Prediction of mechanical fatigue caused by multiple random excitations

A simulation method is presented for the fatigue analysis of automotive and other products that are subjected to multiple random excitations. The method is denoted as frequency domain stress-life fatigue analysis and was implemented in the automotive industry at DAF Trucks N.V. in Eindhoven, The Netherlands. As an example case, a chassis part is analysed. The results of the analysis are consistent with fatigue cracks encountered during testing, which illustrates the effectiveness of the adopted method in the automotive industry

Development of a Damage Quantification Model for Composite Skin-Stiffener Structures

The development of a model-based approach for a damage severity assessment applied on a complex composite skin structure with stiffeners is presented in this paper. Earlier investigations on composite structures with stiffeners revealed that a vibration based structural health monitoring approach, employing the Modal Strain Energy Damage Index (MSE-DI) algorithm can detect and localise delaminations. The next step, performed in the presented part of the research, is to assess the severity of the damage. It is shown that combining results from a fre-quency based analysis and from a modal strain energy based analysis can enhance the quantifica-tion of the severity estimation. This conclusion was drawn by analysing the effect of small masses that were added at a specific location in to mimic a damage, but maintain reversibility of the dam-age. The use of a numerical model to create a virtual test space was found to be valuable for the interpretation of experimental dat

A Decision Support System for Ship Maintenance Capacity Planning

In this paper, the basic framework and algorithms of a decision support system are discussed, which enhance process and capacity planning at a large repair shop. The research is strongly motivated by experiences in a project carried out at a dockyard, which performs repair, overhaul and modification programs for various classes of navy ships. We outline the basic requirements placed upon order acceptance, process planning and capacity scheduling for large maintenance projects. In subsequent sections a number of procedures and algorithms to deal with these requirements, in particular a procedure for workload-based capacity planning, a database system to support process planning are developed, as well as a resource-constrained project scheduling system to support work planning at a more detailed level. The system has been designed to support decision making at the Navy Dockyard in particular, however, we believe that, due to its generic structure, it is applicable to a wide range of project-based manufacturing and maintenance environments