| Stainless steel has been widely used in many engineering fields such as petroleum,paper and chemical because of its excellent corrosion resistance.However,the poor wear resistance of stainless steel hinders its good development prospects.Conventional surface modification techniquessuch as surface coating and anodizing can affect the corrosion resistance of stainless steel,while advanced surface modification technqiuessuch as carburizing,nitriding and laser cladding are of high cost.Inspired by bionic technology,the indroductionof micro-textureson stainless steel surfaces has become an important method to improve the wear resistance of stainless steel.Due to the complexity of friction process and the small length scales of textures,the experimental study of friction characteristics of textured surface is time consuming and costly.Domestic and foreign scholars have generally used finite element simulation to study the friction reduction mechanism of textured stainless steel surface,and obtained many valuable research results.However,previous finite element mainly considered only the texture characteristics such as dynamic pressure lubrication performance,but the effects of friction between the friction pairs and the elastic deformation are neglected.In addition,previous work rarely paidattention to the influence of texture processing quality on the friction characteristics of the textures,which leads to deviation of designed textures to achieve excellent anti-friction effectThefinite element simulationsare necessary to deeply understand the importance of texture processing quality,so as to prepare texture with excellent performance.Therefore,in view of the above problems,this paper uses finite element simulations and experiments to study the friction reduction mechanism and its parameter correlation of microgrooves on stainless steel,mainly focusing on the influence of geometrical parameters and processing quality of microgrooveson friction characteristics.The specific research content includes the following aspects:Based on arbitrary Lagrangian-Eulerian calculation method,a three-dimensional finite element model of friction and wear of different textured samples under lubrication conditions was established.In addition,by consideringthe principle of laser processing and the constraints of each laser machining parameters,the geometric parameters of microgrooves by laser ablation are determined.A friction test scheme for characterizing the friction characteristics of microgrooves was determined,and a characterization method of friction and wear was selected.The three-dimensional finite element simulation was systematically carried out to study the mechanism of friction-reduction of textured stainless steel,and the geometrical parameters(width,depth,density and shape)of the surface microgrooves were studied for the friction and wear of the textured specimen.The geometric parameters were optimized to achieve the best anti-friction effect,which provides a theoretical basis for the study of friction-reductiontextures.Three typicallaser texturing techniquesusing different pulse widths,as femtosecond,picosecond and nanosecond,were used to fabricatemicrogrooves on stainless steel surface,and the friction properties of laser pulsed samples with different pulse widths were studied.At the same time,the corresponding finite element simulationswerecarried out to study the friction reduction mechanism of differentlytextured samples.Furthermore,experimental results and simulation results were mutually verified to demonstratethe influence of laser processing quality onfriction characteristics of textured surface. |
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