Automatic and Exact Symmetry Recognition of Structures Exhibiting High-Order Symmetries

Chen, Yao; Fan, Linzi; Feng, Jian

doi:10.1061/(asce)cp.1943-5487.0000743

Cited by 11 publications

(8 citation statements)

References 59 publications

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“…On the other hand, if the input is discrete, the expected outcome of CASD is approximate symmetry. The common input models for CASD are solid 3D CAD models [3,8,11], cable-strut structures [12,30], voxel models [28], NURBS models [21,24], point clouds [29,31,32], and mesh models [33], etc. Most CASD techniques require complete input models [3,11,12,14,18,[26][27][28]30,32], while some can handle incomplete input models [25,29,31,32].…”

Section: Computer-aided Symmetry Detectionmentioning

confidence: 99%

“…The common input models for CASD are solid 3D CAD models [3,8,11], cable-strut structures [12,30], voxel models [28], NURBS models [21,24], point clouds [29,31,32], and mesh models [33], etc. Most CASD techniques require complete input models [3,11,12,14,18,[26][27][28]30,32], while some can handle incomplete input models [25,29,31,32]. Some CASD techniques use the initial input models for further processing and conversion.…”

Section: Computer-aided Symmetry Detectionmentioning

confidence: 99%

“…Extrinsic symmetry most often uses Euclidean distance between points to measure the symmetry, while intrinsic symmetry is measured by different metrics such as geodesic [27]. The CASD techniques related to 3D objects are focused on recognizing reflectional [3,8,11,[26][27][28][29][30], axisymmetry [3,4,11], cyclic [4,11], translational [11,25], and dihedral symmetry [30], etc. The subject of this study is the detection of exact global and partial axi-and reflectional symmetry in solid 3D CAD models.…”

Section: Computer-aided Symmetry Detectionmentioning

confidence: 99%

“…The common strategy for many CASD techniques [3,8,11,12,14,15,[29][30][31]33,34] is to first generate a set of candidates for the planes of symmetry and/or the axis of symmetry from the given input model. The candidates are, for instance, obtained by principal component analysis [14,15,27], pair matching [8,11,35], incremental rotations around the centroid/center of mass [12,30], from the intrinsic surface properties [3,36], etc.…”

Section: Planes and Axes Of Symmetry Candidatesmentioning

confidence: 99%

See 3 more Smart Citations

A Framework for Detection of Exact Global and Partial Symmetry in 3D CAD Models

2023

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The most common way to retrieve symmetry information (i.e., the planes and axes of symmetry) in 3D CAD models is through visual recognition by engineers. However, engineers are not able to visually recognize exact symmetry in any CAD model, and their ability to recognize symmetry decreases as the number of CAD models increases. To overcome these limitations, computer-aided symmetry detection is employed, which enables the (semi)automatic extraction of the symmetry information in CAD models. Hence, the present paper introduces a symmetry detection framework for 3D CAD models with boundary representation. The novelty of this research was that it addressed the detection of exact and partial axi- and reflectional symmetry in CAD models with analytic and numeric surfaces. Further, symmetry measures were proposed to differentiate exact, partial, or non-symmetry in the CAD model. The framework was implemented into a state-of-the-art CAD system and subjected to performance and time complexity validation. The results showed that the implemented framework’s performance was 0.94 F1-score, and the time complexity was linear with respect to the number of faces in the CAD model. Hence, it was concluded that the framework is suitable for industrial applications to support engineers in symmetry detection.

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Section: Computer-aided Symmetry Detectionmentioning

confidence: 99%

Section: Computer-aided Symmetry Detectionmentioning

confidence: 99%

Section: Computer-aided Symmetry Detectionmentioning

confidence: 99%

Section: Planes and Axes Of Symmetry Candidatesmentioning

confidence: 99%

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A Framework for Detection of Exact Global and Partial Symmetry in 3D CAD Models

2023

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“…Under every symmetry operation, the structure can be transformed into a new configuration that is equivalent or indistinguishable from the original configuration. For structures with finite nodes and members, all symmetry operations can be divided into the following five types [14,30]: (a) the identity E; (b) rotation C n about an n-fold symmetry axis; (c) reflection σ n along a symmetry plane; (d) inverse S 2 ; and (e) improper rotation S n .…”

Section: Group Theory and Its Matrix Representationsmentioning

confidence: 99%

Group-Theoretic Exploitations of Symmetry in Novel Prestressed Structures

Chen

Feng

2018

Symmetry

Self Cite

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In recent years, group theory has been gradually adopted for computational problems of solid and structural mechanics. This paper reviews the advances made in the application of group theory in areas such as stability, form-finding, natural vibration and bifurcation of novel prestressed structures. As initial prestress plays an important role in prestressed structures, its contribution to structural stiffness has been considered. General group-theoretic approaches for several problems are presented, where certain stiffness matrices and equilibrium matrices are expressed in symmetry-adapted coordinate system and block-diagonalized neatly. Illustrative examples on structural stability analysis, force-finding analysis, and generalized eigenvalue analysis on cable domes and cable-strut structures are drawn from recent studies by the authors. It shows how group theory, through symmetry spaces for irreducible representations and matrix decompositions, enables remarkable simplifications and reductions in the computational effort to be achieved. More importantly, before any numerical computations are performed, group theory allows valuable and effective insights on the behavior or intrinsic properties of a prestressed structure to be gained.

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Proposal and evaluation of new models for predicting the FRP contribution to shear strength in reinforced concrete beams using gene expression programming

Alacali,

Akkaya,

Sengun

et al. 2024

Neural Comput & Applic

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Fiber-reinforced polymers (FRP) have been widely used in shear strengthening applications of reinforced concrete (RC) beams. The accurate prediction of the FRP contribution to the shear strength of beams is essential for reliable design. Gene expression programming (GEP) has been widely utilized because it reliably expresses complex relationships between experimental variables. In this study, three new GEP models are proposed for three different strengthening configurations of FRP such as fully-wrapping, U wrapping, and side-bonding to predict the FRP contribution to shear strength. These models are developed using the most comprehensive database containing a total of 811 strengthened beams (350 fully-wrapped, 328 U-wrapped, and 133 side-bonded. Many variables have been considered in the proposed GEP models, including those that have been experimentally effective but are often neglected in existing literature equations, such as the shear span-to-effective depth ratio $$(a/d)$$ ( a / d ) and the stirrup ratio ($${\rho }_{w}$$ ρ w ). Additionally, the reliability of existing equations in the literature and the proposed GEP models for predicting the FRP contribution to shear strength was statistically evaluated. As a result of this evaluation, the proposed GEP models for each strengthening configuration of FRP yielded the most accurate statistical results, with the lowest coefficient of variation (COV), and the highest coefficient of correlation (R).

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Automatic and Exact Symmetry Recognition of Structures Exhibiting High-Order Symmetries

Cited by 11 publications

References 59 publications

A Framework for Detection of Exact Global and Partial Symmetry in 3D CAD Models

A Framework for Detection of Exact Global and Partial Symmetry in 3D CAD Models

Group-Theoretic Exploitations of Symmetry in Novel Prestressed Structures

Proposal and evaluation of new models for predicting the FRP contribution to shear strength in reinforced concrete beams using gene expression programming

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