discretization, or material properties.","PeriodicalId":50137,"journal":{"name":"Journal of Mechanical Design","volume":"94 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73562772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Triply period minimal surface (TPMS) based porous microchannels with freeform surfaces are extensively used in various applications, e.g., bone scaffold design and thermal management. However, TPMS-based porous microchannels designed by most existing solutions are difficult to conform with the boundaries of freeform surfaces, and the integrity of the TPMS unit at the surface boundary is easily destroyed. Therefore, this work proposes a conformal design method for TPMS-based microchannels based on mesh surface conformal parameterization. A novel geometric structure, namely “quasi-quadrilateral”, is presented with this approach to control the size and shape of TPMS unit. Then, a design method of TPMS network topology in the 2D parametric domain of mesh surfaces is proposed to determine the positions of TPMS units. Based on this network topology, an algorithm to generate conformal TPMS units and TPMS-based microchannels is further presented. The result microchannels can automatically adapt to various freeform surfaces, and the quality of TPMS unit is greatly improved. Moreover, the effectiveness and practicability of the proposed approach are validated by comparative experiments studies with existing solutions.
{"title":"A conformal design approach of TPMS-based porous microchannels with freeform boundaries","authors":"ZiPeng Chi, Qinghui Wang, Jing-Rong Li, Hailong Xie","doi":"10.1115/1.4062881","DOIUrl":"https://doi.org/10.1115/1.4062881","url":null,"abstract":"\u0000 Triply period minimal surface (TPMS) based porous microchannels with freeform surfaces are extensively used in various applications, e.g., bone scaffold design and thermal management. However, TPMS-based porous microchannels designed by most existing solutions are difficult to conform with the boundaries of freeform surfaces, and the integrity of the TPMS unit at the surface boundary is easily destroyed. Therefore, this work proposes a conformal design method for TPMS-based microchannels based on mesh surface conformal parameterization. A novel geometric structure, namely “quasi-quadrilateral”, is presented with this approach to control the size and shape of TPMS unit. Then, a design method of TPMS network topology in the 2D parametric domain of mesh surfaces is proposed to determine the positions of TPMS units. Based on this network topology, an algorithm to generate conformal TPMS units and TPMS-based microchannels is further presented. The result microchannels can automatically adapt to various freeform surfaces, and the quality of TPMS unit is greatly improved. Moreover, the effectiveness and practicability of the proposed approach are validated by comparative experiments studies with existing solutions.","PeriodicalId":50137,"journal":{"name":"Journal of Mechanical Design","volume":"45 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72534983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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