共查询到19条相似文献,搜索用时 187 毫秒
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基于流变应力特性的铝合金淬火残余应力数值模拟及试验研究 总被引:3,自引:1,他引:2
依据相关试验数据引入铝合金的流变应力特性曲线,对7075铝合金板材淬火过程进行温度场和应力场的直接热力耦合数值模拟,研究7075铝合金板材最终淬火残余应力的分布规律,并采用盲孔法对7075铝合金板材最终淬火残余应力进行测量,试验测量结果表明考虑铝合金流变应力特性的直接耦合法数值模拟出的铝合金淬火残余应力分布具有很好的准确度,同时借鉴相关文献的试验测量数据对直接耦合和准耦合两种数值模拟方法仿真出的铝合金板材内部最终淬火残余应力分布结果进行比较和评价,评比结果显示考虑铝合金流变应力特性的直接耦合数值模拟结果具有更好的准确度,能够准确模拟出铝合金板材内部最终淬火残余应力在厚度方向上(表面至中层)的非单调分布规律. 相似文献
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7075铝合金板预拉伸工艺研究 总被引:1,自引:0,他引:1
采用直接热力耦合的方法,引入7075铝合金高温下的流变应力特征曲线,对不同厚度的7075铝合金板材在实际淬火工艺下的淬火过程进行数值模拟,揭示铝合金板材淬火残余应力分布规律;考虑铝合金板材拉伸过程中的实际夹持方式,对不同厚度7075铝合金板材实际拉伸过程进行数值模拟,分析对比拉伸后残余应力分布规律,并对拉伸工艺进行优化,确定最佳拉伸率和锯切量,揭示厚度变化对淬火残余应力、拉伸后残余应力以及锯切量的影响规律.利用钻孔法对实际拉伸的7075铝合金板材进行拉伸后残余应力的试验测试,数值模拟结果与试验测试结果相吻合.研究结果表明,随着厚度的增加,淬火残余应力、最佳拉伸率以及锯切量都相应增大,锯切量中过渡区长度为板材厚度的60%~70%. 相似文献
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RV减速器的核心零件为摆线轮,摆线轮的加工也是RV减速器制造的难点.通过分析RV减速器传动中摆线针齿的传动形式对摆线轮的性能要求,确定制造摆线轮的材料为GCr15,并对摆线轮的加工工艺进行了设计.为确定摆线轮加工时的磨削余量,运用ANSYS对摆线轮的淬火工艺进行仿真分析,得到其应力场分布规律和变形情况.经实验并测量实际淬火后零件的变形情况,验证了仿真结果的可靠性.为减小热处理后摆线轮的翘曲变形,设计了摆线轮回火夹具,对摆线轮的生产加工有一定的指导意义. 相似文献
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本文首先阐述了航空薄壁构件加工变形主要成因和控制措施,根据航空薄壁构件异构特点和诸多实际生产经验进一步总结薄壁构件切削加工难点,概述此类零件加工变形控制方法;其次从铝合金材料出厂的初始应力状态展开研究,对制备预拉伸铝合金板材过程中所形成残余应力的变化过程进行研究。基于弹塑性理论,搭建初始残余应力释放过程中的有限元模型。通过剥层测量实验,分析获取其基材内部残余应力的分布情况用以验证所建立有限元模型的正确性。 相似文献
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毛坯残余应力对薄壁件整体加工变形有重要影响。利用大型通用有限元软件ANSYS10.0对钛合金TC4进行退火过程数值模拟研究,通过数值模拟获得了退火过程中温度的变化、残余应力的分布及最终冷却后的残余应力状态。为研究TC4的加工变形规律,提供了具有初始残余应力场的数字化毛坯。 相似文献
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残余应力对航空整体结构件加工变形的影响分析 总被引:9,自引:0,他引:9
基于理论计算和有限元模拟,研究了毛坯的初始残余应力对大型整体结构件数控加工变形的影响,对单向 应力作用的矩形截面梁在剥层过程中的变形挠度值进行了求解。结果表明,理论解与有限元计算值是一致的。面 向工程应用,采用ABAQUS有限元软件模拟了残余应力对隔框类整体结构件加工变形的影响,并进行了试验验证。 有限元仿真结果与试验数值非常吻合。最后,根据工件加工变形的有限元模拟结果,提出了提高整体结构件制造 精度的工艺措施。 相似文献
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Zheng Zhang Liang Li Yinfei Yang Ning He Wei Zhao 《The International Journal of Advanced Manufacturing Technology》2014,73(9-12):1765-1773
The distortion of machined parts is a major concern in the manufacture of aeronautical monolithic structures. We investigated the influence of material removal partition on residual stress in high-strength aluminum alloy parts to minimize machining distortion. In the present study, a methodology of minimizing machining distortion based on an accurate cross-sectional residual stress determination is presented, which can be applied to avoid or minimize part distortions in advance by adapting machining strategies or process conditions. A powerful contour method was used first to measure bulk residual stress within the blank. Next, a finite element model was applied to predict machining distortion based on measured residual stress for analyzing part distortion. Finally, experimental verification was provided by comparing measured distortion and predicted distortion by the finite element analysis. This simulation showed that part distortion is mainly affected by the partition of material removal in T-shaped components. Our results also indicate that distortion can be minimized by optimizing the partition of material removal to ensure a symmetrical distribution of residual stress in the part so that the residual stress-induced bending moment could reach self equilibrium. 相似文献
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Xiaohui Jiang Beizhi Li Jianguo Yang Xiao Yan Zuo 《The International Journal of Advanced Manufacturing Technology》2013,68(1-4):175-186
Residual stress has a sustained impact on the deformation of thin-walled parts after processing, raising the strict restrictions required in their using procedure. In general, with regard to thin-walled parts, different processing parameters will affect the distortion and residual stress generation of the workpiece, which play the key role in the machining. However, controlling the material removal rate is also quite critical to machining of thin-walled parts. In order to reach these goals, based on the relation between residual stress and uncut chip thickness (UCT), a method is proposed by optimizing the milling tool diameters. The research finding reveals that, by improving the tool diameter, at the same circular position, smaller UCT can be achieved. In addition, take 6 and 12 mm tool diameter as analysis cases; larger tool diameter can reduce the residual tensile stress distribution significantly (the ratio ranges from 13.9 to 34.7 %) and improve the material removal rate. Moreover, a typical thin-walled part is evaluated using different tool diameters (6 and 12 mm) by experiments, as the final distortion can be decreased by 60 % with 12-mm tool diameter. The distribution of machined surface and subsurface residual stress is turning to be more uniform. Hence, it proves that, under the goals of maintaining machining accuracy and material removal rate, also improving the distribution of residual stress, it is possible to achieve by controlling the UCT (tool diameters) in the processing of thin-walled. All these findings can help to enhance the milling precision of thin-walled parts, as well as control and optimize the residual stress distribution. 相似文献
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Yu Wei X. W. Wang 《The International Journal of Advanced Manufacturing Technology》2007,33(3-4):260-265
Aerospace thin-walled parts have a complex structure and high accuracy. Factors such as original residual stress, fixing,
and machining may make low-rigidity parts deform easily, which is difficult for traditional craftwork to forecast and control.
Especially in machining big aerospace parts, original residual stress has a great effect on machining deflection. In this
paper finite element model of original residual stress is established to analyze the corresponding deflection by machining
aerospace thin-walled parts. Simulation results are validated consistent with experimental results approximately. At last
the paper puts forward the corresponding mend methods to control the deflection caused by original residual stress during
the actual machining process. 相似文献
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X. Cerutti K. Mocellin 《The International Journal of Advanced Manufacturing Technology》2016,82(1-4):489-499
The manufacturing of aluminium alloy structural aerospace parts involves multiple steps, the principal ones being the forming (rolling, forging etc.), the heat treatments and the machining. During this last step, the final geometry of the part is obtained. Before machining, the workpiece has therefore undergone several manufacturing steps resulting in unequal plastic deformation and metallurgical changes which are both sources of residual stresses. On large and complex aluminium alloy aeronautical parts, up to 90 % of the initial workpiece volume can be removed by machining. During machining, the mechanical equilibrium of the part is in constant evolution due to the redistribution of the initial residual stresses.The residual stress redistribution is the main cause of workpiece deflections during machining as well as of post-machining distortion (after unclamping). Both can lead to the non-conformity of the part with the geometrical and dimensional tolerance specifications and therefore to a rejection of the part or to additional conforming steps. In order to improve the machining accuracy and the robustness of the process, the effect of the residual stresses has to be considered for the definition of the machining process plan. In this paper, a specific numerical tool [2] allowing to predict workpiece deflections during machining and post-machining distortion is used to study the influence of the machining sequence on the machining quality in taking into consideration the initial residual stresses. A first machining process plan defined as the reference case is simulated. Simulation results are then compared with experimental ones showing the feasibility to use the developed tool to predict the machining quality depending on the initial residual stresses, the fixture layout and the machining sequence. Using the computational tool, a method to optimise the machining quality depending on the initial workpiece and on the machining sequence is presented. A machining process plan allowing to respect the tolerance specifications is then defined. This demonstrates the feasibility to adapt and to optimise the machining process plan to ensure conformity of the part with the tolerance specifications. 相似文献