Bonding, adhesive ultrasonic activation

The adhesive can be used in the form of a film, scrim or a coating preapplied to one or both adherends, or a ribbon applied to one of the adherends. Liquid adhesives are generally unsatisfactory. Viscoelastic adhesives are particularly suitable. Ultrasonic activation usually increases the bond strength and reduces curing time where it can be employed as an alternative to conventional thermal or drying processes. ... 

There are a number of techniques in the field of SHM for analyzing structural integrity of bonded composite joints. Most of the conventional monitoring systems, such as microscopic failme analysis, ultrasonic. X-ray, thermography and eddy current method are off-line techniques [10, 11], i.e., it s not possible to monitor real time during the service life. But for adhesively bonded joints, real time in-situ monitoring is required. SHM techniques which enable the possibility of in-situ monitoring include acoustic emission, carbon nanotubes network, active vibration method and backface strain based technique. 

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