An energy method to analyze through thickness thin film fracture during indentation

Morasch, K. R.; Bahr, David F.

doi:10.1016/j.tsf.2006.01.043

Cited by 16 publications

(2 citation statements)

References 29 publications

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“…For very thin films, there was still a shrinkage in volume on crystallization, but much of this volume change could, at least in part, be accommodated by a reduction in the thickness of the melt 8. In addition, very thin films of a polymer have outstanding toughnesses,14–16 which could have also resulted in crack resistance in PTT spherulites.…”

Section: Resultsmentioning

confidence: 99%

Cracking in poly(trimethylene terephthalate) spherulites

Yao

Yang

2008

J of Applied Polymer Sci

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The crack behavior of poly(trimethylene terephthalate) spherulites was studied mainly by polarizing optical microscopy, along with scanning electron microscopy (SEM) and atomic force microscopy (AFM). In addition to the effects of temperature and constraining substrate, another important factor, film thickness, on the formation of crack was first put forward and investigated. The emergence of the first crack occurred at 120 C during cooling after crystallization at 190 C for the sample with a thickness of 31.0 lm. For the spherulites growing between glass sheets, it was interesting that the sample with a thickness of 26.0 lm exhibited the largest number of cracks measured per 200 lm of radius, whereas samples thicker than 100 lm or thinner than 1 lm did not induce the formation of crack. Also, spherulites growing between two polyimide and two Teflon sheets showed no crack. Glass sheets lubricated with silicon oil restrained the number of cracks but did not eliminate cracks. SEM revealed that the cracking was about 900 nm in width. In addition, the AFM results suggest that the cracks had a depth of at least 150 nm. V

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Section: Resultsmentioning

confidence: 99%

Cracking in poly(trimethylene terephthalate) spherulites

Yao

Yang

2008

J of Applied Polymer Sci

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“…We finally present numerical simulations indentation experiments of thin films, a truly two-dimensional problem of significant importance commonly used as testing methodology to measure different physical properties of thin films (Lawn, 1998;Mesarovic and Fleck, 1999;Morasch and Bahr, 2007). We considered a two-dimensional domain Ω ¼ ð−0:5; 0:5Þ 2 discretized by a structured mesh consisting of 1500 Â 1500 nodes (δx ¼ 0:0025) with regularization parameter η ¼ 5δx ¼ 0:005.…”

Section: Indentation Of Thin Filmsmentioning

confidence: 99%