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

Computed tomography features of liparitosis: a pneumoconiosis due to amorphous silica

n/

Clinical Psychology of Oral Health: The Link Between Teeth and Emotions

The effects of oral health conditions on physical and psychosocial dimensions have been a matter of interest for several authors over the last decades. Nevertheless, literature lacks studies that address the relationship between the oral health–related quality of life (OHRQoL) and emotions. The present study aimed to investigate the psychological impact of oral disorders on people's emotional well-being, with a particular attention to gender and age differences. Two hundred twenty-nine dental patients in care at private dental clinics were individually tested. One hundred thirty of them were females (56.8%) and 99 males (43.2%), aged between 18 and 83 years ( M = 38.11; SD = 16.7). For the evaluation, the Profile of Mood States (POMS) and the Oral Health Impact Profile (OHIP-14) were used. Data were analyzed using Pearson's correlations, the ANOVA, and the Kruskal–Wallis test. OHRQoL showed several correlations with all the emotions explored, overcoming the well-known relationship with anxiety and depression ( p < .05). The degree of OHRQoL produced differences on mood states, which could appear normal, moderately altered, or psychopathological ( p < .03). Furthermore, in different life stages, patients showed specific OHRQoL and emotions

Experimental and numerical investigation on the delamination behaviour of PVD-coated tools in turning of austenitic steel

A fundamental wear cause in turning of austenitic steel with coated tools is the delamination of the coating around the cutting edge and the adjacent contact area. This is due to the strong adhesive effect between material and tool. The coating's adhesion is influenced by several terms, e.g. coating process, substrate pre-treatment, coating system, substrate as well as by micro and macro geometry of the tool. This research work is focused on two fundamental aspects: the influence of the macro geometry on the delamination behaviour of the PVD-coating, and the possibility to use FEM simulation of chip formation as a useful tool for the interpretation of the coating's failure. Several orthogonal cutting tests were performed under dry conditions, varying the rake angle between −15° and + 15°. Simultaneously, a FEM-model for the simulation of the thermal and mechanical loads of the tool was developed. The numerical model was verified by comparing simulation and experiments in terms of cutting forces and chip underside temperature. Experimental and numerical results show that high contact stress in the area of the rake face favours the partial removal of the coating by the sliding chip. According to this, large positive rake angles reduce the tendency towards coating delaminatio