铝合金预拉伸板的残余应力评估与变形预测
发布时间:2019-03-06 17:40
【摘要】:在航空航天制造过程中,铝合金是最常用的材料之一。其中,铝合金预拉伸板因其重量轻、强度高的优势被大量用于制造框架结构和薄壁结构等。但是在加工过程中,蕴藏在铝合金预拉伸板的残余应力随着外部材料的去除而不断释放,打破了原有的平衡状态,产生了不可避免的加工变形。本文以铝合金预拉伸板材为研究对象,借助有限元仿真、切削试验等研究手段,对板材的残余应力进行评估,获得了残余应力的分布状态,并将其输入到有限元软件中进行变形预测。同时对有限元软件进行二次开发,提高了其物理仿真与变形预测的计算效率。最终将其应用到实体的变形预测中。主要研究内容如下:(1)使用盲孔法与轮廓法对测量了铝合金预拉伸板的残余应力。为提高测量准确性,针对轮廓法测量残余应力的特殊要求,通过Plackett-Burman结合正交试验方法,揭示了线切割参数对轮廓法切割质量的影响规律,研究表明,送丝速率、丝张力和峰值电流是影响测量精度的三个主因素。当峰值电流为10A、丝张力为20g和送丝速率为180mm/min时切割质量为最优;通过Box-Behnken响应面分析法,获得了表面粗糙度的预测模型,提高了轮廓法评估残余应力的准确性。(2)对于大尺寸的结构件,使用有限元方法进行加工变形的预测时效率很低,不易实现全尺寸、完整结构、复杂切削走刀路径状态下的加工变形准确预测。为了解决这一问题,基于Abaqus软件的有限元仿真及其二次开发技术,本文提出一种采用连续多个静态隐式分析步模拟切削加工过程的加工变形有限元快速仿真方法。开发了相关软件,能够统一施加残余应力并提取后续分析的位移、应力数据。(3)基于测量得到的预拉伸板残余应力,使用二次开发的有限元仿真技术对某型机匣件的加工变形进行了预测,并将仿真结果与切削试验结果进行对比,获得了加工变形的特点。
[Abstract]:Aluminum alloy is one of the most commonly used materials in aerospace manufacturing. Because of its light weight and high strength, aluminum alloy pre-stretching plate is widely used in the manufacture of frame structure and thin-walled structure. However, in the process of machining, the residual stress stored in the aluminum alloy pre-stretching plate is released continuously with the removal of external materials, which breaks the original equilibrium state and produces inevitable machining deformation. In this paper, the residual stress of aluminum alloy pre-drawn sheet is evaluated by means of finite element simulation and cutting test, and the distribution of residual stress is obtained. It is inputted into the finite element software for deformation prediction. At the same time, the secondary development of finite element software improves the calculation efficiency of physical simulation and deformation prediction. Finally, it is applied to the deformation prediction of solid. The main contents are as follows: (1) the residual stress of aluminum alloy pretension plate was measured by blind hole method and profile method. In order to improve the accuracy of measurement, according to the special requirement of measuring residual stress by contour method, the influence of wire cutting parameters on the cutting quality of profile method is revealed by means of Plackett-Burman combined with orthogonal test method. The research shows that wire feeding rate, Wire tension and peak current are the three main factors affecting the measurement accuracy. When the peak current is 10A, the wire tension is 20g and the feeding rate is 180mm/min, the cutting quality is the best. By means of Box-Behnken response surface analysis, the prediction model of surface roughness is obtained, which improves the accuracy of profile method in evaluating residual stress. (2) for large-size structural parts, the prediction model of surface roughness is obtained. When using finite element method to predict machining deformation, the efficiency is very low, and it is not easy to realize full-size, complete structure and accurate prediction of machining deformation under the condition of complicated cutting path. In order to solve this problem, based on the finite element simulation of Abaqus software and its secondary development technology, this paper presents a fast finite element simulation method of machining deformation using continuous static implicit analysis steps to simulate the machining process. Relevant software has been developed, which can uniformly apply residual stress and extract displacement and stress data from subsequent analysis. (3) based on the measured residual stress of pre-drawn plate, The machining deformation of a machine box is predicted by using the secondary developed finite element simulation technology, and the characteristics of the machining deformation are obtained by comparing the simulation results with the results of the cutting test.
【学位授予单位】:沈阳航空航天大学
【学位级别】:硕士
【学位授予年份】:2017
【分类号】:TG146.21
本文编号:2435755
[Abstract]:Aluminum alloy is one of the most commonly used materials in aerospace manufacturing. Because of its light weight and high strength, aluminum alloy pre-stretching plate is widely used in the manufacture of frame structure and thin-walled structure. However, in the process of machining, the residual stress stored in the aluminum alloy pre-stretching plate is released continuously with the removal of external materials, which breaks the original equilibrium state and produces inevitable machining deformation. In this paper, the residual stress of aluminum alloy pre-drawn sheet is evaluated by means of finite element simulation and cutting test, and the distribution of residual stress is obtained. It is inputted into the finite element software for deformation prediction. At the same time, the secondary development of finite element software improves the calculation efficiency of physical simulation and deformation prediction. Finally, it is applied to the deformation prediction of solid. The main contents are as follows: (1) the residual stress of aluminum alloy pretension plate was measured by blind hole method and profile method. In order to improve the accuracy of measurement, according to the special requirement of measuring residual stress by contour method, the influence of wire cutting parameters on the cutting quality of profile method is revealed by means of Plackett-Burman combined with orthogonal test method. The research shows that wire feeding rate, Wire tension and peak current are the three main factors affecting the measurement accuracy. When the peak current is 10A, the wire tension is 20g and the feeding rate is 180mm/min, the cutting quality is the best. By means of Box-Behnken response surface analysis, the prediction model of surface roughness is obtained, which improves the accuracy of profile method in evaluating residual stress. (2) for large-size structural parts, the prediction model of surface roughness is obtained. When using finite element method to predict machining deformation, the efficiency is very low, and it is not easy to realize full-size, complete structure and accurate prediction of machining deformation under the condition of complicated cutting path. In order to solve this problem, based on the finite element simulation of Abaqus software and its secondary development technology, this paper presents a fast finite element simulation method of machining deformation using continuous static implicit analysis steps to simulate the machining process. Relevant software has been developed, which can uniformly apply residual stress and extract displacement and stress data from subsequent analysis. (3) based on the measured residual stress of pre-drawn plate, The machining deformation of a machine box is predicted by using the secondary developed finite element simulation technology, and the characteristics of the machining deformation are obtained by comparing the simulation results with the results of the cutting test.
【学位授予单位】:沈阳航空航天大学
【学位级别】:硕士
【学位授予年份】:2017
【分类号】:TG146.21
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