venturi flumes are measurement structures commonly used in water systems to measure the flow discharge. some of them are not well installed or present some geometrical defects. the objective of this study is to investigate the hydraulic influence of a number of typical wrong installations and geometrical defects of long-throated venturi flumes: significant positive or adverse slopes, humps and ...

A new approach for the geometrical optimization of five-axis-movement is presented in this paper. Regarding a fiveaxis-movement with large tolerances for lead and tilt-angle for example in the case of laser-cutting there are endless ways of generating motions without violating the orientation-tolerances. By regarding the movement of the involved axes it is shown that for a given 5-axis trajecto...

In the Digital Mock-Up (DMU), the parts and the assemblies are used in the nominal configurations. In fact, the tolerances are formally represented in CAD model and the impacts of tolerance stack-up are not considered during the optimization of the mechanical system assemblability and the F.E. Analysis. Then, the improvement of the numerical model requires the tolerance consideration in the CAD...

Physical gages permit verification with low uncertainties but remain expensive and inflexible. With the development of 3D CAD modellers and the progress made in coordinate measuring machines, the concept of the virtual gage appeared. The paper focuses on the implementation rather than the inspection of dimensional and geometrical tolerancing in 3D-CAD models of mechanical assemblies by the use ...

The CAD software seeks to represent the syntax of the geometric tolerances, i.e. their writing on the drawings. We propose to represent their semantics, i.e. their meaning with respect to the part. We show that the meaning of the geometric tolerances can be defined thanks to a model of virtual gauges. These gauges concern geometrical entities of the part which are represented on the three-dimen...

A development of complex mechatronic systems requires a multitude of decentralised designing and processing systems. The various software and file formats which are involved in the development process need a quick and smooth data exchange via standardised data models and interfaces. The ISO 10303 norm STEP (STandard for the Exchange of Product model data) has been developed by the International...

Manufacturing tolerancing is intended to determine the intermediate geometrical and dimensional states of the part during its manufacturing process. These manufacturing dimensions also serve to satisfy not only the functional requirements given in the definition drawing, but also the manufacturing constraints, for example geometrical defects of the machine, vibration and the wear of the cutting...

This paper describes a new technique for global shape improvement based upon features’ positions and geometrical constraints. It suggests a general incremental, framework whereby constraints can be added and integrated in the model reconstruction process, resulting in an optimal trade-off between minimization of the shape fitting error and the constraints’ tolerances. The objects treated are in...