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During the design stage, the ideal simulation and visualization of the mechanical assemblies behavior require the modeling of parts with dimensional and geometrical defects. However, the deviations caused by parts deformations can generate an important difference between the ideal assembly and the real product. In this regard, this paper proposes a tolerance analysis method of CAD assemblies considering non-rigid joints between parts with defects. The determination of realistic rigid components with dimensional and geometrical defects is based on the worst case tolerancing approach and the Small Displacement Torsor (SDT) parameters. The Finite Element (FE) computation is executed to determine deformations of realistic non-rigid part models under external loads. Sub-algorithms to define non-rigid joints between realistic parts are developed. The tolerance analysis is established using the realistic CAD assembly. A case study is presented to evaluate the proposed model. [ABSTRACT FROM AUTHOR]

Nowadays, 3D CAD systems (Computer Aided Design) are extremely important in many sectors related to the modern industry. The wide range of modelling software and their increasingly advanced functionalities have considerably extended the uses of CAD models. Indexing and searching in huge databases for the purpose of reusing a 3D CAD model is still a big challenge for both the industrial and for scientific research fields. This highlights the need for an effective approach that provides accurate results within an acceptable time-frame and that takes into account the re-usability of the model regardless of its modelling software. From this perspective, this paper proposes a new data-intensive approach for the detection of reusable CAD models, similar to a reference one. The proposed method is based on the probabilistic graphical model Bayesian network. The suggested approach is mainly based on two phases: (1) first, the construction of a Bayesian network of models (MBN). The developed network is based on an index of association calculated according to the common reusable sub-parts between the candidate models. (2) Then, the detection of reusable models (through the indirect similarity extracted from the built MBN) based on the graph structure and the probabilistic inference. [ABSTRACT FROM AUTHOR]

This paper proposes a novel method for data reuse and estimation of the manufacturing cost in design phase. The method is founded on the comparison, in manufacturing semantics, between the new product and company database. An Unified Feature Technology (UFT) is used as a multidisciplinary definition of the model better reuse of company knowledge. The developed tool is focused on the calculation of similarity ratio between studied model and mastered models by the company. The comparison model allows the reuse of CAM and cost data. Consequently, the estimated cost and machining parameters of studied model are deduced. The feasibility of the proposed approach is validated through a case study. [ABSTRACT FROM AUTHOR]

Currently, the tolerancing integration in CAD model is among the major interests of most mechanical manufacturers. Several studies and researches have been established to consider the geometrical and dimensional tolerances on the CAD modelers. However, the hypothesis of rigid parts is adopted in the digital mock-up. Thus, several physical factors are neglected; especially the deformations. In this regard, this paper presents a model for considering both tolerances and deformations in CAD model. The dimensional and geometrical tolerances are taken into account by the determination of assemblies configurations with defects basing on the worst case tolerancing. The Finite Elements (FE) computations are realized with realistic models. A method for modeling the realistic mating constraints, between rigid and non-rigid parts, is developed. The case study of an assembly with planar joint is presented. [ABSTRACT FROM AUTHOR]

Rebuilding of CAD model from deformed mesh important displacement case. 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, analysis, CAM). Besides their strong interdependences, both CAD and calculation activities will be built on new emergent technologies in the fields of the data modeling (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. Our research is oriented to CAD/CAM/analysis integration by rebuilding the CAD model starting from the FE results (deformed mesh). This paper presents techniques for rebuilding the geometrical and topological entities of the CAD model starting from a deformed mesh. [ABSTRACT FROM AUTHOR]