Identification of CFRP Surface Condition prior to bonding: Focusing on device-specific contact angle discrepancies
Mews, Franziska (2023)
2023
Master's Programme in Materials Science and Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Hyväksymispäivämäärä
2023-06-26
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202306226896
https://urn.fi/URN:NBN:fi:tuni-202306226896
Tiivistelmä
This work investigates discrepancies between the measurement results of different contact angle meters. Contact angle measurements are a surface inspection method. The surface condition is critical to form an adhesive bond. The focus is on two handheld devices and their measurement results on carbon fibre reinforced plastic (CFRP) structures. The discrepancies between the measurement results are investigated. Furthermore, the reliability of such measurements is analysed.
Contact angle measurements were performed by two devices over the surface of one CFRP sample plates with two different surface treatments. Discrepancies of determined contact angle values were identified. Experiments indicated that the discrepancies derive from the dispensing process. Furthermore, measurements of both devices indicate local variations of contact angle values over the sample surface. To evaluate the correlation between measurement results of the two devices their neighbouring measurements were compared. This comparison was conducted perpendicular to and in the fibre direction of the sample surface. No dependence on the contact angle range was identified.
The reliability of the contact angle measurements on CFRP structures with the handheld devices was investigated. The determined contact angle values obtained on CFRP plates were used to obtain the repeatability limit. As the calculation of the repeatability limit is based on a data set being normal distributed, the distribution of the measurement results was compared with a normal distribution. Disturbances of the obtained results from a normal distribution were observed.
Contact angle measurements were performed by two devices over the surface of one CFRP sample plates with two different surface treatments. Discrepancies of determined contact angle values were identified. Experiments indicated that the discrepancies derive from the dispensing process. Furthermore, measurements of both devices indicate local variations of contact angle values over the sample surface. To evaluate the correlation between measurement results of the two devices their neighbouring measurements were compared. This comparison was conducted perpendicular to and in the fibre direction of the sample surface. No dependence on the contact angle range was identified.
The reliability of the contact angle measurements on CFRP structures with the handheld devices was investigated. The determined contact angle values obtained on CFRP plates were used to obtain the repeatability limit. As the calculation of the repeatability limit is based on a data set being normal distributed, the distribution of the measurement results was compared with a normal distribution. Disturbances of the obtained results from a normal distribution were observed.