| Offcentre-tube-expander is a kind of repair tool invented by Daqing Petroleum and Gas Ltd. It is applied to repair little-channel wells usually. The structure is made up of a cylinder and a offcentre cone. In repairing, the offcentre cone is plugged into the distortion channel, and striked continuously to expand the channels, the tool bears several kinds of non-linear forces that could lead the tool plastic strain and fracture in repairing. This paper gives a mechanics analysis for offcentre-tube-expander by Ansys soft.Firstly, input material properties and build up model of offcentre-tube-expander,damaged casing and surrounding terrane ignoring reasonablely some unimportant parts of the structure. Secondly, mesh the model by solid45 element. For solution veracity, increase the elements' density at tips or stress focus. Finally, bear border conditions. For the reason of the model is symmetry, restricts the symmetry border by displacement. The up,left and back surfaces bear surface load of 30MPa, 6MPa and 9MPa respectively. The faced surface is restricted by displacement. Solve after defined the contact face.After caculated 10°,15°,20° in 60mm channel and in 40mm channel separately, the Mises stress maps are got. From the map, find out the reasonable cone angle in two different channels. The result will offer theory reference for the expander selection.
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