殘餘應力

殘餘應力是指固體材料在產生應力的主要來源去除之後,材料中仍存在的應力。殘餘應力可能是希望出現的特性,也可能是不希望出現的特性。例如就可以在金屬材料(如發動機風扇葉片)加入很深,且對應用有益的壓縮應力,也用在強化玻璃上,可以做為智能手机的玻璃顯示幕,又大又薄,且有抗裂和抗劃傷等性質。不過在結構中不希望出現的殘餘應力可能會使結構提早失效。

產生殘餘應力的機制有許多種,包括非彈性(塑性)變形、(溫度循環下的)溫度梯度或是結構變化(相變)。像焊接產生的熱會造成局部的膨脹,可能是因為熔化的焊料,或是被焊接的工件。當焊件冷卻後,有些部份可能會比其他部份冷卻的更快,就會造成殘餘應力。像半导体器件制造及微机电系统也可能會造成殘餘應力,不同熱力質特性和結晶特性的薄膜材料在不同的製程條件下沈積時,就可能會有殘餘應力。薄膜材料堆疊的應力變化非常複雜,可能有些層是壓縮應力,有些層就變成伸張應力。

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參考資料
延伸閱讀

  • Hosford, William F. 2005. "Residual Stresses." In Mechanical Behavior of Materials, 308–321. Cambridge University Press.
  • Cary, Howard B. and Scott C. Helzer (2005). Modern Welding Technology. Upper Saddle River, 新泽西州: Pearson Education. .
  • Schajer, Gary S. 2013. Practical Residual Stress Measurement Methods. Wiley.
  • Kehl, J.-H., Drafz, R., Pape, F. and Poll, G. 2016. Simulative investigations of the influence of surface indentations on residual stresses on inner raceways for roller element bearings, International Conference on Residual Stresses 2016 (Sydney), [http://www.mrforum.com/wp-content/uploads/open_access/9781945291173/69.pdf DOI: 10.21741/9781945291173-69]

外部連結

  • [http://www.minetek.donetsk.ua/ Energy-saving technology and computerized equipment for vibration stabilization of residual stress (the only CIS 35-year-old Scientific School, who presented in 1988, the world's first installation of computer diagnostics) are intended to stabilize the residual stresses in welds, castings and other non-rigid dynamic metal]
  • [http://www.msm.cam.ac.uk/phase-trans/residual.html Comprehensive resources on Residual stresses at Cambridge University]

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