王华敏,秦国华,林锋,左敦稳,韩雄,陈雪梅.面向7075铝合金预拉伸厚板加工变形控制的变向迭代法[J].稀有金属材料与工程,2019,48(4):1239~1248.[Wang huamin,Qin Guohua,Lin Feng,Zuo Dunwen,Han Xiong,Chen Xuemei.A Crossover Iterative Method of Controlling Machining Deformations for Pre-stretched 7075 Aluminum Alloy Thick Plates[J].Rare Metal Materials and Engineering,2019,48(4):1239~1248.]
面向7075铝合金预拉伸厚板加工变形控制的变向迭代法
投稿时间:2017-10-09  修订日期:2017-12-12
中文关键词:  7075铝合金预拉伸厚板  残余应力  航空整体结构件  加工变形  变向迭代算法
基金项目:国家自然科学基金(项目号51765047、51465045)、江西省主要学科学术和技术带头人资助计划(大型航空整体结构件加工变形的“性能-应力-变形”一体化分析方法)、航空科学基金(项目号2016ZE56011)、江西省自然科学基金(项目号20161BAB206114)资助
中文摘要:
      具有壁薄、尺寸大、加工精度高、材料去除量大等特点的航空整体结构件,其毛坯大多选用预拉伸铝合金厚板。在高速切削成形过程中,随着材料的大量去除,毛坯内初始残余应力势必发生释放,零件只有通过弯曲变形等行为才能达到新的平衡状态,导致加工精度得不到保证,甚至成为废品。因此,研究残余应力释放产生加工变形的演化机制,是控制和保证加工质量的核心所在,对于实现加工过程的高效化和精密化至关重要。首先,依据毛坯分解为去除材料和成形零件两部分,将初始残余应力分为释放应力和有效应力,利用静力平衡条件和弯曲变形理论建立加工变形的分析模型。然后采用有限元方法求解加工变形的分析模型,通过现场加工零件后经测试可知:加工变形的仿真值与测量值相比,无论是幅值水平还是变形曲线,尽管均具有具有很好的吻合性,但由于残余应力的测量误差使得两者亦存在10%左右的幅值误差。最后建立以最小加工变形为目标的零件加工位置优化模型。通过以一定步长正向从最小值开始选取加工位置,根据当前值与上一次取值的变形方向差异,确定下一次取值的步长及其方向,若变形方向相同则以相同步长继续正向取值,否则减小步长反向取值,直至步长的绝对值在阈值范围之内,提出求解加工位置优化模型的变向迭代方法。与企业实际使用的中间位置法相比,变向迭代方法能够使得加工变形减小99.79%。
A Crossover Iterative Method of Controlling Machining Deformations for Pre-stretched 7075 Aluminum Alloy Thick Plates
英文关键词:pre-stretched 7075 aluminum alloy thick plate  residual stresses  aeronautical monolithic components  machining deformation  crossover iterative algorithm
英文摘要:
      Aeronautical monolithic components are characteristic of thin wall, large size, high machining accuracy, many material removals, and so on. The pre-stretched aluminum alloy thick plates are usually selected as blanks of aeronautical monolithic components. In the following process of high speed machining, the residual stresses will release from the blanks with the removal of material. In sequence, a new equilibrium of residual stresses can be achieved by the workpiece deformations which can strongly impact the machining quality. Therefore, the effect of residual stress release on machining deformation is investigated to control the machining quality. It is very crucial for the realization of machining process with high efficiency and precise. Above all, according to separation of a blank into removed materials and formed workpiece, the initial residual stresses can be divided into released stresses and efficient stresses so that the analysis model of machining deformations is deduced by the static equilibrium conditions and bend deformation theory. And then, finite element method is employed to solve the analysis model of machining deformations. The experiment of machined workpieces, carried out in NC machining factory, shows that both the amplitude and deformation curve, the simulated results are good agreement with the measured data. However, the measurement error of residual stresses causes 10% difference of the amplitude of the simulated results with the experimental values. Finally, an optimal model with the objective of minimum machining deformation is formulated to find the proper machining position. Therefore, a crossover iterative method is next suggested for the proposed optimal model. The initial machining position is selected from the minimum value with a given step along the positive direction. According to the sign difference of machining deformations at the current position with the last one, the step and its direction can be determined for the next selection. If the sign of the current deformation is same as the previous deformation, the step and its direction for the next position is same as the current position. Otherwise, it is chosen with the decrease step along the negative direction. The search procedure for the machining position is exceeded until the absolute value of the current step is within the given threshold value. In comparison with middle position method which is usually adopted by the enterprises, the presented crossover iterative method can decrease 99.79% machining deformations.
作者单位E-mail
王华敏 南京航空航天大学 机电学院 33008@nchu.edu.cn 
秦国华 南昌航空大学 航空制造工程学院 qghwzx@126.com 
林锋 南昌航空大学 航空制造工程学院  
左敦稳 南京航空航天大学 机电学院  
韩雄 成都飞机工业集团有限责任公司 数控加工厂  
陈雪梅 成都飞机工业集团有限责任公司 数控加工厂  
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