Advanced Joining Technologies for Automotive Lightweight Structures: Self-piercing Riveting (SPR)
Sponsored by: ACerS Manufacturing Division, TMS Aluminum Committee
Program Organizers: Yan Huang, Brunel University London; Carla Barbatti, Constellium; Yingchun Chen, Dura Automotive Systems
Tuesday 8:00 AM
October 11, 2022
Room: 317
Location: David L. Lawrence Convention Center
Session Chair: Carla Barbatti, Constellium; Yan Huang, Brunel University London
8:00 AM Introductory Comments
8:05 AM Keynote
Self-Pierce Riveting of Aluminium and Mixed Material Car Body Structures: Paul Briskham1; 1Atlas Copco IAS Ltd
Car designers must achieve high levels of crash safety performance while also minimising weight to reduce the amount of energy consumed by driving. To achieve these contradictory goals the latest car body designs are using aluminium closures, aluminium bodysides, large aluminium die castings, hot formed high strength aluminium alloys, dual phase high strength steels, and hot stamped press hardened steels. There is also a desire for using narrower flanges to improve driver visibility by reducing pillar sizes plus reduce the amount of material required to gain cost and weight savings. These trends are driving advances in mechanical fastening technologies. This presentation will give an overview of the latest developments in Self-Pierce Riveting technologies, showing some examples of how the latest rivet technologies are being utilised by car designers to achieve their design goals.
8:45 AM Keynote
Development of Solid-state Resistance Spot Joining Method: Hidetoshi Fujii1; 1Osaka University
We have developed a new joining method, which allows carbon steel to be welded in a solid state. The electorde consists of a central pressure rod made of tungsten carbide, which is responsible only for applying pressure, and a cylindrical electrode made of a copper-chromium alloy, which is responsible only for energizing the electrode. The center presser rod was pressurized by an AC servo press. The cylindrical copper electrode is controlled separately from the central pressure rod. The welding temperature can be controlled by the applied pressure given by the central pressure rod. The sound S45C joints were successfully welded below the A1 point (723 degC) without martensitic transformation. A high strength steel such as HT1180 or dissimilar materials are also welded within 1s. We succeeded in obtaining high-strength joints that achieves plug failure at the base metal for all combinations.
9:05 AM
Investigation into the Effect of Interlock Area on the Strength of Self-Pierce Rivets: Lewis Jepps1; Paul Briskham2; 1University of Sheffield; 2Atlas Copco
Different Self-Pierce Rivets can be combined with different dies to cover a wide range of joint stacks. Often, there are a number of combinations that work for each joint stack meaning the optimal joint can be found by comparing cross-section parameters. Currently the parameters used are the interlock in the vertical and horizontal direction. This XY measurement does not accurately assess the amount of material above the flared rivet tip that needs to be defeated to pull out the rivet. In this study we showcase a new measurement approach where the area of the material above the rivet tip is measured to more accurately predict joint performance. An investigation of the relationship between the size of the ‘arealock’ and the strength of the joint in cross tension has indicated it is possible to predict both the strength and the energy absorbed at failure within 10% error
9:25 AM
Influence of Process Parameters on Joint Formation and Load-bearing Capacity for a Versatile Self-piercing Riveting Process: Fabian Kappe1; Mathias Bobbert1; Gerson Meschut1; 1Paderborn University
In multi-material design, materials with different properties are combined to adapt a structure to the application of force and thus reduce weight to achieve the climate targets. However, the increasing number of materials used and the number of resulting joints has led to the development of a various number of joining processes, which are strongly bound to their intended use and have therefore difficulties reacting to changed boundary conditions. Therefore, new, versatile joining technologies are required. The versatile self-piercing riveting (V-SPR) process represents one possible approach. Here, multi-range capable rivets are used which can be adapted to the thickness of the joint by a joining system with extended actuator technology. In this study, the joining process is analysed according to the material flow during joint formation and the influence of the process parameters on the joints characteristics as well as the load-bearing capacity.
9:45 AM
Effect of Processing Parameters on the Mechanical Performance of High Velocity Riveted (HVR) Joints through Finite Element Modeling: Daniel Ramirez Tamayo1; Lei Li1; Benjamin Schuessler1; Vineet Joshi1; Ayoub Soulami1; 1Pacific Northwest National Laboratories
Strong and reliable joining of AA 6061-T6 plates was achieved via HVR. By using a powder-actuated system, a metallurgical bond was created between the plates upon subsequent impact with the rivet. The lap shear strengths of HVR joints outperformed about 50% when compared to those of adhesively bonded plates.In this work, a 3D finite element (FE) model was developed to gain a full understanding of the HVR process, such as heat generation, plastic deformation, and joint integrity. A lap shear simulation following the HVR modeling will be carried out to correlate HVR joint performance with the processing parameters. Once the FE model was validated against experimental observations, the effects of varying the rivet material, rivet shape, and die design on the HVR joint will be analyzed through a parametric study. This will guide the experiment with an appropriate selection of process parameters to achieve better HVR joint qualities.
10:05 AM Break
10:25 AM
Solid Phase Joining of AA6061-T6 Joints via High Velocity Riveting: Benjamin Schuessler1; Daniel Ramirez Tamayo1; Sridhar Niverty1; Lei Li1; Ayoub Soulami1; Vineet Joshi1; 1Pacific Northwest National Laboratory
AA6061-T6 plates were joined together via a high velocity riveting technique with an aluminum alloy rivet at room temperature. Utilizing a powder actuated system to accelerate a striker, a metallurgical joint was formed at the interface of the plates upon impact. The dynamic behavior of aluminum at high strain rates coupled with high temperatures and pressures experienced at the bond interface produced a microstructure of recrystallized grains and sizes in the sub-micron scale and was characterized using transmission electron microscope. Interfaces were also imaged using x-ray tomography which showed a continuous weld throughout the circumference of the joint. This new riveting technique produced favorable lap shear performance compared to flow-drill screw or clinch riveted joints of comparable material combinations. By creating a joint using aluminum rivets, the recyclability challenges are addressed and create a pathway for energy conscious manufacturing pipelines that promote energy reductions for the automotive and aerospace industries.