Simulation of the rolling of stator vanes Harm Wisselink
Contact info: Harm Wisselink Han Huetink Martien van Dijk Andre van Leeuwen h.h.wisselink@wb.utwente.nl j.huetink@wb.utwente.nl ID_eldim@eldim.nl ID_eldim@eldim.nl Introduction ELDIM manufactures among others stator vanes for the compressor of an aero engine (figure 1). These vanes are produced by a cold rolling process. The development of a rolling process for a new type of vane can take several cycles of trial and error, before all requirements are fulfilled. from strips of sheet metal
Analysis of guillotining and slitting, finite element simulations
Guillotining and slitting are two sheet metal cutting processes, which produce long straight cuts and can be seen as stationary processes. The analysis of these two processes is the subject of this thesis. This research project is part of a cluster of IOP projects on sheet metal cutting, originating from industrial requests for more fundamental knowledge, as sheet metal cutting is still mainly based on experience and trial and error. The objective is to develop models of guillotining and slitting to increase the insight and to contribute to the quality and productivity of these shearing processes.
Experimental investigation of the geotechnical properties and microstructure of lime-stabilized saline soils under freeze-thaw cycling
Abstract The Song-Nen Plain in northeastern China holds one of the three largest expanses of soda saline-alkali soil in the world. Due to its disadvantageous geotechnical properties, the saline soil in this area is unable to meet the needs of construction projects. This study evaluates the stabilizing effect of adding lime to such soils. Specifically, it investigates how the physicochemical and mechanical properties and microstructure of soda saline-alkali soil are altered by lime and how these changes are affected by both freeze-thaw cycling and the duration of curing. The results reveal that adding lime to saline soil transforms clay particles into sand and silt particles and causes the pore size distribution (PSD) to become bimodal, with small-pore and macropore populations. An increase in lime content leads to an increase in the unconfined compressive strength (UCS) but a gradual decrease in both the cation exchange capacity (CEC) and plastic index. Freeze-thaw cycles break up coarse particles and aggregate finer particles, increasing the diameter of macropores and decreasing the USC; however, the effect on specimens with >9% lime is negligible. It is further shown that the geotechnical properties of the soil change immediately after the addition of lime, indicating that the cation exchange reaction takes place very quickly. Furthermore, the pozzolanic reaction leads to an increase in the percentage of sand-sized particles and a decrease in porosity after 28 days of curing. Overall, these results indicate that it is feasible to use lime to improve the engineering properties of soda saline-alkali soil in this area.