![]() Most studies on SPR concentrated on comparing the mechanical properties of joints manufactured by SPR and RSW techniques. With the growing use of SPR, comes the need to understand the failure mechanisms of SPR joints, however, literature survey on joint performance is lacking. Other advantages and disadvantages of SPR process are reported. To date, SPR is still the first choice in automotive applications when considering the intensive use of aluminium. Heat curing may also affect the properties of the joined materials and induce problems, such as debonding, distortion or even fracture of adhesive due to the differences in thermal expansion coefficients between adhesive and adherends. Some adhesives require heat curing after bonding to reach the required strength, and this may take up to weeks to complete. ![]() Whilst adhesive bonding can join almost all types of materials, even when one of the joining materials is non-metallic, e.g., polymers and composites, careful surface preparation, such as surface cleaning and surface treatment need to be carried out prior to bonding. Friction stir is a more time consuming process (2‒5 s) than RSW (<1 s) and SPR (1‒2 s), and clinching is normally used to join non-load bearing structures, such as trunk lid and engine hoods due to its low joint strength. RSW, on the other hand, is typically used in welding steels than welding other light alloys. This is because hybrid use of different lightweight alloys, such as magnesium with aluminium alloys or aluminium with advanced high strength steel can sometimes be difficult or impossible to weld due to differences in thermal, physical and chemical properties.Ĭompared with other joining techniques such as RSW, friction stir spot welding (FSSW) and its variant “linear” friction stir welding (FSW), clinching and adhesive bonding, SPR has proven to be an effective process to join dissimilar materials, from aluminium with composite to aluminium with advanced high strength steel. The increasing interest in the use of lightweight and high strength ratio materials in vehicle fabrication to reduce the weight of vehicle is due to the urgent need to reduce fuel consumption and greenhouse gas emissions, and hence, is partly the cause of renewed interest in SPR technology. Since then, a significant progression has been the application of SPR technique to both space frame (Audi A2) and monocoque designs (Jaguar). SPR only rose to prominence during the last decades when it was adopted by Audi to join the structural panels in the all-aluminium Audi A8. Although RSW of aluminium is still possible using specially designed electrodes, SPR is still the most preferred option for joining aluminium components. Aluminium can also react and contaminate the copper spot welding tip, reducing the tool life. RSW is not suitable for aluminium joints because aluminium has high thermal conductivity and low melting point the electrical conductivity of aluminium also makes the electrical current requirement for RSW process high. It was first developed as an alternative to the resistance spot welding (RSW) process for joining of aluminium. Self-piercing riveting (SPR) process was originated around half a century ago and it was mainly used by appliance and packaging industry. This paper is divided into three major sections: 1) joint failures focusing on joint defects originated from the SPR process and joint failure modes under different mechanical loading conditions, 2) joint corrosion issues, and 3) joint optimisation via process parameters and advanced techniques. ![]() In this paper, SPR joints of advanced materials and their corresponding failure mechanisms are discussed, aiming to provide the foundation for future improvement of SPR joint quality. However, SPR joining of these advanced light materials remains a challenge as these materials often lack a good combination of high strength and ductility to resist the large plastic deformation induced by the SPR process. The application of SPR in the automotive sector has become increasingly popular mainly due to the growing use of lightweight materials in transportation applications. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |