No abstract

The rotational self-loosening of bolted joints under cyclic loading is a process, which means a screw rotation against the assembly direction by periodic load cycles. Thus, the preload balance is released and the clamping function is no longer maintained. The effect is well known, but prevention is usually performed experimentally only after occurrence of self-loosening events. The paper gives a systematic presentation of the dimensioning and the possibility to consider self-loosening in the development process. The procedure for self-loosening dimensioning and the influences are demonstrated with safety-relevant multi-bolted connections from the automotive industry. The aim of this paper is to provide a numerical design method with finite element analysis for detecting and understanding of the self-loosening process at bolted joints. Another focus of the work is to investigate the self-loosening behaviour under combined loading with a superposition of translation and rotation. Combined loading can lead to self-loosening even before reaching the limit of self-loosening for transverse loading. The computational results of the numerical simulation (FEA) are compared with experimental investigations.

No abstract

The title of this paper covers two questions: a) Which items have to be considered for ‘Standardized Calculation’? b) Which ‘requirements’ have to be focused in future? The contribution starts with the fundamental approach of bolted joint mechanics, looks to the focus of present design standards and lists the main risks for bolted joints today. From this the future requirements are derived. Examples are given to selected aspects. Conclusions are drawn to overcome the future challenges for bolted joint design with five needs.

Energy Efficiency today is important for engineering design of new technical component systems; almost any design engineer knows about this. But in many cases the (design) engineers do not think about the significant contribution of optimized fastening systems. This paper shows the fundamental influences and gives examples with numeric values. Conclusions with respect to all main steps in life time are drawn which should be considered for future developments of fastening systems in energy efficient products.