Meccanica最新文献_第10页

A statistical boundary for 3D rarefied flows through meshes: implementation to a new version of dsmcFoam+ and wind tunnel validation 穿过网格的三维稀流统计边界：在新版 dsmcFoam+ 中的实施和风洞验证

IF 2.7 3区工程技术

Meccanica Pub Date : 2024-06-26 DOI: 10.1007/s11012-024-01840-z

Tristan Staszak

{"title":"A statistical boundary for 3D rarefied flows through meshes: implementation to a new version of dsmcFoam+ and wind tunnel validation","authors":"Tristan Staszak","doi":"10.1007/s11012-024-01840-z","DOIUrl":"https://doi.org/10.1007/s11012-024-01840-z","url":null,"abstract":"<p>The Direct Simulation Monte Carlo (DSMC) method has become a standard tool for rarefied aerodynamics and microchannel flows. However, the performance benefits of DSMC, such as adaptive grid sizes and number of particles, are constrained by the need to resolve small geometric details of mesh applications within relatively large simulation volumes. The requirement for a sufficient number of particles in even the smallest cells imposes a significant computational burden. A novel set of cyclic statistical boundary conditions is proposed to address the computational bottleneck associated with simulating micrometre-scale structures prevalent in atmospheric and space research under rarefied flow conditions. These conditions account for the geometric parameters of a geometric mesh and the angular dependency of impacting particles, aiming to alleviate the computational challenges posed by conventional approaches. Validation against wind tunnel measurements demonstrates excellent agreement for one of the implemented boundaries, able to simulate fine meshes for conditions of rocket soundings in the Mesosphere. The newly developed boundary conditions are implemented within the advanced DSMC solver, dsmcFoam+ framework. For this study, the solver is ported from OpenFOAM<sup>®</sup> version 2.4.0 to the OpenFOAM<sup>®</sup> version v2306 to leverage recent code developments, particularly in dynamic meshes, load balancing, and barycentric particle tracking. This advancement enhances the capabilities of DSMC simulations, offering improved fidelity and accuracy in capturing rarefied flow phenomena.</p>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"25 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141507600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

A numerical model for total bending fatigue life estimation of carburized spur gears considering the hardness gradient and residual stress 考虑硬度梯度和残余应力的渗碳直齿轮总弯曲疲劳寿命估算数值模型

IF 1.9 3区工程技术

Meccanica Pub Date : 2024-06-21 DOI: 10.1007/s11012-024-01841-y

Xianshun Sun, Jun Zhao, Shaokang Song, Yongliang Lu, Huiyang Sun

{"title":"A numerical model for total bending fatigue life estimation of carburized spur gears considering the hardness gradient and residual stress","authors":"Xianshun Sun, Jun Zhao, Shaokang Song, Yongliang Lu, Huiyang Sun","doi":"10.1007/s11012-024-01841-y","DOIUrl":"10.1007/s11012-024-01841-y","url":null,"abstract":"<div><p>The paper introduces a novel three-dimensional numerical model considering hardness gradient and residual stress to predict carburized gears’ total bending fatigue life. The crack initiation life was forecasted by the strain life method, considering hardness gradient and residual stress. Linear elastic stresses and strains in the tooth root fillet were corrected by Neuber’s rule for elastic–plastic material behavior. The tooth root area of the spur gear is segmented into layers using the thin slice method, and the fatigue properties of each layer are determined using the multilayer method. The crack propagation life was predicted by the extended finite element method (XFEM), considering hardness gradient and residual stress. Fracture surface analysis with electron microscopy determines the exact location where cracks initiate. The high-speed camera records the path and life of crack propagation. Single-tooth bending fatigue life (STBF) tests are conducted to validate the proposed model. The predicted fatigue lifetimes, failure locations, and crack propagation paths agree well with the experimental results.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"59 7","pages":"1037 - 1060"},"PeriodicalIF":1.9,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141507596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Tribo-dynamic modelling and analysis for a high-speed helical gear system with time-varying backlash and friction under Elastohydrodynamic Lubrication condition 弹性流体动力润滑条件下具有时变间隙和摩擦力的高速斜齿轮系统的三动态建模与分析

IF 1.9 3区工程技术

Meccanica Pub Date : 2024-06-20 DOI: 10.1007/s11012-024-01793-3

Zhibin Zheng, Hongzhi Yan, Jiangming Wu, Min Ge, Yin Zhang

{"title":"Tribo-dynamic modelling and analysis for a high-speed helical gear system with time-varying backlash and friction under Elastohydrodynamic Lubrication condition","authors":"Zhibin Zheng, Hongzhi Yan, Jiangming Wu, Min Ge, Yin Zhang","doi":"10.1007/s11012-024-01793-3","DOIUrl":"10.1007/s11012-024-01793-3","url":null,"abstract":"<div><p>High-speed gear reducers are highly sensitive to vibration and noise, especially in new-energy vehicles. Hence, the current nonlinear dynamics model of gears does not fully consider the influence of tooth microstructure on backlash and friction. This study establishes a nonlinear friction dynamics model for a high-speed helical gear system, which includes time-varying dynamic backlash and friction coefficient based on the fractal characterization of tooth roughness. Furthermore, it investigates the influence of tooth surface roughness on the dynamic performance by taking into account the interaction between friction and vibration under Elastohydrodynamic Lubrication (EHL). Theoretical simulation results show that an increase in tooth roughness leads to an overall deterioration in the dynamic performance of the helical gear system; however, local optimization can also be observed. In the case of a dynamic tooth backlash, the amplitude of displacement oscillations increases, and the number of frequencies increases; in terms of frictional coefficient, the amplitude of displacement oscillations increases, but the change is small compared with that of the dynamic tooth backlash, and the number of frequencies in the spectrum decreases. The results indicate that the proposed model can provide a reference for controlling the tooth roughness of high-speed gears.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"59 7","pages":"1019 - 1036"},"PeriodicalIF":1.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141507597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Exploratory habitation vehicles with trim intrinsic control 具有微调内在控制功能的探索性居住飞行器

IF 2.7 3区工程技术

Meccanica Pub Date : 2024-06-19 DOI: 10.1007/s11012-024-01839-6

Andrea Manuello, Amedeo Manuello, Giuseppe Carlo Marano

{"title":"Exploratory habitation vehicles with trim intrinsic control","authors":"Andrea Manuello, Amedeo Manuello, Giuseppe Carlo Marano","doi":"10.1007/s11012-024-01839-6","DOIUrl":"https://doi.org/10.1007/s11012-024-01839-6","url":null,"abstract":"<p>Considering the space environment and its critical issues and consequent risks, the challenge is to define the way and tools with which future astronauts will be able to act, live and work in space and, in particular on the Moon and Mars, exploiting, at the state of art, knowledge of innovative science, engineering and technology. On the Moon and Mars, the most obvious environmental factors are extreme temperature fluctuations, low gravity and the virtual absence of atmosphere and magnetosphere. The health of a human body can be damaged by reduced values of gravity. Due to the reduced gravity on the Moon and Mars, human bones and muscles are unloaded and begin to weaken. It increases the risk of bone fractures and atrophied muscles for astronauts returning to Earth from prolonged missions. The magnetosphere and atmosphere on Earth shield from much of the dangerous solar and cosmic radiation. Radiation with extremely high energies can damage even living tissue. The surface of the Moon and Mars has been crushed by millions of impacts of celestial bodies such as asteroids, leaving a layer of regolith that could be very deep depending on the areas of the planets. The habitation module, described in this paper, is carried by a vehicle equipped with two pairs of compass shaped legs that act as supports for the habitation module capable of maintaining a certain controlled height with respect to the ground as well as a horizontal attitude, during the movement of the compass. A system of ropes wound on pulleys allows to control the height of the habitat with respect to the ground, control the structure in movement, descent and ascent. The habitat can also be lowered to the ground. The geometry of the shape of the pulleys, around which the ropes are wound, is determined in such a way that the habitation module remains at a certain height during the movement defined by the two compass-shaped advancement supports. The paper describes and analyzes the movement of the pulleys during the entire phase of the movement of the habitation module and their geometric shape is discussed.</p>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"1 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141528569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Well-conditioned AI-assisted sub-matrix selection for numerically stable constrained form-finding of reticulated shells using geometric deep Q-learning 利用几何深度 Q-learning，为网状壳的数值稳定约束寻形提供条件良好的人工智能辅助子矩阵选择

IF 2.7 3区工程技术

Meccanica Pub Date : 2024-06-19 DOI: 10.1007/s11012-024-01769-3

K.-M. M. Tam, R. Maia Avelino, D. Kudenko, T. Van Mele, P. Block

{"title":"Well-conditioned AI-assisted sub-matrix selection for numerically stable constrained form-finding of reticulated shells using geometric deep Q-learning","authors":"K.-M. M. Tam, R. Maia Avelino, D. Kudenko, T. Van Mele, P. Block","doi":"10.1007/s11012-024-01769-3","DOIUrl":"https://doi.org/10.1007/s11012-024-01769-3","url":null,"abstract":"<p>The selection of well-conditioned sub-matrices is a critical concern in problems across multiple disciplines, particularly those demanding robust numerical stability. This research introduces an innovative, AI-assisted approach to sub-matrix selection, aimed at enhancing the form-finding of reticulated shell structures under the xy-constrained Force Density Method (also known as Thrust Network Analysis), using independent edge sets. The goal is to select a well-conditioned sub-matrix within a larger matrix with an inherent graph interpretation where each column represents an edge in the corresponding graph. The selection of ill-conditioned edges poses a significant challenge because it can render large segments of the parameter space numerically unstable, leading to numerical sensitivities that may impede design exploration and optimisation. By improving the selection of edges, the research assists in computing a pseudo-inverse for a critical sub-problem in structural form-finding, thereby enhancing numerical stability. Central to the selection strategy is a novel combination of deep reinforcement learning based on Deep Q-Networks and geometric deep learning based on CW Network. The proposed framework, which generalises across a trans-topological design space encompassing patterns of varying sizes and connectivity, offers a robust strategy that effectively identifies better-conditioned independent edges leading to improved optimisation routines with the potential to be extended for sub-matrix selection problems with graph interpretations in other domains.</p>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"130 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141528568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Discrete maximum principle in Hamel’s formalism for nonholonomic optimal control 哈默尔非整体最优控制形式主义中的离散最大原则

IF 1.9 3区工程技术

Meccanica Pub Date : 2024-06-19 DOI: 10.1007/s11012-024-01790-6

Bin Huang, Zhonggui Yi, Donghua Shi

引用次数: 0

Bandgaps in phononic crystal third-order shear deformation microbeams 声子晶体三阶剪切形变微梁中的带隙

IF 1.9 3区工程技术

Meccanica Pub Date : 2024-06-18 DOI: 10.1007/s11012-024-01823-0

G. Y. Zhang, T. Wang, J. Hong

{"title":"Bandgaps in phononic crystal third-order shear deformation microbeams","authors":"G. Y. Zhang, T. Wang, J. Hong","doi":"10.1007/s11012-024-01823-0","DOIUrl":"10.1007/s11012-024-01823-0","url":null,"abstract":"<div><p>Periodic composite beams play an important role in the bandgap design of phononic crystals. However, for thick beams or high frequencies, conventional theoretical displacement assumptions for beams have limitations. Therefore, it is desirable to improve the accuracy of the vibration frequencies and bandgaps of phononic crystals by using higher-order beam theory. In this work, a modified couple stress theory accounting for the microstructure effect is combined with the third-order shear deformation beam theory to quantitatively study bandgaps in phononic crystal microbeams under different thicknesses and geometric parameters. The elastic wave band structure of the phononic crystal beams is calculated using an improved plane wave expansion method and compared numerically with the finite element model. In addition, compared with the Bernoulli–Euler and Timoshenko beams, the current third-order shear beam has better prediction accuracy for the first bandgap. The numerical results also show that the microstructure effect is significant at the micron scale. Furthermore, at all length scales, the bandgap sizes change significantly with the change in unit cell length and volume ratio.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"59 9","pages":"1425 - 1433"},"PeriodicalIF":1.9,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141528572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 optimization of broaching tool tooth distribution 拉刀齿分布的分析和数值优化

IF 1.9 3区工程技术

Meccanica Pub Date : 2024-06-18 DOI: 10.1007/s11012-024-01831-0

Zsolt Iklodi, Jokin Munoa, Zoltan Dombovari

{"title":"Analytical and numerical optimization of broaching tool tooth distribution","authors":"Zsolt Iklodi, Jokin Munoa, Zoltan Dombovari","doi":"10.1007/s11012-024-01831-0","DOIUrl":"10.1007/s11012-024-01831-0","url":null,"abstract":"<div><p>This paper presents a detailed mathematical analysis of the effect of tooth distribution on the stability of broaching operations. Analytic and numeric techniques are employed to analyse a simplified one-degree-of-freedom mechanical model of variable pitch broaching, to assess its stability, and to find the optimal tooth distances maximizing robustness against harmful self-excited chatter vibrations. A novel modelling approach, considering a theoretical infinitely long broaching tool, draws parallels with variable pitch milling, and analytic formulas for tuning milling cutters are extended to broaching tools. For a further increase of robustness, and to take feasibility constraints into account, a goal function based on the semi-discretization and spectral collocation techniques is implemented in a direct numeric optimisation framework. A new, detailed derivation of the corresponding parameter gradients is presented to enable the use of gradient descent techniques. Since broaching is inherently a time-limited process, optimal parameters found in this manner are then validated via time domain simulations to show the desirable transient behaviours achievable by this ideal tuning of the tool geometry.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"59 9","pages":"1435 - 1464"},"PeriodicalIF":1.9,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11012-024-01831-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141507599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Odd-viscosity induced surfactant-laden shear-imposed viscous film over a slippery incline: a stability analysis 湿滑斜面上的奇异粘度诱导表面活性剂剪切粘性薄膜：稳定性分析

IF 1.9 3区工程技术

Meccanica Pub Date : 2024-06-17 DOI: 10.1007/s11012-024-01837-8

Md. Mouzakkir Hossain, Sukhendu Ghosh, Harekrushna Behera

{"title":"Odd-viscosity induced surfactant-laden shear-imposed viscous film over a slippery incline: a stability analysis","authors":"Md. Mouzakkir Hossain, Sukhendu Ghosh, Harekrushna Behera","doi":"10.1007/s11012-024-01837-8","DOIUrl":"10.1007/s11012-024-01837-8","url":null,"abstract":"<div><p>This research focuses on the stability analysis of an odd viscosity-induced shear-imposed Newtonian fluid flowing down an inclined slippery bed having an insoluble surfactant at the top of the liquid surface. The Orr-Sommerfeld boundary value problem is developed by applying the normal mode approach to the infinitesimal perturbed fluid flow and solved using the numerical method Chebyshev spectral collocation. The numerical results confirm the existence of Yih mode and Marangoni mode in the longwave zone. For the clean/contaminated surface of the film flow, the presence of an odd or Hall viscosity coefficient reduces the surface wave energy and delays the transition from laminar to perturbed flow. Also, it has stabilizing nature on the unstable Marangoni mode as well. The growth rate of both clean and contaminated liquid surfaces becomes more/less when the stronger external shear acts along the downstream/upstream direction of fluid flow. Further, the slip parameter leads to a lower critical Reynolds number and makes the liquid surface more unstable. An increase in the critical Reynolds number due to the stronger Marangoni force ensures that the insoluble surfactant has the potential to dampen the Yih mode instability. Moreover, the unstable shear mode occurs in the finite wavenumber regime with very high inertial force and a small angle of inclination. The two-fold variation of the shear mode instability is possible with respect to the imposed shear. However, the inclusion of the odd viscosity coefficient in the viscous falling film may advance the shear mode instability.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"59 9","pages":"1381 - 1401"},"PeriodicalIF":1.9,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141528571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 and design of isostatic thick origami structures 等静压厚折纸结构的模拟和设计

IF 1.9 3区工程技术

Meccanica Pub Date : 2024-06-17 DOI: 10.1007/s11012-024-01815-0

Andrea Micheletti, Alessandro Tiero, Giuseppe Tomassetti

{"title":"Simulation and design of isostatic thick origami structures","authors":"Andrea Micheletti, Alessandro Tiero, Giuseppe Tomassetti","doi":"10.1007/s11012-024-01815-0","DOIUrl":"10.1007/s11012-024-01815-0","url":null,"abstract":"<div><p>Thick origami structures are considered here as assemblies of polygonal panels hinged to each other along their edges according to a corresponding origami crease pattern. The determination of the internal actions in equilibrium with the external loads in such structures is not an easy task, owing to their high degree of static indeterminacy, and the likelihood of unwanted self-balanced internal actions induced by manufacturing imperfections. Here, we present a method for reducing the degree of static indeterminacy which can be applied to several thick origami structures to make them isostatic. The method utilizes sliding hinges, which allow relative translation along the hinge axis, to replace conventional hinges. After giving the analytical description of both types of hinges and describing a rigid folding simulation procedure based on the integration of the exponential map, we present the static analysis of a series of noteworthy examples based on the Miura-ori pattern, the Yoshimura pattern, and the Kresling pattern. Our method, based on kinematic-static duality, provides a novel design paradigm that can be applied for the design and realization of thick origami structures with adequate strength to resist external actions.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"59 9","pages":"1403 - 1423"},"PeriodicalIF":1.9,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11012-024-01815-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141528570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0