基于损伤力学刀具失效机理的极端制造高效铣削基础研究

The cutting method of large equipment parts with water chamber head for typical parts is heavy-duty cutting of extreme manufacturing. In the heavy-duty milling process of water chamber head, the damage accumulation and evolution of cemented carbide tool material under the effect of cyclic thermal-mechanical load have a great influence on cutting performance and service life of the tool, and it has the problems of severe tool failure, low service life and low cutting efficiency. The damage mechanism of cemented carbide tool is studied based on damage mechanics. And the damage variable expression of the tool is established so as to describe insert damage accurately. The technology of detection and process monitoring of tool material damage is researched so as to determine the damage parameters. The damage constitutive relation and damage evolution equation of the tool are established, so the complete process of tool damage can be revealed. The initial conditions, failure criteria and life prediction model are established. The damage resistance of the insert is studied from the aspects of insert material, structure and coating so as to improve the service life of the tool. The efficient layered milling cutter structure is optimized designed and developed. The optimized objective function is established with minimal damage, maximum cutting tool life as constraint so as to optimize the processing technic of water chamber head. The research results can provide a basis for the revelation of damage nature of cemented carbide insert during heavy-duty milling, solving the problem of tool failure and improving the efficiency of processing. These have important theoretical and practical significance.

以水室封头为典型零件的大型装备零件的切削加工方式是极端制造中的重型切削加工。水室封头重型铣削过程中，在循环热-机械载荷作用下硬质合金刀具材料发生损伤的累积和演化，对刀具的切削性能及使用寿命影响很大，存在刀具失效严重、使用寿命低和切削效率低等问题。基于损伤力学进行硬质合金刀具损伤机理研究，建立刀具损伤变量表达式，从而准确描述刀具损伤程度；进行刀具材料损伤的检测与过程监测技术研究，并确定刀具损伤参数；建立刀具损伤本构关系和损伤演化方程，揭示刀具损伤的完整过程；建立刀具损伤的初始条件、失效准则及寿命预测模型；从刀片材料、结构、涂层角度进行刀片抗损伤性能研究，提高刀具的使用寿命，开发设计高效分层铣削刀具结构；建立以损伤最小、刀具寿命最长的优化目标函数，优化水室封头加工工艺。研究结果可以为揭示重型铣削中硬质合金刀具损伤的本质，解决重型铣削刀具失效问题和提高加工效率提供依据，有重要的理论与实际意义。

为减缓水室封头重型铣削过程中的刀具失效，提高刀具使用寿命，从损伤力学角度深入探索切削过程中刀具失效问题，对其损伤破坏的过程与规律的研究是一个基础性且具有重要意义的课题。本项目进行基于损伤力学刀具失效机理的极端制造高效铣削基础研究，其主要成果包括：.（1）针对水室封头材料重型铣削载荷特点，采用试验与有限元分析相结合的方法，对切削过程中刀具承受载荷特性进行了分析；探讨了切削过程刀具热-机械应力分布情况，对刀具损伤失效形式和机理进行了分析；建立了硬质合金刀具损伤变量表达式，揭示了重型铣削过程中硬质合金刀具损伤一般规律；.（2）进行了硬质合金刀具材料的高温力学试验，分析了刀具材料性能随温升的变化规律；提出并进行了基于OpenCV阈值化方法对试件高温拉伸断口裂纹进行了检测和分析，从微观角度探究了刀具材料的损伤形成和演化及其对刀具材料力学性能影响规律；.（3）分析了刀具材料损伤初始损伤应力-应变关系，探究了有效应力与损伤变量的关系；在霍普金森压杆试验基础上，建立了硬质合金刀具材料损伤本构关系及损伤演化方程；建立了刀具材料裂纹扩展模型并确定了临界损伤条件；.（4）进行了硬质合金刀具冲击断裂极限分析，确定了重型铣削过程中刀具损伤失效判据；建立了硬质合金材料低周疲劳损伤模型和高周疲劳损伤模型，探究了损伤变量与载荷循环次数的关系；提出基于损伤力学的刀具寿命预测方法，确定了刀具材料疲劳寿命模型参数，对硬质合金刀具疲劳寿命进行了预测；.（5）根据水室封头重型铣削刀具损伤机理、损伤模型和寿命预测模型，从刀片材料、结构、涂层角度进行了刀片抗损伤性能研究，对分层铣削刀具结构进行了优化；基于刀具最小损伤和寿命最长建立优化目标函数，采用遗传算法对切削参数进行优化，提高分层铣刀系统的抗损伤性能和大型零件的铣削效率。.研究结果为解决刀具失效问题和提高加工效率提供依据，为大型难加工材料零件重型高效铣削加工提供理论基础与技术支持。