International Journal of Mechanical Sciences最新文献_第4页

Study of grain stresses and crystallographic slips in duplex steel using neutron diffraction 利用中子衍射研究双相钢中的晶粒应力和结晶滑移

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-09-20 DOI: 10.1016/j.ijmecsci.2024.109745

In this work, a novel method for determination of the stress tensor for groups of grains having preferred texture orientations and Critical Resolved Shear Stresses (CRSSs) necessary for activation of slip systems was applied to study the elastic-plastic properties of textured duplex steel. The methodology is based on in situ neutron diffraction measurements of lattice strains for groups of grains in the ferritic and austenitic phases during tensile test.

Using the stress tensors determined for selected grains, the evolution of the Resolved Shear Stress (RSS) was analysed. As a result, for the first time CRSS values for slip systems activated in both phases of duplex steels have been determined directly from experimental data. The important advantage of the used novel methodology is that the grain stress tensor and CRSSs were determined for representative volumes of polycrystalline grains, without the use of any elastic-plastic models. It was found that, due to the heat treatment of the material, the ferritic phase is significantly harder than the austenitic phase, leading to high yield stress value for the steel under study. For the first time, the evolution of the stress tensor and RSS for austenitic grains with different orientations was determined experimentally and the different mechanical behaviour of these grains was demonstrated.

Finally, the experimental data were compared with the multi-scale Elastic-Plastic Self-Consistent (EPSC) model, which used experimental CRSSs as input data. The agreement of the predicted grain stress and macroscopic stress-strain relationship with the experimental results obtained from the tensile test positively verified the Eshelby-type grain interaction used in the EPSC model. Determining representative CRSS values from the experiment for two-phase textured material, as done for the first time in this work, reduces the number of input parameters of mechanical multiscale models by increasing their unambiguity and allowing their verification.

在这项工作中，采用了一种新方法来确定具有优先纹理取向的晶粒组的应力张量和激活滑移系统所需的临界分辨剪切应力 (CRSS)，以研究纹理双相钢的弹塑性特性。该方法基于拉伸试验期间对铁素体和奥氏体晶粒组晶格应变的原位中子衍射测量。结果，首次从实验数据中直接确定了在双相钢两相中激活的滑移系统的 CRSS 值。所使用的新方法的重要优势在于，晶粒应力张量和 CRSS 是针对多晶晶粒的代表性体积确定的，无需使用任何弹塑性模型。研究发现，由于材料经过热处理，铁素体相的硬度明显高于奥氏体相，导致所研究钢材的屈服应力值较高。最后，实验数据与使用实验 CRSS 作为输入数据的多尺度弹塑性自洽（EPSC）模型进行了比较。预测的晶粒应力和宏观应力-应变关系与拉伸试验的实验结果一致，这从正面验证了 EPSC 模型中使用的 Eshelby 型晶粒相互作用。从实验中确定两相纹理材料的代表性 CRSS 值是这项工作中首次完成的，它减少了机械多尺度模型的输入参数数量，提高了模型的明确性，并允许对其进行验证。

{"title":"Study of grain stresses and crystallographic slips in duplex steel using neutron diffraction","authors":"","doi":"10.1016/j.ijmecsci.2024.109745","DOIUrl":"10.1016/j.ijmecsci.2024.109745","url":null,"abstract":"<div><div>In this work, a novel method for determination of the stress tensor for groups of grains having preferred texture orientations and Critical Resolved Shear Stresses (CRSSs) necessary for activation of slip systems was applied to study the elastic-plastic properties of textured duplex steel. The methodology is based on in situ neutron diffraction measurements of lattice strains for groups of grains in the ferritic and austenitic phases during tensile test.</div><div>Using the stress tensors determined for selected grains, the evolution of the Resolved Shear Stress (RSS) was analysed. As a result, for the first time CRSS values for slip systems activated in both phases of duplex steels have been determined directly from experimental data. The important advantage of the used novel methodology is that the grain stress tensor and CRSSs were determined for representative volumes of polycrystalline grains, without the use of any elastic-plastic models. It was found that, due to the heat treatment of the material, the ferritic phase is significantly harder than the austenitic phase, leading to high yield stress value for the steel under study. For the first time, the evolution of the stress tensor and RSS for austenitic grains with different orientations was determined experimentally and the different mechanical behaviour of these grains was demonstrated.</div><div>Finally, the experimental data were compared with the multi-scale Elastic-Plastic Self-Consistent (EPSC) model, which used experimental CRSSs as input data. The agreement of the predicted grain stress and macroscopic stress-strain relationship with the experimental results obtained from the tensile test positively verified the Eshelby-type grain interaction used in the EPSC model. Determining representative CRSS values from the experiment for two-phase textured material, as done for the first time in this work, reduces the number of input parameters of mechanical multiscale models by increasing their unambiguity and allowing their verification.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":null,"pages":null},"PeriodicalIF":7.1,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142359532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Stress-induced warpage estimation of advanced semiconductor copper interconnect processes 先进半导体铜互连工艺的应力诱发翘曲估算

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-09-19 DOI: 10.1016/j.ijmecsci.2024.109744

The growth of the semiconductor industry is driven by the demand for electronic products and high transistor density. However, complex manufacturing processes generate residual stress and result in wafer warpage. Therefore, mastering wafer warpage has become a crucial challenge. This study proposes a process-oriented simulation methodology with simulation-based equivalent material method to overcome the difficulty of finite element modeling and the substantial amount of computation time. Three different methodologies, including volume percentage, representative volume element, and Timoshenko bi-material approach, are discussed due to the estimation of residual stress for equivalent material. In addition, each methodology is validated through process-oriented simulations and comparison with measurement data. The Timoshenko bi-material approach is efficient in predicting warpage in the back end of line (BEOL) interconnects and provides a comprehensive understanding of the warpage variation that occurs during different stages of BEOL.

电子产品的需求和高晶体管密度推动了半导体行业的发展。然而，复杂的制造工艺会产生残余应力，导致晶片翘曲。因此，掌握晶圆翘曲已成为一项重要挑战。本研究提出了一种以工艺为导向的仿真方法，并采用基于仿真的等效材料法，以克服有限元建模的困难和大量的计算时间。针对等效材料残余应力的估算，讨论了三种不同的方法，包括体积百分比法、代表性体积元素法和 Timoshenko 双材料法。此外，每种方法都通过面向过程的模拟和与测量数据的比较进行了验证。Timoshenko 双材料方法能有效预测生产线后端 (BEOL) 互连中的翘曲，并能全面了解 BEOL 不同阶段中发生的翘曲变化。

引用次数: 0

Regimes in the axisymmetric stiction of thin elastic plates 薄弹性板的轴对称滞留机制

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-09-19 DOI: 10.1016/j.ijmecsci.2024.109740

This work considers the adhesion of a thin, prestressed elastic plate to the bottom of a microcavity – a scenario that can be found frequently in thin-film devices from pressure sensors to microfluidics. This adhesion phenomenon is also referred to as stiction in the field of nano/microelectromechanical systems (N/MEMS); the geometry we consider is axisymmetric (thereby we term this problem axisymmetric stiction). Motivated by the extreme thinness of increasingly exploited nanofilms such as 2D materials in functional devices, various limiting regimes of the axisymmetric stiction problem that arise due to the interplay of the bending, stretching, and pretension effects are discussed. Specifically, key dimensionless physical parameters in this problem are discussed and the range of these parameters for the classification of different regimes is outlined. This classification allows for analytical/asymptotic solutions for the critical adhesion conditions and the adhesion length in different regimes, many of which are not yet available in the literature. These analytical results are verified numerically and also compared with experiments based on 3-500 nm thick 2D materials. As such, this work provides a complete overview of the physically relevant regimes associated with axisymmetric stiction, establishing a regime diagram that can be directed used for the evaluation of the structural reliability of rapidly emerging thin plate devices.

这项研究考虑的是预应力弹性薄板与微腔底部的粘附问题--这种情况经常出现在从压力传感器到微流控的薄膜设备中。这种粘附现象在纳米/微机电系统（N/MEMS）领域也被称为stiction；我们考虑的几何形状是轴对称的（因此我们称这个问题为轴对称stiction）。由于越来越多的纳米薄膜（如功能器件中的二维材料）厚度极薄，我们讨论了由于弯曲、拉伸和预拉伸效应的相互作用而产生的轴对称粘滞问题的各种极限状态。具体而言，讨论了这一问题中的关键无量纲物理参数，并概述了这些参数在不同状态分类中的范围。通过这种分类，可以得到临界粘附条件和不同状态下粘附长度的分析/渐近解，其中许多解法在文献中尚未出现。这些分析结果得到了数值验证，并与基于 3-500 nm 厚二维材料的实验进行了比较。因此，这项工作提供了与轴对称粘滞相关的物理相关制度的完整概述，建立了制度图，可直接用于评估快速出现的薄板设备的结构可靠性。

{"title":"Regimes in the axisymmetric stiction of thin elastic plates","authors":"","doi":"10.1016/j.ijmecsci.2024.109740","DOIUrl":"10.1016/j.ijmecsci.2024.109740","url":null,"abstract":"<div><div>This work considers the adhesion of a thin, prestressed elastic plate to the bottom of a microcavity – a scenario that can be found frequently in thin-film devices from pressure sensors to microfluidics. This adhesion phenomenon is also referred to as stiction in the field of nano/microelectromechanical systems (N/MEMS); the geometry we consider is axisymmetric (thereby we term this problem <em>axisymmetric stiction</em>). Motivated by the extreme thinness of increasingly exploited nanofilms such as 2D materials in functional devices, various limiting regimes of the axisymmetric stiction problem that arise due to the interplay of the bending, stretching, and pretension effects are discussed. Specifically, key dimensionless physical parameters in this problem are discussed and the range of these parameters for the classification of different regimes is outlined. This classification allows for analytical/asymptotic solutions for the critical adhesion conditions and the adhesion length in different regimes, many of which are not yet available in the literature. These analytical results are verified numerically and also compared with experiments based on 3-500 nm thick 2D materials. As such, this work provides a complete overview of the physically relevant regimes associated with axisymmetric stiction, establishing a regime diagram that can be directed used for the evaluation of the structural reliability of rapidly emerging thin plate devices.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":null,"pages":null},"PeriodicalIF":7.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Stress fields at skin-stringer junctions in composite aircraft fuselages 复合材料飞机机身蒙皮-弦杆连接处的应力场

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-09-19 DOI: 10.1016/j.ijmecsci.2024.109737

This paper presents a semi-analytical analysis approach for the determination of stress fields in the vicinity of skin-stringer junctions in stiffened composite panels. The situation considered in this paper is representative for a typical stiffened panel in a modern composite aircraft fuselage. The analysis method employs a two-tier approach employing a global model based on CLPT on the one hand, and a local approach on the other hand in the form of a layerwise displacement formulation. This allows for the detailed computation of the stress concentrations in the vicinity of the skin-stringer junction. The layerwise formulation utilizes a discretization of the laminate layers into mathematical layers. The principle of the minimum of the total elastic potential yields the governing equations of the given problem, and an exponential approach leads to a quadratic eigenvalue problem that can be solved numerically. The analysis method shows excellent accuracy of the stress results in comparison with comparative finite element computations at a fraction of the computational time and effort that is required for numerical analyses.

本文提出了一种半分析方法，用于确定加劲复合板蒙皮-弦杆连接处附近的应力场。本文所考虑的情况是现代复合材料飞机机身中典型的加劲板。分析方法采用了两层方法，一方面是基于 CLPT 的全局模型，另一方面是分层位移公式形式的局部方法。这样就可以详细计算蒙皮-弦杆交界处附近的应力集中。分层计算法将层压板离散化为数学层。根据总弹性势能最小的原理，可得出给定问题的控制方程，并通过指数方法得出二次特征值问题，从而进行数值求解。与有限元计算相比，该分析方法的应力结果具有极高的准确性，而所需的计算时间和工作量仅为数值分析的一小部分。

{"title":"Stress fields at skin-stringer junctions in composite aircraft fuselages","authors":"","doi":"10.1016/j.ijmecsci.2024.109737","DOIUrl":"10.1016/j.ijmecsci.2024.109737","url":null,"abstract":"<div><div>This paper presents a semi-analytical analysis approach for the determination of stress fields in the vicinity of skin-stringer junctions in stiffened composite panels. The situation considered in this paper is representative for a typical stiffened panel in a modern composite aircraft fuselage. The analysis method employs a two-tier approach employing a global model based on CLPT on the one hand, and a local approach on the other hand in the form of a layerwise displacement formulation. This allows for the detailed computation of the stress concentrations in the vicinity of the skin-stringer junction. The layerwise formulation utilizes a discretization of the laminate layers into mathematical layers. The principle of the minimum of the total elastic potential yields the governing equations of the given problem, and an exponential approach leads to a quadratic eigenvalue problem that can be solved numerically. The analysis method shows excellent accuracy of the stress results in comparison with comparative finite element computations at a fraction of the computational time and effort that is required for numerical analyses.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":null,"pages":null},"PeriodicalIF":7.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020740324007781/pdfft?md5=fb41720f3d68d147a12e8b0f425073cb&pid=1-s2.0-S0020740324007781-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142306457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Deep-learning-based generative design for optimal reactive silencers 基于深度学习的最佳反应式消音器生成设计

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-09-19 DOI: 10.1016/j.ijmecsci.2024.109736

A deep-learning-based generative design method is proposed to improve the frequency-dependent characteristics of a reactive silencer, and it has been validated both numerically and experimentally. The noise attenuation performance of the reactive silencer is evaluated with its transmission loss (TL), which varies with frequency and strongly depends on the partition layout inside the reactive silencer. The artificial neural network model for the generative design of the reactive silencer consists of three subnetwork models: the generator, predictor, and converter. The generator model created numerous partition layouts, and their TL curves were estimated using the predictor model. A converter model was developed to identify the frequency-dependent characteristics of the TL curves in a low-dimensional latent space. The latent space was extensively investigated to successfully select the optimal partition layouts satisfying given design requirements, including the target shape of the TL curve and its averaged target TL value. The effectiveness of the proposed method was demonstrated by applying it to three reactive silencer design problems with different design requirements. Among the three optimal silencers, one was physically investigated, and its noise attenuation performance was validated with an acoustic experiment. Because the artificial neural network model of the proposed method was developed for a normalized silencer and requires no prior knowledge of acoustics, it can be easily applied to reduce duct noise in the industry.

本文提出了一种基于深度学习的生成设计方法，用于改进反应式消音器的频率相关特性，并通过数值和实验进行了验证。反应式消音器的噪声衰减性能通过其传输损耗（TL）进行评估，TL 随频率变化，并与反应式消音器内部的分区布局密切相关。用于反应式消音器生成设计的人工神经网络模型由三个子网络模型组成：生成器、预测器和转换器。生成器模型创建了许多分区布局，并使用预测器模型估算了它们的 TL 曲线。转换器模型的开发是为了在低维潜在空间中识别 TL 曲线的频率相关特性。通过对潜空间的广泛研究，成功地选择了满足给定设计要求的最佳分区布局，包括 TL 曲线的目标形状及其平均目标 TL 值。通过将该方法应用于三个具有不同设计要求的反应式消音器设计问题，证明了该方法的有效性。对三个最佳消音器中的一个进行了物理研究，并通过声学实验验证了其噪声衰减性能。由于所提方法的人工神经网络模型是针对归一化消音器开发的，不需要声学方面的先验知识，因此很容易应用于降低工业管道噪声。

{"title":"Deep-learning-based generative design for optimal reactive silencers","authors":"","doi":"10.1016/j.ijmecsci.2024.109736","DOIUrl":"10.1016/j.ijmecsci.2024.109736","url":null,"abstract":"<div><div>A deep-learning-based generative design method is proposed to improve the frequency-dependent characteristics of a reactive silencer, and it has been validated both numerically and experimentally. The noise attenuation performance of the reactive silencer is evaluated with its transmission loss (TL), which varies with frequency and strongly depends on the partition layout inside the reactive silencer. The artificial neural network model for the generative design of the reactive silencer consists of three subnetwork models: the generator, predictor, and converter. The generator model created numerous partition layouts, and their TL curves were estimated using the predictor model. A converter model was developed to identify the frequency-dependent characteristics of the TL curves in a low-dimensional latent space. The latent space was extensively investigated to successfully select the optimal partition layouts satisfying given design requirements, including the target shape of the TL curve and its averaged target TL value. The effectiveness of the proposed method was demonstrated by applying it to three reactive silencer design problems with different design requirements. Among the three optimal silencers, one was physically investigated, and its noise attenuation performance was validated with an acoustic experiment. Because the artificial neural network model of the proposed method was developed for a normalized silencer and requires no prior knowledge of acoustics, it can be easily applied to reduce duct noise in the industry.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":null,"pages":null},"PeriodicalIF":7.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142318860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Shape and topology optimization method with generalized topological derivatives 使用广义拓扑导数的形状和拓扑优化方法

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-09-19 DOI: 10.1016/j.ijmecsci.2024.109735

This paper introduces a novel method for shape and topology optimization based on a generalized approach for evaluating topological derivatives, which are essential for the integration of shape and topology optimization. Traditionally, evaluating these derivatives presents significant mathematical challenges due to the discontinuity introduced by the insertion of a hole within the domain of interest. To overcome this issue, the study employs Helmholtz-type partial differential equations (PDEs) to construct a filtered objective functional. This approach ensures differentiability across the material and void phases and continuity over the fixed design domain while maintaining the same evaluation value as the original objective functional. By considering differentiability, continuity conditions, and the relationship between shape and topological derivatives during asymptotic analysis, generalized topological derivatives are obtained through established mathematical procedures. These topological derivatives exhibit a direct correlation with the PDE solutions and demonstrate satisfactory smoothness, thereby facilitating refined shapes in optimization strategies. Furthermore, an effective shape update algorithm is proposed, which directly integrates topological derivatives into structural optimization problems, simplifying their implementation and improving efficiency. Finally, the efficacy of the proposed methodology is demonstrated through its application to various optimal design problems, including stiffness maximization, compliant mechanisms, and eigenfrequency maximization. Verification results further highlight its potential to enhance existing methods for addressing more practical and complex optimization challenges.

本文介绍了一种新颖的形状和拓扑优化方法，该方法基于拓扑导数评估的通用方法，拓扑导数对于形状和拓扑优化的整合至关重要。传统上，由于在感兴趣的域内插入一个孔会带来不连续性，因此评估这些导数会带来巨大的数学挑战。为了克服这一问题，本研究采用了亥姆霍兹型偏微分方程（PDE）来构建过滤目标函数。这种方法确保了材料阶段和空隙阶段的可微分性以及固定设计域的连续性，同时保持了与原始目标函数相同的评估值。在渐近分析过程中，通过考虑可微分性、连续性条件以及形状导数和拓扑导数之间的关系，可以通过既定的数学程序获得广义拓扑导数。这些拓扑导数与 PDE 解直接相关，并表现出令人满意的平滑性，从而有助于优化策略中的精细形状。此外，还提出了一种有效的形状更新算法，该算法将拓扑导数直接整合到结构优化问题中，简化了实施过程并提高了效率。最后，通过应用于各种优化设计问题，包括刚度最大化、顺从机构和特征频率最大化，证明了所提方法的有效性。验证结果进一步凸显了该方法在增强现有方法以应对更实际、更复杂的优化挑战方面的潜力。

{"title":"Shape and topology optimization method with generalized topological derivatives","authors":"","doi":"10.1016/j.ijmecsci.2024.109735","DOIUrl":"10.1016/j.ijmecsci.2024.109735","url":null,"abstract":"<div><div>This paper introduces a novel method for shape and topology optimization based on a generalized approach for evaluating topological derivatives, which are essential for the integration of shape and topology optimization. Traditionally, evaluating these derivatives presents significant mathematical challenges due to the discontinuity introduced by the insertion of a hole within the domain of interest. To overcome this issue, the study employs Helmholtz-type partial differential equations (PDEs) to construct a filtered objective functional. This approach ensures differentiability across the material and void phases and continuity over the fixed design domain while maintaining the same evaluation value as the original objective functional. By considering differentiability, continuity conditions, and the relationship between shape and topological derivatives during asymptotic analysis, generalized topological derivatives are obtained through established mathematical procedures. These topological derivatives exhibit a direct correlation with the PDE solutions and demonstrate satisfactory smoothness, thereby facilitating refined shapes in optimization strategies. Furthermore, an effective shape update algorithm is proposed, which directly integrates topological derivatives into structural optimization problems, simplifying their implementation and improving efficiency. Finally, the efficacy of the proposed methodology is demonstrated through its application to various optimal design problems, including stiffness maximization, compliant mechanisms, and eigenfrequency maximization. Verification results further highlight its potential to enhance existing methods for addressing more practical and complex optimization challenges.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":null,"pages":null},"PeriodicalIF":7.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142318863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Modelling of axial thrust force considering 3D rolling deformation 考虑三维滚动变形的轴向推力模型

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-09-18 DOI: 10.1016/j.ijmecsci.2024.109738

The axial thrust force in the rolling deformation zone is influenced by interconnected factors, such as the metal transverse flow velocity, rolling pressure distribution, and strip shear deformation, often resulting in roll wear and a lower strip surface quality. Despite its significance in the design and manufacturing of strip mills, the available literature primarily focuses on the single-variable complete difference method as a means of evaluating this force. In this study, a novel approach is proposed for calculating the axial thrust force in the rolling deformation zone, incorporating the coupling variables of the 3D rolling space. The accuracy of the results is confirmed using data obtained from an industrial test rig, indicating that the axial thrust force in the rolling deformation zone can be precisely calculated through the integration of the energy method and the 3D difference method. The results indicate that the axial thrust force decreases with the transverse flow of the metal and the transverse shear deformation of the strip. It increases with a non-uniform distribution of rolling pressure and grows as the crossover angle increases. Conversely, the axial thrust force decreases with an increasing reduction rate of the strip. In general, a non-uniform distribution of rolling pressure enhances the axial thrust force, albeit with a minor effect when the crossover angle exceeds 0.8° Conversely, metal transverse flow significantly reduces the axial thrust force when the crossover angle is small (φ < 0.4°), but only marginally so when the crossover angle falls within the range of 0.4° to 1.0°

轧制变形区的轴向推力受金属横向流速、轧制压力分布和板带剪切变形等相互关联因素的影响，通常会导致轧辊磨损和板带表面质量下降。尽管这种力在板带轧机的设计和制造中非常重要，但现有文献主要集中在将单变量完全差分法作为评估这种力的手段。本研究提出了一种计算轧制变形区轴向推力的新方法，其中包含三维轧制空间的耦合变量。利用从工业试验台获得的数据证实了计算结果的准确性，表明通过能量法和三维差分法的整合，可以精确计算滚动变形区的轴向推力。结果表明，轴向推力随着金属的横向流动和带材的横向剪切变形而减小。轴向推力随着轧制压力的不均匀分布而增大，并随着交叉角的增大而增大。相反，轴向推力随着带钢减薄率的增加而减小。相反，当交叉角较小时（φ < 0.4°），金属横向流动会显著减小轴向推力，但当交叉角在 0.4°至 1.0°范围内时，轴向推力会略有减小。

{"title":"Modelling of axial thrust force considering 3D rolling deformation","authors":"","doi":"10.1016/j.ijmecsci.2024.109738","DOIUrl":"10.1016/j.ijmecsci.2024.109738","url":null,"abstract":"<div><div>The axial thrust force in the rolling deformation zone is influenced by interconnected factors, such as the metal transverse flow velocity, rolling pressure distribution, and strip shear deformation, often resulting in roll wear and a lower strip surface quality. Despite its significance in the design and manufacturing of strip mills, the available literature primarily focuses on the single-variable complete difference method as a means of evaluating this force. In this study, a novel approach is proposed for calculating the axial thrust force in the rolling deformation zone, incorporating the coupling variables of the 3D rolling space. The accuracy of the results is confirmed using data obtained from an industrial test rig, indicating that the axial thrust force in the rolling deformation zone can be precisely calculated through the integration of the energy method and the 3D difference method. The results indicate that the axial thrust force decreases with the transverse flow of the metal and the transverse shear deformation of the strip. It increases with a non-uniform distribution of rolling pressure and grows as the crossover angle increases. Conversely, the axial thrust force decreases with an increasing reduction rate of the strip. In general, a non-uniform distribution of rolling pressure enhances the axial thrust force, albeit with a minor effect when the crossover angle exceeds 0.8° Conversely, metal transverse flow significantly reduces the axial thrust force when the crossover angle is small (<em>φ</em> < 0.4°), but only marginally so when the crossover angle falls within the range of 0.4° to 1.0°</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":null,"pages":null},"PeriodicalIF":7.1,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142306472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Space–time topology optimization for anisotropic materials in wire and arc additive manufacturing 线材和电弧增材制造中各向异性材料的时空拓扑优化

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-09-18 DOI: 10.1016/j.ijmecsci.2024.109712

Wire and Arc Additive Manufacturing (WAAM) has great potential for efficiently producing large metallic components. However, like other additive manufacturing techniques, materials processed by WAAM exhibit anisotropic properties. Assuming isotropic material properties in design optimization thus leads to less efficient material utilization. Instead of viewing WAAM-induced material anisotropy as a limitation, we consider it an opportunity to improve structural performance. This requires the integration of process planning into structural design. In this paper, we propose a novel method to utilize material anisotropy to enhance the performance of structures both during fabrication and in their use. Our approach is based on space–time topology optimization, which simultaneously optimizes the structural layout and the fabrication sequence. To model material anisotropy in space–time topology optimization, we derive the material deposition direction from the gradient of the pseudo-time field, which encodes the fabrication sequence. Numerical results demonstrate that leveraging material anisotropy effectively improves the performance of intermediate structures during fabrication as well as the overall structure.

线弧增材制造（WAAM）在高效生产大型金属部件方面具有巨大潜力。然而，与其他增材制造技术一样，WAAM 加工的材料也具有各向异性。因此，在优化设计时假设材料具有各向同性，会降低材料利用效率。我们不会将 WAAM 引起的材料各向异性视为一种限制，而是将其视为提高结构性能的机会。这就需要将工艺规划与结构设计相结合。在本文中，我们提出了一种利用材料各向异性来提高结构在制造和使用过程中性能的新方法。我们的方法基于时空拓扑优化，可同时优化结构布局和制造顺序。为了在时空拓扑优化中建立材料各向异性模型，我们从伪时域梯度推导出材料沉积方向，伪时域梯度编码了制造顺序。数值结果表明，利用材料各向异性可以有效改善制造过程中的中间结构以及整体结构的性能。

{"title":"Space–time topology optimization for anisotropic materials in wire and arc additive manufacturing","authors":"","doi":"10.1016/j.ijmecsci.2024.109712","DOIUrl":"10.1016/j.ijmecsci.2024.109712","url":null,"abstract":"<div><div>Wire and Arc Additive Manufacturing (WAAM) has great potential for efficiently producing large metallic components. However, like other additive manufacturing techniques, materials processed by WAAM exhibit anisotropic properties. Assuming isotropic material properties in design optimization thus leads to less efficient material utilization. Instead of viewing WAAM-induced material anisotropy as a limitation, we consider it an opportunity to improve structural performance. This requires the integration of process planning into structural design. In this paper, we propose a novel method to utilize material anisotropy to enhance the performance of structures both during fabrication and in their use. Our approach is based on space–time topology optimization, which simultaneously optimizes the structural layout and the fabrication sequence. To model material anisotropy in space–time topology optimization, we derive the material deposition direction from the gradient of the pseudo-time field, which encodes the fabrication sequence. Numerical results demonstrate that leveraging material anisotropy effectively improves the performance of intermediate structures during fabrication as well as the overall structure.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":null,"pages":null},"PeriodicalIF":7.1,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0020740324007537/pdfft?md5=6cb6e1b0e3fd63ce43b17fc4eac3b07f&pid=1-s2.0-S0020740324007537-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142306471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Vibration suppression in SDOF systems coupled to a nonlinear energy sink under colored noise 彩色噪声下与非线性能量汇耦合的 SDOF 系统的振动抑制

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-09-17 DOI: 10.1016/j.ijmecsci.2024.109718

This study analyzes the stochastic vibration suppression and optimization of the single-degree-of-freedom (SDOF) system equipped with the cubic stiffness nonlinear energy sink (NES) under colored noise excitation. Two theoretical methods are proposed: an integrated method (denoted as EL-ELM) that combines evolutionary Lyapunov theory with the equivalent linearization method, and the other is an empirical formula. Using EL-ELM, the coupled nonlinear system is simplified to an equivalent linear stochastic system, allowing for a theoretical analysis of the impact of NES structural parameters on suppression performance and the precise determination of optimal parameter configurations for the best suppression effects. Subsequently, based on the results from the EL-ELM and the response data, an empirical formula has been developed that clearly describes the comprehensive laws governing the optimal NES parameters as they vary with vibration system parameters and stochastic excitation. Through error analysis and comparison of the two methods, it is found that the empirical formula significantly outperforms EL-ELM in terms of accuracy and computational cost, but it is contingent on solid prior knowledge. This study explores the influence of NES structural parameters on the system’s dynamic response and energy, further validating the effectiveness of the proposed methods in identifying optimal structural parameters. The phenomenon of targeted energy transfer (TET) under different NES structural parameters is also explained. The methodologies introduced in this study have strengthened the theory of vibration suppression. Specifically, the empirical formula excels in accuracy and computational efficiency by effectively using prior knowledge. The EL-ELM method, owing to its theoretical insights, is vital for analyzing complex stochastic nonlinear models. Combining these approaches offers guidance for advancing vibration control in theoretical and practical domains.

本研究分析了单自由度（SDOF）系统在彩色噪声激励下的随机振动抑制和优化问题，该系统配备了立方刚度非线性能量汇（NES）。本文提出了两种理论方法：一种是将进化李雅普诺夫理论与等效线性化方法相结合的综合方法（称为 EL-ELM），另一种是经验公式。利用 EL-ELM，耦合非线性系统被简化为等效线性随机系统，从而可以从理论上分析 NES 结构参数对抑制性能的影响，并精确确定最佳参数配置，以获得最佳抑制效果。随后，根据 EL-ELM 的结果和响应数据，开发了一个经验公式，清晰地描述了最佳 NES 参数随振动系统参数和随机激励变化的综合规律。通过误差分析和两种方法的比较，发现经验公式在精度和计算成本方面明显优于 EL-ELM，但这取决于扎实的先验知识。本研究探讨了 NES 结构参数对系统动态响应和能量的影响，进一步验证了所提方法在确定最佳结构参数方面的有效性。此外，还解释了不同 NES 结构参数下的目标能量转移（TET）现象。本研究引入的方法加强了振动抑制理论。具体而言，经验公式通过有效利用先验知识，在准确性和计算效率方面表现出色。EL-ELM 方法由于其理论洞察力，对于分析复杂的随机非线性模型至关重要。将这些方法结合起来，可为在理论和实践领域推进振动控制提供指导。

{"title":"Vibration suppression in SDOF systems coupled to a nonlinear energy sink under colored noise","authors":"","doi":"10.1016/j.ijmecsci.2024.109718","DOIUrl":"10.1016/j.ijmecsci.2024.109718","url":null,"abstract":"<div><div>This study analyzes the stochastic vibration suppression and optimization of the single-degree-of-freedom (SDOF) system equipped with the cubic stiffness nonlinear energy sink (NES) under colored noise excitation. Two theoretical methods are proposed: an integrated method (denoted as EL-ELM) that combines evolutionary Lyapunov theory with the equivalent linearization method, and the other is an empirical formula. Using EL-ELM, the coupled nonlinear system is simplified to an equivalent linear stochastic system, allowing for a theoretical analysis of the impact of NES structural parameters on suppression performance and the precise determination of optimal parameter configurations for the best suppression effects. Subsequently, based on the results from the EL-ELM and the response data, an empirical formula has been developed that clearly describes the comprehensive laws governing the optimal NES parameters as they vary with vibration system parameters and stochastic excitation. Through error analysis and comparison of the two methods, it is found that the empirical formula significantly outperforms EL-ELM in terms of accuracy and computational cost, but it is contingent on solid prior knowledge. This study explores the influence of NES structural parameters on the system’s dynamic response and energy, further validating the effectiveness of the proposed methods in identifying optimal structural parameters. The phenomenon of targeted energy transfer (TET) under different NES structural parameters is also explained. The methodologies introduced in this study have strengthened the theory of vibration suppression. Specifically, the empirical formula excels in accuracy and computational efficiency by effectively using prior knowledge. The EL-ELM method, owing to its theoretical insights, is vital for analyzing complex stochastic nonlinear models. Combining these approaches offers guidance for advancing vibration control in theoretical and practical domains.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":null,"pages":null},"PeriodicalIF":7.1,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Parametric instability analysis of rotors under anisotropic boundary conditions 各向异性边界条件下转子的参数失稳分析

IF 7.1 1区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Mechanical Sciences

Pub Date : 2024-09-16 DOI: 10.1016/j.ijmecsci.2024.109739

Ensuring rotor stability is a major concern in engineering, as instabilities can lead to catastrophic failures. Existing literature shows that anisotropic boundary conditions significantly affect the parametric instability characteristics of rotors under periodical axial loads. However, there is little literature systematically analyzing the formation mechanism of parametric resonance under these boundary conditions or providing a detailed classification of the parametric instability regions. Therefore, this paper presents a comprehensive parametric instability analysis of a rotor subjected to periodic axial loads under anisotropic boundary conditions. A novel approach based on the multiple scales method is proposed to address anisotropy in the boundary conditions. Using this approach, the analytical boundaries of the parametric instability regions are derived, and a proof regarding the absence of certain parametric resonances is presented. These analytical solutions are validated by numerical results obtained from the discrete transition matrix method, which form the basis for systematically investigating the effects of anisotropy in direct or cross-coupling stiffness/damping coefficients on the rotor instability. The key scientific contributions of this work include: Deriving analytical instability boundaries, providing a more efficient alternative to purely numerical methods while maintaining high accuracy; Demonstrating the absence of parametric resonance of difference type under both isotropic or anisotropic boundary conditions; Discovering that anisotropy in stiffness coefficients can induce self-interaction within a given forward or backward whirl mode, as well as interaction between two forward or two backward whirl modes, leading to additional instability regions; Reducing anisotropy in direct damping coefficients may increase critical dynamic load coefficients, potentially enhancing rotor safety; If the cross-coupling stiffness coefficients exceed the threshold for triggering intrinsic instability, the rotor may become unstable in all operating conditions. All these findings offer insights into the stability management of rotors under various operating conditions and provide valuable guidance for designing and operating safer, more efficient rotor systems.

确保转子的稳定性是工程领域的一个主要问题，因为不稳定性可能导致灾难性故障。现有文献表明，各向异性边界条件会显著影响转子在周期性轴向载荷作用下的参数失稳特性。然而，很少有文献系统地分析这些边界条件下参数共振的形成机理，或对参数失稳区域进行详细的分类。因此，本文对各向异性边界条件下承受周期性轴向载荷的转子进行了全面的参数失稳分析。本文提出了一种基于多尺度法的新方法来解决边界条件中的各向异性问题。利用这种方法，得出了参数不稳定性区域的分析边界，并证明不存在某些参数共振。离散过渡矩阵法获得的数值结果验证了这些分析解，为系统研究直接或交叉耦合刚度/阻尼系数各向异性对转子不稳定性的影响奠定了基础。这项工作的主要科学贡献包括推导出分析不稳定性边界，在保持高精度的同时，为纯数值方法提供了更有效的替代方法；证明在各向同性或各向异性边界条件下均不存在差分类型的参数共振；发现刚度系数的各向异性可在给定的前向或后向旋流模式内引起自相互作用，以及两个前向或两个后向旋流模式之间的相互作用，从而导致额外的不稳定区域；降低直接阻尼系数的各向异性可能会增加临界动载荷系数，从而提高转子的安全性；如果交叉耦合刚度系数超过了引发内在不稳定性的阈值，转子可能会在所有运行条件下变得不稳定。所有这些发现为转子在各种运行条件下的稳定性管理提供了启示，并为设计和运行更安全、更高效的转子系统提供了宝贵的指导。

{"title":"Parametric instability analysis of rotors under anisotropic boundary conditions","authors":"","doi":"10.1016/j.ijmecsci.2024.109739","DOIUrl":"10.1016/j.ijmecsci.2024.109739","url":null,"abstract":"<div><div>Ensuring rotor stability is a major concern in engineering, as instabilities can lead to catastrophic failures. Existing literature shows that anisotropic boundary conditions significantly affect the parametric instability characteristics of rotors under periodical axial loads. However, there is little literature systematically analyzing the formation mechanism of parametric resonance under these boundary conditions or providing a detailed classification of the parametric instability regions. Therefore, this paper presents a comprehensive parametric instability analysis of a rotor subjected to periodic axial loads under anisotropic boundary conditions. A novel approach based on the multiple scales method is proposed to address anisotropy in the boundary conditions. Using this approach, the analytical boundaries of the parametric instability regions are derived, and a proof regarding the absence of certain parametric resonances is presented. These analytical solutions are validated by numerical results obtained from the discrete transition matrix method, which form the basis for systematically investigating the effects of anisotropy in direct or cross-coupling stiffness/damping coefficients on the rotor instability. The key scientific contributions of this work include: Deriving analytical instability boundaries, providing a more efficient alternative to purely numerical methods while maintaining high accuracy; Demonstrating the absence of parametric resonance of difference type under both isotropic or anisotropic boundary conditions; Discovering that anisotropy in stiffness coefficients can induce self-interaction within a given forward or backward whirl mode, as well as interaction between two forward or two backward whirl modes, leading to additional instability regions; Reducing anisotropy in direct damping coefficients may increase critical dynamic load coefficients, potentially enhancing rotor safety; If the cross-coupling stiffness coefficients exceed the threshold for triggering intrinsic instability, the rotor may become unstable in all operating conditions. All these findings offer insights into the stability management of rotors under various operating conditions and provide valuable guidance for designing and operating safer, more efficient rotor systems.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":null,"pages":null},"PeriodicalIF":7.1,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142306473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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