Self-piercing riveting-a review

© The Author(s) 2017. This article is published with open access at Springerlink.com.Self-piercing riveting (SPR) is a cold mechanical joining process used to join two or more sheets of materials by driving a rivet piercing through the top sheet or the top and middle sheets and subsequently lock into the bottom sheet under the guidance of a suitable die. SPR is currently the main joining method for aluminium and mixed-material lightweight automotive structures. SPR was originated half century ago, but it only had significant progress in the last 25 years due to the requirement of joining lightweight materials, such as aluminium alloy structures, aluminium-steel structures and other mixed-material structures, from the automotive industry. Compared with other conventional joining methods, SPR has many advantages including no pre-drilled holes required, no fume, no spark and low noise, no surface treatment required, ability to join multi-layer materials and mixed materials and ability to produce joints with high static and fatigue strengths. In this paper, research investigations that have been conducted on self-piercing riveting will be extensively reviewed. The current state and development of SPR process is reviewed and the influence of the key process parameters on joint quality is discussed. The mechanical properties of SPR joints, the corrosion behaviour of SPR joints, the distortion of SPR joints and the simulation of SPR process and joint performance are reviewed. Developing reliable simulation methods for SPR process and joint performance to reduce the need of physical testing has been identified as one of the main challenges.Peer reviewe

Numeryczne modelowanie kształtowania i obciążania połączeń nitowanych bezotworowo

abstractEN: In this paper authors presented modeling of SPR joint under load. Two commercial codes based on the FEM have been applied: MSC_SuperForm and MSC_Marc-Mentat. The 2D model of the joint formation has been proposed, and after simulation of the joint formation, the shape of it has been developed to 3D model. The stress and strain states have been superimposed on the 3D model and finally loading simulation based on the shear test schedule has been carried out.score:

Bimetallic Micro-Punches for Micro-Blanking Processes

Rapid development of micro-machines, which partly needs metallic micro-parts, is nowadays a fact. A very promising way of micro-parts manufacturing is micro-blanking. For a quite complicated 2D shapes, like micro-gears, dies might be rather easy manufactured by wire-cutting. Production of micro-punches seems to be much more difficult. In this article a solution of manufacturing of micro-punches consisting of two components: punch body based on standard micro-punches and mechanically joined end – bimetallic micro-punch – is proposed. Joining process is based on the extrusion, after which a shaped end must be hardened and finally sharpened. Within this work an experimental stack-up equipped with a special measuring system and unique flexible micro-tools was developed. Simplified processes of bimetallic micro-punch manufacturing was completed as well as FEM analysis

Analiza numeryczna procesu bezotworowego nitowania–SPR

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Verification of numerical modelling of the SPR joint by experimentul stack-up

abstractEN: In recent years self-piercing riveting (SPR) technique became one of the most promising, especially in the automotive industry, for joining different materials, mainly because of lack of several limitations traditionally associated with most widely used spot-welding. Self piercing riveted joints also differ significantly from other types of riveted joints such as those used in aircraft structures owing to the manner in which the joint is produced. In self-piercing riveting, a tubular rivet made usually from a high-strength steel alloy is forced through a pair of partially overlapping sheets that are supported by a circular die with an axisymmetric cavity. Although SPR is already applied by the industry with success, there is still lack of precise design criteria to obtain optimal strength of the joint. This fact limits this technology to be used more often. To have optimum strength of any SPR joint type (various materials, sheet thickness etc.) a set of analysis tools are needed. One is widely verified numerical model and other is experimental tolling allow to quickly join any shape. In Department of Metal Forming Warsaw University of Technology there are some projects carried out related with the SPR process. They are two directions specified: traditional (macro) technology and application of SPR in microforming area. After several trails of numerical modeling of both forming and loading different SPR joints the authors specified a general guidelines to carry out numerical simulaton of the SPR with a success. Now, a design of original experimental tools is verified. Both, forming a joint and its strength became aims of FEM simulation as the most promising tool to analyse various aspects of the joint development. The mechanical response of a self-piercing riveted joint is determined by both the residual stresses after the piercing operation and the stress and displacement fields induced by the applied loads. In this paper three-dimensional finite element analysis of riveted joints is performed to evaluate the load  induced local mechanical behavior and response features measured in the laboratory. To consider residual stresses due to piercing two-dimensional analysis of joining process giving information of stress/strain field existing around a joint are performed. First, 2D axisymmetrical FEM model is analysed to obtain SPR joint. Then stress/strain field got from 2D simulation is superimposed on 3D FEM model to analyze strength of a joint by loading in standard test schedule. Finally, experiments on originally designed tool stack up are carried out. The shape of a joint, force flow during joint formation and force flow during loading a jont are compared between FEM simulations and experiments. Numerical simulation of both forming SPR joint and modeling of loading/strength of a joint are performed with commercial software MSC.Marc and MSC.SuperForm based on the FEM. Two sets od dies and thickness of material to be joint were chosen for verification. Finally, comparison of the results of numerical simulations and experimets are presented.score:

Recent development in finite element analysis of self-piercing riveted joints

Self-piercing riveting (SPR) is a high-speed mechanical fastening technique which is suitable for point-joining advanced lightweight sheet materials that are dissimilar, coated, and hard to weld. Major advances have been made in recent years in SPR technique. Latest literature relating to finite element analysis (FEA) of SPR joints is reviewed in this paper. The recent development in FEA of SPR joints are described with particular reference to three major factors that influence the success of SPR technique: SPR process, failure mechanism, and mechanical behavior of SPR joints. The main FE methods used in FEA of SPR joints are discussed and illustrated with brief case studies from the literature. Areas where further useful progress can be made are also identified