排序方式: 共有19条查询结果,搜索用时 31 毫秒
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考虑混合H2/H∞控制问题的降阶控制器的设计问题.基于线性矩阵不等式(LMI),分别‘给出了连续和离散情形下混合H2/H∞问题的降阶控制器的设计. 相似文献
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辊弯成形因其高效、节能、节材等特点在许多领域得到广泛应用,而辊弯成形机机构和尺寸设计的合理性对成本和成形精度都有重要影响。将定截面辊弯成形机的模型等效简化,导入到ABAQUS软件中进行板料成形过程的有限元仿真分析,得到与实际生产接近的工作状态下的成形机受力情况,进而对成形机机架中承载的重要零件进行校核分析,并对设计方案的可行性和板料的成形缺陷进行研究。结果表明:数值模拟能为上轴的弹性变形研究和轴承等重要零件的选取提供合理的依据;用螺钉代替调整螺杆承载的方案是可行的;辊弯成形1200 MPa级超高强钢板料时的回弹和纵向弯曲较为明显,需加入过弯和矫正。 相似文献
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基于ABAQUS有限元软件,采用完全耦合热应力分析法,建立了高强度钢的局部加热辊弯有限元模型,并在模型中添加相应的热传导、热对流和热辐射边界条件.通过分析相应的温度、应力与应变场的分布,发现辊弯变形区为主要高温区,此区域的散热量和生热量基本相等.其等效应变主要发生在弯角变形区,逐渐靠近弯角变形区部位的塑性应变逐渐明显并且不断变大,弯角中心的应变最大. 相似文献
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An original plastic equivalent model was proposed to solve the problem of excessive FEM simulation time when designing the press bend forming path and optimizing the process parameters of press bend forming of the integrally stiffened aircraft panels. Based on the in-depth analysis of the mechanics of the bending and springback of the detailed model and the equivalent model of the integral panels, the plastic equivalent model of the virtual material with special initial yield stress and hardening coefficients was constructed. FEM results indicate that the objective of getting the similar contour with the same press bend forming path is achieved with the error less than 6%, and the efficiency of FEM simulation is improved by more than 80%. The plastic equivalent model is valuable and essential for the further research on the press bend forming process of large scale complicated integral panels. 相似文献
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为了探究TA2纯钛板的成形极限,通过电化学腐蚀方法印制网格,在室温下使用BCS-50AR板材试验机分别对厚度为0.5和0.8 mm的TA2纯钛板进行了Nakizima胀形试验。通过网格分析系统采集网格的畸变,获得材料的主、次应变,并绘制了TA2纯钛板在室温下的成形极限图。根据单位体积塑性功相等的原理改进了Hill48屈服准则,并求出了TA2纯钛板对应的各向异性系数。将M-K失稳准则和改进的Hill48屈服准则相结合,对TA2纯钛板的成形极限进行了理论预测,理论预测结果与试验结果基本吻合,但整体略低于试验结果。所做研究对于今后板料成形极限的研究提供了重要的研究方法,并且对实际生产具有着重要的工程应用价值。 相似文献
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In order to design the press bend forming path of aircraft integral panels,a novel optimization method was proposed, which integrates FEM equivalent model based on previous study,the artificial neural network response surface,and the genetic algorithm.First,a multi-step press bend forming FEM equivalent model was established,with which the FEM experiments designed with Taguchi method were performed.Then,the BP neural network response surface was developed with the sample data from the FEM experiments.Furthe... 相似文献