An adaptive collocation method for structural fuzzy uncertainty analysis

2020 ◽  
Vol 37 (9) ◽  
pp. 2983-2998
Author(s):  
Lei Wang ◽  
Chuang Xiong ◽  
Qinghe Shi
Keyword(s):  
Uncertainty Analysis ◽  
Collocation Method ◽  
Membership Function ◽  
Interval Uncertainty ◽  
Engineering Practice ◽  
Analysis Method ◽  
Content Type ◽  
Fuzzy Uncertainty ◽  
Uncertain Variables ◽  
The Membership Function

Purpose Considering that uncertain factors widely exist in engineering practice, an adaptive collocation method (ACM) is developed for the structural fuzzy uncertainty analysis. Design/methodology/approach ACM arranges points in the axis of the membership adaptively. Through the adaptive collocation procedure, ACM can arrange more points in the axis of the membership where the membership function changes sharply and fewer points in the axis of the membership where the membership function changes slowly. At each point arranged in the axis of the membership, the level-cut strategy is used to obtain the cut-level interval of the uncertain variables; besides, the vertex method and the Chebyshev interval uncertainty analysis method are used to conduct the cut-level interval uncertainty analysis. Findings The proposed ACM has a high accuracy without too much additional computational efforts. Originality/value A novel ACM is developed for the structural fuzzy uncertainty analysis.

Modification optimization-based fatigue life analysis and improvement of EMU gear

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yong-Hua Li ◽  
Chi Zhang ◽  
Hao Yin ◽  
Yang Cao ◽  
Xiaoning Bai
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Engineering Practice ◽  
Analysis Method ◽  
Intelligent Algorithm ◽  
Transient Dynamic Analysis ◽  
Content Type ◽  
Gear Modification ◽  
Life Analysis ◽  
Fatigue Life Analysis

PurposeThis paper proposes an improved fatigue life analysis method for optimal design of electric multiple units (EMU) gear, which aims at defects of traditional Miner fatigue cumulative damage theory.Design/methodology/approachA fatigue life analysis method by modifying S–N curve and considering material difference is presented, which improves the fatigue life of EMU gear based on shape modification optimization. A corrected method for stress amplitude, average stress and S–N curve is proposed, which considers low stress cycle, material difference and other factors. The fatigue life prediction of EMU gear is carried out by corrected S–N curve and transient dynamic analysis. Moreover, the gear modification technology combined with intelligent optimization method is adopted to investigate the approach of fatigue life analysis and improvement.FindingsThe results show that it is more corresponded to engineering practice by using the improved fatigue life analysis method than the traditional method. The function of stress and modification amount established by response surface method meets the requirement of precision. The fatigue life of EMU gear based on the intelligent algorithm for seeking the optimal modification amount is significantly improved compared with that before the modification.Originality/valueThe traditional fatigue life analysis method does not consider the influence of working condition and material. The life prediction results by using the method proposed in this paper are more accurate and ensure the safety of the people in the EMU. At the same time, the combination of intelligent algorithm and gear modification can improve the fatigue life of gear on the basis of accurate prediction, which is of great significance to the portability of EMU maintenance.

Rendering optimal design under various uncertainties

2019 ◽  
Vol 37 (1) ◽  
pp. 345-367
Author(s):  
Hui Lü ◽  
Kun Yang ◽  
Wen-bin Shangguan ◽  
Hui Yin ◽  
DJ Yu
Keyword(s):  
Reliability Analysis ◽  
Optimization Design ◽  
Design Method ◽  
Possibility Theory ◽  
Response Analysis ◽  
Analysis Method ◽  
Unified Framework ◽  
Central Difference ◽  
Content Type ◽  
Uncertain Variables

Purpose The purpose of this paper is to propose a unified optimization design method and apply it to handle the brake squeal instability involving various uncertainties in a unified framework. Design/methodology/approach Fuzzy random variables are taken as equivalent variables of conventional uncertain variables, and a unified response analysis method is first derived based on level-cut technique, Taylor expansion and central difference scheme. Next, a unified reliability analysis method is developed by integrating the unified response analysis and fuzzy possibility theory. Finally, based on the unified reliability analysis method, a unified reliability-based optimization model is established, which is capable of optimizing uncertain responses in a unified way for different uncertainty cases. Findings The proposed method is extended to perform squeal instability analysis and optimization involving various uncertainties. Numerical examples under eight uncertainty cases are provided and the results demonstrate the effectiveness of the proposed method. Originality/value Most of the existing methods of uncertainty analysis and optimization are merely effective in tackling one uncertainty case. The proposed method is able to handle the uncertain problems involving various types of uncertainties in a unified way.

Quantitative assessment of risks on construction projects using fault tree analysis with hybrid uncertainties

2019 ◽  
Vol 19 (1) ◽  
pp. 48-70 ◽  
Author(s):  
Shahab Shoar ◽  
Farnad Nasirzadeh ◽  
Hamid Reza Zarandi
Keyword(s):  
Risk Analysis ◽  
Uncertainty Analysis ◽  
Fuzzy Set ◽  
Fault Tree ◽  
Analysis Method ◽  
Content Type ◽  
Quantitative Risk Analysis ◽  
Probability Of Occurrence ◽  
Hybrid Uncertainty ◽  
The Impact

Purpose The purpose of this paper is to present a fault tree (FT)-based approach for quantitative risk analysis in the construction industry that can take into account both objective and subjective uncertainties. Design/methodology/approach In this research, the identified basic events (BEs) are first categorized based on the availability of historical data into probabilistic and possibilistic. The probabilistic and possibilistic events are represented by probability distributions and fuzzy numbers, respectively. Hybrid uncertainty analysis is then performed through a combination of Monte Carlo simulation and fuzzy set theory. The probability of occurrence of the top event is finally calculated using the proposed FT-based hybrid uncertainty analysis method. Findings The efficiency of the proposed method is demonstrated by implementing in a real steel structure project. A quantitative risk assessment is performed for weld cracks, taking into account of both types of uncertainties. An importance analysis is finally performed to evaluate the contribution of each BE to the probability of occurrence of weld cracks and adopt appropriate response strategies. Research limitations/implications In this research, the impact of objective (aleatory) dependence between the occurrences of different BEs and subjective (epistemic) dependence between estimates of the epistemically uncertain probabilities of some BEs are not considered. Moreover, there exist limitations to the application of fuzzy set rules, which were used for aggregating experts’ opinions and ranking purposes of the BEs in the FT model. These limitations can be investigated through further research. Originality/value It is believed that the proposed hybrid uncertainty analysis method presents a robust and powerful tool for quantitative risk analysis, as both types of uncertainties are taken into account appropriately.

The “Halalification” of tourism

2017 ◽  
Vol 8 (4) ◽  
pp. 558-577 ◽  
Author(s):  
Faiza Khan ◽  
Michelle Callanan
Keyword(s):  
Design Methodology ◽  
Secondary Data ◽  
Market Segment ◽  
Analysis Method ◽  
Review Of Literature ◽  
Primary Research ◽  
Content Type ◽  
Starting Point ◽  
Practical Implications

Purpose The purpose of this paper is to address the confusing use of terminology associated with tourism undertaken by Muslims and to identify key concerns associated with this type of tourism. Design/methodology/approach This is an exploratory study and adopts a critical review of literature following the evolutionary concept analysis method. Content analysis of popular UK media, UK-based tour operators’ websites and tourism strategies of destinations popular with Muslim tourists were conducted to examine the use of terminology. Findings There is no clear difference between the various terms (halal, Muslim friendly, Islamic, etc.) used. Overall, academia uses the term Islamic tourism, while the industry and media use various terms. Among destinations, however, there is no clear and consistent use of terminology. A key concern of Islamic tourism is the role of certification in assuring travellers and the lack of standardisation of halal certification. Research limitations/implications The paper is based on literature review and secondary data analysis. It lacks primary research. Practical implications This study highlights the need for consistent use of terminology across industry. Another implication is the issue surrounding halal certification of food and the importance of trust in the seller/service provide. Another trend that industry providers need to consider is the growth of the Muslim millennial traveller and the needs of this market segment. Originality/value The paper highlights the importance of studying the Muslim tourist market and provides a starting point for further research. It highlights several issues such as the need to develop a typology of Muslim tourists. Of particular interest is the concern whether halal values in danger of being commodified in the absence of a universal agreed criterion for halal certification.

A Probabilistic and Interval Hybrid Reliability Analysis Method for Structures with Correlated Uncertain Parameters

2015 ◽  
Vol 12 (04) ◽  
pp. 1540006 ◽  
Author(s):  
C. Jiang ◽  
J. Zheng ◽  
B. Y. Ni ◽  
X. Han
Keyword(s):  
Reliability Analysis ◽  
Structural Reliability ◽  
Correlation Coefficients ◽  
Analysis Method ◽  
Analysis Model ◽  
Probability Interval ◽  
Uncertain Variables ◽  
Uncertainty Model ◽  
Sample Correlation ◽  
Hybrid Reliability

This paper proposes a probability-interval mixed uncertainty model considering parametric correlations and a corresponding structural reliability analysis method. First of all, we introduce the sample correlation coefficients to express the correlations between different kinds of uncertain variables including probability and interval variables. Then dependent parameters are transformed into independent ones through a matrix transformation. A reliability analysis model is put forward, and an efficient method is built to obtain the reliability index or failure probability interval of the structure. Finally, four numerical examples are provided to verify the validity of the method.

Study on Energy Consumption Analysis Method of Distributed Cryogenic Separation System

2013 ◽  
Vol 732-733 ◽  
pp. 52-56
Author(s):  
Zhi Guo Wang ◽  
Lei Zhang ◽  
Chai Ling Yin
Keyword(s):  
Energy Use ◽  
Exergy Analysis ◽  
Waste Heat ◽  
Engineering Practice ◽  
Analysis Method ◽  
Analysis Model ◽  
Two Stage ◽  
Separation Plant ◽  
Flow Energy ◽  
Saving Effect

Cryogenic separation method is the main method to recycle NGL (Natural Gas Liquid). Oilfield two-stage expansion NGL cryogenic separation plant is a complex system composed of varieties of material flow, energy flow and equipments, is a typical distributed energy use system composed of three parts, energy supply, energy use and waste heat recovery. In this paper, according to the process characteristics of two-stage expansion cryogenic separation plant, three-box analysis method was used, the system was compartmentalized into six subsystems, represented the exergy analysis model of system—unit—equipment, given the specific analysis process and the assessment rules for the NGL system. Using the practical operational data, the writers conduct the exergy analysis on the operational working condition of Daqing oilfield NGL system. Based on the calculation results, this paper raises some proposals to improve the operational efficiency, and achieved a good energy saving effect in engineering practice.

An environmental impact analysis method of machine-tool cutting units based on LCA

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Junli Shi ◽  
Junyu Hu ◽  
Mingyang Ma ◽  
Huaizhi Wang
Keyword(s):  
Environmental Impact ◽  
Machine Tool ◽  
Energy Demand ◽  
Impact Analysis ◽  
Primary Energy ◽  
Analysis Method ◽  
Environmental Impact Analysis ◽  
Content Type ◽  
Primary Energy Demand ◽  
Tool Cutting

Purpose The purpose of this paper is to present a method for the environmental impact analysis of machine-tool cutting, which enables the detailed analysis of inventory data on resource consumption and waste emissions, as well as the quantitative evaluation of environmental impact. Design/methodology/approach The proposed environmental impact analysis method is based on the life cycle assessment (LCA) methodology. In this method, the system boundary of the cutting unit is first defined, and inventory data on energy and material consumptions are analyzed. Subsequently, through classification, five important environmental impact categories are proposed, namely, primary energy demand, global warming potential, acidification potential, eutrophication potential and photochemical ozone creation potential. Finally, the environmental impact results are obtained through characterization and normalization. Findings This method is applied on a case study involving a machine-tool turning unit. Results show that primary energy demand and global warming potential exert the serious environmental impact in the turning unit. Suggestions for improving the environmental performance of the machine-tool turning are proposed. Originality/value The environmental impact analysis method is applicable to different machine tools and cutting-unit processes. Moreover, it can guide and support the development of green manufacturing by machinery manufacturers.

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