B5

Working Group B | Form-closed joint & Force-closed joint

 
 

Mechanical joining of dissimilar materials by shear clinching processes without pre-punching (shear clinching)

Prof. Dr.-Ing. habil. Marion Merklein, Universität Erlangen
Prof. Dr.-Ing. Gerson Meschut, Universität Paderborn

 
 

Abstract:

Due to the increasing environmental awareness, the focus of the manufacturing and the usage of products is on sustainability. The reduction of the emission of pollutants of vehicles demands the consequent use of lightweight strategies. Thus, modern cars are built in a multi-material design. The specific properties in terms of functional performance, process robustness and reliability and resource consumption can be optimised by combining demand-adapted materials. Therefore, the production of reliable joints via joining technologies, which are adequate for the used materials, is required. The different properties of the joining partners are a challenge as often technologies for the joining of similar materials cannot be applied. Mechanical joining technologies, which have been established for the joining of dissimilar materials, are limited by the mechanical properties of the joining partners. For example clinching of ultra-high strength steels like press hardened 22MnB5 is not possible due to their high tensile strength and their low ductility. Shear-clinching, which is investigated by the Laboratory for Material and Joining Technology and the Institute of Manufacturing Technology within the frame of this project, has great potential for the joining of dissimilar materials with high differences regarding their mechanical properties, like aluminium and high strength steels. Different from conventional clinching, the die-sided sheet material is indirectly cut by applying force through the upper joining partner. By the subsequent extrusion of the punch-sided material in the cut out hole, a form and force fitting joint is created.

For a fundamental analysis, the modelling of the process and the numerical investigation of tool- and process-sided parameters was done within the first phase of the project. The numerical model provides the material properties, which are influenced by the cutting and joining process, for the numerical analysis of the joint formation in shear-clinching. This was based on the LFT’s characterization of the aluminium alloy AA6016 T4, which is used as punch-sided material and the steels 22MnB5 in the press hardened condition and HCT780X, which are used on the die-side. Following this, suitable tool technologies for the shear-clinching with a C-frame press and an O-frame press were developed by the LWF and the LFT respectively. While C-frame presses offer the advantage of a good accessibility, O-frame presses have a higher rigidity, which reduces the machine-sided influence on the process. In the next step the influence of various tool- and process-sided parameters and the load capacity of shear-clinched joints were investigated by both institutes. The geometry of the outer punch was identified as crucial for the formation of the joint.

In the second phase of the project, the material flow during the process and the decisive parameters were analysed numerically and approaches for the control of the material flow were shown. After the further development of the tool concepts, the deformation of the machine and the process stability were investigated with the C-frame press at the LWF. Furthermore, different variations were analysed in the O-frame press by the Institute of Manufacturing Technology. Next to the quasi-static analysis of the joint strength of shear-clinched specimen, the failure behaviour for dynamic loads was also investigated by the LWF.

 
 
Focus of the third phase
Focus of the third phase
 
 

After the basic analysis of the process within the first two phases, the investigation of the tool loads during shear-clinching will be investigated by the LFT in the third phase of the project. Therefore, the numerical model, which has been developed in the previous phases, is enhanced by the aspect of the tool loads. Moreover, the wear behaviour of the active tool elements during the running-in phase will be investigated experimentally. This includes the analysis of the influence of the tool wear on the process stability. By this, the design of tools with a high lifetime and low wear will be possible. Within the third phase of the project, the influence of tool- and process-sided parameters on the bending of shear-clinched multi-element specimen will be investigated by the Laboratory for Material and Joining Technology. Within this analysis, the distance between the joints and the joining order will be varied. Moreover, the knowledge, which was gained in the first two phases, will be transferred on a new joining task by the LFT and the LWF by using a new punch-sided material. This includes the numerical prognosis of the joint formation and the validation of the numerical model for the new material combination. With regard of an application of the technology in the automotive industry, the impact of corrosion on the joint strength and approaches for corrosion protection will be investigated by the LWF in order to gain transferable knowledge with regard of the performance.

 
 

Publications:

2018   
  Investigation of the influence of tool-sided parameters on deformation and occurring tool loads in shear-clinching processes Han, D.; Hörhold, R.; Wiesenmayer, S.; Merklein, M.; Meschut, G.:
In: Procedia Manufacturing 15(2018), S. 1346–1353
  Numerical Investigation of the Tool Load in Joining by Forming of Dissimilar Materials Using Shear-Clinching Technology Wiesenmayer, S.; Müller, M.; Dornberger, P.; Han, D.; Hörhold, R.; Meschut, G.; Merklein, M.:
In: Key Engineering Materials 767(2018), S. 397–404
  Shear-Clinching of Multi-Element Specimens of Aluminium Alloy and Ultra-High-Strength Steel Han, D.; Hörhold, R.; Müller, M.; Wiesenmayer, S.; Merklein, M.; Meschut, G.:
Key Engineering Materials 767(2018), S. 389–396
2017   
  Specimen´s Geometry Related Influences on Load-Bearing Capacity of Joining Aluminium and UHSS by Innovative Shear-Clinching Hörhold, R.; Müller, M.; Merklein, M.; Meschut, G.:
In: Journal of Materials Science Research 6(2017)4, published online
2016   
  Mechanical properties of an innovative shear-clinching technology for ultra-high-strength steel and aluminium in lightweight car body structures Hörhold, R.; Müller, M.; Merklein, M.; Meschut, G.:
In: Welding in the World 60(2016)3, S. 613–620
  Fundamental Studies on a Novel Die Concept for Round-Point Shear-Clinching Hörhold, R.; Müller, M.; Merklein, M.; Meschut, G.:
In: AIP Conference Proceedings 1769(2016)100003, S. 1–6
  Numerische Untersuchung des Werkstoffflusses beim Fügen artungleicher Werkstoffe mittels Schneidclinchen Müller, M.; Hörhold, R.; Meschut, G.; Merklein, M.:
In: Brosius, A. (Hrsg.): Tagungsband SFU 2016, 2016, S. 158–165
2015   
  Development of a testing method for the identification of friction coefficients for numerical modeling of the shear-clinching process Müller, M.; Vierzigmann, U.; Hörhold, R.; Meschut, G.; Merklein, M.
In: Key Eng. Mater. 639, 2015, S. 469–476
  FE-based study of the cutting operation within joining by forming of dissimilar materials using shear-clinching technology Müller, M.; Hörhold, R.; Meschut, G.; Merklein, M.
In: Adv. Mater. Res. 794, 2015, S. 304–311
2014   
  Basic Investigations of Non-Pre-Punched Joining by Forming of Aluminium Alloy and High Strength Steel with Shear-Clinching Technology Merklein, M.; Meschut, G.; Müller, M.; Hörhold, R.
In: Key Eng. Mater. 611–612, 2014, S. 1413–1420
  Analysis of material behaviour in experimental and simulative setup of joining by forming of aluminium alloy and high strength steel with shear-clinching technology Müller, M.; Hörhold, R.; Merklein, M.; Meschut, G.
In: Adv. Mater. Res. 966–967, 2014, S. 549–556
  Adaption des Ringstauchversuchs für die Untersuchung der tribologischen Bedingungen beim Fügen warmumgeformter Stähle mittels Schneidclinchen Müller, M.; Vierzigmann, U.; Hörhold, R.; Meschut, G.; Merklein, M.
In: M. Merklein (Hrsg.): 9. Erlanger Workshop Warmblechumformung, Meisenbach, 2014, S. 163–174
  Potenziale und Grenzen der Simulation in der Fertigungstechnik Merklein, M.; Andreas, K.; Gröbel, D.; Hildenbrand, P.; Müller, M.; Noneder, J.; Zimmermann, A.; Schneider, T.; Vierzigmann, U.
In: In: simufact engineering GmbH (Edtr.): Tagungsband 15. RoundTable – Simulating Manufacturing, 2014, S. 1-38
2013   
  Grundlegende Untersuchungen zur Verbindung von pressgehärtetem Stahl und Aluminium mittels Schneidclinchen Merklein, M.; Meschut, G.; Müller, M.; Hörhold, R.
In: A. Brosius (Hrsg.): Tagungsband – 20. Sächsiche Fachtagung Umformtechnik, 2013, S. 63–72
 
 

back to working groups