scholarly journals Parametric Analysis of the Sensitivity of a Prestressed Concrete Beam Using the DOE Simulation Technique

2019 ◽  
Vol 65 (4) ◽  
pp. 97-112
Author(s):  
Sz. Woliński ◽  
T. Pytlowany

AbstractThe paper presents the method of simplified parametric analysis of the sensitivity of a pre-tensioned concrete beam. The presented approach is based on the DOE (design of experiments) data collection which is simulation technique allowing for identification of variables deciding about the effectiveness and costs of designed structures. Additionally, application of the hyper-surface of the construction response allows designers to the development of multi-dimensional trade-off graphs to facilitate, the assessment of the scope of changes in random state variables permitted due to the adequate criteria and selection of their values close to optimum. Design basics, procedures and results of the presented considerations of sensitivity assessment and reliability of the structure has been shown on the example of a pre-stressed concrete beam designed in accordance with the requirements and procedures of Eurocode 2

Author(s):  
Ebrahim Hosseini ◽  
Shafiqur Rehman ◽  
Ashkan Alimoradi

Turn-milling is a hybrid machining process which used benefits of interrupted cutting for proceeding of round bars. However, number of controllable parameters in the hybrid process is numerous that makes optimizing the process complicated. In the present study, an optimization work has been proposed to investigate the trade-off between production rate and cutting force in roughing regime as well surface roughness and tensile residual stress in finishing regime. Number of 43 experiments based on response surface methodology was designed and carried out to gather required data for development of quadratic empirical models. Then, the adequacy and importance of process factors were analyzed using analysis of variances. Finally, desirability function was used to optimize the process in rough and finish machining regimes. The obtained results showed that selection of eccentricity and cutter speed at their maximum working range can effectively enhance the quality characteristics in both the roughing and finishing regimes.


Transport ◽  
2012 ◽  
Vol 27 (3) ◽  
pp. 250-262 ◽  
Author(s):  
Johan Woxenius

The trade-off between flexibility and specialisation implies delicate tasks for transport system designers and marketing managers. The outcome of their efforts ranges from highly specialised solutions for a restricted number of users and types of cargoes to very open systems for common use adapted to accommodate a wide variety of transport demands. The purpose of this article is to adapt theories on openness and trade-offs, characterise a selection of flexible and specialised European short sea shipping concepts and analyse how substantial changes in the future character of the competition with road and rail can affect the development of ro-ro shipping in the South Baltic Sea. A matrix with commercial openness and technological openness on the axes is used for categorising sub-segments in the empirical context of the South Baltic Sea. Foreseeable changes in key cost and competition parameters until 2020 are taken into account in discussing potential scenarios. A plausible outcome for the ferry/ro-ro shipping segment is that a branch with slow services for unaccompanied freight will be diverted from the current homogenous market offerings. During the study, the Swedish Orient Line launched a service with these characteristics, which is analysed in a case study.


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