共查询到20条相似文献,搜索用时 171 毫秒
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复合射孔器的结构设计与载荷和设计准则密切相关。为了研究在复合射孔过程中爆燃压力与火药装药量的关系,利用LS-DYNA进行了数值模拟,得到不同装药量下爆燃压力大小的P-t曲线,以及射孔枪身的残余变形量。通过静强度、塑性极限和动强度准则计算,对比数值分析的动态载荷结果,提出了射孔枪身结构设计的动态塑性流变设计新方法,为射孔枪的结构设计技术提供了一条新路径。 相似文献
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基于流固耦合完成复合喷管流动换热、传热过程温度场的数值模拟,编写了计算流体力学(CFD)与有限单元法(FEM)的接口程序,快速实现温度载荷和机械载荷数据的传递,提出了复合喷管热结构耦合计算一种新的策略。利用直接约束法考虑了复合喷管部件界面间高温碳化带来的结构边界非线性因素。计算结果表明耦合方法得到的复合喷管温度场是合理的,高温下界面间结构功能退化问题对于变形特征以及应力场影响很显著。 相似文献
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为进一步揭示气体介质中液滴破碎的机理与影响因素,采用LES与VOF相结合的方法对液滴破碎过程进行了数值模拟,计算结果与实验结果符合较好,并且优于前人RANS模拟的计算结果。在此基础上,对多工况液滴破碎进行了LES/VOF模拟,分析计算结果发现,液滴破碎初期,液滴的尾涡效应影响液滴的初始变形位置,在变形过程中,液滴表面压力分布直接影响液滴的破碎状态;另外,在一定初始速度范围内,液滴破碎过程保持一致,但初始速度对液滴变形破碎时间及强度影响明显。 相似文献
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变形破碎特性对SLD结冰过程影响 总被引:2,自引:1,他引:1
基于结冰过程数值模拟,针对过冷大水滴(SLD)条件下的变形破碎特性及其对成冰过程影响进行了研究。利用动态阻力计算模型,分析了水滴变形对水滴运动轨迹影响,采用基于泰勒类比理论的计算模型,研究了水滴破碎过程、子液滴粒径分布特性等。完成了NACA 0012翼型典型SLD结冰算例的数值分析,与参考文献计算结果和实验数据进行对比。结果表明:对于SLD结冰,变形和破碎主要改变了水滴运动轨迹和表面撞击水分布,使水滴撞击极限变小,在加入变形破碎特性的计算模型后,可以较好预测结冰极限位置和冰形轮廓,说明该方法对SLD变形破碎效应及其影响的模拟是可行和正确的。 相似文献
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通过杯杯型轴对称复合挤压两种宏观缺陷并存的上限分析表达式,研究了该变形方式下两种宏观缺陷并存区域与正挤部分、反挤部分变形程度和坯料相对余厚的关系。本文的模型及结论被实验结果所证实。 相似文献
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《中国航空学报》2020,33(12):3495-3508
Deformation resulting from residual stress has been a significant issue in machining. As allowance allocation can directly impact the residual stress on part deformation, it is essential for deformation control. However, it is difficult to adjust allowance allocation by traditional simulation methods based on residual stress, as the residual stress cannot be accurately measured or predicted, and many unexpected factors during machining process cannot be simulated accurately. Different from traditional methods, this paper proposes an allowance allocation method based on dynamic approximation via online inspection data for deformation control of structural parts. An Autoregressive Integrated Moving Average (ARIMA) model for dynamic allowance allocation is established so as to approach the minimum deformation, which is based on the in-process deformation inspection data during the alternative machining process of upside and downside. The effectiveness of the method is verified both by simulation cases and real machining experiments of aircraft structural parts, and the results show that part deformation can be significantly reduced. 相似文献
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以复合材料U型构件为研究对象,采用数值模拟的方法对U型件进行热压罐温度场的模拟,模拟出在不同时间段工装和工件的温度分布情况,模拟工件在工装传热和变形影响下的内部传热、固化度、最终变形情况和残余应力水平等。根据模拟结果,优化热压罐固化工艺参数,从而改善固化热变形问题,根据分析结果制定补偿方案并实施验证,同时优化工装结构形式,采用工装型面补偿技术对零件固化变形进行预补偿。结果表明,补偿后零件变形后的外形与理论几何外形相差1.37mm,验证了补偿技术的可行性。工装型面补偿技术可以有效提高复合材料结构件的制造精度。 相似文献
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《中国航空学报》2022,35(8):314-323
Process-induced deformation is an important limiting factor to the application of high performance composite structures. An alternative method to reduce process-induced deformation is proposed by introducing prestress to a single layer or part of the layers instead of all the applicable layers. In this method, the necessary prestress level that applied to the single layer was in the reasonable range. Two kinds of unsymmetric laminates are manufactured at varying prestress levels. The experimental results described that the curing deformation is changed rapidly with the growing prestress level and flipped after a certain prestress level. Moreover, there is a good linear relationship between prestress level and final curing deformation, which gives a convenient way to calculate the prestress level that can fully counteract the curing deformation. The numerical model to predict the curing deformation was built. A good agreement between the numerical and the experimental results shows the effectiveness of the numerical model. To predict the prestress level that can fully counteract the curing deformation, an analytical model is also proposed. Theoretically, the prestress method can fully counteract the curing deformation of the specimens, while the experimental results show that the prestressing layer reduces more than 80% of the curing deformation. 相似文献
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A new grid deformation technology with high quality and robustness based on quaternion 总被引:1,自引:1,他引:0
Quality and robustness of grid deformation is of the most importance in the field of aircraft design, and grid in high quality is essential for improving the precision of numerical simulation. In order to maintain the orthogonality of deformed grid, the displacement of grid points is divided into rotational and translational parts in this paper, and inverse distance weighted interpolation is used to transfer the changing location from boundary grid to the spatial grid. Moreover, the deformation of rotational part is implemented in combination with the exponential space mapping that improves the certainty and stability of quaternion interpolation. Furthermore, the new grid deformation technique named ‘‘layering blend deformation' is built based on the basic quaternion technique, which combines the layering arithmetic with transfinite interpolation(TFI) technique. Then the proposed technique is applied in the movement of airfoil, parametric modeling, and the deformation of complex configuration, in which the robustness of grid quality is tested. The results show that the new method has the capacity to deal with the problems with large deformation, and the ‘‘layering blend deformation' improves the efficiency and quality of the basic quaternion deformation method significantly. 相似文献
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铝合金厚板淬火残余应力的有限元模拟及其对加工变形的影响 总被引:10,自引:1,他引:9
航空整体结构件在加工过程中容易发生较大变形。为了研究毛坯的初始残余应力对整体结构件加工变形的影响,采用准耦合方法,利用有限元软件ABAQUS模拟7075铝合金毛坯的淬火过程,研究该过程中温度的变化和残余应力的分布规律,并在含有淬火残余应力的毛坯上进行材料去除模拟。结果表明,模拟产生的比例件的变形与实际加工的比例件的变形非常近似,从而证明了毛坯的初始残余应力是引起整体结构件加工变形的主要因素,同时验证了准耦合淬火模拟的有效性。 相似文献