Abstract: The mechanical analysis is at the heart of the life cycle of mechanical products. To accelerate the design and simulation tasks, we need to adapt the Computer Aided Design (CAD) model before the simulation process. This pre-processing task consists in adapting the CAD geometry, performing an mesh, specifying boundary conditions and loads, etc. This work presents a hybrid method based on an original algorithm in order to adapt and simplify the design geometric model to a simulation by the finite element method. It consists in the idealization of the CAD geometry by eliminating details (holes, chamfers, etc.) and fuses the faces using an energetic method. These details increase the computing time due to a refined mesh in these details, which are considered as constraints hubs, without providing more precision in the simulation. An implementation of the proposed algorithm on the Open Cascade platform is also presented. The last part of this paper presents an example of a mechanical part, which is simulated before and after simplification. The results of simulation illustrate the major contribution of the proposed method in terms of computing time without affecting the quality of results.
Abstract: Current researches aim at the best control and integration of activities related to the product life cycle. That’s why integrating the simulation of assembly/disassembly operations in development process of mechanical product is an increasing aspect of CAD (computer aid design) and VR (virtual reality) research. In order to help designer in early stages in analyzing accessibility and disassembly aptitude of components this paper develops an automatic disassembly methodology of CAD models.
This methodology allows identifying of geometric entities of parts connection. Deduced from connection entities parameters, authorized movement directions of components are verified by interference tests. If tested directions are valid, disassembly sequences are generated and assembly state is updated. Then target, time and disassembled pieces number are saved to be used for computing optimal sequences. Using the application programming interfaces (API) of SolidWorks and Opencascade development platform, the developed methodology was applied to an example illustrated in this paper to show its efficiency.
Abstract: At present, the simulation is at the heart of the product development cycle. To
accelerate the design and simulation cycle, it is necessary to prepare the Computer Aided
Design (CAD) model before the simulation process. This pre-processing task consists in
cleaning the CAD geometry, performing a mesh, specifying conditions boundary and loads,
etc. This paper presents a method based on an original algorithm in order to prepare the
design geometric model to a simulation by the finite element method. It consists in the
idealization of the CAD geometry by eliminating details (holes, chamfers, etc.). These details
increase the computing time due to a refined mesh in these details, which are considered as
constraints hubs, without providing more precision in the simulation. An implementation of
the proposed algorithm on the Open Cascade platform is also presented. The last part of this
paper presents two examples of mechanical parts, which are simulated before and after
idealization. The simulation’s results show the major contribution of the proposed method in
terms of gain in computing time without loss of accuracy on the simulation’s results.
Abstract: For several years, researchers have focused on improving the integration of the CAD, CAM and
Analysis through a better communication between the various analysis tools. This tendency to integrate
the CAD/Analysis and automation of the corresponding processes requires data sharing between the
various tasks using an integrated product model. We are interested in this research orientation to
CAD/CAM/Analysis integration by rebuilding the CAD model (BREP), starting from the Analysis results
(deformed mesh). Because this problem is complex, it requires to be split into several complementary
parts. This paper presents an original interoperability process between the CAD and CAE. This approach
is based on a new technique of rebuilding the CAD surface model (Nurbs, Bezier, etc.) starting from
triangulation (meshed surface) as a main step of the BREP solid model. In our work, the advantages of
this approach are identified using a centrifugal pump example.
Abstract: At present, the simulation is at the heart of the product development cycle. To accelerate the design
and simulation cycle, it is necessary to prepare the CAD model before the simulation process. This preprocessing
task consists on cleaning the CAD geometry, performing a mesh, specifying conditions boundary and
loads, etc. This paper presents a method based on an original algorithm in order to prepare the design geometric
model to a simulation by the finite element method. It consists on the idealization of the CAD geometry by
eliminating details (holes, chamfers, etc.). These details increase the computing time due to a refined mesh in
these details, which are considered as constraints hubs, without providing more precision in the simulation. An
implementation of the proposed algorithm on the Open Cascade platform is also presented. The last part of this
paper presents two examples of mechanical parts, which are simulated before and after idealization. The
simulation results show the major contribution of the proposed method in terms of gain in computing time
without loss of accuracy on the simulation results.
Abstract: Tolerance Analyses and optimisations methodology in integrated design:
TOL ANALYSES. Real parts of a batch are theoretically all identical but physically all different. Their
dimensions cannot be the same. A dimension is tolerable if its deviation remains close enough to the ideal
value. This deviation is limited by two values, either bounds of an interval or the mean and the variance
of a batch. Usually, we define two extreme bonds of dimensions, called tolerances that must be determined
wisely. A tolerancing uses syntactic and grammatical information to provide a sense. The aim of this article
is to propose and validate a methodology for assistance in the selection and verification of tolerances. This
methodology is based on two complementary approaches: the method at worst case and the Monte Carlo
method. An implementation computer showed the feasibility of the tool as well as the major contribution
of the methodology proposed in aid to the
Abstract: Nowadays, not only the production but also the design of industrial products is subject to
severe constraints in terms of time, quality and delay. In order to satisfy these constraints,
it is necessary to efficiently integrate the most recurrent tasks of the design process. For
a large majority of mechanical products, the integration of mechanical analysis into the
design process is one of the most obvious and crucial requirements, particularly during the
early stages of design. This article presents an original model of design and analysis process
interoperability, based on the concept of mechanical analysis features and a semantically
rich product model. It is intended to support a variety of typical analysis tasks that
are frequently required during the mechanical design process. The authors firstly present
a brief survey of CAD/analysis integration approaches in order to position their contribution
within this domain. Then, a general structure of analysis features is justified by
means of experimental results. In order to highlight the modes of interoperability between
design and analysis, the authors detail the main characteristics of the product model upon
which the design activity is based. This delineation is followed by a formal description of
the analysis features, and a proposition for their organisation in feature catalogues. The
authors then consider the implementation aspect for these models, and present a scenario
illustrating the benefits and current limitations of their approach. The evaluation of the
approach is discussed in the conclusion.
Abstract: Nowadays, the design activity of industrial products is subject to several constraints of time, quality and delay. In order to respect these constraints, it is necessary to efficiently integrate the most reccurent tasks involved in the design processes. In this article, we firstly introduce a global assessment on pricipale work related to the problemsq of CAD / Analysis integration. After having introduced the adopted research methodology, we propose the CAD / Analysis integration model, and an original concept called Analysis Feature, able to support typical analysis tasks usually encountered in mechanical design. Lastly, we present the specifications of the implementation model and a validation example.
Abstract: Current researches aim at the best control and integration of activities related to the product life cycle. That’s why
integrating the simulation of assembly/disassembly operations in development process of mechanical product is an
increasing aspect of CAD (computer aid design) and VR (virtual reality) research. In order to help designer in early stages in
analyzing accessibility and disassembly aptitude of components this paper develops an automatic disassembly methodology
of CAD models.
This methodology allows identifying of geometric entities of parts connection. Deduced from connection entities parameters,
authorized movement directions of components are verified by interference tests. If tested directions are valid disassembly
sequences are generated and assembly state is updated. Then target, time and disassembled pieces number are saved to be
used for computing optimal sequences. Using the application programming interfaces (API) of SolidWorks and Opencascade
development platform, the developed methodology was applied to an example illustrated in this paper to show its efficiency.
Abstract: The simulation is at the heart of the product development cycle. To accelerate the design and simulation tasks, it is necessary to adapt the Computer Aided Design (CAD) model before the simulation process. This pre-processing task consists in adapting the CAD geometry, performing a mesh, specifying boundary conditions and loads, etc. This work presents a hybrid method based on an original algorithm in order to adapt and simplify the design geometric model to a simulation by the finite element method. It consists in the idealization of the CAD geometry by eliminating details (holes, chamfers, etc.) and fuses the faces using energetic method. These details increase the computing time due to a refined mesh in these details, which are considered as constraints hubs, without providing more precision in the simulation. An implementation of the proposed algorithm on the Open Cascade platform is also presented. The last part of this paper present example of mechanical part, which is simulated before and after simplification. The results of simulation illustrate the major contribution of the proposed method in terms of computing time without affect the quality of results.
Abstract: At present, numeric simulation is at the heart of the product development cycle. To accelerate the design and simulation tasks, it is necessary to prepare the CAD model before the simulation process. This pre-processing task consists on cleaning the CAD geometry, performing a mesh, specifying boundary conditions and loads, etc. This paper presents a method based on an original algorithm in order to prepare the design geometric model to a simulation by the finite element method. It consists on the idealization of the CAD geometry by eliminating details (holes, chamfers, etc.). These details increase the computing time due to a refined mesh in these details, which are considered as constraints hubs, without providing more precision in the simulation. An implementation of the proposed algorithm on the Open Cascade platform is also presented. The last part of this paper presents an example of mechanical part, which is simulated before and after idealization. The simulation results show the major contribution of the proposed method in terms of gain in computing time without loss of accuracy on the simulation results.
Abstract: In recent years, the PLM (Product Life cycle Management) is considered as an independent process,
like the other activities of the enterprise (enterprise resource management, the production management,
management of the relationship with customers, etc.). The objective of a PLM system is the product management
throughout it life cycle. However, collaborative activities are far from being as efficient because PLM systems
manage a large quantity of product data coming from various activities. The establishment of a PLM system that
can effectively manage all the collaborative activities is very necessary. This article presents a study of setting up
a PLM system in order to manage the design and analysis activities. This management should take into account
not only to product model (technical data management), but also the interoperability between design and analysis
processes.
Abstract: Current researches aim at the best control and integration of activities related to the product
life cycle. That’s why integrating the simulation of assembly/disassembly operations in
development process of mechanical product is an increasing aspect of CAD and VR research.
In order to help designer in early stages in analyzing accessibility and disassemblability of
components this paper develops an automatic disassembly methodology of CAD models.
This methodology allows identifying of geometric entities of parts connection. Deduced from
connection entities parameters, authorized movement directions of components are verified
by interference tests. If tested directions are valid disassembly sequences are generated and
assembly state is updated. Then target, time and disassembled pieces number are saved to be
used for computing optimal sequences. Using the application programming interfaces (API)
of SolidWorks and Opencascade development platform, the developed methodology was
applied to an example illustrated in this paper to show its efficiency.
Abstract: Tolerancing is an evolving field. It has a paramount importance from the engineering
department that the department of methods. It tackles in the first approximation problems
assemblability of rigid parts in the in 1-Diemsional. For the sake of accuracy (fidelity), the three –
dimensional or bi – directional cases are taken into account for moving models increasingly
complex, incorporating the distortion of parts and their defects forms.
Our work seeks to address these issues. It is based mainly on arithmetical and statistics methods.
We are dealing, in this article, the problem of unidirectional tolerancing of solid and rigid parts.
A new approach for analysis and synthesis of tolerances, with two points of view that the worst
case point of view and the statistical point of view, is presented. The Monte Carlo method will be
used for simulation. Examples would finally validate the proposed approach.
Abstract: The tolerancing step has a great importance in the design process. It characterises the relationship between the different sectors of the product life cycle: Design, Manufacturing and Control. We can distinguish several methods to assist the tolerancing process in the design. Based on arithmetic and statistical method, this paper presents a new approach of analysis and verification of tolerances. The chosen approach is based on the Worst Case Method as an arithmetic method and Monte Carlo method as a statistical method. In this paper, we compare these methods and we present our main approach, which is validated using an example of 1 D tolerancing.
Abstract: The statistical analysis of tolerances is a recently used approach in the mechanical product design process. Its objective is to assist the designer in the specification and verification process of tolerances. This approach can providing what will happen in production at the design stage. This article presents an integrate tolerances–design approach based on two complementary methods: the worst case method and the Monte Carlo method. The implementation of the proposed method is done using Matlab. An example of validation will illustrate the main functionality of the proposed method.
Abstract: For several years research has been brought to improve integration of CAD, CAM and Analysis through better communication between the various analysis tools. This tendency to integrate CAD/Analysis and automation of the corresponding processes requires the data sharing between the various tasks using an integrated product model. Our activity deals with this research orientation on CAD/CAM/Analysis integration by rebuilding the CAD model (BREP), starting from the Analysis results (deformed mesh). The complexity of this problem requires to be split into several complementary parts. This paper presents an original interoperability process between CAD and CAE. This approach is based on a new technique of rebuilding of a CAD model of surface (Nurbs, Bezier, etc.) starting from triangulation (meshed surface) as a main step of the BREP solid model. In this paper, The advantages of this approach are identified using the design of a centrifugal pump.
Abstract: The integration of the tolerances in environment CAD is an essential spot when designing and the manufacture product processes. The main objective is to have parts and assembly in conformity with the schedule of conditions functional and satisfy the customer. Its objective is helping the designer by developing a CAD environment able to create and import easily the CAD model. This geometrical model will be associated zones of variation of the dimensions. Thus, the tolerance concept will not be regarded as a simple annotation but becomes integrated information into the data structure of the product. This paper presents an algorithm of tolerances integration. The implementation of this algorithm is carried out under the OpenCascade platform. An illustration example will apprehend the various stages of the tolerances integration algorithm.
Abstract: In order to perform a Finite Element analysis, the details identification and elimination is a crucial task in a geometrical simplification process. Its objective is to clean (idealization) and adapt the CAD model for the mechanical analysis step. This article describes the principal methods of details identification on a B-rep model, and presents an identification algorithm which takes account the details size. This algorithm can includes other criteria like material, boundary conditions, etc. We use OpenCascade platform to implement our method. Finally, a validation example illustrates the principal steps in order to locate and eliminate details from a CAD model.
Abstract: Nowadays, we attend a development of work in project mode which is characterized by the mobilization of multiple competences. The globalisation of the markets as well as the reduction in costs and in delays for developing new products led to the development of collaborative working tools in a distant way ensuring the structuring, the follow-up, and the traceability of the exchanges. That induced a considerable increase in the needs of inter-applications communication and total coherence of the support systems of the various product models (CAD, Calculation, CAM).
Besides their strong interdependences, both CAD and calculation activities will be built on new emergent technologies in the fields of the data modelling (model of product) and of the processes (interoperability) in order to be able to take into account the handling of heterogeneous objects (geometry, meshing, deformation, etc). Indeed, in a context of collaborative work, the numerical integration of these two activities: CAD and Calculation became one of the main concerns in CAD/CAM. The required objective here is to promote sharing the data without manual transformations in order to improve the flow of information between CAD and Calculation while guaranteeing the reliability and the traceability of the data. The object of this article is to trace four complementary approaches of numerical integration and interoperability of the CAD and mechanical Calculation processes developed in collaboration between the Mechanical Engineering Laboratory (MA 05) of the ENI of Monastir (Tunisia), LAMIH-UMR CNRS 8530 of the University of Valenciennes (France)
Abstract: The numerical simulation using Finite Element (FE) method is a main activity in the design –
validation process of mechanical products. Using this method and CAD tools can give an efficient
advantage in the CAD – Analysis loop. The geometric model (mesh) used in the FE method is mainly
obtained from the CAD model (CSG, B-Rep). In order to reduce the analysis time without bringing
precision on computation results we propose to integrate a new link in the design and analysis
interoperability process. This link is named Idealization or simplification of CAD model. So, the
automation of the idealization task is important in the CAD-Analysis integration process.
In this paper, we propose an idealization approach which mainly depends on the geometry, the
solicitations and the behavior of material. According to the analysis goal, the designer can have
several alternatives of analysis models which depend on the level of eliminated details and the
abstraction level (1D, 2D or 3D). The non manifold models should not be a barrier to the considered
analysis model.
In this article, we start with a positioning of several geometry simplification methods for CAD models
in order to generate Analysis models adapted with the considered analysis point of view. Based on this
state of the art, we present the idealization approach in an integrated design context. Then, we propose
our general method of the CAD geometry idealization. This one is based on an original algorithm
witch integrate tow alternatives approach (selective approach and automatic approach). In order to
emphasize our contribution. In order to present the importance of the idealization task in an integrated
design process, we present some examples of idealized form features (parallelepiped, cylinder, wedge)
implemented with OpenCacade code. Finally, an example of mechanical part using implemented form
features is developed. The output of the algorithm is some proposed analysis models based on the
CAD model of the part
Abstract: The numerical simulation using Finite Element (FE) method is a main activity in the design – validation process of mechanical products. Using this method and CAD tools can give an efficient advantage in the CAD – Analysis loop. The geometric model (mesh) used in the FE method is mainly obtained by a simplification of CAD model. So, the automation of the simplification task named Idealization task is important in the CAD-Analysis integration process. This paper presents several geometry simplification methods for CAD models in order to generate Analysis models adapted with the considered analysis point of view. Based on this state of the art, an idealization algorithm is proposed. Finally, a validation and some conclusions are presented.
Abstract: In CAD process, the idealization is an important and complex task. The main goal of the idealization process is to adapt the CAD geometry in to an analysis model using the Finte Element Method. This paper presents several idealization methods and introduces the proposed idealization method. This approach takes in account not only the geometry aspect, but also the boundary conditions and the material properties.
Abstract: In this paper, we propose an idealization approach which mainly depends on the geometry, the solicitations and the behaviour of material. According to the analysis goal, the designer can have several alternatives of analysis models which depend on the level of eliminated details and the abstraction level (1D, 2D or 3D). The non manifold models should not be a barrier to the considered analysis model. In this article, we start with a positioning of the idealization approach in an integrated design context. Then, we propose our general method of the CAD geometry idealization. In order to emphasize our contribution, we present some examples of mechanical parts idealization.
Abstract: The goal of this paper is to present three main approaches of numerical integration and interoperability of design and analysis processes. These approaches are developed in collaboration between the Laboratory of Mechanical Engineering of the ENI of Monastir (Tunisia), the LAMIH of the University of Valenciennes (France) and the Department of Mechanical engineering of the University of Quebec (Canada).
