Ultrasonic welding (USW) technique is currently applied in the packaging industry for consumer goods, but also in automotive, lightweight construction, in medicine and the electric industry. [1] Apart from the advantages of a low energy consumption, short process durations, low temperature, and the absence of additional materials, one of the main potentials is the capability of joining dissimilar materials. Especially the combination of metal and fibre reinforced plastics (FRP) has been subject of numerous studies in the past decades. [2] To design and construct highly efficient ultrasonically welded structures, the correct estimation of their mechanical behaviour is essential. This behaviour significantly depends on the joints’ interface, which can be categorised with respect to the resulting joint strength as depicted in Figure 1a. Considering metal/FRP joints for example, a stronger interlocking of the fibres with the metallic joining partner can be correlated with higher mechanical strength. [3,4]  

Interface sections were transferred into finite element (FE) models and suitable contact conditions were applied to describe the joints’ behaviour on the microscale in correlation with its respective mechanical strength (see Figure 1b) to calculate the stress and strain distribution under load (see Figure 1c). With the help of these microscale models, the mechanical behaviour of various multi-material systems has been successfully simulated under different external loading conditions. These findings further promote the development of models to investigate simplified three-dimensional structures and real components (see Figure 1d).

References

[1] F. Lambiase; F. Balle; L.-A. Blaga; F. Liu; S. Amanico-Filho Composite Structures, 2021, 266

[2] F. Balle; G. Wagner; D. Eifler Mat.-wiss. u. Werkstofftech., 2007, 38, 934-938

[3] M. Liesegang; S. Arweiler; T. Beck; F. Balle JMMP, 2021, 5

[4] F. Staab; M. Liesegang; F. Balle Composite Structures, 2020, 248