The Research On Mechanical Characteristics Of Cutting Coal And Rock And Optimization Design For Coal Plow Bits

Coal plow is the mining machinery for thin seams. Plow is becoming more and more urgent because of automation, less people or unmanned working face for seam mining. Designing plow should fully consider mechanical properties, strength and life issues of the main components in early, but at present traditional design method is adopted, with long development cycle, high cost, it cannot predict in advance cutting force for the plow cutting coal and rock.The main idea of this paper as follows:Based on the actual usage of plow, considering the current design status of coal plow, basing on the experimental studies on cutting coal and rock of plow, combined with the theoretical study on cutting coal and rock of plow, by building the constitutive mode of cutting coal and rock, simulation analysis was carried out on the cutting coal and rock of plow bits,getting the load data of cutting coal and rock for plow bits, conducting optimization design for plow bis.The main research contents around the idea include:(1)Through actually testing cutting resistance and new test system of Plow bit about resistance on the self-developed plow test bed, obtaining the load datas results for different cutter spacing, cutting depth, hardness, analyzing the influence law for various factors on the coal and rock mechanical Characteristics.(2) By studying the crushing mechanism of the plowing cutting coal and rock, analysis the main factors on influencing the process for cutting coal and rock, analyzing the main geometric parameters and working parameters of the plow on the effect of coal and rock crushing. By analyzing the method for calculating cutting force,and calculating the experimental data, analyzing peak load and load spectrum of plow bits;(3) Basing on the basic characteristics of testing false coal wall, amending the existing constitutive model, studying the several stages for linear elastic deformation and creep, plastic yielding, hardening, and finally brittle cracking of the constitutive units, establishing the coal and rock damage constitutive model for cutting coal and rock used in this test;(4) Finite element software ANSYS/ls-dyna is used to establish dynamics model for cutting process, simulating the mechanics characteristic and the dynamic stress of plow bits contacting with coal and rock each other for cutting, gainning the three-way force load curve of plow bits based on structure parameters of bits and the working condition of plow; solving the load identification problem,providing the calculation data for optimizing design of plow bits;(5) According to the designing requirements of plow, combined with the traditional optimization design method, through establishing the mechanical model of alloy head weld joint; conducting the multi-objective optimization design aiming at reducing the cutting energy consumption and minimal stress of weld joint, this paper proposes a kind of multi-objective optimization design method based on CAE technology.