Transverse ridge cracking in tensile fragmentation tests of thin brittle coatings on polymer substrates

Modelling the effect of temperature on crack onset strain of brittle coatings on polymer substrates

a r t i c l e i n f o The effect of temperature on the crack onset strain (COS) of brittle coatings on polymer substrates was investigated through a series of temperature-controlled tensile tests carried out in situ under an optical microscope. It was observed that the failure of such materials under tensile strain was strongly affected by temperature, but the exact behaviour was heavily depend...

Cracking of brittle coatings adhesively bonded to substrates of unlike modulus

The role of elastic mismatch in determining critical conditions for indentation fracture in brittle coatings on substrates of unlike modulus was investigated. A model transparent trilayer system, consisting of a glass coating layer bonded to a thick substrate of different glass or polymer by a thin layer of epoxy adhesive, facilitated in situ observations of crack initiation and propagation. A ...

the washback effect of discretepoint vs. integrative tests on the retention of content in knowledge tests

در این پایان نامه تاثیر دو نوع تست جزیی نگر و کلی نگر بر به یادسپاری محتوا ارزیابی شده که نتایج نشان دهندهکارایی تستهای کلی نگر بیشتر از سایر آزمونها است

Channel cracking in thin films on substrates of finite thickness

Solutions are presented for the elastic plane-strain problem of a crack in a coating on a compliant substrate of finite thickness. Analysis of the problem shows that substrate thickness has a significant effect on the steady-state energy release rate for channel cracks. This is so over a wide range of elastic mismatch between film and substrate, but is especially important if the substrate is m...

Ultra-thin optical interference coatings on rough and flexible substrates