Research On Portable Abrasive Water Jet Cutting Equipment For Shipbuilding

Cutting and welding are indispensable processes in ship construction.Deformation control in production process is very important to the accuracy control of ship products.For a long time,the research on ship welding deformation control has been more in-depth and extensive,but the effect of cutting methods on the strain accumulation of sheet metal and components has rarely been reported.At present,the thermal cutting methods of steel and aluminium structure ship plates and components are mostly oxyacetylene cutting,plasma cutting,laser cutting and so on.Segmental edge trimming and other mechanical grinding are mostly used for thermal cutting or thermal effect.Because of the existence of heat-affected zone,there are residual stress and thermal deformation after cutting(or dressing),and the formation of chemical vapor,metal and paint film dust during cutting has adverse effects on workers’ health and environment.For the sheet under 4 mm,the thermal deformation caused by the thermal cutting mode has a dominant effect on the cutting accuracy.Abrasive water jet cutting technology is widely used,but due to the size and functional applicability of equipment,there is no relevant equipment applied to the edge processing of hull components.Therefore,this paper attempts to apply abrasive water jet cutting technology to the edge processing of steel-aluminium structure yacht components,and proposes a design scheme of portable abrasive water jet cutting system based on the principle of jet pump.In this paper,Emphasis is laid on the comprehensive solution of the problems that the former mixed abrasive water jet can’t cut continuously and the latter mixed abrasive water jet can’t cut portable,so that it can meet the actual demand of edge cutting of steel and aluminum structure yacht components.It is hoped that one kind of equipment can cut different materials,and can effectively reduce the thermal stagnation of thin plate in hot cutting process,so as to achieve high precision and green cutting of thin plate components of ship hull.The main research contents are as follows:(1)Through quantitative analysis of single and comprehensive indexes of common cutting methods for steel-aluminium structure,the technical applicability and greenness of abrasive water jet cutting for steel-aluminium structure yacht sheet are discussed.(2)The design objectives of continuous abrasive water jet cutting,low pressure cutting and multi-station/working condition cutting of ships are achieved by mixing abrasive with jet pump.Through theoretical calculation,a portable abrasive water jet cutting system is built,the main parameters and equipment dimensions of the system are determined,and the system is modeled based on SolidWorks software.(3)Solid-liquid two-phase flow model in Fluent software was used to optimize the jet pump and nozzle,and DPM model was used to analyze the abrasive trajectory and wear of the wall in the jet pump and nozzle.(4)The cutting depth range of the portable abrasive water jet cutting system is calculated;conducting temperature and thermal retention experiments of different cutting methods for Q235 steel and 5083 aluminum alloy blocks with different thickness is done and the cutting process of Q235 steel and 5083 aluminum alloy blocks with 4mm thickness is simulated by LS DYNA.