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为了研究聚乙烯材料在不同应变率下的压缩力学性能,通过准静态实验和动态实验获得聚乙烯材料不同应变率下的应力应变曲线,分析发现:聚乙烯的弹性模量和屈服强度随应变率增大而增大,具有明显的黏弹塑性;聚乙烯材料进入塑性阶段,其应力应变曲线在不同应变率下具有相近的变化趋势,即塑性切向模量近似相同。根据聚乙烯材料的压缩力学性能,建立了弹性区、屈服点和塑性区的分段本构模型。该模型的屈服点和塑性段与实验结果吻合较好,由于弹性段采用线弹性模型,与实验结果存在一定偏差,可近似描述材料的弹性行为。 相似文献
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THE GENERALIZED PHASE SPECTRUM METHOD FOR TIME DELAY ESTIMATION 总被引:2,自引:0,他引:2
The concept of the Generalized Phase Spectrum(GPS)TDE is put forward.The variance ofthe GPS TDE is calculated.The relation between the GPS TDE and the GCC TDE is derived.Amultipath signal model is considered.The method of Amplitude Square(AS)weighting for TDE isproposed and the comparison between the AS TDE and the Phase Data(PD)TDE is made in the mul-tipath environment.The results of theoretical calculation and computer simulation experiment showthat the performance of the AS weighting TDE is superior to that of the PD TDE.GPS TDE can effi-ciently utilize single chip FFT processor to simplify the signal processing equipment,mitigate com-putation load and raise estimate speed for TDE. 相似文献
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