Dimensioning of Punctiform Metal-Composite Joints: A Section-Force Related Failure Criterion

Abstract

Reliable line production processes and simulation tools play a central role for the structural integration of thermoplastic composites in advanced lightweight constructions. Provided that material-adapted joining technologies are available, they can be applied in heavy-duty multi-material designs (MMD). A load-adapted approach was implemented into the new fully automatic and faulttolerant thermo mechanical flow drill joining (FDJ) concept. With this method it is possible to manufacture reproducible high strength FRP/metal-joints within short cycle times and without use of extra joining elements for the first time. The analysis of FDJ joints requires a simplified model of the joint to enable efficient numerical simulations. The present work introduces a strategy in modeling a finite-element based analogous-approach for FDJ-joints with glass fiber reinforced polypropylene and high-strength steel. Combined with a newly developed section-force related failure criterion, it is possible to predict the fundamental failure behavior in multi-axial stress states. The functionality of the holistic approach is illustrated by a demonstrator that represents a part of a car body-in-white structure. The comparison of simulated and experimentally determined failure loads proves the applicability for several combined load cases.

Fatigue behaviour of material-adapted fibre-reinforced polymer/metal joints

“…Accordingly, FDJ joints contain, in contrast to established technologies, a process-related reinforcement in the critical areas next to the joint [7]. Further investigations and findings on the FDJ joining concept are described in [8][9][10].…”

Influence of cathodic dip painting on the mechanical strength of material-adapted composite/metal joints

“…After numerous investigations on parameter studies, design rules and material combinations [4][5][6], the novel joining technique has to be qualified for the use in conventional automotive manufacturing processes. Since all car body structures are passing through a conventional automotive process chain, the joining techniques need to be resistant to all temperature loads and chemicals, applied during the production processes, e.g., in vehicle lacquering.…”