P 1006 – Design of low temperature cured adhesive joints in steel-FRP constructions under crash loads
In the light of sustainability and the necessity to save resources, the importance of the development and the production of lightweight products has become a focal point of interest. Many of these concepts are characterized by the term multi-material-design. Weight savings can be achieved by the use of high-strength-steels in combination with FRP, which are distinguished as lightweight materials due to their excellent mechanical properties in relation to their density. To realize multi-material-design the joining technique plays a special role. For steel – FRP compounds low temperature cured adhesive are used.
The failure behavior of an adhesively bonded FRP-hybrid structure is significantly more diverse and more difficult to anticipate than that of a steel-steel compound. Whereas the steel-steel-compound usually fails in form of cohesive failure either of the adhesive layer or the adherend, provided that the adhesive strength between the adhesive and the joining partners is sufficient, FRPs – due to their anisotropic structure – fail in form of fiber fractures, interfiber fractures as well as delaminations.
However, the implementation of the lightweight concept must not affect the customerspecific requirement for security. Especially the crash behavior of steel – FRP compounds has to be considered. The overall aim of this research project was to develop a method for the design of low temperature cured adhesive FRP compounds under crash load. In this context the compound means the combination of FRP and typical metals, corresponding to the low temperature bodyshop, such as KTL coated or painted steel sheets. The focus is on the analysis of the influence of the structural design of FRPs as well as on the construction of the joining zone under crash load. In this way, the total potential of the high-performance materials (steel in combination with FRP) can be fully used.
The results obtained in the research project enable steel manufactures to construct and optimal adhesively bonded steel-FRP compounds under crash load, so that new lightweight constructions can be realized at reduced test costs for steel manufactures and processors.
Only available in german language.
FOSTA – Research Association for Steel Application