Van Thao Le

Extraction of features for combined additive manufacturing and machining processes in a remanufacturing context

The emergence of additive manufacturing (AM) techniques in the last 30 years allows to build complex part by adding material in a layer-based fashion or spraying the material directly into the part or a substrate. Taking into account performance of these techniques in a ‘new remanufacturing strategy’ can open new ways to transform an end-of-life (EoL) part into a new part intended for another product. The strategy might allow a considerable material proportion of existing parts to be reused directly for producing new parts without passing through the recycling stage. In this work, the strategy enables the transformation of existing parts into desired parts is first presented. The strategy uses an adequate sequence of additive and subtractive operations, as well as inspection operations to achieve the geometry and quality of final parts. This sequence will be designed from a set of AM features and machining features, which are extracted from available technical information and the CAD models of existing part, and final part. The core of the paper focuses on the feature extraction approach. The approach development is based on the knowledge of AM processes and machining process, as well as the specifications of final part.

Effects of Hydraulic Loading History on Suffusion Susceptibility of Cohesionless Soils

AbstractSuffusion is a selective erosion of fine particles under the effect of seepage flow within the matrix of coarser particles. This complex phenomenon appears as a combination of three process...

New Apparatus for Assessing Soil Suffusion Susceptibility Under Two Flow Directions

Suffusion is the process of selective erosion of fine particles within the matrix of coarse soil particles under the effect of seepage flow. Suffusion can induce important modifications in the hydraulic and mechanical characteristics of the soil in different flow directions. Thus, to ensure the safety assessment of hydraulic earth structures, the experimental models need to match the reality of the body of dikes or dams with horizontal flow. In this paper, a new multi-directional flow apparatus is described for characterizing soil sensibility for the suffusion process and to study the effect of flow direction. A series of suffusion tests was performed using this new device with vertical flow or horizontal flow on both gap graded soils and widely graded soils. All tested specimens were subjected to a multi-stage hydraulic gradient. The comparison of the results of the new device with results obtained from another device in vertical flow was realized. The specimens have the same initial hydraulic conductivity and suffusion susceptibility classification with both devices. Furthermore, for specimens characterized by limited soil anisotropy, the suffusion susceptibilities of these soils are quite identical under vertical flow and horizontal flow. These results permit to validate the new device and the experimental method.