Volume 13: Design, Reliability, Safety, and Risk最新文献

{"title":"Journal Bearing With Controllable Radial Clearance","authors":"Shahrbanoo Farkhondeh Biabnavi, M. Rashidi","doi":"10.1115/IMECE2018-86748","DOIUrl":"https://doi.org/10.1115/IMECE2018-86748","url":null,"abstract":"This work presents the novel design of a smart hydrodynamic journal bearing with adjustable radial clearance. The dynamic behavior of this bearing was mathematically modeled and examined. Finite Element Analyses were conducted to determine the effort needed to change and maintain a desired value for the radial clearance. First, the bearing set was modelled as a two-degrees-of-freedom dynamic system. For an initial value of a radial clearance of c = 0.0508 mm, the bearing set exhibited an unstable behavior under its postulated operating condition. A Generic Algorithm (GA) was used to define an objective function so that an optimum value of c could be determined in order to ring the bearing into a stable operating condition. The GA determined the value of radial clearance of c = 0.0051 mm for this purpose. Second, a Jeffcott rotor was modeled as an eight-degrees-of-freedom vibratory stem supported by two identical smart bearings. For an initial value of c = 0.025 mm, the disk’s peak-to-peak vibrations amplitude was determined to be 8 × 10−5 meter and 8.5 × 10−5 m along two orthogonal axes of a reference frame respectively. The GA was used to determine a new value for the radial clearance of the supporting bearings in order to reduce the disk’s vibration level. A new value of radial clearance c was determined to be 0.095 mm which in turn reduced the vibrations of the dick from 8 × 10−5 and 8.5 × 10−5 meter to 3.5 × 10−5 and 2.5 × 10−5 m respectively.","PeriodicalId":201128,"journal":{"name":"Volume 13: Design, Reliability, Safety, and Risk","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125940811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparing Contact Stress Estimates of Some Straight Bevel Gears With ISO 10300 Standards","authors":"E. Osakue, Lucky Anetor","doi":"10.1115/IMECE2018-86572","DOIUrl":"https://doi.org/10.1115/IMECE2018-86572","url":null,"abstract":"The pitting resistance of straight bevel gears, like other gears, is commonly assessed on the basis of the contact stress in a gear mesh. A new contact stress model for straight bevel gears is used to estimate the contact stress in some gearset designs and compared with predictions from ISO 10300 bevel gear standards. In the cases considered, the new model contact stresses defer from the ISO values in the range of 13% to 33%, with the ISO predictions generally on the higher side. These deviations appear to be somewhat high but not unreasonable because of obvious differences in the two models. The ISO standard uses the mid facewidth cone radius in its contact stress model while the new model uses the cone backend radius which is larger than the mid facewidth cone radius. Another contributing factor is that the load service factor values evaluated from ISO methods are generally higher than those of the new model values, based largely on American Gear Manufacturers Association (AGMA) methods. It should be noted that the power ratings for all the design cases studied are below 10 kW.","PeriodicalId":201128,"journal":{"name":"Volume 13: Design, Reliability, Safety, and Risk","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124882852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Occupational Safety Implications of the Changing Energy Mix","authors":"Jeremy M. Gernand","doi":"10.1115/IMECE2018-86678","DOIUrl":"https://doi.org/10.1115/IMECE2018-86678","url":null,"abstract":"Renewable energy and natural gas are displacing coal and nuclear power in many parts of the world as sources of electricity. While, the environmental benefits of such changes seem clear, the impact on worker safety, especially in developed nations is less clear. Coal mining is a relatively dangerous occupation, though one that has grown significantly safer in recent decades. Manufacturing and installation of solar photovoltaic (PV) power may pose less risk to workers on a per hour basis, but the number of worker hours necessary to generate a Megawatt-hour of electricity is currently higher for solar PV than it is for coal-generated power. The implications for the overall occupational burden of accidental deaths and injuries has not been previously detailed. This paper presents the results of a Monte Carlo sensitivity analysis for changes in total worker injuries and injury rates under different assumptions for the future energy mix in developed nations. Projections from the Energy Information Agency (EIA) and other organizations together with documented productivity gains for the various energy industries provide test cases for this analysis. The analysis indicates that future occupational fatality and injury burden of the energy sector is highly dependent on improvements in safety in the expanding industries, while specific projections on the share of specific technologies is less critical. This result highlights the need to invest in occupational risk mitigation in these industries.","PeriodicalId":201128,"journal":{"name":"Volume 13: Design, Reliability, Safety, and Risk","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128342644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Post-Failure Recovery Strategies for Metrorail Transit Networks With Washington D.C. As a Case Study","authors":"Yalda Saadat, Yanjie Zhang, Dongming Zhang, B. Ayyub, Hong-wei Huang","doi":"10.1115/IMECE2018-87471","DOIUrl":"https://doi.org/10.1115/IMECE2018-87471","url":null,"abstract":"Metro-Rail transit systems are large-scale networks in numerous modern urban areas that play prominent direct and supportive roles in providing efficient mobility for sustaining communities and local economies. Any event leading to failure of a metro-rail network could have serious societal consequences, such as dramatic effect on the safety and wellbeing of commuters in addition to direct and indirect costs from its diminished performance that lead to resilience loss. Potential performance losses might exhibit complexity and pose a challenge for measurement and prediction. Hence, measuring the resilience of such a network enables its efficient enhancement in a cost-effective manner. Enhancing resilience highly depends on identifying recovery strategies with special attention not only to restoring connectedness but also on reducing associated failure and recovery costs. An effective recovery strategy must demonstrate rapid optimal restoration of a disrupted system while minimizing the cost of the disruption. The objective of this paper is to identify effective recovery strategies to reduce the performance loss and to minimize the total cost of a network during and after a disruptive event, using Washington D.C. Metro with its 91 stations and 140 links as a case study. Method of measuring performance loss in this paper, illustrates that the best recovery sequence typically reflects the order of components ranked based on their degree of vulnerability in the network. Also, the proposed cost model provides a basis to decision makers to identify an optimal recovery strategy according to both paramount recovery sequence and minimum cost consideration.","PeriodicalId":201128,"journal":{"name":"Volume 13: Design, Reliability, Safety, and Risk","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128949706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Whole Operation Life Cycle Model of Gas Turbine Blades Under Multi-Physics Based on Variation of Blade Profile Parameters","authors":"Dengji Zhou, Tingting Wei, Shixi Ma, Hui-sheng Zhang, Z. Lu, S. Weng","doi":"10.1115/IMECE2018-87040","DOIUrl":"https://doi.org/10.1115/IMECE2018-87040","url":null,"abstract":"For long-term operation, blades start to show some defects with increasing operating hours, such as fouling, erosion, corrosion, damage and tip clearance. As the basic unit components of gas turbines, the health conditions of blades directly affect the energy conversation efficiency and service life of the whole equipment. The process from first installation to scrap is blades’ whole operation life cycle. It is an effective way to establish the whole operation life cycle model of blades for real-time monitoring, troubleshooting and prevention, so as to improve the management of equipment. The current research on the whole operation life cycle model is mostly limited to a single subject, such as thermal effects or stress effects. It lacks a profound analysis of this issue from the multi-disciplinary perspective. Meanwhile, the deterioration of blades influence on geometry variation of the blade surface is not taken into consideration in detail. Therefore, the current blade life model is not accurate enough to represent the actual situation. In this paper, the typical gas path deterioration is characterized by blade profile parameters, including the increment of the blade leading edge thickness, the increment of the blade trailing edge, and the change of the blade surface roughness in the whole operation life cycle model of blades. The influencing factors of aerodynamics and strain are synthetically characterized through the study of their multi-disciplinary influence mechanism. And the relationship between the corresponding influencing factors and the variation of blade profile parameters is established. Thus, the numerical simulation model under multi-physics is built to reveal its distribution and trends of the flow field and stress in the gas path. The result shows that it can protect the blades, ensure safe and stable operation, and reduce the deterioration rate.","PeriodicalId":201128,"journal":{"name":"Volume 13: Design, Reliability, Safety, and Risk","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123108974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization Methods for Controlling Stresses at Contacting Surfaces of Interference Fit Assemblies Under Axial and Torsional Loads","authors":"C. S. Florio","doi":"10.1115/IMECE2018-88180","DOIUrl":"https://doi.org/10.1115/IMECE2018-88180","url":null,"abstract":"While the nonuniformity of the diameter of a shaft can be optimized to reduce damaging stress concentrations at the ends of the contact region that are typically found in interference fits between uniform diameter shafts and hubs, the resulting shape changes may adversely affect the joint strength. A more robust design may be achieved if the surface profile is optimized under both interference fit and functional loads. A novel gradientless structural shape optimization method is applied in this work with a unique multiobjective formulation that includes the contact interactions and their effects on the shaft. The method incorporates surface-averaged based optimization goals, which consider both local and global variations, so that the optimization of the entire contacting region can be readily achieved. The formulation has no system-dependent parameters, weighting factors, or stopping criterion, allowing for its broad application to design and compare systems of varying geometries, loads, and meshes. The method was used to attain design goals specific to contacting interfaces subjected to interference, axial, and torsional loads, achieving a 50% improvement in the stress state uniformity over the entire contract region in all cases. Through the presented method, the relative influence of each optimization goal on the resulting shape is demonstrated.","PeriodicalId":201128,"journal":{"name":"Volume 13: Design, Reliability, Safety, and Risk","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131739888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using Multi-Channel Human-System Interaction for User-Centered Product Design","authors":"O. Sankowski, D. Krause","doi":"10.1115/IMECE2018-88091","DOIUrl":"https://doi.org/10.1115/IMECE2018-88091","url":null,"abstract":"User-centered product design (UCPD) and especially its methods and tools offer a lot of benefits to product development. By using specific data of the user group or by including them into the design process, systems with better functionality and usability arise. However, including the users in an optimum manner means to include them over the whole product development process, which is costly and often too time-consuming regarding the ever shorter product life cycles. An extensive application of UCPD methods is therefore usually not practical for industry.\u0000 In order to (1) support the user-centered development process in general and (2) support the selection of appropriate UCPD methods, a multi-channel human-system interaction framework is proposed. It is derived from existing human-computer and human-machine interaction models and further includes additional factors influencing the human-system interaction. However, the framework itself needs further and more detailed elaboration and discussion and currently lacks an allocation of UCPD methods.","PeriodicalId":201128,"journal":{"name":"Volume 13: Design, Reliability, Safety, and Risk","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132274273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Applications of the Monte Carlo Method for Estimating the Reliability of Components Under Multiple Cyclic Fatigue Loadings","authors":"Xiaobin Le","doi":"10.1115/IMECE2018-86130","DOIUrl":"https://doi.org/10.1115/IMECE2018-86130","url":null,"abstract":"In reliability-based mechanical design, reliability replaces the traditional factor of safety as the measurement index of the safety of mechanical components. More than 90% of metal components under cyclic fatigue loadings in industries fail because of fatigue. The P-S-N curve fatigue theory (Probability - Stress level - Number of cycles) is one of the current important fatigue theories. It is very important to know how to determine the reliability of components under different loading-induced cyclic stresses for reliability-based mechanical design. The Monte Carlo method is a powerful numerical simulation in almost every field such as optimization, numerical integration, and generating draws from a probability distribution. Literature reviews show the Monte Carlo method is successfully implemented to estimate the reliability of components under single loading-induced cyclic stress. However, there is little literature about implementing the Monte Carlo method to estimate the reliability of components under multiple loading-induced cyclic stress by using the P-S-N curve fatigue theory. The purpose of this paper is to develop a new Monte Carlo computational algorithm to calculate the reliability of components under several cyclic loadings using the P-S-N curve fatigue theory. Two key concepts in the widely-accepted Miner rule in fatigue theory are that fatigue damage is linear cumulative and the fatigue damage because of different cyclic stress is independent. Based on these two key concepts, this paper has successfully developed a new Monte Carlo computational algorithm to calculate the reliability of components under multiple loading-induced cyclic stresses using the P-S-N curve fatigue theory. The results obtained by the developed computational algorithm is validated by results obtained from two published methods. The results by the developed computational algorithm is again validated by the K-D probabilistic model. Based on validation studies, the relative differences in the results between the proposed method and the published methods are in the range of 0.66% to 2.98%. Therefore, the developed Monte Carlo computational algorithm is validated and can provide an acceptable estimation of the reliability of components under several cyclic fatigue loadings using the P-S-N curve fatigue theory.","PeriodicalId":201128,"journal":{"name":"Volume 13: Design, Reliability, Safety, and Risk","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132901509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reliability-Based Optimal Design of a Micro-Grid System Under Natural Disasters","authors":"Zhetao Chen, Zhimin Xi","doi":"10.1115/IMECE2018-88139","DOIUrl":"https://doi.org/10.1115/IMECE2018-88139","url":null,"abstract":"This paper proposes reliability-based optimal design of a micro-grid system under service disruptions due to natural disasters. The objective is to determine the minimum number of generators and their distributions in the micro-grid so that the system’s recoverability (or resilience) and operation efficiency can be guaranteed under random failure scenarios of the power transmission lines. Power flow analysis combing with the Monte Carlo simulation (MCS) are used for uncertainty propagation analysis to quantify the system’s recoverability distribution and the transmission efficiency distribution under random failure scenarios of the transmission lines. The optimal allocation of the generators is much more reliable compared to the deterministic solutions without considering various uncertainties in the system. The proposed work is demonstrated through a 12-bus power system.","PeriodicalId":201128,"journal":{"name":"Volume 13: Design, Reliability, Safety, and Risk","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129171887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Examining Pulmonary Toxicity of Engineered Nanoparticles Using Clustering for Safe Exposure Limits","authors":"V. Ramchandran, Jeremy M. Gernand","doi":"10.1115/IMECE2018-87431","DOIUrl":"https://doi.org/10.1115/IMECE2018-87431","url":null,"abstract":"Experimental toxicology studies for the purposes of setting occupational exposure limits for aerosols have drawbacks including excessive time and cost which could be overcome or limited by the development of computational approaches. A quantitative, analytical relationship between the characteristics of emerging nanomaterials and related toxicity is desired to better assist in the subsequent mitigation of toxicity by design. Quantitative structure activity relationships (QSAR’s) and meta-analyses are popular methods used to develop predictive toxicity models. A meta-analysis for investigation of the dose-response and recovery relationship in a variety of engineered nanoparticles was performed using a clustering-based approach. The primary objective of the clustering is to categorize groups of similarly behaving nanoparticles leading to the identification of any physicochemical differences between the various clusters and evaluate their contributions to toxicity. The studies are grouped together based on their similarity of their dose-response and recovery relationship, the algorithm utilizes hierarchical clustering to classify the different nanoparticles. The algorithm uses the Akaike information criterion (AIC) as the performance metric to ensure there is no overfitting in the clusters. The results from the clustering analysis of 2 types of engineered nanoparticles namely Carbon nanotubes (CNTs) and Metal oxide nanoparticles (MONPs) for 5 response variables revealed that there are at least 4 or more toxicologically distinct groups present among the nanoparticles on the basis of similarity of dose-response. Analysis of the attributes of the clusters reveals that they also differ on the basis of their length, diameter and impurity content. The analysis was further extended to derive no-observed-adverse-effect-levels (NOAEL’s) for the clusters. The NOAELs for the “Long and Thin” variety of CNTs were found to be the lowest, indicating that those CNTs showed the earliest signs of adverse effects.","PeriodicalId":201128,"journal":{"name":"Volume 13: Design, Reliability, Safety, and Risk","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123492451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}