Biomimetic Design Of Turning Tool For Carbon Fiber Reinforced Polymer Based On Bamboo Rat Incisors

Carbon Fiber Reinforced Polymer(CFRP)is a two-phase composite material with high specific strength and high specific modulus of carbon fiber as reinforcement phase and antifatigue and corrosion resistant resin as matrix phase.It is widely used in aerospace,military,medical and other fields.However,CFRP is a difficult-to-machine material,and the surface quality of the workpiece is poor and the tool wear is serious after machining.In order to solve these problems,most methods are to optimize processing parameters and improve processing methods,but the improvement effect is limited;the other part is based on bionics method,the research content tends to subjectively design and improve the direction and structure of microtexture,lack of objective bionic principle as theoretical guidance.This thesis seeks answers from the perspective of biology.Studies have shown that when rodents of the bamboo rat eat fiber plants such as bamboo,their incisors show strong cutting ability and wear resistance.The most obvious and special structure of the bamboo rat incisors is its "crescent-depression" morphology similar to the wear of the rake face of turning tool.This morphology has undergone long-term evolution and preservation,which must play an important role that cannot be ignored.Therefore,based on the observation and analysis of this phenomenon,this thesis compares the behavior of bamboo rat incisors cutting fiber bamboo to cutting carbon fiber reinforced polymers with turning tools,and applies the special "crescent-depression" morphology structure on bamboo rat incisors to the tool rake face for bionic tool design.Firstly,based on the decisive role of cutting force in the cutting process,the cutting force of CFRP is modeled in this thesis,and it is found that the tangent function of the rake face friction angle is proportional to the cutting force.Moreover,the friction angle will decrease when the contact state between the tool surface and the chip changes from the complete contact state of the tool-chip to the incomplete contact state,which plays an important role in reducing the cutting force.This research provides an objective theoretical support for the further study of the morphology of the bamboo rat "crescent-depression".Secondly,according to the fitting formula,the morphology characteristic curve of the lower incisors "crescent-depression" of the bamboo rat is reconstructed,and the depth and width of the characteristic curve were optimized by the overall scaling method.Considering the distance between the characteristic curve and the cutting edge and the rake angle of the tool,the orthogonal experiment was designed.The bionic tool models with different parameters obtained from the design were imported into Abaqus software to complete the simulation analysis of CFRP turning.The cutting force was taken as the characterization object,and the size of the cutting force was extracted.The optimal bionic curve morphology parameters were obtained through data analysis.In order to ensure the strength of the tool,the strength of the bionic tool with the optimal bionic morphology was checked by static analysis.Finally,based on the above research results,two kinds of bionic cutters are manufactured :one is to place the optimal bionic "crescent-depression" groove on the flat cutter surface(the rake face of the cutter is plane);another is to replace the curve groove on the cutting tool of carbon fiber composites recommended by the industry with bionic curve groove.Through turning test,the two designed bionic tools were tested and verified,and the study found that the performance of bionic tools was better.The two bionic tools designed in this paper both show excellent performance,and achieve the goal of reducing tool wear and improving the surface quality of workpiece.In summary,for carbon fiber reinforced polymers,the bionic turning tool design method proposed in this thesis provides research ideas and development directions for the bionic design of CFRP turning tools,which has played a certain role in promoting the further development of carbon fiber reinforced composites.