The Influence of Engine Characteristics on Patrol Aircraft Life Cycle Cost Optimization

Author(s):  
A. J. Schuetz

A conceptual design study has been conducted for an all-new, land-based patrol aircraft for the U.S. Navy. The selected propulsion system was a conceptual high-speed turboprop. An antisubmarine warfare mission was chosen for the design flight profile. Probable peacetime utilization was postulated so that the engine duty cycle could be estimated. Aircraft designs were optimized for minimum takeoff gross weight (TOGW) and for minimum life cycle cost (LCC). It was shown that the aircraft performance requirements and design constraints bound the optimization process so tightly that the same point design is obtained for both TOGW and LCC criteria. The contribution of the engine costs to the overall life cycle costs was examined. The sensitivity of the aircraft optimization to the engine characteristics — specific fuel consumption (SFC), length, diameter, and cost — was analyzed. It was determined that SFC is the most significant engine characteristic.

2021 ◽  
Vol 11 (21) ◽  
pp. 10316
Author(s):  
Stojan Kravanja ◽  
Uroš Klanšek ◽  
Tomaž Žula

This paper presents a study showing the optimization of the mass, direct (self-manufacturing) costs, and energy life-cycle costs of composite floor structures composed of a reinforced concrete slab and steel I-beams. In a multi-parametric study, mixed-integer non-linear programming (MINLP) optimizations are carried out for different design parameters, such as different loads, spans, concrete and steel classes, welded, IPE and HEA steel profiles, and different energy consumption cases. Different objective functions of the composite structure are defined for optimization, such as mass, direct cost, and energy life-cycle cost objective functions. Moreover, three different energy consumption cases are proposed for the energy life-cycle cost objective: an energy efficient case (50 kWh/m2), an energy inefficient case (100 kWh/m2), and a high energy consumption case (200 kWh/m2). In each optimization, the objective function of the structure is subjected to the design, load, resistance, and deflection (in)equality constraints defined in accordance with Eurocode specifications. The optimal results calculated with different criteria are then compared to obtain competitive composite designs. Comparative diagrams have been developed to determine the competitive spans of composite floor structures with three different types of steel I beam: those made of welded sections and those made of IPE or HEA sections, respectively. The paper also answers the question of how different objective functions affect the amount of the calculated costs and masses of the structures. It has been established that the higher (more wasteful) the energy consumption case is, the lower the obtained masses of the composite floor structures are. In cases with higher energy consumption, the energy life-cycle costs are several times higher than the costs determined in direct cost optimization. At the end of the paper, a recommended optimal design for a composite floor system is presented that has been developed on the multi-parametric energy life-cycle cost optimization, where the energy efficient case is considered. An engineer or researcher can use the recommendations presented here to find a suitable optimal composite structure design for a desired span and uniformly imposed load.


2021 ◽  
Vol 13 (12) ◽  
pp. 6974
Author(s):  
Charlotte Cambier ◽  
Waldo Galle ◽  
Niels De De Temmerman

In addition to the environmental burden of its construction and demolition activities, the Flemish housing market faces a structural affordability challenge. As one possible answer, this research explores the potential of so-called expandable houses, being built increasingly often. Through specific design choices that enable the disassembly and future reuse of individual components and so align with the idea of a circular economy, expandable houses promise to provide ever-changing homes with a smaller impact on the environment and at a lower cost for clients. In this paper, an expandable house suitable for various housing needs is conceived through a scenario-based research-by-design approach and compared to a reference house for Flanders. Subsequently, for both houses the life cycle costs are calculated and compared. The results of this exploration support the proposition that designing expandable houses can be a catalyst for sustainable, circular housing development and that households could benefit from its social, economic and ecological qualities. It requires, however, a dynamic perspective on evaluating their life-cycle impact.


2015 ◽  
Vol 187 ◽  
pp. 6-13 ◽  
Author(s):  
Jingzheng Ren ◽  
Liang Dong ◽  
Lu Sun ◽  
Michael Evan Goodsite ◽  
Shiyu Tan ◽  
...  

2021 ◽  
Author(s):  
Amir Fereidouni Kondri

This report presents the methodology for determining least cost energy efficient upgrade solutions in new residential housing using brute force sequential search (BFSS) method for integration into the reference house to reduce energy consumption while minimizing the net present value (NPV) of life cycle costs. The results showed that, based on the life cycle cost analysis of 30 years, the optimal upgrades resulted in the average of 19.25% (case 1), 31% (case 2a), and 21% (case 2b) reduction in annual energy consumption. Economic conditions affect the sequencing of the upgrades. In this respect the preferred upgrades to be performed in order are; domestic hot water heating, above grade wall insulation, cooling systems, ceiling insulation, floor insulation, heat recovery ventilator, basement slab insulation and below grade wall insulation. When the gas commodity pricing becomes high, the more energy efficient upgrades for domestic hot water (DHW) get selected at a cost premium.


2015 ◽  
Vol 31 (4) ◽  
pp. 1969-1990 ◽  
Author(s):  
T. Y. Yang ◽  
M. Murphy

Steel is one of the most popular seismic force–resisting systems (SFRS) in use worldwide. In Canada, several SFRS have been prequalified for use in the national and provincial building codes. The design of each SFRS has been covered comprehensively in literature. However, no guidance has been provided in selecting the optimum system for a project. In this paper, a prototype building located in Vancouver, Canada, was designed nine times to utilize each of the prequalified SFRS. Detailed seismic hazard and finite element models were developed for each system. The performance in terms of initial construction and life-cycle cost was used to rank each SFRS. The result of this analysis shows that the eccentrically braced configuration has the lowest material usage and life cycle maintenance cost; it is therefore the most economic system in this study. The presented methodology is transparent and can be easily adopted by engineers to select the most economic seismic system for projects with different configurations and geometries than those given in this research. Furthermore, this system introduces a metric with which to estimate the life-cycle costs of a structure taking into account seismic damage over the service life.


Author(s):  
Giuseppe F. De Luca ◽  
Marco Giannetti ◽  
Ennio Guarino ◽  
Roberto Ibba

2014 ◽  
Vol 43 ◽  
pp. 32-40 ◽  
Author(s):  
Kong Fah Tee ◽  
Lutfor Rahman Khan ◽  
Hua Peng Chen ◽  
Amir M. Alani

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