ComBoNDT @ the 11th International Workshop on Structural Health Monitoring (IWSHM)

The ComBoNDT project participated in the 11th International Workshop on Structural Health Monitoring (IWSHM) which took place from 12th to 14th of September 2017 at Stanford, California, USA making a presentation entitled "Study of adhesive bonds by mechanical tests, ultrasounds and electro-mechanical impedance method". The presentation deals with adhesive bonding of CFRP plates. Adhesive bonding of composites is considered as good alternative to riveting, provided that good tools are available to assess the bond quality after manufacturing and during the lifetime of structures. The performance of an adhesive bond depends on the physico-chemical properties of the adherent surfaces. A weak bond can be caused by improper surface preparation before bonding. In the research reported herein, modifications of one of the surfaces to bebonded were considered. These modifications are realized using chemical contamination or thermal treatment. The influence of surface modification on bond performance was investigated by electromechanical impedance (EMI) method, ultrasounds and mechanical tests. In the EMI method, a piezoelectric transducer was mounted at the middle of each sample surface. Using an impedance analyzer the electrical parameters were measured for wide frequency band. Due to piezoelectric effect the electrical response of a piezoelectric transducer is related to mechanical response of the sample to which the transducers is attached. The ultrasonic testing (UT) was focused on C-scan analysis taking into consideration the amplitude and time of flight of the signals. Aprobewith 10MHz central frequencywas used, to highlight different effects on the responses. Mode-I and Mode-II fracture toughness tests were conducted aiming to gain knowledge on the influence of surface modification on the bond strength. The performed investigation showed that bond quality is influenced by the bond modifications.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 636494.

This project is endorsed by the European Aeronautics Science Network - EASN.

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