scholarly journals A Novel Method to Assess Safety of Buried Pressure Pipelines under Non-Random Process Seismic Excitation based on Cloud Model

2019 ◽  
Vol 9 (4) ◽  
pp. 812 ◽  
Author(s):  
Peng Zhang ◽  
Yihuan Wang ◽  
Guojin Qin
Keyword(s):  
Random Process ◽  
Earthquake Engineering ◽  
Random Vibration ◽  
Cloud Model ◽  
Quantitative Description ◽  
Assessment Method ◽  
Small Sample ◽  
Seismic Excitation ◽  
Convex Model ◽  
Novel Method

It is necessary to conduct a safety assessment for pipelines which are regarded as important lifeline projects after an earthquake. Since the random process of loading in earthquake engineering requires a large amount of samples, this paper establishes a non-random vibration method based on convex model theory and applies it to small sample engineering. Moreover, a space–time analytical model of buried pipeline and a finite element model are established to solve the dynamic response of pipelines with non-random process seismic excitation. Furthermore, the randomness of the stress values of the pipeline subjected to earthquake and the fuzziness of the degree of damage to pipelines are considered. Therefore, a novel method for assessing damage to pipelines is proposed based on cloud model. The results indicate that an analysis of non-random vibration combined with the cloud inference method can solve the fuzziness and randomness of the quantitative description and qualitative concept conversion for damage evaluation of pipelines. The method is also an adaptive and effective assessment method for pipelines exposed to earthquake and is able to promote safety management of pipeline engineering.

scholarly journals Safety Assessment of Casting Workshop by Cloud Model and Cause and Effect–LOPA to Protect Employee Health

2020 ◽  
Vol 17 (7) ◽  
pp. 2555 ◽  
Author(s):  
Qingwei Xu ◽  
Kaili Xu ◽  
Fang Zhou
Keyword(s):  
Safety Assessment ◽  
Cloud Model ◽  
Least Square Method ◽  
Assessment Method ◽  
Employee Health ◽  
Least Square ◽  
Entropy Weight ◽  
Safety Level ◽  
Cause And Effect ◽  
Assessment Approach

Safety assessment of a casting workshop will provide a clearer understanding of the important safety level required for a foundry. The main purpose of this study was to construct a composite safety assessment method to protect employee health using the cloud model and cause and effect–Layer of Protection Analysis (LOPA). In this study, the weights of evaluation indicators were determined using the subjective analytic hierarchy process and objective entropy weight method respectively. Then, to obtain the preference coefficient of the integrated weight more precisely, a new algorithm was proposed based on the least square method. Next, the safety level of the casting workshop was presented based on the qualitative and quantitative analysis of the cloud model, which realized the uncertainty conversion between qualitative concepts and their corresponding quantitative values, as well as taking the fuzziness and randomness into account; the validity of cloud model evaluation was validated by grey relational analysis. In addition, cause and effect was used to proactively identify factors that may lead to accidents. LOPA was used to correlate corresponding safety measures to the identified risk factors. 6 causes and 19 sub-causes that may contribute to accidents were identified, and 18 potential remedies, or independent protection layers (IPLs), were described as ways to protect employee health in foundry operations. A mechanical manufacturing business in Hunan, China was considered as a case study to demonstrate the applicability and benefits of the proposed safety assessment approach.

Probabilistic Distribution of Parameters Applied to PFM Analysis for Piping in China Experimental Fast Reactor

2013 ◽  
Author(s):  
Min Qi ◽  
Yueying Wang ◽  
Jia Liu
Keyword(s):  
Fracture Mechanics ◽  
Fast Reactor ◽  
Safety Assessment ◽  
Small Sample Size ◽  
Research Work ◽  
Assessment Method ◽  
Small Sample ◽  
Probabilistic Distribution ◽  
Structure Dimension ◽  
China Experimental Fast Reactor

The safety assessment method based on probabilistic fracture mechanics (PFM) is well applied to pressure vessel and piping. The PFM analysis is more reasonable and reliable than determinate fracture mechanics (DFM) method. In PFM analysis, the uncertainty of main assessment parameters, such as loads, material character parameters, structure dimension and defect sizes are considered to be random, and the probabilistic distribution of these parameters are determined with the theory of probability statistics. Related to the practical engineering of China experimental fast reactor (CEFR), this paper has done some research work on the parameters probabilistic distribution, and a method was given to determine the optimum fitting probabilistic distribution function of parameters applied to PFM analysis for piping in the small sample size. The work of this paper makes the foundation of the further probabilistic safety assessment of CEFR piping.

scholarly journals Impact Assessment of Habitat and Hydromorphological Alterations in Two Heavily Modified Lakes

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 622
Author(s):  
Dionissis Latinopoulos ◽  
Chrysoula Ntislidou ◽  
Ifigenia Kagalou
Keyword(s):  
Quality Assessment ◽  
Impact Assessment ◽  
Water Framework Directive ◽  
Habitat Quality ◽  
Natural Environment ◽  
Quantitative Description ◽  
Assessment Method ◽  
Habitat Modification ◽  
Lake Morphology ◽  
Habitat Quality Assessment

A description of hydromorphological pressures is required by the Water Framework Directive, however, there is not a commonly accepted assessment method. This study aims to explore a description tool application, not used before in Greece, for the quantification of the human impact extent on natural environment. Thus, in lakes Kastoria and Pamvotis, the Lake Habitat Survey was applied in the field and remotely to map the pressures, to examine confidence, suitability and ease of applicability through plot quantitative description, to calculate the “Lake Habitat Quality Assessment”, “Lake Habitat Modification Score” and “Alteration of Lake Morphology Score” indices.

scholarly journals Application of a Cloud Model-Set Pair Analysis in Efficacy Assessment for Diabetic Ulcers

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Le Kuai ◽  
Jia-qi Xing ◽  
Jing-ting Zhang ◽  
Xun-zhe Xu ◽  
Min-feng Wu ◽  
...  
Keyword(s):  
Cloud Model ◽  
Assessment Method ◽  
Set Pair Analysis ◽  
Connection Degree ◽  
Diabetic Ulcers ◽  
Efficacy Assessment ◽  
Model Set ◽  
Importance Assessment ◽  
Pair Analysis ◽  
Assessment Results

Because treatment of diabetic ulcers includes various uncertainties, efficacy assessments are needed and significant. In previous studies, set pair analysis (SPA) has been applied to the efficacy assessments of traditional Chinese medicine (TCM) that pick out uncertainties related to the development and prognosis of disease. Optimized clinical protocols of SPA improve clinical efficacy. In the article, cloud model (CM) is employed to improve SPA, and a novel efficacy assessment method for a treatment of diabetic ulcers is proposed based on the cloud model-set pair analysis (CM-SPA). It is recommended to replace connection degree (CD) with cloud connection degree (CCD) that the efficacy assessment results are shown as normal clouds. Then, three diabetic ulcers patients treated with TCM made importance assessment by both CM-SPA and AHP based SPA. The comparison of assessment results shows that the CM-SPA is efficacious for the efficacy assessment of a treatment for diabetic ulcers and the results will be more scientific and accurate via CM-SPA.

Novel Assessment Method for Support Conditions of Concrete Pavement under Traffic Loads using Distributed Optical Sensing Technology

2020 ◽  
Vol 2674 (4) ◽  
pp. 42-56
Author(s):  
Mengyuan Zeng ◽  
Difei Wu ◽  
Hongduo Zhao ◽  
Hui Chen ◽  
Zeying Bian
Keyword(s):  
Frequency Spectrum ◽  
Assessment Method ◽  
Concrete Pavement ◽  
The Novel ◽  
Moving Loads ◽  
Traffic Loads ◽  
Sensing Technology ◽  
Novel Method ◽  
Support Conditions ◽  
The Impact

Loss of support is a common concrete pavement distress that may affect pavement performance directly. Previous studies have proved that vibration-based methods have the potential for detecting loss of support in a more efficient way but this is limited by loading conditions. This paper presents a further study concerning the effects of moving loads and proposes a novel method for assessing support conditions of concrete pavement under traffic loads using distributed optical vibration sensing technology. First, finite element analysis and laboratory tests were conducted to investigate the impact of loss of support on pavement vibration induced by moving loads with reference to the frequency spectrum. The impact of loading conditions, including loading position and speed, was also studied using the same methods. The results indicate that both loss of support and loading characteristics have a considerable effect on the distribution of the frequency spectrum. It is proved that weighted frequency can be utilized for assessment of support conditions under a specific loading condition. It is suggested the loading position needs to be close to the measurement point (distance < 0.3 m) to obtain stable and reliable data for assessment of support conditions. In addition, the loading speed should be adequately fast and steady (4 to 5 m/s) to ensure the significance of the effect of loss of support. A field test was conducted in an airport, and the novel assessment method was validated by comparing it with a conventional deflection-based method. The novel method proved to be reliable for implementation in practice.

scholarly journals An approximate mathematical model for estimating the influence of vibrations on attached elements of a mobile robot video system

2021 ◽  
pp. 20-26
Author(s):  
A. A. Lobaty ◽  
M. М. Tatur ◽  
A. K. Ibrahim
Keyword(s):  
Mathematical Model ◽  
Differential Equations ◽  
Mobile Robot ◽  
Random Process ◽  
Random Vibration ◽  
Experimental Studies ◽  
Mobile Platform ◽  
Special Equipment ◽  
Video System ◽  
Vibration Process

The problem of constructing and applying of mathematical model for assessing the influence of vibrations on the attached elements of the video system of a mobile robot is solved. This robot is considered as a mobile platform for placing of the special equipment for various purposes. The analysis of mathematical models and the results of experimental studies of vibrations of multi-support wheeled machine and its structural elements has been conducted. On the basis of this analysis, the form of a stochastic mathematical model of vibrations of the structure of a mobile robot has been substantiated. The vibration model is specified as a correlation function or spectral density of a random process for various conditions of the robot’s movement. Differential equations of the shaping filter for modeling а random vibration process with given characteristics are presented. Differential equations for the probabilistic moments of the vibration process are presented. Based on the equations for the probabilistic moments and the proposed formula, an assessment of events, which consist in exceeding the vibration amplitude of a given level was carried out. These events are named as outliers of a random process and characterize the range within the basic properties of the equipment installed on the mobile platform are preserved. An analytical study of a mathematical model to determine the intensity of emissions of a random vibration process has been carried out. The probabilistic characteristics of the vibration process and the intensity of emissions are determined. The obtained theoretical results make it possible to assess the performance of the elements of a video system installed on a mobile platform and to formulate the basic requirements for tolerances for their parameters. The results of computer modeling clearly showed the efficiency of the proposed mathematical model for assessing the influence of vibrations.

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