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3 个结果
  • 简介:Veryhighcyclefatigue(VHCF)propertiesofalowtemperaturetemperingbearingsteelGCr15withsmoothandhole-defectspecimensarestudiedbyemployingarotarybendingtestmachinewithfrequencyof52.5Hz.Bothsmoothandhole-defectspecimensbreakinVHCFregimewithsomedifferenceinfatiguecrackinitiation.Forsmoothspecimens,afinegranulararea(FGA)isobservednearthegrainboundaryinthefracturesurfaceofthespecimensbrokenafter10~7cycles.ButnoFGAisobservedinthehole-defectspecimensbrokeninVHCFregime,andtheVHCFcrackdoesnotinitiatefromthesmallholeatthesurfaceasitdoesatloworhighcyclefatigueregime.InternalstressisemployedtoexplaintheVHCFbehaviorofthesetwotypesofspecimens.Atlast,anadvanceddislocationmodelbasedonTanakaandMuramodelisproposedtoillustratetheinternalstressprocessandtopredictfatiguecrackinitiationlifewithFGAobservedinthefractureregion.

  • 标签: GCR15轴承钢 光滑试样 标本 缺陷 高周疲劳 疲劳裂纹萌生寿命
  • 简介:Inthisnote,wewillgiveanewproofoftheblow-upcriterionofsmoothsolutionstothe3Dincompressiblemagneto-hydrodynamicequationsbyasimpleapplicationofGagliardo-Nirenberg’sinequality.

  • 标签: 不可压缩 BLOW-UP 光滑解 MHD方程 三维 标准