Journal of Mechanics最新文献_第4页

Computational Aerodynamics With Isogeometric Analysis 计算空气动力学与等几何分析

IF 1.7 4区工程技术

Journal of Mechanics Pub Date : 2023-02-17 DOI: 10.1093/jom/ufad002

Y. Bazilevs, K. Takizawa, T. Tezduyar, A. Korobenko, T. Kuraishi, Yuto Otoguro

{"title":"Computational Aerodynamics With Isogeometric Analysis","authors":"Y. Bazilevs, K. Takizawa, T. Tezduyar, A. Korobenko, T. Kuraishi, Yuto Otoguro","doi":"10.1093/jom/ufad002","DOIUrl":"https://doi.org/10.1093/jom/ufad002","url":null,"abstract":"\u0000 The superior accuracy isogeometric analysis (IGA) brought to computations in fluid and solid mechanics has been yielding higher fidelity in computational aerodynamics. The increased accuracy we achieve with the IGA is in the flow solution, in representing the problem geometry, and, when we use the IGA basis functions also in time in a space–time (ST) framework, in representing the motion of solid surfaces. It is of course as part of a set of methods that the IGA has been very effective in computational aerodynamics, including complex-geometry aerodynamics. The set of methods we have been using can be categorized into those that serve as a core method, those that increase the accuracy, and those that widen the application range. The core methods are the residual-based variational multiscale (VMS), ST-VMS, and arbitrary Lagrangian–Eulerian VMS methods. The IGA and ST-IGA are examples of the methods that increase the accuracy. The complex-geometry IGA mesh generation method is an example of the methods that widen the application range. The ST Topology Change method is another example of that. We provide an overview of these methods for IGA-based computational aerodynamics and present examples of the computations performed. In computational flow analysis with moving solid surfaces and contact between the solid surfaces, it is a challenge to represent the boundary layers with an accuracy attributed to moving-mesh methods and represent the contact without leaving a mesh protection gap.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42833550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Influence on structure and fracture mechanics evaluations of a BWR feedwater nozzle following weld overlay repair 堆焊修复对沸水堆给水喷嘴结构及断裂力学评价的影响

IF 1.7 4区工程技术

Journal of Mechanics Pub Date : 2023-01-01 DOI: 10.1093/jom/ufad008

Ru-Feng Liu, Ming-Chung Young

{"title":"Influence on structure and fracture mechanics evaluations of a BWR feedwater nozzle following weld overlay repair","authors":"Ru-Feng Liu, Ming-Chung Young","doi":"10.1093/jom/ufad008","DOIUrl":"https://doi.org/10.1093/jom/ufad008","url":null,"abstract":"This present paper summarizes applying weld overlay repair on the feedwater nozzle in a boiling water reactor, and evaluates the influence on the structure and fracture mechanics of the component. The requirements for utilizing a full structural weld overlay, including the weld overlay design, effects of welding residual stresses (WRSs), impacts of weld shrinkage, prediction of potential flaw growth, and influence on ASME Code Section III design evaluations, are further defined in ASME Code Case N-504–2. In order to confirm the effectiveness of the weld overlay design of the nozzle, the WRSs following overlay installation were determined using engineering simulation software. The impacts of weld shrinkage from overlay welding are also addressed. The shrinkage stresses were evaluated via a numerical model of the attached piping system to ensure the design margins of the pipe structure. Since the weld overlay technique is well known to be effective in mitigating crack initiation or cracking to leakage, a fatigue crack growth prediction under ASME Code Section XI must be conducted to address the fatigue qualification of the affected component. The ASME Code Section III construction qualification of the whole nozzle region must consider the applicable thermal transient stresses, structural discontinuities, and bimetallic effects that are caused by the weld overlay. This investigation proves that the current stress analyses of the nozzle and the pipe structure are not significantly affected by the added overlay mass, so the structural integrity of the component can be ensured, meeting the requirements of ASME Code Case N-504–2.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61542385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Simulation of unconfined seepage in soil–rock mixture slope by virtual element method 用虚元法模拟土石混合体边坡无侧限渗流

IF 1.7 4区工程技术

Journal of Mechanics Pub Date : 2023-01-01 DOI: 10.1093/jom/ufad011

Yinghao Sun, Qi Yi, Jiao Wang, Guanhua Sun, Shan Lin

引用次数: 0

Preface Recent advances in isogeometric analysis 等几何分析的新进展

IF 1.7 4区工程技术

Journal of Mechanics Pub Date : 2023-01-01 DOI: 10.1093/jom/ufac051

引用次数: 0

Pressure-sensitive paint measurements on the cavity with passive control devices under transonic flow 用无源控制装置对跨声速流腔进行压敏涂料测量

4区工程技术

Journal of Mechanics Pub Date : 2023-01-01 DOI: 10.1093/jom/ufad023

Jun-Kai Ouyang, Yi-Ting Liao, Yen-Ting Hsu, Cheng-Chi Lee, Yu-Hung Lin, Chung-Lung Chen, Wei-Hsiang Wang

引用次数: 0

A numerical investigation of microtube length effect on convective boiling 微管长度对对流沸腾影响的数值研究

4区工程技术

Journal of Mechanics Pub Date : 2023-01-01 DOI: 10.1093/jom/ufad029

Hua-Yi Hsu, Yu-Chen Lin, Zong-You Chen, Ying Wang, Cheng-En Li, Shong-Han Pai, Chia-Wei Lin

{"title":"A numerical investigation of microtube length effect on convective boiling","authors":"Hua-Yi Hsu, Yu-Chen Lin, Zong-You Chen, Ying Wang, Cheng-En Li, Shong-Han Pai, Chia-Wei Lin","doi":"10.1093/jom/ufad029","DOIUrl":"https://doi.org/10.1093/jom/ufad029","url":null,"abstract":"Abstract The microtube length significantly influences the convective boiling process and associated heat transfer characteristics. Other than high heat transfer, low pressure drop is also desired to improve the energy efficiency of the pumping system. This work numerically investigates the microtube length effect on heat transfer and pressure drops of convective boiling with the volume of fluid (VOF) method. The simulation results of vapor formation, heat transfer coefficient, and pressure drop are shown with different microtube lengths L = 2–20 mm. The onset of boiling is around 2 mm away from the mass flux inlet. The subcooled boiling regime can be observed between 2 and 10 mm. Three distinct regimes, liquid single-phase flow, bubbly flow, and plug flow, are shown in the longer microtubes (L = 15 mm and 20 mm). It is found that shorter microtubes can lead to less bubble formation with higher heat transfer and lower pressure drop. The average heat transfer coefficient can achieve 2432 W/(m2K) with a lower quasi-steady total pressure drop Δp|total of 32.8 Pa inside a 2-mm-long microtube. This work offers a detailed study of the impact of microtube length on convective boiling, along with pertinent physical insights. It may serve as an indicator for future microscale heat transfer application designs.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135211540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An investigation on the evolution of strain localization zone in metallic materials based on tensile tests and a 1-D nonlocal model 基于拉伸试验和一维非局部模型的金属材料应变局部化区演化研究

4区工程技术

Journal of Mechanics Pub Date : 2023-01-01 DOI: 10.1093/jom/ufad024

Wei Chen, Lizhi Xia, Yin Yao

{"title":"An investigation on the evolution of strain localization zone in metallic materials based on tensile tests and a 1-D nonlocal model","authors":"Wei Chen, Lizhi Xia, Yin Yao","doi":"10.1093/jom/ufad024","DOIUrl":"https://doi.org/10.1093/jom/ufad024","url":null,"abstract":"Abstract Metallic materials exhibit pronounced strain localization during damage and failure, posing a challenge in damage mechanics when predicting the change in the size of the strain localization zone. In this study, uniaxial tensile tests were carried out to observe changes in the size of the strain localization zone during the loading of aluminum and low-carbon steel. The initial and final states of the two metallic materials during deformation localization were compared. The strain localization zone shrank gradually with the increase in the load, which agrees with existing electronic speckle pattern interferometry (ESPI) results. This experimental phenomenon was further analyzed theoretically. By establishing the relationship between the material characteristic length and the damage, the variation of the material characteristic length was revealed, and the form of the nonlocal kernel function with a varying characteristic length was determined. The results demonstrated that within the framework of nonlocal damage theory, the nonlocal kernel function with a varying characteristic length can be used to satisfactorily simulate the gradual shrinkage of the strain localization zone of metallic materials with the damage evolution. Therefore, this study provides an effective theoretical tool for predicting the size of the strain localization zone.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"301 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135550048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analytical and numerical investigation on the effects of landslide acceleration in landslide-generated tsunamis 滑坡引发海啸中滑坡加速效应的分析与数值研究

4区工程技术

Journal of Mechanics Pub Date : 2023-01-01 DOI: 10.1093/jom/ufad025

Peter H-Y Lo, I-Chi Chan

{"title":"Analytical and numerical investigation on the effects of landslide acceleration in landslide-generated tsunamis","authors":"Peter H-Y Lo, I-Chi Chan","doi":"10.1093/jom/ufad025","DOIUrl":"https://doi.org/10.1093/jom/ufad025","url":null,"abstract":"Abstract Submarine landslides are capable of causing locally catastrophic tsunamis. A landslide necessarily begins its motion by accelerating from a halt. However, the role of landslide acceleration on the tsunami generated by a landslide remains understudied. Assuming an idealized configuration, in this study we cast the landslide acceleration problem as an extension to the existing knowledge on landslide-generated tsunamis above a flat sea bottom. By using the Green’s function approach, we derived new analytical solutions for the tsunami generated by an accelerating submarine landslide. Consistent with the observations in existing studies, we found that a slower landslide acceleration results in a longer but smaller leading submarine landslide tsunami wave. Based on a large number of numerical simulations, empirical formulas were established to quantify the wave modification factors due to landslide acceleration. Combining existing analytical solutions and the newly determined empirical formulas, we assembled semi-analytical solutions that can be easily used to predict the characteristics of the tsunami generated by an accelerating submarine landslide.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135653641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Correction Factors to Biaxial Bending Strength of Thin Silicon Die in the Ball-on-Ring Test by Considering Geometric Nonlinearity and Material Anisotropy 考虑几何非线性和材料各向异性的薄硅模环球试验中双向弯曲强度的修正因素

4区工程技术

Journal of Mechanics Pub Date : 2023-01-01 DOI: 10.1093/jom/ufad026

M Y Tsai, P J Hsieh, T C Kuo

{"title":"Correction Factors to Biaxial Bending Strength of Thin Silicon Die in the Ball-on-Ring Test by Considering Geometric Nonlinearity and Material Anisotropy","authors":"M Y Tsai, P J Hsieh, T C Kuo","doi":"10.1093/jom/ufad026","DOIUrl":"https://doi.org/10.1093/jom/ufad026","url":null,"abstract":"Abstract The ball-on-ring test (BoR) is one of the standard tests for biaxial bending, suggested in ASTM F394-78. This test has been applied to determine the biaxial bending strength of silicon dies to avoid the die edge effect of the three-point bending tests. However, from the literature, when the relatively thin silicon dies are tested, this test suffers from a contact-nonlinearity effect, due to a maximum applied stress moving away from the loading pin center before the specimen failure, and thus results in overestimated maximum stress calculated by the theoretical linear solution. This study aims to investigate this mechanical issue experimentally, theoretically and numerically by taking into account the specimen material anisotropy and thickness effects on the maximum stresses and deflections, and then propose new correction factor equations to the theoretical linear solutions, based on the numerical fitting results of the geometric nonlinear finite element solutions. Those correction factor equations proposed in this study are material-property independent, but specimen thickness dependent, which can be estimated by an interpolation function. It has been proved that the BoR test using the conventional theory associated with the proposed correction factor equations can successfully determine the bending strength of the thin silicon dies on untreated surfaces, which mostly fails in the contact-nonlinear region.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"171 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135839030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Research on fault diagnosis method of turbocharger rotor based on Hu-SVM-RFE 基于Hu-SVM-RFE的涡轮增压器转子故障诊断方法研究

4区工程技术

Journal of Mechanics Pub Date : 2023-01-01 DOI: 10.1093/jom/ufad028

Chunyu Zhang, Xinyang Qiu, Haiyu Qian, Yun Liu, Junchao Zhu

{"title":"Research on fault diagnosis method of turbocharger rotor based on Hu-SVM-RFE","authors":"Chunyu Zhang, Xinyang Qiu, Haiyu Qian, Yun Liu, Junchao Zhu","doi":"10.1093/jom/ufad028","DOIUrl":"https://doi.org/10.1093/jom/ufad028","url":null,"abstract":"Abstract Several parameters need to be monitored for turbocharger rotor faults and the overlap between different fault parameters as well as the redundancy of data, which leads to increased calculation time and reduced classification accuracy. To improve the recognition rate of turbocharger rotor faults, a recursive elimination method based on the support vector machine-recursive feature elimination (SVM-RFE) combined with improved Hu invariant moments is developed for the axial orbit feature extraction of turbocharger rotor with rotor fault. Firstly, improved Hu-invariant moments are extracted for different rotor fault axis orbits, and then the feature ranking and selection are performed by the SVM-RFE method to filter out the feature combinations with higher classification recognition rates. Then, the feature matrix of the Hu-SVM-RFE algorithm screening combination was identified for classification using each of the three diagnostic algorithms. The results show that the optimal feature subset obtained by the Hu-SVM-RFE method can ensure the richness of the fault information of the turbocharger rotor with small number of features. And, a high classification rate can be obtained with low time consumption in combination with the probabilistic neural network (PNN) algorithm. Therefore, Hu-SVM-RFE feature screening method combined with PNN fault diagnosis technology has high accuracy and efficiency, which is of great significance for online fault identification of the supercharger rotor.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135008438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0