Startup Methodology for Production Flow Simulation Projects Assessing Environmental Sustainability

Environmental impact assessments for companies and products are important to increase sales and reduce environmental impact. To support improvements and detailed analyses, researchers have extended the use of simulation of production flows to include sustainability performance indicators. The research cases performed until recently lack standardized methodology and thus have comparability issues and an increase number of common faults. By using a common methodology and gathering best practice, future cases can gain a lot. Especially noted by the authors is that the project startup phase is critical for success. This paper proposes a methodology to support the startup phases of simulation projects with sustainability aspects in production flows. The methodology is developed and applied in an automotive industry study presented in this paper. Using a rigid project startup, such as the proposed methodology, reduces iterations during modeling and data collection and decreases time spent on modeling

Incidence of early posterior shoulder dislocation in brachial plexus birth palsy

<p>Abstract</p> <p>Background</p> <p>Posterior dislocation of the shoulder in brachial plexus birth palsy during the first year of life is rare but the incidence increases with age. The aim was to calculate the incidence of these lesions in children below one year of age.</p> <p>Methods</p> <p>The incidence of brachial plexus birth lesion and occurrence of posterior shoulder dislocation was calculated based on a prospective follow up of all brachial plexus patients at an age below one in Malmö municipality, Sweden, 2000–2005.</p> <p>Results</p> <p>The incidence of brachial plexus birth palsy was 3.8/1000 living infants and year with a corresponding incidence of posterior shoulder dislocation (history, clinical examination and x-ray) during the first year of 0.28/1000 living infants and year, i.e. 7.3% of all brachial plexus birth palsies.</p> <p>Conclusion</p> <p>All children with a brachial plexus birth lesion (incidence 3.8‰) should be screened, above the assessment of neurological recovery, during the first year of life for posterior dislocation of the shoulder (incidence 0.28‰) since such a condition may occur in 7% of children with a brachial plexus birth lesion.</p

Modelling and Simulation of Train-Track Interaction including Wear Prediction

Many problems in railway traffic arise as a result of the dynamic interaction between rolling trains and tracks. The problems include both instantaneous effects due to induced vibrations of track and vehicle, and more long-term processes of a detrimental nature. This thesis deals with the instantaneous dynamics of the train-track system, and its influence on rail corrugation development as a long-term phenomenon. For this purpose, both numerical and experimental studies are made although the emphasis is laid on numerical studies. <p />A numerical method for the simulation of dynamic train-track interaction was devised. The method includes descriptions of the vehicle, track and their coupling. The dynamically coupled moving load problem is treated in the time domain; the method enables a three-dimensional motion of the vehicle traversing a flexible track. The compound formulation forms a basis for studies of trains on tangent tracks and in curves. The proposed train-track interaction model, together with a wear model, constitutes a framework within which the effects of the compound longitudinal, lateral and vertical dynamics on rail corrugation growth can be investigated. For a tangent track model, calibrated to experimental results from full-scale field measurements, numerical simulations indicate that a high corrugation growth rate at certain wavelengths corresponds to some specific vibrational modes of the coupled train-track system. <p />The numerical studies also include issues related to computational efficiency. It is found that a staggered time-stepping approach is advantageous in train-track interaction simulations. For the same reason, model reduction techniques are also employed

Modelling and Simulation of Train-Track Interaction including Wear Prediction

Many problems in railway traffic arise as a result of the dynamic interaction between rolling trains and tracks. The problems include both instantaneous effects due to induced vibrations of track and vehicle, and more long-term processes of a detrimental nature. This thesis deals with the instantaneous dynamics of the train-track system, and its influence on rail corrugation development as a long-term phenomenon. For this purpose, both numerical and experimental studies are made although the emphasis is laid on numerical studies. A numerical method for the simulation of dynamic train-track interaction was devised. The method includes descriptions of the vehicle, track and their coupling. The dynamically coupled moving load problem is treated in the time domain; the method enables a three-dimensional motion of the vehicle traversing a flexible track. The compound formulation forms a basis for studies of trains on tangent tracks and in curves. The proposed train-track interaction model, together with a wear model, constitutes a framework within which the effects of the compound longitudinal, lateral and vertical dynamics on rail corrugation growth can be investigated. For a tangent track model, calibrated to experimental results from full-scale field measurements, numerical simulations indicate that a high corrugation growth rate at certain wavelengths corresponds to some specific vibrational modes of the coupled train-track system. The numerical studies also include issues related to computational efficiency. It is found that a staggered time-stepping approach is advantageous in train-track interaction simulations. For the same reason, model reduction techniques are also employed