Direct Modification of Semantically-Enriched Finite Element Meshes

Behaviour analysis loop is largely performed on virtual product model before its physical manufacturing. The last avoids high expenses in terms of money and time spent on intermediate manufacturing. It is gainful from the reality to the virtuality but the process could be further optimized especially during the product behaviour optimization phase. This process involves repetition of four main processing steps: CAD design and modification, mesh creation, Finite Element (FE) model generation with the association of physical and geometric data, FE Analysis. The product behaviour analysis loop is performed on the first design solution as well as on the numerous successive product optimization loops. Each design solution evaluation necessitates the same time as required for the first product design that is particularly crucial in the context of maintenance. In this paper we propose a new framework for CAD-less product optimisation through FE analysis which reduces the model preparation activities traditionally required for FE model creation. More concretely, the idea is to directly operate on the firstly created FE mesh, enriched with physical/geometric semantics, to perform the product modications required to achieve its optimised version. In order to accomplish the proposed CAD-less FE analysis framework, modification operators acting on both the mesh geometry and the associated semantics need to be devised. In this paper we discuss the underlying concepts and present possible components for the development of such operators. A high-level operator specification is proposed according to a modular structure that allows an easy realisation of different mesh modication operators. Here, two instances of this high-level operator are described: the planar cracking and the drilling. The realised prototypes validated on industrial FE models show clearly the feasibility of this approach

Filleting sharp edges of multi-partitioned volume finite element meshes

International audiencePurpose – The purpose of this paper is to set up a new framework to enable direct modifications of volume meshes enriched with semantic information associated to multiple partitions. An instance of filleting operator is prototyped under this framework and presented in the paper.Design/methodology/approach – In this paper, a generic mesh modification operator has been designed and a new instance of this operator for filleting finite element (FE) sharp edges of tetrahedral multi-partitioned meshes is also pro-posed. The filleting operator works in two main steps. The outer skin of the tetrahedral mesh is first deformed to round user-specified sharp edges while satisfying constraints relative to the shape of the so-called Virtual Group Boundaries. Then, in the filleting area, the positions of the inner nodes are relaxed to improve the aspect ratio of the mesh elements.Findings – The classical mainstream methodology for product behaviour optimization involves the repetition of four steps: CAD modelling, meshing of CAD models, enrichment of models with FE simulation semantics and FEA. This paper highlights how this methodology could be simplified by two steps: simulation model modification and FEA. The authors set up a new framework to enable direct modifications of volume meshes enriched with semantic information associated to multiple and the corresponding fillet operator is devised.Research limitations/implications – The proposed framework shows only a paradigm of direct modifications of semantic enriched meshes. It could be further more improved by adding or changing the modules inside. The fillet operator does not take into account the exact radius imposed by user.With this proposed fillet operator the mesh element density may not be enough high to obtain wished smoothness.Originality/value – This paper fulfils an identified industry need to speed up the product behaviour analysis process by directly modifying the simulation semantic enriched meshes

Semantic-preserving mesh direct drilling

Advances in modeling of discrete models have allowed the development of approaches for direct mesh modeling and modification. These tools mainly focus on modeling the visual appearance of the shape which is a key criterion for animation or surgical simulation. Most of the time, the resulting mesh quality as well as the semantics preservation capabilities are not considered as key features. These are the limits we overcome in this paper to enable fast and efficient mesh modifications when carrying out numerical simulations of product behaviors using the Finite Element (FE) analysis. In our approach, the modifications involve the resolution of an optimization problem where the constraints come from the shapes of the operating tools and the FE groups (sets of mesh entities) used to support the semantic information (e.g. boundary conditions, materials) contained in the FE mesh model and required for FE simulation. The overall mesh quality, a key point for accurate FE analysis, is guaranteed while minimizing an objective function based on a mechanical model of bar networks which smoothes the repositioning of nodes. Principle of the devised mesh operators is exemplified through the description of a 2D/3D mesh drilling operator. The proposed mesh modification operators are useful in the context of fast maintenance studies and help engineers to assess alternative design solutions aimed at improving the physical behavior of industrial machinery

Direct modification of semanticaly-enriched finite element meshes

International audienceBehaviour analysis loop is largely performed on virtual product model before its physical manufacturing. The last avoids high expenses in terms of money and time spent on intermediate manufacturing. It is gainful from the reality to the virtuality but the process could be further optimized especially during the product behaviour optimization phase. This process involves repetition of four main processing steps: CAD design and modification, mesh creation, Finite Element (FE) model generation with the association of physical and geometric data, FE Analysis. The product behaviour analysis loop is performed on the rst design solution as well as on the numerous successive product optimization loops. Each design solution evaluation necessitates the same time as required for the first product design that is particularly crucial in the context of maintenance. In this paper we propose a new framework for CAD-less product optimisation through FE analysis which reduces the model preparation activities traditionally required for FE model creation. More concretely, the idea is to directly operate on the rstly created FE mesh, enriched with physical/geometric semantics, to perform the product modi cations required to achieve its optimised version. In order to accomplish the proposed CAD-less FE analysis framework, modification operators acting on both the mesh geometry and the associated semantics need to be devised. In this paper we discuss the underlying concepts and present possible components for the development of such operators. A high-level operator speci cation is proposed according to a modular structure that allows an easy realisation of di erent mesh modification operators. Here, two instances of this high-level operator are described: the planar cracking and the drilling. The realised prototypes validated on industrial FE models show clearly the feasibility of this approach

Semantic-preserving mesh direct drilling

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Semantic-preserving mesh direct drilling

Advances in modeling of discrete models have allowed the development of approaches for direct mesh modeling and modification. These tools mainly focus on modeling the visual appearance of the shape which is a key criterion for animation or surgical simulation. Most of the time, the resulting mesh quality as well as the semantics preservation capabilities are not considered as key features. These are the limits we overcome in this paper to enable fast and efficient mesh modifications when carrying out numerical simulations of product behaviors using the Finite Element (FE) analysis. In our approach, the modifications involve the resolution of an optimization problem where the constraints come from the shapes of the operating tools and the FE groups (sets of mesh entities) used to support the semantic information (e.g. boundary conditions, materials) contained in the FE mesh model and required for FE simulation. The overall mesh quality, a key point for accurate FE analysis, is guaranteed while minimizing an objective function based on a mechanical model of bar networks which smoothes the repositioning of nodes. Principle of the devised mesh operators is exemplified through the description of a 2D/3D mesh drilling operator. The proposed mesh modification operators are useful in the context of fast maintenance studies and help engineers to assess alternative design solutions aimed at improving the physical behavior of industrial machinery

Sharp edge filleting of enriched FE meshes

Nowadays, the use of Computer-Aided Engineering (CAE) system in product design has become mainstream. However, the adopted process from Computer-Aided Design (CAD) product definition to numerical simulation could be further improved to avoid going backward to the CAD model for model modification. To this aim, we propose a generic mesh modification operator whose architecture is detailed in this paper. A new instance of this operator for filleting FE tetrahedral meshes is also proposed. The filleting operator works in two main steps. The external skin of the tetrahedral mesh is first deformed to round user-specified sharp edges. Then, in the filleting area, the positions of the inner nodes are relaxed to improve the aspect ratio of the mesh elements. Several examples illustrate the interest of such a CAD-less approach

Algorithms for Geometric Optimization and Enrichment in Industrialized Building Construction

The burgeoning use of industrialized building construction, coupled with advances in digital technologies, is unlocking new opportunities to improve the status quo of construction projects being over-budget, delayed and having undesirable quality. Yet there are still several objective barriers that need to be overcome in order to fully realize the full potential of these innovations. Analysis of literature and examples from industry reveal the following notable barriers: (1) geometric optimization methods need to be developed for the stricter dimensional requirements in industrialized construction, (2) methods are needed to preserve model semantics during the process of generating an updated as-built model, (3) semantic enrichment methods are required for the end-of-life stage of industrialized buildings, and (4) there is a need to develop pragmatic approaches for algorithms to ensure they achieve required computational efficiency. The common thread across these examples is the need for developing algorithms to optimize and enrich geometric models. To date, a comprehensive approach paired with pragmatic solutions remains elusive. This research fills this gap by presenting a new approach for algorithm development along with pragmatic implementations for the industrialized building construction sector. Computational algorithms are effective for driving the design, analysis, and optimization of geometric models. As such, this thesis develops new computational algorithms for design, fabrication and assembly, onsite construction, and end-of-life stages of industrialized buildings. A common theme throughout this work is the development and comparison of varied algorithmic approaches (i.e., exact vs. approximate solutions) to see which is optimal for a given process. This is implemented in the following ways. First, a probabilistic method is used to simulate the accumulation of dimensional tolerances in order to optimize geometric models during design. Second, a series of exact and approximate algorithms are used to optimize the topology of 2D panelized assemblies to minimize material use during fabrication and assembly. Third, a new approach to automatically update geometric models is developed whereby initial model semantics are preserved during the process of generating an as-built model. Finally, a series of algorithms are developed to semantically enrich geometric models to enable industrialized buildings to be disassembled and reused. The developments made in this research form a rational and pragmatic approach to addressing the existing challenges faced in industrialized building construction. Such developments are shown not only to be effective in improving the status quo in the industry (i.e., improving cost, reducing project duration, and improving quality), but also for facilitating continuous innovation in construction. By way of assessing the potential impact of this work, the proposed algorithms can reduce rework risk during fabrication and assembly (65% rework reduction in the case study for the new tolerance simulation algorithm), reduce waste during manufacturing (11% waste reduction in the case study for the new panel unfolding and nesting algorithms), improve accuracy and automation of as-built model generation (model error reduction from 50.4 mm to 5.7 mm in the case study for the new parametric BIM updating algorithms), reduce lifecycle cost for adapting industrialized buildings (15% reduction in capital costs in the computational building configurator) and reducing lifecycle impacts for reusing structural systems from industrialized buildings (between 54% to 95% reduction in average lifecycle impacts for the approach illustrated in Appendix B). From a computational standpoint, the novelty of the algorithms developed in this research can be described as follows. Complex geometric processes can be codified solely on the innate properties of geometry – that is, by parameterizing geometry and using methods such as combinatorial optimization, topology can be optimized and semantics can be automatically enriched for building assemblies. Employing the use of functional discretization (whereby continuous variable domains are converted into discrete variable domains) is shown to be highly effective for complex geometric optimization approaches. Finally, the algorithms encapsulate and balance the benefits posed by both parametric and non-parametric schemas, resulting in the ability to achieve both high representational accuracy and semantically rich information (which has previously not been achieved or demonstrated). In summary, this thesis makes several key improvements to industrialized building construction. One of the key findings is that rather than pre-emptively determining the best suited algorithm for a given process or problem, it is often more pragmatic to derive both an exact and approximate solution and then decide which is optimal to use for a given process. Generally, most tasks related to optimizing or enriching geometric models is best solved using approximate methods. To this end, this research presents a series of key techniques that can be followed to improve the temporal performance of algorithms. The new approach for developing computational algorithms and the pragmatic demonstrations for geometric optimization and enrichment are expected to bring the industry forward and solve many of the current barriers it faces