On the General Evaluation of Customer Requirements During Conceptual Design

1999 ◽  
Vol 121 (1) ◽  
pp. 92-97 ◽  
Author(s):  
Y. M. Huang

Customer requirements must be satisfied for a product to succeed in the market. Evaluation of customer requirements plays an important role during the conceptual design phase of various design methodologies. However, since customer requirements are continuously revised during design processes, much effort, time, and money are required. Twenty items are recommended to organize customer requirements and enhance efficiency. The relative importance of these recommended items, without regard to the product, is evaluated by using the pairs comparison method. The weighting factors for all recommended items are then calculated. The relative importance of the items shows that safety, quality, environment and performance are the most important. The relative importance and the weighting factors of the items from this study suggest that their use in the process during preliminary or lead time conceptual design of various design methods can assist with cost and time reductions.

2016 ◽  
Vol 826 ◽  
pp. 40-44 ◽  
Author(s):  
Fei Cao ◽  
Ming Chen ◽  
Mei Li Wen Wu

The purpose of this paper is to study the conceptual design and optimization of a compound coaxial helicopter. At the conceptual design phase, the compound coaxial helicopter design work was based on the conventional helicopter and fix-wing aircraft design method. The intersection of these aspects makes the design work more complex, thus, a program for the sizing and performance optimization was developed for the aircraft. The program included the total weight design, aerodynamic analysis, flight dynamics analysis, performance calculation and particle swarm optimization analysis. Under the restricted condition of the flight performance requirements, optimize the design parameters which make the weight efficiency factor decrease. Therefore, the study of optimum design process was warranted.


Author(s):  
Daniel Krus ◽  
Katie Grantham Lough

When designing a product, the earlier the potential risks can be identified, the more costs can be saved, as it is easier to modify a design in its early stages. Several methods exist to analyze the risk in a system, but all require a mature design. However, by applying the concept of “common interfaces” to a functional model and utilizing a historical knowledge base, it is possible to analyze chains of failures during the conceptual phase of product design. This paper presents a method based on these “common interfaces” to be used in conjunction with other methods such as Risk in Early Design in order to allow a more complete risk analysis during the conceptual design phase. Finally, application of this method is demonstrated in a design setting by applying it to a thermal control subsystem.


2012 ◽  
Vol 9 (73) ◽  
pp. 1767-1773 ◽  
Author(s):  
Tyler Skorczewski ◽  
Angela Cheer ◽  
Peter C. Wainwright

Suction feeding is the most common form of prey capture across aquatic feeding vertebrates and many adaptations that enhance efficiency and performance are expected. Many suction feeders have mechanisms that allow the mouth to form a planar and near-circular opening that is believed to have beneficial hydrodynamic effects. We explore the effects of the flattened and circular mouth opening through computational fluid dynamics simulations that allow comparisons with other mouth profiles. Compared to mouths with lateral notches, we find that the planar mouth opening results in higher flow rates into the mouth and a region of highest flow that is positioned at the centre of the mouth aperture. Planar mouths provide not only for better total fluid flow rates through the mouth but also through the centre of the mouth near where suction feeders position their prey. Circular mouths are shown to provide the quickest capture times for spherical and elliptical prey because they expose the prey item to a large region of high flow. Planar and circular mouths result in higher flow velocities with peak flow located at the centre of the mouth opening and they maximize the capacity of the suction feeders to exert hydrodynamic forces on the prey.


2018 ◽  
Vol 19 (1) ◽  
pp. 201-225 ◽  
Author(s):  
Wahid Palash ◽  
Yudan Jiang ◽  
Ali S. Akanda ◽  
David L. Small ◽  
Amin Nozari ◽  
...  

A forecasting lead time of 5–10 days is desired to increase the flood response and preparedness for large river basins. Large uncertainty in observed and forecasted rainfall appears to be a key bottleneck in providing reliable flood forecasting. Significant efforts continue to be devoted to developing mechanistic hydrological models and statistical and satellite-driven methods to increase the forecasting lead time without exploring the functional utility of these complicated methods. This paper examines the utility of a data-based modeling framework with requisite simplicity that identifies key variables and processes and develops ways to track their evolution and performance. Findings suggest that models with requisite simplicity—relying on flow persistence, aggregated upstream rainfall, and travel time—can provide reliable flood forecasts comparable to relatively more complicated methods for up to 10 days lead time for the Ganges, Brahmaputra, and upper Meghna (GBM) gauging locations inside Bangladesh. Forecasting accuracy improves further by including weather-model-generated forecasted rainfall into the forecasting scheme. The use of water level in the model provides equally good forecasting accuracy for these rivers. The findings of the study also suggest that large-scale rainfall patterns captured by the satellites or weather models and their “predictive ability” of future rainfall are useful in a data-driven model to obtain skillful flood forecasts up to 10 days for the GBM basins. Ease of operationalization and reliable forecasting accuracy of the proposed framework is of particular importance for large rivers, where access to upstream gauge-measured rainfall and flow data are limited, and detailed modeling approaches are operationally prohibitive and functionally ineffective.


2017 ◽  
Vol 107 (09) ◽  
pp. 640-646
Author(s):  
J. Jaensch ◽  
A. Neyrinck ◽  
A. Lechler ◽  
A. Prof. Verl

Maschinen und besonders Anlagen werden meist in individuellen Prozessen entwickelt. Bereits in der Angebots- und Konzeptionsphase werden im direkten Austausch mit dem Auftraggeber unterschiedliche Varianten diskutiert und iteriert. Zur Bewertung der Varianten sind neben den Anschaffungskosten unter anderem laufzeitabhängige Größen wie Taktzeiten und Energieeffizienz zu untersuchen. Der Beitrag stellt einen Ansatz zur simulationsbasierten Untersuchung für die automatisierte Variantengenerierung von Anlagen vor.   The development of machines or plants is a very individual process. Within the conceptual design phase, many different variants have to be discussed with customers and adapted to their needs. For a decent evaluation of the different variants, many parameters beyond static values such as costs are important. Term-dependent values like cycle times and energy efficiency also have to be investigated. This paper presents a method for the automated generation of plant variants based on simulation.


2018 ◽  
Vol 29 (11) ◽  
pp. 665-689
Author(s):  
C. Hartmann ◽  
R. Chenouard ◽  
E. Mermoz ◽  
A. Bernard

Author(s):  
R. J. Engel ◽  
P. J. Tyler ◽  
L. R. Wood ◽  
D. T. Entenmann

Westinghouse has been a strong supporter of Reliability, Availability, and Maintainability (RAM) principles during product design and development. This is exemplified by the actions taken during the design of the 501F engine to ensure that high reliability and availability was achieved. By building upon past designs, utilizing those features most beneficial, and improving other areas, a highly reliable product was developed. A full range of RAM tools and techniques were utilized to achieve this result, including reliability allocations, modelling, and effective redesign of critical components. These activities began during the conceptual design phase and will continue throughout the life cycle of these engines until they are decommissioned.


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