WIT transactions on modelling and simulation最新文献_第2页

A Second-Order Dynamic Friction Model Compared to Commercial Stick–Slip Models 二阶动态摩擦模型与商业粘滑模型的比较

WIT transactions on modelling and simulation Pub Date : 2023-08-11 DOI: 10.3390/modelling4030021

G. Rill, Matthias Schuderer

{"title":"A Second-Order Dynamic Friction Model Compared to Commercial Stick–Slip Models","authors":"G. Rill, Matthias Schuderer","doi":"10.3390/modelling4030021","DOIUrl":"https://doi.org/10.3390/modelling4030021","url":null,"abstract":"Friction has long been an important issue in multibody dynamics. Static friction models apply appropriate regularization techniques to convert the stick inequality and the non-smooth stick–slip transition of Coulomb’s approach into a continuous and smooth function of the sliding velocity. However, a regularized friction force is not able to maintain long-term stick. That is why dynamic friction models were developed in recent decades. The friction force depends herein not only on the sliding velocity but also on internal states. The probably best-known representative, the LuGre friction model, is based on a fictitious bristle but realizes a too-simple approximation. The recently published second-order dynamic friction model describes the dynamics of a fictitious bristle more accurately. It is based on a regularized friction force characteristic, which is continuous and smooth but can maintain long-term stick due to an appropriate shift in the regularization. Its performance is compared here to stick–slip friction models, developed and launched not long ago by commercial multibody software packages. The results obtained by a virtual friction test-bench and by a more practical festoon cable system are very promising. Thus, the second-order dynamic friction model may serve not only as an alternative to the LuGre model but also to commercial stick–slip models.","PeriodicalId":89310,"journal":{"name":"WIT transactions on modelling and simulation","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75342886","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}

引用次数: 2

Modeling of Human-Exoskeleton Alignment and Its Effect on the Elbow Flexor and Extensor Muscles during Rehabilitation 人体外骨骼对准模型及其对康复过程中肘关节屈伸肌的影响

WIT transactions on modelling and simulation Pub Date : 2023-07-20 DOI: 10.3390/modelling4030020

Clarissa Rincon, Pablo Delgado, N. Hakansson, Yimesker Yihun

{"title":"Modeling of Human-Exoskeleton Alignment and Its Effect on the Elbow Flexor and Extensor Muscles during Rehabilitation","authors":"Clarissa Rincon, Pablo Delgado, N. Hakansson, Yimesker Yihun","doi":"10.3390/modelling4030020","DOIUrl":"https://doi.org/10.3390/modelling4030020","url":null,"abstract":"Human-exoskeleton misalignment could lead to permanent damages upon the targeted limb with long-term use in rehabilitation. Hence, achieving proper alignment is necessary to ensure patient safety and an effective rehabilitative journey. In this study, a joint-based and task-based exoskeleton for upper limb rehabilitation were modeled and assessed. The assessment examined and quantified the misalignment present at the elbow joint as well as its effects on the main flexor and extensor muscles’ tendon length during elbow flexion-extension. The effects of the misalignments found for both exoskeletons resulted to be minimal in most muscles observed, except the anconeus and brachialis. The anconeus muscle demonstrated a relatively higher variation in tendon length with the joint-based exoskeleton misalignment, indicating that the task-based exoskeleton is favored for tasks that involve this particular muscle. Moreover, the brachialis demonstrated a significantly higher variation with the task-based exoskeleton misalignment, indicating that the joint-based exoskeleton is favored for tasks that involve the muscle.","PeriodicalId":89310,"journal":{"name":"WIT transactions on modelling and simulation","volume":"56 47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77580983","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}

引用次数: 0

High-Throughput Numerical Investigation of Process Parameter-Melt Pool Relationships in Electron Beam Powder Bed Fusion 电子束粉末床熔合过程参数-熔池关系的高通量数值研究

WIT transactions on modelling and simulation Pub Date : 2023-07-10 DOI: 10.3390/modelling4030019

Christoph Breuning, Jonas Böhm, M. Markl, C. Körner

{"title":"High-Throughput Numerical Investigation of Process Parameter-Melt Pool Relationships in Electron Beam Powder Bed Fusion","authors":"Christoph Breuning, Jonas Böhm, M. Markl, C. Körner","doi":"10.3390/modelling4030019","DOIUrl":"https://doi.org/10.3390/modelling4030019","url":null,"abstract":"The reliable and repeatable fabrication of complex geometries with predetermined homogeneous properties is still a major challenge in electron beam powder bed fusion (PBF-EB). Although previous research identified a variety of process parameter–property relationships, the underlying end-to-end approach, which directly relates process parameters to material properties, omits the underlying thermal conditions. Since the local properties are governed by the local thermal conditions of the melt pool, the end-to-end approach is insufficient to transfer predetermined properties to complex geometries and different processing conditions. This work utilizes high-throughput thermal simulation for the identification of fundamental relationships between process parameters, processing conditions, and the resulting melt pool geometry in the quasi-stationary state of line-based hatching strategies in PBF-EB. Through a comprehensive study of over 25,000 parameter combinations, including beam power, velocity, line offset, preheating temperature, and beam diameter, process parameter-melt pool relationships are established, processing boundaries are identified, and guidelines for the selection of process parameters to the achieve desired properties under different processing conditions are derived.","PeriodicalId":89310,"journal":{"name":"WIT transactions on modelling and simulation","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85486430","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}

引用次数: 1

Modelling of the Solidifying Microstructure of Inconel 718: Quasi-Binary Approximation Inconel 718凝固组织模拟:准二元近似

WIT transactions on modelling and simulation Pub Date : 2023-06-22 DOI: 10.3390/modelling4030018

N. Kropotin, Y. Fang, Chukhlanov V. Yu., M. Seyring, K. Freiberg, S. Lippmann, T. Pinomaa, A. Laukkanen, N. Provatas, P. Galenko

引用次数: 0

A Novel Mesoscopic Drill Bit Model for Deep Drilling Applications 一种适用于深部钻井的新型介观钻头模型

WIT transactions on modelling and simulation Pub Date : 2023-06-20 DOI: 10.3390/modelling4020017

M. Ichaoui, F. Schiefer, G. Ostermeyer

{"title":"A Novel Mesoscopic Drill Bit Model for Deep Drilling Applications","authors":"M. Ichaoui, F. Schiefer, G. Ostermeyer","doi":"10.3390/modelling4020017","DOIUrl":"https://doi.org/10.3390/modelling4020017","url":null,"abstract":"This paper deals with the development of a novel mesoscopic model of polycrystalline diamond compact (PDC) drill bits that can be implemented in complex drill string models for simulations to analyse the influence of rock inhomogeneities or the impact of anti-whirl bits on drill string dynamics. In contrast to existing modelling approaches, the model is developed at a mesoscopic level, where the basic bit–rock interaction is taken from the macroscopic bit model and the cutting characteristics are summarised at a microscopic cutting level into a simplified configuration via cutting blades. This model can therefore effectively describe asymmetries and thus interactions between the torsional and lateral dynamics of the drill bit, and is particularly suitable for investigating the effects of drilling into rock inhomogeneities and fault zones on drilling dynamics. By integration into a complex drill string model, simulation studies of drilling through a sandwich formation were carried out. The simulation results allow detailed stability statements and show the influence of formation properties and bit design on torsional and lateral drill string dynamics.","PeriodicalId":89310,"journal":{"name":"WIT transactions on modelling and simulation","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80823915","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}

引用次数: 0

On the Characterization of Viscoelastic Parameters of Polymeric Pipes for Transient Flow Analysis 用于瞬态流动分析的聚合物管道粘弹性参数表征

WIT transactions on modelling and simulation Pub Date : 2023-06-20 DOI: 10.3390/modelling4020016

Giuseppe Pezzinga

{"title":"On the Characterization of Viscoelastic Parameters of Polymeric Pipes for Transient Flow Analysis","authors":"Giuseppe Pezzinga","doi":"10.3390/modelling4020016","DOIUrl":"https://doi.org/10.3390/modelling4020016","url":null,"abstract":"The behaviour of polymeric pipes in transient flows has been proved to be viscoelastic. Generalized Kelvin–Voigt (GKV) models perform very well when simulating the experimental pressure. However, in the literature, no general indications on the evaluation of the model parameters are given. In the present study, the calibration of GKV model parameters is carried out using a micro-genetic algorithm for experimental tests of transient flows in polymeric pipes taken from the literature. The results confirm that the higher the number of Kelvin–Voigt elements, the better the reproduction of experimental tests, but it is difficult to search for general rules for parameter characterization. Assuming a Kelvin–Voigt (KV) model with a single element, it is shown that the retardation time is related to the oscillation period that can be obtained from the elastic modulus and from easily evaluable pipe characteristics. A simple procedure is then proposed for the characterization of the viscoelastic parameters that can be used by manufacturers and technicians. Considering the limits of such a model, the procedure has to be considered as a first step for the characterization of the viscoelastic parameters of more complex models.","PeriodicalId":89310,"journal":{"name":"WIT transactions on modelling and simulation","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135187311","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}

引用次数: 0

Modeling the Global Annual Carbon Footprint for the Transportation Sector and a Path to Sustainability 交通运输部门全球年度碳足迹模型和可持续发展之路

WIT transactions on modelling and simulation Pub Date : 2023-06-15 DOI: 10.3390/modelling4020015

Vikram Mittal, Rajesh Shah

{"title":"Modeling the Global Annual Carbon Footprint for the Transportation Sector and a Path to Sustainability","authors":"Vikram Mittal, Rajesh Shah","doi":"10.3390/modelling4020015","DOIUrl":"https://doi.org/10.3390/modelling4020015","url":null,"abstract":"The transportation industry’s transition to carbon neutrality is essential for addressing sustainability concerns. This study details a model for calculating the carbon footprint of the transportation sector as it progresses towards carbon neutrality. The model aims to support policymakers in estimating the potential impact of various decisions regarding transportation technology and infrastructure. It accounts for energy demand, technological advancements, and infrastructure upgrades as they relate to each transportation market: passenger vehicles, commercial vehicles, aircraft, watercraft, and trains. A technology roadmap underlies this model, outlining anticipated advancements in batteries, hydrogen storage, biofuels, renewable grid electricity, and carbon capture and sequestration. By estimating the demand and the technologies that comprise each transportation market, the model estimates carbon emissions. Results indicate that based on the technology roadmap, carbon neutrality can be achieved by 2070 for the transportation sector. Furthermore, the model found that carbon neutrality can still be achieved with slippage in the technology development schedule; however, delays in infrastructure updates will delay carbon neutrality, while resulting in a substantial increase in the cumulative carbon footprint of the transportation sector.","PeriodicalId":89310,"journal":{"name":"WIT transactions on modelling and simulation","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80053577","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}

引用次数: 0

Business Process Management Analysis with Cost Information in Public Organizations: A Case Study at an Academic Library 基于成本信息的公共组织业务流程管理分析:以某高校图书馆为例

WIT transactions on modelling and simulation Pub Date : 2023-05-23 DOI: 10.3390/modelling4020014

Barbara Kissa, Elias Gounopoulos, Maria Kamariotou, F. Kitsios

{"title":"Business Process Management Analysis with Cost Information in Public Organizations: A Case Study at an Academic Library","authors":"Barbara Kissa, Elias Gounopoulos, Maria Kamariotou, F. Kitsios","doi":"10.3390/modelling4020014","DOIUrl":"https://doi.org/10.3390/modelling4020014","url":null,"abstract":"Public organizations must provide high-quality services at a lower cost. In order to accomplish this goal, they need to apply well accepted cost methods and evaluate the efficiency of their processes using Business Process Management (BPM). However, only a few studies have evaluated the addition of cost information to a process model in a public organization. The aim of the research is to evaluate the combination of cost data to process modeling in an academic library. Our research suggests a new and easy to implement process analysis in three phases. We have combined qualitative (i.e., interviews with the library staff) and quantitative research methods (i.e., estimation of time and cost for each activity and process) to model two important processes of the academic library of the University of Macedonia (UoM). We have modeled the lending and return processes using Business Process Model and Notation (BPMN) in an easy-to-understand format. We have evaluated the costs of each process and sub process with the use of Time-Driven Activity-Based Costing (TDABC) method. The library’s managers found our methodology and results very helpful. Our analysis confirmed that the combination of workflow and cost analysis may significantly improve the decision-making procedure and the efficiency of an organization’s processes. However, we need to further research and evaluate the appropriateness of the combination of various cost and BPM methods in other public organizations.","PeriodicalId":89310,"journal":{"name":"WIT transactions on modelling and simulation","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90539629","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}

引用次数: 1

Optimising Maintenance Workflows in Healthcare Facilities: A Multi-Scenario Discrete Event Simulation and Simulation Annealing Approach 优化医疗保健设施中的维护工作流:多场景离散事件模拟和模拟退火方法

WIT transactions on modelling and simulation Pub Date : 2023-05-09 DOI: 10.3390/modelling4020013

Joseph Mwanza, A. Telukdarie, Tak Igusa

{"title":"Optimising Maintenance Workflows in Healthcare Facilities: A Multi-Scenario Discrete Event Simulation and Simulation Annealing Approach","authors":"Joseph Mwanza, A. Telukdarie, Tak Igusa","doi":"10.3390/modelling4020013","DOIUrl":"https://doi.org/10.3390/modelling4020013","url":null,"abstract":"Healthcare systems in low-resource settings need effective methods for managing their scant resources, especially people and equipment. Digital technologies may provide means for circumventing the constraints hindering low-income economies from improving their healthcare services. Although analytical and simulation techniques, such as queuing theory and discrete event simulation, have already been successfully applied in addressing various optimisation problems across different operational contexts, the literature reveals that their application in optimisation of healthcare maintenance systems remains relatively unexplored. This study considers the problem of maintenance workflow optimisation with respect to labour, equipment availability and cost. The study aims to provide objective means for forecasting resource demand, given a set of task requests with varying priorities and queue characteristics that flow from multiple queues, and in parallel, into the same maintenance process for resolution. The paper presents how discrete event simulation is adopted in combination with simulated annealing to develop a decision-support tool that helps healthcare asset managers leverage operational performance data to project future asset-performance trends objectively, and thereby determine appropriate interventions for optimal performance. The study demonstrates that healthcare facilities can achieve efficiency in a cost-effective manner through tool-generated maintenance strategies, and that any future changes can be expeditiously re-evaluated and addressed.","PeriodicalId":89310,"journal":{"name":"WIT transactions on modelling and simulation","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76829422","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}

引用次数: 1

Molecular Dynamics Simulations Correlating Mechanical Property Changes of Alumina with Atomic Voids under Triaxial Tension Loading 三轴拉伸载荷下氧化铝力学性能变化与原子空隙的分子动力学模拟

WIT transactions on modelling and simulation Pub Date : 2023-05-05 DOI: 10.3390/modelling4020012

Junhao Chang, Zengtao Chen, J. Hogan

{"title":"Molecular Dynamics Simulations Correlating Mechanical Property Changes of Alumina with Atomic Voids under Triaxial Tension Loading","authors":"Junhao Chang, Zengtao Chen, J. Hogan","doi":"10.3390/modelling4020012","DOIUrl":"https://doi.org/10.3390/modelling4020012","url":null,"abstract":"The functionalization of nanoporous ceramics for applications in healthcare and defence necessitates the study of the effects of geometric structures on their fundamental mechanical properties. However, there is a lack of research on their stiffness and fracture strength along diverse directions under multi-axial loading conditions, particularly with the existence of typical voids in the models. In this study, accurate atomic models and corresponding properties were meticulously selected and validated for further investigation. Comparisons were made between typical material geometric and elastic properties with measured results to ensure the reliability of the selected models. The mechanical behavior of nanoporous alumina under multiaxial stretching was explored through molecular dynamics simulations. The results indicated that the stiffness of nanoporous alumina ceramics under uniaxial tension was greater, while the fracture strength was lower compared to that under multiaxial loading. The fracture of nanoporous ceramics under multi-axial stretching, was mainly dominated by void and crack extension, atomic bond fracture, and cracking with different orientations. Furthermore, the effects of increasing strain rates on the void volume fraction were found to be similar across different initial radii. It was also found that the increasing tension loading rates had greater effects on decreasing the fracture strain. These findings provide additional insight into the fracture mechanisms of nanoporous ceramics under complex loading states, which can also contribute to the development of higher-scale models in the future.","PeriodicalId":89310,"journal":{"name":"WIT transactions on modelling and simulation","volume":"121 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78434414","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}

引用次数: 0