Papers by Julian Vorderbrüggen
Production Engineering
Recent developments in automotive and aircraft industry towards a multi-material design pose chal... more Recent developments in automotive and aircraft industry towards a multi-material design pose challenges for modern joining technologies due to different mechanical properties and material compositions of various materials such as composites and metals. Therefore, mechanical joining technologies like clinching are in the focus of current research activities. For multi-material joints of metals and thermoplastic composites thermally assisted clinching processes with advanced tool concepts are well developed. The material-specific properties of fibre-reinforced thermoplastics have a significant influence on the joining process and the resulting material structure in the joining zone. For this reason, it is important to investigate these influences in detail and to understand the phenomena occurring during the joining process. Additionally, this provides the basis for a validation of a numerical simulation of such joining processes. In this paper, the material structure in a joint resul...
Development of a rivet geometry for solid self-piercing riveting of thermally loaded CFRP-metal joints in automotive construction
Composite Structures
Entwicklung eines Clinchverfahrens für thermoplastische FKV in Mischbauweise
Materials, 2021
Clinching continuous fibre reinforced thermoplastic composites and metals is challenging due to t... more Clinching continuous fibre reinforced thermoplastic composites and metals is challenging due to the low ductility of the composite material. Therefore, a number of novel clinching technologies has been developed specifically for these material combinations. A systematic overview of these advanced clinching methods is given in the present paper. With a focus on process design, three selected clinching methods suitable for different joining tasks are described in detail. The clinching processes including equipment and tools, observed process phenomena and the resultant material structure are compared. Process phenomena during joining are explained in general and compared using computed tomography and micrograph images for each process. In addition the load bearing behaviour and the corresponding failure mechanisms are investigated by means of single-lap shear tests. Finally, the new joining technologies are discussed regarding application relevant criteria.
Applied Sciences, 2020
Joining is a key enabler for a successful application of thermoplastic composites (TPC) in future... more Joining is a key enabler for a successful application of thermoplastic composites (TPC) in future multi-material systems. To use joining technologies, such as resistance welding for composite-metal joints, auxiliary joining elements (weld inserts) can be integrated into the composite and used as an interface. The authors pursue the approach of embedding metal weld inserts in TPC during compression moulding without fibre damage. The technology is based on the concept of moulding holes by a pin and simultaneously placing the weld insert in the moulded hole. Subsequently, the composite component can be joined with metal structures using conventional spot welding guns. For this purpose, two different types of weld inserts were embedded in glass fibre reinforced polypropylene sheets and then welded to steel sheets. A simulation of the welding process determined suitable welding parameters. The quality of the joints was analysed by microsections before and after the welding process. In ad...
AIP Conference Proceedings, 2019
This paper describes the influence of the process temperature and die design on the material stru... more This paper describes the influence of the process temperature and die design on the material structure as well as the load carrying capacity of clinched metal-glass fibre reinforced thermoplastics (GFRP) components. It also discusses approaches for a simulation-based process development to identify an appropriate heating strategy and the associated process parameters. The heat is initiated in a defined area around the joining zone with the aim of a controlled softening of the thermoplastic matrix, which occurs close to the melting temperature, ensuring low-damage fibre displacement during the clinching process. The evaluation of joining-induced fibre damage is carried out with the aid of microscopy analysis.
Composite Structures, 2019
Due to the excellent mechanical properties fiber-reinforced plastics (FRP) are increasingly being... more Due to the excellent mechanical properties fiber-reinforced plastics (FRP) are increasingly being used in technical lightweight products in order to achieve a multimaterial design. Due to different melting temperatures, the use of conventional thermal joining technologies is restricted, and the demand of efficient mechanical and adhesive joining technologies is increasing. Within the scope of this publication, the damage behavior of selfpiercing riveted hybrid joints using carbon fiber reinforced plastics and metals is analyzed and evaluated in detail regarding the requirements of the automotive industry. Subsequently, hybrid joints are subjected to a thermal profile, which is modelled on the cathodic dip coating drying process in the automotive paint shop. It is shown that the oven process induces damage in the CFRP to self-piercing full riveted joints, which is shown in the form of fiber breaks as well as inter-fiber breaks and delamination. Also, with regard to these effects, geometric optimizations of the self-piercing rivet are carried out, which prevent damages occurring during the oven process. A combination of both optimizations, resulting from the joining and the oven process, leads to a material-and requirement-compliant joining technology, which enables the low-damage joining of CFRP with metals along the automotive process chain.
Fügetechnik: Schlüsseltechnologie für ressourceneffiziente Hochleistungsverbundsysteme
Uploads
Papers by Julian Vorderbrüggen