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Reliability based multiobjective optimization for design of structures subject to random vibrations

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第1期9卷 15-25页

作者： Giuseppe Carlo MARANO department of Environmental Engineering and Sustainable development Technical University of Bari viale del Turismo 10-74100 Taranto Italy

Based on a multiobjective approach whose objective function (OF) vector collects stochastic reliability performance and structural cost indices, a structural optimization criterion for mechanical systems subject to random vibrations is presented for supporting engineer’s design. This criterion differs from the most commonly used conventional optimum design criterion for random vibrating structure, which is based on minimizing displacement or acceleration variance of main structure responses, without considering explicitly required performances against failure. The proposed criterion can properly take into account the design-reliability required performances, and it becomes a more efficient support for structural engineering decision making. The multiobjective optimum (MOO) design of a tuned mass damper (TMD) has been developed in a typical seismic design problem, to control structural vibration induced on a multi-storey building structure excited by nonstationary base acceleration random process. A numerical example for a three-storey building is developed and a sensitivity analysis is carried out. The results are shown in a useful manner for TMD design decision support.

关键词： Structural optimization Multiobjective optimization (MOO) Random vibration Tuned mass damper (TMD)

A Tabu-search-based Algorithm for Distribution Network Restoration to Improve Reliability and Resiliency

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Journal of Modern Power Systems and Clean Energy 2023年第1期11卷 302-311页

作者： Alessandro Bosisio Alberto Berizzi Daniele Lupis Andrea Morotti Gaetano Iannarelli Bartolomeo Greco Energy department of Politecnico di Milano MilanItaly E-distribuzione MonzaItaly Unareti Electrical Network Planning department MilanItaly department of Astronautics Electrical and Energy Engineering of the Sapienza UniversityRomeItaly Technological development department of the DSO Unareti MilanItaly Unareti market development and Special Projects department MilanItaly IEEE

Fault restoration techniques have always been crucial for distribution system operators(DSOs).In the last decade,it started to gain more and more importance due to the introduction of output-based regulations where DSO performances are evaluated according to frequency and duration of energy supply *** paper presents a tabu-searchbased algorithm able to assist distribution network operational engineers in identifying solutions to restore the energy supply after permanent *** to the network property,two objective functions are considered to optimize either reliability or *** mathematical formulation includes the traditional feeders,number of switching operation limit,and radiality *** to the DSO of Milan,Unareti,the proposed algorithm has been tested on a real distribution network to investigate its effectiveness.

关键词： Distribution system operators(DSOs) heuristic algorithms power system reliability power system restoration resiliency

Maximizing biomass utilization: An integrated strategy for coproducing multiple chemicals

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Journal of Energy Chemistry 2025年第1期100卷 180-191页

作者： Byeongchan Ahn Sua Jo Jonggeol Na J.Jay Liu Young-Ju Kim Wangyun Won department of Chemical and Biological Engineering Korea University department of Chemical Engineering (Integrated process) Kyung Hee University department of Chemical Engineering and Materials Science Ewha Womans University department of Chemical Engineering Pukyong National University Resources Engineering Plant Research department Korea Institute of Geoscience and Mineral Resources

Lignocellulosic biomass is one of the viable solutions to alleviate the global warming. However, the limited utilization of biomass majorly focused on cellulose and hemicellulose restricts the economic and environmental feasibilities. To cope with this issue, we proposed an integrated process of co-producing 1,6-hexanediol（1,6-HDO） with tetrahydrofuran and adipic acid from biomass, referred to as Strategy A. To compare the impacts of lignin upgrading and feedstock, Strategy B, which co-produces tetrahydrofuran alone, and Strategy C, which is the traditional route to produce 1,6-HDO from fossil fuels, were used. Heat networks are also designed to reduce operating costs and indirect carbon emissions due to energy consumption, saving 87% and 83% of the heat and cooling requirements, respectively, in Strategy A. The market competitiveness of Strategy A was evaluated by determining the minimum selling price through techno-economic analysis, and sustainability was thoroughly investigated by quantifying the environmental impacts through both midpoint and endpoint life-cycle assessments（LCAs）.Strategy A was found to be the most favorable both economically（USRDSCHARDOLLAR3,402/ton） and environmentally（-26.9 kg CO2eq.）. This indicates that lignin valorization is not only economically but also environmentally preferred. Finally, changes in economic and environmental feasibilities depending on economic, process, and environmental parameters were investigated using sensitivity and uncertainty analyses. The results of these analyses provide valuable insight into bio-based chemical production.

关键词： Biorefinery Carbon mitigation Climate change Global warming Lignin utilization Bioeconomy

Fuzzy-entropy based robust optimization criteria for tuned mass dampers

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Earthquake Engineering and Engineering Vibration 2010年第2期9卷 285-294页

作者： Giuseppe Carlo Marano Giuseppe Quaranta Sara Sgobba department of Environmental Engineering and Sustainable development Technical University of Bari department of Structural Engineering and Geotechnics University of Rome "La Sapienza" Faculty of Engineering International University UNINETTUNO

Tuned mass dampers (TMD) are well known as one of the most widely adopted devices in vibration control passive strategies. In the past few decades,many methods have been developed to find the optimal parameters of a TMD installed on a structure and subjected to a random base excitation process,but most of them are usually based on an implicit assumption that all of the structural parameters are deterministic. However,in many real cases this simplification is unacceptable,so robust optimal design criteria becomes aviable alternative to better support engineers in the design process. In Robust Design Optimization (RDO) approaches,indeed the solution must be able to not only minimize the performance but also to limitits variation induced by uncertainty. Most of the currently available RDO methods are based on a probabilistic description of the model uncertainty,even if in many cases they are not able to explicitly include the influence of all the possible sources of uncertainties. Therefore,in this study,a fuzzy version of the robust TMD design optimization problem is proposed. The consistency of the fuzzy approach is studied with respect to the available non-probabilistic formulations reported in the literature and an application to an example of a robust design of a linear TMD subjected to base random vibrations in the presence of fuzzy uncertainties. The results show that the proposed fuzzy-based approach is able to give a set of optimal solutions both in terms of structural efficiency and sensitivity to mechanical and environmental uncertainties.

关键词： tuned mass damper random vibration robust design fuzzy variable expected value fuzzy entropy

Simulation of the Interaction between Driver and Seat

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Chinese Journal of Mechanical Engineering 2013年第6期26卷 1234-1242页

作者： DU Xiaoming REN Jindong SANG Chunlei LI Lemeng technical development department Faw-Volkswagen Automotive Co. Ltd. State Key Lab of Automotive Dynamic Simulation Jilin University

Test is one of methods to acquire human-seat pressure distribution in driving, with the deficiency of being uneasy to obtain the stress information of soft tissue inside human body and the sheer force of interface between human and seat, which can be obtained by simulation. But current simulation method focuses mainly on calculation itself other than combining it with posture prediction and cab packaging parameters, which cause it difficult to acquire accurate pressure calculation results without accurate posture of human body, and make it almost meaningless to design optimization. Therefore, a human body geometric model with posture change capability is built and linked up with Cascade Prediction Model（CPM）, which takes cab packaging parameters as inputs. A detailed finite element model of driver human body is constructed and used to conduct the driver-seat interaction simulation between human body and seat. Good accordance of pressure distribution is observed between simulation and test, which validates the simulation. In addition to the distribution pattern, curves on key sections are used to analyze the pressure and shear stress on the seat surface, as well as soft tissue stress inside human body. The simulation shows that the maximum stress of buttocks locates under the ischial tuberosity, and the maximum stress of trunk occurs near the scapula posterior and the lower waist. These are the places where fatigue usually occurs. The maximum pressure of seat appears at the driver-seat contact area corresponding to the driver＇s maximum skin tissue stress. In order to guide the seat design and cab packaging and study the influence of posture to pressure distribution, finite element models for different levels of cab packaging parameters are created by using CPM. The pressure distributions are calculated and their tendencies varying with cab packaging parameters are obtained. The method presented provides a new way to accurately simulate the interaction between driver

关键词： seating comfort pressure distribution posture prediction model packaging parameters

Hot Ductility Behavior and Slab Crack Performance of Microalloyed Steels During Continuous Casting

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Hot Ductility Behavior and Slab Crack Performance of Microal...

Non-cycloplegic spherical equivalent refraction in adults:comparison of the double-pass system,retinoscopy,subjective refraction and a table-mounted autorefractor

“第十届中国钢铁年会”暨“第六届宝钢学术年会”

作者： JANSTO Steven G. technical & market development department CBMM North AmericaInc.

This research shows that high carbon equivalent microalloyed steels which exhibit inherently lower hot ductility,through the hot tensile test as measured by percent reduction in area(%RA),still exhibit sufficient ductility to satisfactorily meet the unbending stress and strain gradients existing in the straightening section of most industrial *** results indicate only 10%

关键词： continuous casting equiaxed-columnar grain transition zone hot ductility

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International Journal of Ophthalmology(English edition) 2013年第5期6卷 618-625页

作者： Meritxell Vilaseca Montserrat Arjona Jaume Pujol Elvira Peris Vanessa Martìnez Centre for Sensors Instruments and Systems Development(CD6)Technical University of Catalonia University Vision Centre (CUV) Department of Optics and OptometryTechnical University of Catalonia

AIM:To evaluate the accuracy of spherical equivalent(SE) estimates of a double-pass system and to compare it with retinoscopy,subjective refraction and a table mounted ***:Non-cycloplegic refraction was performed on 125 eyes of 65 healthy adults(age 23.5±3.0 years) from October 2010 to January 2011 using retinoscopy,subjective refraction,autorefraction(Auto kerato refractometer TOPCON KR-8100,Japan) and a double pass system(Optical Quality Analysis System,OQAS,Visiometrics S.L.,Spain).Nine consecutive measurements with the double-pass system were performed on a subgroup of 22 eyes to assess *** evaluate the trueness of the OQAS instrument,the SE laboratory bias between the double pass system and the other techniques was ***:The SE mean coefficient of repeatability obtained was *** correlations could be established between the OQAS and the SE obtained with retinoscopy(r=0.956,P<0.001),subjective refraction(r=0.955,P<0.001) and autorefraction(r=0.957,P<0.001).The differences in SE between the double-pass system and the other techniques were significant(P<0.001),but lacked clinical relevance except for retinoscopy;Retinoscopy gave more hyperopic values than the double-pass system-0.51±0.50D as well as the subjective refraction-0.23±0.50D;More myopic values were achieved by means of autorefraction 0.24±0.49D. CONCLUSION:The double-pass system provides accurate and reliable estimates of the SE that can be used for clinical *** technique can determine the correct focus position to assess the ocular optical ***,it has a relatively small measuring range in comparison with autorefractors(-8.00 to +5.00D),and requires prior information on the refractive state of the patient.

关键词： double-pass system optical quality retinoscopy autorefraction subjective refraction accuracy repeatability trueness

Tribological Properties of CrN Coated H13 Grade Tool Steel

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Journal of Iron and Steel Research International 2014年第2期21卷 240-245页

作者： Erdem Atar zgür Alpaslan zgür elik Hüseyin imenoglu department of Materials Science and Engineering Gebze Institute of Technology Small and Medium Sized Enterprises development Organization Metallurgical and Materials Engineering department Istanbul Technical University

The characteristics of CrN coated martensitic H13 grade tool steels were studied. CrN coatings were depos- ited by the arc physical vapor deposition （PVD） before and after the pulse plasma nitriding of the samples. The PVD and plasma nitriding techniques were applied in relevant workshops by following the commercial practice parameters. Experimental results showed that CrN coating deposited on the nitrided surfaces exhibited superior scratch and wear resistances as compared to that deposited on the original martensitic surface.

关键词： CrN coating nitriding PVD tool steel wear

Conductometric Titration for the Prediction of Conductivity in Solutions with Polymeric Membranes

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Journal of Electronic Science and Technology 2017年第4期15卷 342-350页

作者： María José Lavorante Juan Isidro Franco Research and development of Renewable Energy department at CITEDEF Institute of Scientific and Technical Research for the Defense Villa Martelli B1603ALO Argentina

The analytical technique of conductometric titration is used to characterize polymeric *** technique allows obtaining the polymer dry weight capacity(DWC) and the extent of reaction and establishing the optimal number of water molecules per sulfonic *** this particular case the polymer material under study was Nafion?*** different reactions were made: Neutralization and *** of them allow obtaining the same *** titrations could be considered as a good method to study the neutralization and exchange reactions for polymeric materials used in fuel cells or *** implementation of this analytical technique allows reducing operation time of those types of *** waiting time between determinations permits to say that the amount of reactant consumed and products obtained were the same after each addition of titrant.

关键词： Conductivity conductometric titration polymeric membranes