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Analysis and Design of Lateral Framing Systems for Multi-Story Steel Buildings 多层钢结构横向框架体系的分析与设计
IF 14.3 1区 工程技术 Q1 MECHANICS Pub Date : 2023-03-27 DOI: 10.3390/applmech4020022
Husam Al Dughaishi, Jawad Al Lawati, M. Alosta, S. Mahmood, M. F. Al-Kazee, N. Yusoff, A. Milad
This study focused on identifying the most appropriate structural system for multi-story buildings and analyzing its response to lateral loads. The study analyzed and compared the different structural systems to determine the most suitable option. The study aims to utilize three lateral framing systems (moment, braced, and diagrid) in order to investigate which system needs the least amount of steel to meet the design requirements. Thus, in order to determine the estimated steel savings of this system as compared to the moment and braced frames, the four-story and eight-story buildings that are 96′ × 96′ in the plane and utilize moment frames, braced frame, and diagrid framing structural systems are presented. Based on the American Society of Civil Engineers (ASCE) 7–10, load combinations are considered for the designs, and the RAM structural analysis is used for the modeling and analysis of the structural systems. The findings of this study’s illustrations were the optimum for the analysis of wind of 176 kips and seismic loads of 122 kips, the building’s lateral displacements, which were the lowest at 0.045 inches, the story drift, the story stiffness, and the story shear for each structural system. In addition, the diagrid system also had the least amount of shear for all the stories, suggesting that it is better able to manage the lateral forces. These results indicate that the diagrid system is a more efficient structural system and can be recommended for use in multi-story buildings.
本研究的重点是确定最适合多层建筑的结构体系,并分析其对横向荷载的响应。研究分析和比较了不同的结构体系,以确定最合适的方案。该研究旨在利用三种横向框架系统(弯矩、支撑和网格),以研究哪种系统需要最少的钢材来满足设计要求。因此,为了确定该系统与弯矩框架和支撑框架相比的估计钢材节约量,在平面上采用96 ' × 96 '的四层和八层建筑,并采用弯矩框架、支撑框架和网格框架结构系统。基于美国土木工程师学会(American Society of Civil Engineers, ASCE) 7-10,在设计中考虑荷载组合,并采用RAM结构分析对结构体系进行建模和分析。本研究插图的结果对于176 kips的风和122 kips的地震荷载、建筑物的横向位移(最低为0.045英寸)、楼层漂移、楼层刚度和每个结构系统的楼层剪力的分析是最优的。此外,在所有楼层中,网格系统也具有最小的剪切量,这表明它能够更好地管理侧向力。这些结果表明,网格结构体系是一种更有效的结构体系,可以推荐用于多层建筑。
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引用次数: 0
Combining Digital Image Correlation and Acoustic Emission to Characterize the Flexural Behavior of Flax Biocomposites 结合数字图像相关和声发射表征亚麻生物复合材料的弯曲行为
IF 14.3 1区 工程技术 Q1 MECHANICS Pub Date : 2023-03-21 DOI: 10.3390/applmech4010021
M. Habibi, L. Laperrière
Understanding the effect of staking sequences and identifying the damage occurring within a structure using a structural health monitoring system are the keys to an efficient design of composite-based parts. In this research, a combination of digital image correlation (DIC) and acoustic emission (AE) is used to locate and classify the type of damage depending on the stacking sequence of the laminate during flexural loading. As a first step, the results of the strain fields for unidirectional, cross-ply, and quasi-isotropic laminates were compared to discuss their global behavior and to correlate the different damage patterns with the possible failure mechanisms. The damage was then addressed using a comprehensive interpretation of the acoustic emission signatures and the K-means classification of the acoustic events. The development of each damage mechanism was correlated to the applied load and expressed as a function of the loading rate to highlight the effect of the stacking sequence. Finally, the results of DIC and AE were combined to improve the reliability of the damage investigation without limiting the failure mechanism to matrix cracking, interfacial failure, and fiber breakage, as expected by the unsupervised event clustering.
利用结构健康监测系统了解桩接序列的影响并识别结构内部发生的损伤是有效设计复合材料部件的关键。本研究采用数字图像相关(DIC)和声发射(AE)相结合的方法,根据层压板在弯曲加载过程中的堆叠顺序对损伤类型进行定位和分类。首先,比较了单向、交叉铺层和准各向同性层合板的应变场结果,讨论了它们的整体行为,并将不同的损伤模式与可能的破坏机制联系起来。然后利用声发射特征的综合解释和声事件的K-means分类来解决损伤。每种损伤机制的发展都与外加荷载相关,并表示为加载速率的函数,以突出堆叠顺序的影响。最后,将DIC和AE的结果结合起来,提高了损伤研究的可靠性,而不像无监督事件聚类所期望的那样,将破坏机制局限于基体开裂、界面破坏和纤维断裂。
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引用次数: 3
Real-Time Detection of Faults in Rotating Blades Using Frequency Response Function Analysis 基于频响函数分析的旋转叶片故障实时检测
IF 14.3 1区 工程技术 Q1 MECHANICS Pub Date : 2023-03-15 DOI: 10.3390/applmech4010020
Ravi Prakash Babu Kocharla, M. Kolli, Muralimohan Cheepu
Turbo machines develop faults in the rotating blades during operation in undesirable conditions. Such faults in the rotating blades are fatigue cracks, mechanical looseness, imbalance, misalignment, etc. Therefore, it is crucial that the blade faults should be detected and diagnosed in order to minimize the severe damage of such machines. In this paper, vibration analysis of the rotating blades is conducted using an experimental laboratory setup in order to develop a methodology to detect faults in the rotating blades. The faults considered for the study include cracks and mechanical looseness for which dynamic responses are recorded using a laser vibrometer. Analysis has been carried out by comparing the frequency response function spectrums of the fault blade with those of the healthy blade related to the resonance frequency. The Internet of Things and wireless sensor networks are implemented to transmit the measured data to the cloud platform. A support vector machine algorithm is used for preparing the learning model in order to extract and classify the faults of the rotating blades. It can be clearly seen from the results that there is variation in the frequency response function spectrums of healthy and faulty conditions of the rotating blades.
涡轮机器在不理想的条件下运行时,旋转叶片会出现故障。旋转叶片的故障有疲劳裂纹、机械松动、不平衡、不对中等。因此,对叶片故障进行检测和诊断是至关重要的,以尽量减少这类机器的严重损害。本文利用实验装置对旋转叶片进行了振动分析,以建立一种检测旋转叶片故障的方法。研究中考虑的故障包括裂纹和机械松动,使用激光振动计记录其动态响应。将故障叶片的频响函数谱与健康叶片的频响函数谱与共振频率进行对比分析。实现物联网和无线传感器网络,将测量数据传输到云平台。采用支持向量机算法建立学习模型,对旋转叶片故障进行提取和分类。从结果可以清楚地看出,旋转叶片健康状态和故障状态的频响函数谱存在变化。
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引用次数: 4
Data-Driven, Physics-Based, or Both: Fatigue Prediction of Structural Adhesive Joints by Artificial Intelligence 数据驱动,物理驱动,或两者兼而有之:基于人工智能的结构粘合接头疲劳预测
IF 14.3 1区 工程技术 Q1 MECHANICS Pub Date : 2023-03-08 DOI: 10.3390/applmech4010019
P. Fernandes, G. C. Silva, D. Pitz, Matteo Schnelle, K. Koschek, C. Nagel, V. C. Beber
Here, a comparative investigation of data-driven, physics-based, and hybrid models for the fatigue lifetime prediction of structural adhesive joints in terms of complexity of implementation, sensitivity to data size, and prediction accuracy is presented. Four data-driven models (DDM) are constructed using extremely randomized trees (ERT), eXtreme gradient boosting (XGB), LightGBM (LGBM) and histogram-based gradient boosting (HGB). The physics-based model (PBM) relies on the Findley’s critical plane approach. Two hybrid models (HM) were developed by combining data-driven and physics-based approaches obtained from invariant stresses (HM-I) and Findley’s stress (HM-F). A fatigue dataset of 979 data points of four structural adhesives is employed. To assess the sensitivity to data size, the dataset is split into three train/test ratios, namely 70%/30%, 50%/50%, and 30%/70%. Results revealed that DDMs are more accurate, but more sensitive to dataset size compared to the PBM. Among different regressors, the LGBM presented the best performance in terms of accuracy and generalization power. HMs increased the accuracy of predictions, whilst reducing the sensitivity to data size. The HM-I demonstrated that datasets from different sources can be utilized to improve predictions (especially with small datasets). Finally, the HM-I showed the highest accuracy with an improved sensitivity to data size.
本文从实现的复杂性、对数据大小的敏感性和预测精度等方面对数据驱动模型、物理模型和混合模型进行了比较研究。采用极端随机树(ERT)、极端梯度增强(XGB)、LightGBM (LGBM)和基于直方图的梯度增强(HGB)构建了四个数据驱动模型(DDM)。基于物理的模型(PBM)依赖于Findley的临界平面方法。结合从不变应力(HM- i)和Findley应力(HM- f)中获得的数据驱动和基于物理的方法,开发了两种混合模型(HM)。采用四种结构胶粘剂979个数据点的疲劳数据集。为了评估对数据大小的敏感性,将数据集分为三个训练/测试比率,即70%/30%,50%/50%和30%/70%。结果表明,与PBM相比,ddm更准确,但对数据集大小更敏感。在不同的回归量中,LGBM在准确率和泛化能力方面表现最好。hmm提高了预测的准确性,同时降低了对数据大小的敏感性。HM-I证明了来自不同来源的数据集可以用来改进预测(特别是小数据集)。最后,HM-I显示出最高的准确性,并提高了对数据大小的敏感性。
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引用次数: 5
Electro-Chemo-Mechanical Challenges and Perspective in Lithium Metal Batteries 锂金属电池的电化学-机械挑战与展望
IF 14.3 1区 工程技术 Q1 MECHANICS Pub Date : 2023-03-03 DOI: 10.1115/1.4057039
K. Naik, B. Vishnugopi, Joy Datta, D. Datta, P. Mukherjee
The development of next-generation batteries, utilizing electrodes with high capacities and power densities requires a comprehensive understanding and precise control of material interfaces and architectures. Electro-chemo-mechanics plays an integral role in the morphological evolution and stability of such complex interfaces. Volume changes in electrode materials and the chemical interaction of electrode/electrolyte interfaces result in non-uniform stress fields and structurally-different interphases, fundamentally affecting the underlying transport and reaction kinetics. The origin of this mechanistic coupling and its implications on degradation is uniquely dependent on the interface characteristics. In this review, the distinct nature of chemo-mechanical coupling and failure mechanisms at solid-liquid interfaces and solid-solid interfaces is analyzed. For lithium metal electrodes, the critical role of surface/microstructural heterogeneities on the solid electrolyte interphase (SEI) stability and dendrite growth in liquid electrolytes, and on the onset of contact loss and filament penetration with solid electrolytes (SEs) is summarized. With respect to composite electrodes, key differences in the microstructure-coupled electro-chemo-mechanical attributes of intercalation- and conversion-based chemistries are delineated. Moving from liquid to solid electrolytes in such cathodes, we highlight the significant impact of solid-solid point contacts on transport/mechanical response, electrochemical performance, and failure modes such as particle cracking and delamination. Lastly, we present our perspective on future research directions and opportunities to address the underlying electro-chemo-mechanical challenges for enabling next-generation lithium metal batteries.
利用高容量和功率密度电极的下一代电池的开发需要对材料界面和结构的全面理解和精确控制。电化学力学在这种复杂界面的形态演变和稳定性中起着不可或缺的作用。电极材料的体积变化和电极/电解质界面的化学相互作用导致应力场不均匀和界面相结构不同,从根本上影响了潜在的传输和反应动力学。这种机械耦合的起源及其对降解的影响是唯一依赖于界面特性的。本文分析了固-液界面和固-固界面化学-力学耦合的独特性质和破坏机制。对于锂金属电极,总结了表面/微观结构的非均质性对固体电解质界面相(SEI)稳定性和枝晶生长的关键作用,以及对固体电解质(SEs)接触损失和灯丝渗透的发生的关键作用。对于复合电极,在微观结构耦合电化学-机械属性的插层和转化为基础的化学描述的关键差异。在这种阴极中,从液体电解质到固体电解质,我们强调了固体-固体点接触对传输/机械响应、电化学性能和失效模式(如颗粒破裂和分层)的重要影响。最后,我们提出了我们对未来研究方向和机会的看法,以解决实现下一代锂金属电池的潜在电化学机械挑战。
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引用次数: 5
Closed Form Solution in the Buckling Optimization Problem of Twisted Shafts 扭轴屈曲优化问题的封闭解
IF 14.3 1区 工程技术 Q1 MECHANICS Pub Date : 2023-02-28 DOI: 10.3390/applmech4010018
V. Kobelev
The counterpart for Euler’s buckling problem is Greenhill’s problem, which studies the forming of a loop in an elastic beam under torsion. In the context of twisted shafts, the optimal shape of the beam along its axis is searched. A priori form of the cross-section remains unknown. For the solution of the actual problem, the stability equations take into account all possible convex and simply connected shapes of the cross-section. The cross-sections are similar geometric figures related by a homothetic transformation with respect to a homothetic center on the axis of the beam and vary along its axis. The distribution of material along the length of a twisted shaft is optimized so that the beam is of the constant volume and will support the maximal moment without spatial buckling. The applications of the variational method for stability problems are illustrated in this manuscript.
与欧拉屈曲问题相对应的是格林希尔问题,研究弹性梁在扭转作用下的环的形成。在扭曲轴的情况下,寻找梁沿其轴线的最佳形状。横截面的先验形式仍然未知。对于实际问题的求解,稳定性方程考虑了截面的所有可能的凸形和单连通形状。横截面是相似的几何图形,通过相对于光束轴线上的均匀中心的均匀变换而相关,并沿其轴线变化。优化了材料沿扭曲轴长度的分布,使梁具有恒定的体积,并能承受最大弯矩而无空间屈曲。本文阐述了变分方法在稳定性问题中的应用。
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引用次数: 0
Free-Form Deformation Parameterization on the Aerodynamic Optimization of Morphing Trailing Edge 变形后缘气动优化中的自由变形参数化
IF 14.3 1区 工程技术 Q1 MECHANICS Pub Date : 2023-02-28 DOI: 10.3390/applmech4010017
M. Negahban, M. Bashir, R. Botez
Every aerodynamic optimization is proceeded by a parameterization of the studied aerial object, and due to its influence on the final optimization process, careful attention should be made in choosing the appropriate parameterization method. An aerodynamic optimization of a morphing trailing edge is performed using a free-form deformation parameterization technique with the purpose of examining the influence of the initial conditions of the parameterization on the optimization results, namely on the number of control points. High-fidelity gradient-based optimization using the discrete adjoint method is established by the coupling of OpenFOAM and Python within the DAFoam optimization framework. The results indicate that the number of control points has a considerable effect on the optimization process, in particular on the convergence, objective function value, and on the deformation feasibility.
每一次气动优化都是通过对研究对象进行参数化来进行的,由于参数化对最终优化过程的影响,因此在选择合适的参数化方法时应慎重考虑。采用自由变形参数化技术对变形后缘进行气动优化,目的是考察参数化初始条件对优化结果的影响,即对控制点数量的影响。在DAFoam优化框架内,通过OpenFOAM和Python的耦合,建立了基于离散伴随方法的高保真梯度优化。结果表明,控制点的数量对优化过程有相当大的影响,特别是对收敛性、目标函数值和变形可行性的影响。
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引用次数: 1
Prediction of Effective Elastic and Thermal Properties of Heterogeneous Materials Using Convolutional Neural Networks 利用卷积神经网络预测非均质材料的有效弹性和热性能
IF 14.3 1区 工程技术 Q1 MECHANICS Pub Date : 2023-02-27 DOI: 10.3390/applmech4010016
H. Béji, T. Kanit, T. Messager
The aim of this study is to develop a new method to predict the effective elastic and thermal behavior of heterogeneous materials using Convolutional Neural Networks CNN. This work consists first of all in building a large database containing microstructures of two phases of heterogeneous material with different shapes (circular, elliptical, square, rectangular), volume fractions of the inclusion (20%, 25%, 30%), and different contrasts between the two phases in term of Young modulus and also thermal conductivity. The contrast expresses the degree of heterogeneity in the heterogeneous material, when the value of C is quite important (C >> 1) or quite low (C << 1), it means that the material is extremely heterogeneous, while C= 1, the material becomes totally homogeneous. In the case of elastic properties, the contrast is expressed as the ratio between Young’s modulus of the inclusion and that of the matrix ( C = EiEm), while for thermal properties, this ratio is expressed as a function of the thermal conductivity of both phases (C = λiλm). In our work, the model will be tested on two values of contrast (10 and 100). These microstructures will be used to estimate the elastic and thermal behavior by calculating the effective bulk, shear, and thermal conductivity values using a finite element method. The collected databases will be trained and tested on a deep learning model composed of a first convolutional network capable of extracting features and a second fully connected network that allows, through these parameters, the adjustment of the error between the found output and the expected one. The model was verified using a Mean Absolute Percentage Error (MAPE) loss function. The prediction results were excellent, with a prediction score between 92% and 98%, which justifies the good choice of the model parameters.
本研究的目的是开发一种利用卷积神经网络预测非均质材料有效弹性和热行为的新方法。这项工作首先包括建立一个大型数据库,其中包含具有不同形状(圆形,椭圆形,方形,矩形)的非均质材料的两相微观结构,夹杂物的体积分数(20%,25%,30%),以及两相在杨氏模量和导热系数方面的不同对比。对比表示非均质材料的非均质程度,当C值相当大(C >> 1)或很低(C << 1)时,表示材料极不均质,而C= 1则表示材料完全均质。对于弹性性能,对比表示为夹杂物的杨氏模量与基体的杨氏模量之比(C = EiEm),而对于热性能,该比值表示为两相导热系数的函数(C = λiλm)。在我们的工作中,模型将在两个对比度值(10和100)上进行测试。这些微观结构将用于通过使用有限元方法计算有效体积,剪切和导热系数值来估计弹性和热行为。收集到的数据库将在深度学习模型上进行训练和测试,该模型由能够提取特征的第一个卷积网络和第二个完全连接的网络组成,该网络允许通过这些参数调整发现输出和预期输出之间的误差。使用平均绝对百分比误差(MAPE)损失函数对模型进行了验证。预测结果很好,预测分数在92% ~ 98%之间,说明模型参数选择的很好。
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引用次数: 1
Special Issue of Applied Mechanics Reviews in Collaboration with the Journal of Electrochemical Energy Conversion and Storage 与电化学能量转换与存储杂志合作出版的《应用力学评论》特刊
IF 14.3 1区 工程技术 Q1 MECHANICS Pub Date : 2023-02-24 DOI: 10.1115/1.4056961
H. Dankowicz, W. Chiu
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引用次数: 0
Stability of Heterogeneous Beams with Three Supports—Solutions Using Integral Equations 三支承非均质梁的稳定性——用积分方程求解
IF 14.3 1区 工程技术 Q1 MECHANICS Pub Date : 2023-02-22 DOI: 10.3390/applmech4010015
L. Kiss, A. Messaoudi, G. Szeidl
It is our main objective to find the critical load for three beams with cross sectional heterogeneity. Each beam has three supports, of which the intermediate one is a spring support. Determination of the critical load for these beams leads to three point boundary value problems (BVPs) associated with homogeneous boundary conditions—the mentioned BVPs constitute three eigenvalue problems. They are solved by using a novel solution strategy based on the Green functions that belong to these BVPs: the eigenvalue problems established for the critical load are transformed into eigenvalue problems governed by homogeneous Fredholm integral equations with kernels that can be given in closed forms provided that the Green function of each BVP is known. Then the eigenvalue problems governed by the Fredholm integral equations can be manipulated into algebraic eigenvalue problems solved numerically by using effective algorithms. It is an advantage of the way we attack these problems that the formalism established and the results obtained remain valid for homogeneous beams as well. The numerical results for the critical forces can be applied to solve some stability problems in the engineering practice.
我们的主要目标是找出具有截面非均匀性的三梁的临界载荷。每根梁有三个支撑物,中间的是弹簧支撑物。这些梁的临界载荷的确定导致了与齐次边界条件相关的三点边值问题(BVPs)——上述BVPs构成了三个特征值问题。通过使用一种基于属于这些BVP的Green函数的新颖解决策略来解决这些问题:为临界负荷建立的特征值问题被转换为由具有核的齐次Fredholm积分方程控制的特征值问题,该方程可以以封闭形式给出,只要每个BVP的Green函数是已知的。然后利用有效的算法将Fredholm积分方程控制的特征值问题转化为数值求解的代数特征值问题。我们处理这些问题的方法的一个优点是,所建立的形式主义和所得到的结果对均质梁也是有效的。临界力的数值计算结果可用于解决工程实践中的一些稳定性问题。
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引用次数: 0
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Applied Mechanics Reviews
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