Fuzzy Comprehensive Evaluation on the Failure Mode Having Initial Imperfection Shell

The aggregate gradation of asphalt mixture is one of the most important factors affecting the service life of asphalt pavement. In order to study the gradation of asphalt mixture with the best comprehensive performance, this study puts forward a new method of mineral aggregate gradation optimization based on the fuzzy analytic hierarchy process and comprehensive evaluation method, aiming at the multi-level and multi-index evaluation of the road performance of asphalt mixture. First, the orthogonal test design method is applied to design nine target gradations with coarse aggregate (>4.75 mm) and fine aggregate (<4.75 mm) of AC-20 (asphalt concrete) mixture serving as two factors and the upper, middle, and lower positions of the gradation curve as three levels, and then the road performance test research is carried out. Second, a comprehensive model for evaluation of road performance of mineral aggregate gradation is established. A fuzzy complementary judgment matrix is constructed, and the index weights of each level and the hierarchical total ranking weight are calculated. Then, the membership function is introduced into the comprehensive evaluation model for the road performance of mineral aggregate gradation, and the membership values of each index of asphalt mixture road performance are obtained. Finally, the fuzzy comprehensive evaluation method is used to find out the comprehensive evaluation value of the road performance of the nine graded asphalt mixtures, and the mineral aggregate gradation is optimized. The research results show that the 1# gradation of the asphalt mixture has the highest comprehensive road performance evaluation value, and the combination of the fuzzy hierarchical analysis process and comprehensive evaluation method can more objectively and comprehensively evaluate the comprehensive road performance of the asphalt mixture and provide a useful reference for the optimal selection of asphalt mixture mineral gradation.

With international practice and needs of business own development, it' s has become more and more common to carry out EPC project general contract in enterprises' contract. The EPC model covers basically the entire project construction process and comparing with the traditional contract model, the risk of general contactor is the biggest undoubtedly. To the ambiguity and uncertainty of risk assessment information, this paper presents the fuzzy comprehensive risk evaluation method for EPC general contractor risk assessment. Through the analysis of the EPC model to determine the risk source and loss of general contractor and then use the fuzzy comprehensive evaluation method to realize the quantization of the possibility of risk occurrence and risk loss. By the quantified possibility of risk occurrence and loss consequences to calculate the risk gene and get the risk quantized valve ultimately. The example shows that fuzzy comprehensive risk evaluation method can realize quantitative treatment of fuzzy and uncertain information and can practically and effectively evaluate the EPC general contractor's risk.

ABSTRACTSteel products which have various characteristic (e.g. high ductility, high yield stress, low yield stress and high weldability) are used as main structures by diversification of demanded application, and technology for steel manufacturing has developed. Because steel square tubular member is processed by cold‐forming and welding in the process of manufacturing, residual stress will exist in the products. Moreover, due to the cold‐forming process, geometrical initial imperfection, i.e., global and local, will exist. These initial imperfection are still remained even so the technology for steel manufacturing is developed. However, effect of the initial imperfection on elasto‐plastic behaviour of square hollow section columns under compressive axial force with bending moment is not clarified. In this paper, firstly, the effect of individual initial imperfection (e.g. initial global imperfection, initial local imperfection or residual stress) on elasto‐plastic performance is investigated independently; comparison between the experimental results are shown. It is shown that initial local imperfection has a significant impact on elasto‐plastic performance. Secondly, the effect of composite initial imperfections is investigated. The amplitude of the local imperfection is the most influential initial imperfection on the deformation capacity of the column, and the deformation capacity decreased with an increase of the amplitude of local imperfection. Validation of the numerical simulation were also performed and recommend values of imperfections are shown.

With the social progress and economic development, people have put forward requirements for the ecological operation of built reservoirs. However, there are conflicts between the ecological landscape and the existing benefits such as irrigation and flood control, so it is necessary to build a decision-making model for the comprehensive value of the ecological operation of reservoirs. Taking a reservoir project which needs to satisfy multi-objective requirements as an example, this paper proposes a set of decision-making methods for ecological operation of built reservoirs based on improved comprehensive fuzzy comprehensive evaluation method and constructs a multi-objective decision-making model and optimization strategy combination. Through case analysis in this paper, the improved comprehensive fuzzy evaluation method has a good effect on multi-objective decision-making of ecological dispatching of built reservoirs. The research shows that the combination strategy of improving the reservoir’s water storage capacity and the water-saving supporting transformation measures has a good effect, which can reduce the waste of the reservoir diversion project and large-scale high-efficiency water-saving transformation project construction. It embodies the idea of water-saving priorities and space balance and has broad application prospects in the optimization of reservoir ecological dispatch.

Concrete-filled steel tubes subjected to axial compression: Life-cycle based performance

The evaluation of burst-proneness risks has affected the coal and rock mining progress and development. The quality evaluation system framework of burst-proneness risks indexes is established. Fuzzy evaluation index system is proposed to take into account various factors. As to index system, comprehensive fuzzy evaluation model and methods are setup and used to check for practical example. Using comprehensive fuzzy evaluation model and case study, it is concluded that, based on burst-proneness risk evaluation index system, comprehensive fuzzy evaluation method is applied to evaluate and solve the unclear boundary of some burst-proneness risks indexes and inaccurate fuzziness, which is proved to be practicable and feasible.

Battery inconsistency evaluation based on hierarchical weight fusion and fuzzy comprehensive evaluation method

Aiming at the problem that the multi-objective evaluation of performance and the weighting coefficients of indexes is difficult to find, a fuzzy comprehensive performance evaluation method of rolling linear guide (RLG) is proposed. Considering the static and dynamic indexes, a structure model containing nine weighting coefficients was constructed. The performance evaluation function was established by the compromise programming method and the average power method, while weighting coefficients were determined by the improved analytic hierarchy process (I-AHP); the mathematical model was obtained to evaluate the RLG in a certain application. The evaluation results show that the confidence of the static, dynamic and comprehensive performance of the RLG is 59.21 %, 81.97 %, and 63.34 %, respectively. The feasibility of the method was verified by numerical simulation. This method indicates the pros and cons of the performance of the RLG and also indicates the direction for its optimized design.

In this paper, the nonlinear post-buckling analysis of imperfect two-dimensional quasicrystal cylindrical shells is performed. The nonlinear governing equations are established by considering initial geometric imperfection, higher-order shear deformation theory and phonon-phason fields coupling effect. The load-shortening curves and buckling modes are obtained by the Galerkin’s method. Numerical results are compared with the existing results and excellent agreements are obtained. Effects of geometrical parameters, initial imperfection and phonon-phason fields coupling effect on the critical load and imperfection sensitivity of two-dimensional quasicrystal cylindrical shells are discussed in detail.

In order to solve the existent problems of incomplete and ambiguous information during the evaluation on the multiple constraints factors of city underground space development and utilization, this paper applies analytic hierarchy process and fuzzy comprehensive evaluation method to construct the comprehensive evaluation index system of the multiple constraint factors of city underground space development and utilization, then Yuzhong district, Yubei district, Beibei district in Chongqing respectively as an example, and comprehensively to evaluate the multiple constraint factors of city underground space development and utilization. Example analysis shows that, it has high feasibility and effectiveness that applies the method of fuzzy comprehensive evaluation to the multiple constraint factors of city underground space development and utilization, and it can contribute to solve fuzziness and uncertainty problems of the evaluation process.

The reasonable use of water resources has become an important issue for the sustainable development of humanity in the future. Many researches focus on groundwater quality inspection, but not groundwater quality assessment. This paper aims to study groundwater quality evaluation models based on multi-scale fuzzy comprehensive evaluation and big data analysis methods. We combine coarse-grained multi-scale fuzzy entropy and fuzzy comprehensive evaluation method to establish a groundwater quality evaluation model based on big data environment. The evaluation of groundwater samples from 327 test points in Huangpu District, Xuhui District, Hongkou District, and Putuo District of Shanghai was conducted. The results show that the overall condition of Shanghai groundwater is better, and more than 94% of samples qualified as drinking water sources. The method presented in this paper not only guarantees that the coarse-grained data on all scales are consistent with the length of the original data, but also avoids the phenomenon of data loss, which greatly improves the accuracy of subsequent algorithms.

In the context of the advancing construction engineering field in China, there has been a significant increase in the adoption of building information modeling (BIM) technology within engineering–procurement–construction (EPC) projects. This emerging technology is expected to significantly influence the decision‐making practices of professionals in the construction and engineering domain. Consequently, there is an urgent need for comprehensive research focused on construction management specifically pertaining to the effectiveness of construction developer management. This study examines seven representative EPC projects where BIM technology was implemented and it considers various factors that have the potential to influence project decision‐making while taking into account time and cost considerations. A comprehensive multidimensional evaluation method that combines the analytic hierarchy process (AHP) and the fuzzy comprehensive evaluation method is introduced in this study. The results of this study emphasize that the efficiency enhancement strategies derived from the judgment indicator method demonstrate favorable practical outcomes. This research highlights the importance of a comprehensive evaluation method combining the AHP and the fuzzy comprehensive evaluation method to enhance decision‐making efficiency for construction developer management staff.

Effective and comprehensive evaluation of cold stress is critical for healthy dairy cow breeding in the winter. Previous studies on dairy cow cold stress have considered thermal environmental factors but not physiological factors or air quality. Therefore, this study aimed to propose a multilevel fuzzy comprehensive evaluation (FCE) method for cold stress in dairy cows based on the analytic hierarchy process (AHP) and a genetic algorithm (GA). First, the AHP was used to construct an evaluation index system for cold stress in dairy cows from 3 dimensions: thermal environment (temperature, relative humidity, wind speed, and illumination), physiological factors (respiratory rate, body surface temperature), and air quality [NH3, CO2, inhalable particulate matter (PM10)]. Second, the consistency test of the judgment matrix was transformed into a nonlinear constrained optimization problem and solved using the GA. Next, based on fuzzy set theory, the comment set and membership function were established to classify the degree of cold stress into 5 levels: none, mild, moderate, high, and extreme. Then, the degree of cold stress in cows was obtained using multilevel fuzzy comprehensive judgment. To investigate the effect of illumination indicators on cold stress in dairy cows, 24 prelactation cows from the south and north sides were selected for a 117-d comprehensive cold stress evaluation. The results showed that the mean mild cold stress durations were 605.3 h (25.22 d) and 725.5 h (30.23 d) and the moderate cold stress durations were 67.2 h (2.8 d) and 96 h (4.0 d) on the south and north sides, respectively. Simultaneously, generalized linear mixed model showed that there were significant correlations between the daily cold stress duration and milk yield, feeding time, lying time, and active steps in the cows on both sides. This method can reasonably indicate cow cold stress conditions and better guide cold protection practices in actual production.

Buckling investigations on a nuclear reactor inner vessel model

The paper proposed a new system of spatial structure: steel- concrete composite ribbed shell, and briefly compared the three analysis methods considering the initial imperfections of structures: the random imperfection mode method, the consistent imperfection mode method and the improved random imperfection mode method. By using of the consistent imperfection mode method and nonlinear finite element analysis software ANSYS, we analyzed a composite steel-concrete ribbed shell with the span of 40m and span ratio f/L=1/4, which is simply supported at its surrounding and is subjected to uniform loading along it’s whole span. The critical load and instability regions of this shell are presented. The results show that with the increasing of the initial imperfections, the value of critical load decreased from 27% to 36%; the trend of load-displacement curve and the location of structural instability regions remain unchanged, only the shape of instability regions will change. This indicted that the effect of the initial imperfections within composite ribbed shell is far less than its influence to the single-layer shell. The steel-concrete composed ribbed shell is not sensitive to the initial geometric imperfections and shows a strong post-buckling performance.