Multi-objective robust design optimization of an engine mounting system

International audienceThis paper introduces a new method to support designers to find optimal and robust solutions of engine mounting system. The mounting system design is a compromise between isolation of the vehicle from engine vibration and constraining the motion of the powertrain within vehicle packaging. Based on the classical pendulum mounting system of a front wheel drive vehicle with a transversely four-cylinder engine, this study deals with the definition of a new global engine mounting concept for the NVH (Noise Vibration and Harshness) improvement of the vehicle characteristics at idle speed. The practical application of the numerical optimization is complicated by the fact that engine mounting system is a stochastic system. Its characteristics have a probabilistic nature. Multi-Objective Genetic Algorithm (MOGA), i.e. Pareto-optimization, is taken as the appropriate framework for the definition and the solution of the addressed multi-objective robust optimization problem. An experimental correlation analysis has been conducted on a Pareto-optimal solution to show the model accuracy

Index to 1984 NASA Tech Briefs, volume 9, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1984 Tech B Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Preliminary design studies of an advanced general aviation aircraft

The preliminary design results are presented of the advanced aircraft design project. The goal was to take a revolutionary look into the design of a general aviation aircraft. Phase 1 of the project included the preliminary design of two configurations, a pusher, and a tractor. Phase 2 included the selection of only one configuration for further study. The pusher configuration was selected on the basis of performance characteristics, cabin noise, natural laminar flow, and system layouts. The design was then iterated to achieve higher levels of performance

Powertrain Modal Analysis for Defining the Requirements for a Vehicle Drivability Study

The powertrain of a car plays a major role in establishing the vehicle’s offered comfort due to vibrations because it is the heaviest single component installed on the chassis; therefore, when oscillating, it transmits considerable forces to the chassis, inducing unwanted vibrations. For this reason, it is important to identify some associated properties with the powertrain suspension system that describe the performance of its rigid body dynamics. In this way, we could place constraints and requirements on these quantities in order to exclude all the configurations that cause intolerable levels of vibrations, and include all the others in the analysis for further evaluation. The definition of these requirements is critical: a poor setting of requirements excludes potentially good powertrain suspension setups and includes those ones with a drivability index that is too poor. In this paper, we identify a set of quantities that show correlation with the vibration performance of the powertrain setup. A method for testing the specificity of the requirements is also shown in order to evaluate which requirements perform best when it comes to filtering engine suspension setups that provide an acceptable level of vibrations

Aeronautical Engineering: A special bibliography with indexes, supplement 51

This bibliography lists 206 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System in November 1974

Task 6 -- Advanced turbine systems program conceptual design and product development

The Allison Engine Company has completed the Task 6 Conceptual Design and Analysis of Phase 2 of the Advanced Turbine System (ATS) contract. At the heart of Allison`s system is an advanced simple cycle gas turbine engine. This engine will incorporate components that ensure the program goals are met. Allison plans to commercialize the ATS demonstrator and market a family of engines incorporating this technology. This family of engines, ranging from 4.9 MW to 12 MW, will be suitable for use in all industrial engine applications, including electric power generation, mechanical drive, and marine propulsion. In the field of electric power generation, the engines will be used for base load, standby, cogeneration, and distributed generation applications

Selection of the Most Sustainable Renewable Energy System for Bozcaada Island: Wind vs. Photovoltaic

Energy production without destroying the environment has been one of the most crucial issues for people living in today’s world. In order to analyze whole environmental and/or economic impacts of the energy production process, life cycle assessment (LCA) and life cycle cost (LCC) are widely used. In this study, two distinct renewable energy systems are assessed. First, a land-based wind farm, which has been operating in Bozcaada Island since 2000, is compared to a proposed solar photovoltaic power plant in terms of Energy Pay-Back Time (EPBT) periods and greenhouse gas (GHG) emissions and life cycle cost. The energy production process including the recycling phase evaluated “from cradle to grave” using GaBi software for both cases. All scenarios are compared by considering different impact categories such as global warming potential (GWP), acidification potential (AP), and eutrophication potential (EP). Following this, levelized unit cost to produce 1 MWh electricity (LUCE) is calculated for both systems. This study revealed that LCA and LCCA are useful and practical tools that help to determine drawbacks and benefits of different renewable energy systems considering their long-term environmental and economic impacts. Our findings show that onshore wind farms have a number of benefits than proposed photovoltaic power plants in terms of environmental and cost aspects.</jats:p

Aeronautical Engineering: A continuing bibliography with indexes, supplement 106

This bibliography lists 388 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1979

Cogeneration computer model assessment: Advanced cogeneration research study

Cogeneration computer simulation models to recommend the most desirable models or their components for use by the Southern California Edison Company (SCE) in evaluating potential cogeneration projects was assessed. Existing cogeneration modeling capabilities are described, preferred models are identified, and an approach to the development of a code which will best satisfy SCE requirements is recommended. Five models (CELCAP, COGEN 2, CPA, DEUS, and OASIS) are recommended for further consideration