In-situ measurement of loading stresses with X-ray diffraction for yield locus determination

The application of the X-ray diffraction method is introduced to solve the problem of inhomogeneous deformation fields in the specimens used for sheet metal characterization. In this method, strains are measured on one side of a specimen with optical measurement systems. On the other side, loading stresses on a specimen are captured with an X-ray diffractometer mounted on a universal testing machine. By this way, the whole stress-strain history of a material point is tracked during testing. The method was first applied to uniaxial tension tests, whereby the applicability of the theory of stress factors and effective X-ray elastic constants were tested. The relaxation behavior of a sheet material which shows itself as stress drops during in-situ experimentation was characterized and compensated by a visco-plastic material model for different stress states. The proposed method was applied to characterize aluminum alloy AA5182 under plane strain tension and shear conditions and the results were compared with the conventionally obtained yield locus. Numerical analyses of a workpiece with the Vegter and Yld2000-2D material models show that the enriched yield locus definition with accurate plane strain tension and shear stresses captures the experimentally obtained surface strains more precisely.     

e-Navigation and situation-dependent manoeuvring assistance to enhance maritime emergency response

Safe ship handling in every situation and under all prevailing circumstances of ship status and the environment is a core element contributing to the safety of the maritime transportation system. Especially in case of emergencies, there is a need for quick, accurate and reliable information to manoeuvre a ship safely. This paper focusses on investigations into enhanced response to maritime emergencies by means of onboard manoeuvring support. The research and discussions are done exemplarily for person overboard (PoB) accidents. PoB is a typical situation for application of manoeuvring assistance and decision support, e.g. in order to return quickly to the position of the accident. Based on the analysis of selected accident case studies and existing solutions representing the technical state-of-the-art, shortcomings will be identified and discussed, and a potential approach for advanced manoeuvring support in the context of e-Navigation-based requirements will be introduced and discussed.     

A Control Authority Transition System for Collision and Accident Avoidance

Summary This paper addresses the problems ensuing with the human being who is controlling the technical system, especially problems related to his skill levels, driving habits, capabilities and decisions (especially when impaired by drugs, fatigue or physical handicaps). It may be possible to improve the ability of a driver to operate a vehicle safely if certain parameters in the control of the vehicle are adjusted according to the driver's normal characteristics. Value has already been established for tailoring certain attributes such as seat, pedals, steering wheel position and mirrors to a given driver through memory functions. This research concentrates on assessing a driver's operating characteristics and modifying the control to improve safe operation of the vehicle on a real-time basis.