Papers by Keyword: Fastening

Abstract: A 3-D solid finite element simulation of sheet forming processes is briefly discussed. Examples of cold or warm deep-drawing and sheet hydro forming are presented. Sheet work-pieces can be assembled to produce complex components by using different techniques: such as welding or mechanical fastening. They must also be simulated in order to evaluate and optimise the quality of the parts; examples of hemming and of self piercing riveting are described. Structural computation allows us to evaluate the strength of a component and especially the strength of the joining. In the future, more precise optimization of the components will be possible by the transfer of data from the previous stages of sheet forming and joining, to the structural computation code. This input data will be firstly the distribution of residual stresses, the evolution of local properties such as elastic limit, damage and anisotropy. An example of structural computation on a system of two sheets assembled by a single rivet is presented.

Abstract: The common joining techniques for Mg sheet and die cast alloys such as riveting, friction-stir welding and adhesive bonding all introduce additional challenges for protection in the joining areas. First of all, the sheet products are prone to high rate of corrosion due to surface contamination. Introduction of iron-rich contaminants can be encountered from the friction-stir welding process. Although powder coating on top of conversion pre-treatments is practical for mitigating corrosion, the lap-shear adhesion of such surfaces can be negatively impacted when the adhesively bonded joints are exposed to a corrosion environment. Anodized surfaces are better in terms of their ability to retain adhesion strength, but their resistance to galvanic corrosion is an issue. Development of galvanically compatible coatings for steel rivets will benefit the adaptation of riveting as a joining technology for magnesium.