Pub Date : 2024-05-30DOI: 10.1088/1361-651x/ad4c81
Tarek Iraki, Lukas Morand, Norbert Link, Stefan Sandfeld and Dirk Helm
The crystallographic texture of metallic materials is a key microstructural feature that is responsible for the anisotropic behavior, e.g. important in forming operations. In materials science, crystallographic texture is commonly described by the orientation distribution function, which is defined as the probability density function of the orientations of the monocrystal grains conforming a polycrystalline material. For representing the orientation distribution function, there are several approaches such as using generalized spherical harmonics, orientation histograms, and pole figure images. Measuring distances between crystallographic textures is essential for any task that requires assessing texture similarities, e.g. to guide forming processes. Therefore, we introduce novel distance measures based on (i) the Earth Movers Distance that takes into account local distance information encoded in histogram-based texture representations and (ii) a distance measure based on pole figure images. For this purpose, we evaluate and compare existing distance measures for selected use-cases. The present study gives insights into advantages and drawbacks of using certain texture representations and distance measures with emphasis on applications in materials design and optimal process control.
{"title":"Accurate distances measures and machine learning of the texture-property relation for crystallographic textures represented by one-point statistics","authors":"Tarek Iraki, Lukas Morand, Norbert Link, Stefan Sandfeld and Dirk Helm","doi":"10.1088/1361-651x/ad4c81","DOIUrl":"https://doi.org/10.1088/1361-651x/ad4c81","url":null,"abstract":"The crystallographic texture of metallic materials is a key microstructural feature that is responsible for the anisotropic behavior, e.g. important in forming operations. In materials science, crystallographic texture is commonly described by the orientation distribution function, which is defined as the probability density function of the orientations of the monocrystal grains conforming a polycrystalline material. For representing the orientation distribution function, there are several approaches such as using generalized spherical harmonics, orientation histograms, and pole figure images. Measuring distances between crystallographic textures is essential for any task that requires assessing texture similarities, e.g. to guide forming processes. Therefore, we introduce novel distance measures based on (i) the Earth Movers Distance that takes into account local distance information encoded in histogram-based texture representations and (ii) a distance measure based on pole figure images. For this purpose, we evaluate and compare existing distance measures for selected use-cases. The present study gives insights into advantages and drawbacks of using certain texture representations and distance measures with emphasis on applications in materials design and optimal process control.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"32 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141196730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-29DOI: 10.1088/1361-651x/ad4d0c
Ruotong Wang, Yaqiong Fan, Huiyang Huang and Hua Huang
Microcapsule self-healing has become popular for microcrack repairing in resin mineral composites, and the cracking performance of microcapsule directly affect their repair efficiency on the matrix material. In this study, the problem of how the volume of microcapsule core affects the cracking performance of microcapsule is addressed. Based on the extended finite element method, the representative volume element (RVE) considering the volume of microcapsule core is established by combining the cohesive zone model and the fluid cavity model. On this basis, a numerical simulation study of the cracking performance of RVE with different volumes of microcapsule core under dynamic loading is conducted to investigate the triggered cracking process of the fully filled and incompletely filled microcapsules besides their cracking behavior, respectively. This study provides a reference for the preparation of microcapsules and the numerical simulation of microcapsule mechanical properties.
{"title":"Micro-scale study of microcapsule cracking performance based on XFEM and fluid cavity model","authors":"Ruotong Wang, Yaqiong Fan, Huiyang Huang and Hua Huang","doi":"10.1088/1361-651x/ad4d0c","DOIUrl":"https://doi.org/10.1088/1361-651x/ad4d0c","url":null,"abstract":"Microcapsule self-healing has become popular for microcrack repairing in resin mineral composites, and the cracking performance of microcapsule directly affect their repair efficiency on the matrix material. In this study, the problem of how the volume of microcapsule core affects the cracking performance of microcapsule is addressed. Based on the extended finite element method, the representative volume element (RVE) considering the volume of microcapsule core is established by combining the cohesive zone model and the fluid cavity model. On this basis, a numerical simulation study of the cracking performance of RVE with different volumes of microcapsule core under dynamic loading is conducted to investigate the triggered cracking process of the fully filled and incompletely filled microcapsules besides their cracking behavior, respectively. This study provides a reference for the preparation of microcapsules and the numerical simulation of microcapsule mechanical properties.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"49 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141196886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-28DOI: 10.1088/1361-651x/ad4b4b
Utkarsh Bhardwaj and Manoj Warrier
The morphology of a collision cascade is an important aspect in understanding the formation of defects and their distribution. While the number of sub-cascades is an essential parameter to describe the cascade morphology, the methods to compute this parameter are limited. We present a method to compute the number of sub-cascades from the primary damage state of the collision cascade. Existing methods analyze peak damage state or the end of ballistic phase to compute the number of sub-cascades which is not always available in collision cascade databases. We use density based clustering algorithm from unsupervised machine learning domain to identify the sub-cascades from the primary damage state. To validate the results of our method we first carry out a parameter sensitivity study of the existing algorithms. The study shows that the results are sensitive to input parameters and the choice of the time-frame analyzed. On a database of 100 collision cascades in W, we show that the method we propose, which analyzes primary damage state to predict number of sub-cascades, is in good agreement with the existing method that works on the peak state. We also show that the number of sub-cascades found with different parameters can be used to classify and group together the cascades that have similar time-evolution and fragmentation. It is seen that the number of SIA and vacancies, % defects in clusters and volume of the cascade, decrease with increase in the number of sub-cascades.
碰撞级联的形态是了解缺陷形成及其分布的一个重要方面。虽然子级联的数量是描述级联形态的基本参数，但计算这一参数的方法却很有限。我们提出了一种从碰撞级联的主要损伤状态计算子级联数量的方法。现有方法通过分析峰值损伤状态或弹道阶段结束来计算子级联的数量，而碰撞级联数据库中并不总是有这种数据。我们使用无监督机器学习领域的基于密度的聚类算法，从主损伤状态中识别出子级联。为了验证我们方法的结果，我们首先对现有算法进行了参数敏感性研究。研究表明，结果对输入参数和分析时间范围的选择很敏感。在一个包含 W 中 100 个碰撞级联的数据库中，我们发现我们提出的方法（通过分析主要损坏状态来预测子级联的数量）与现有的基于峰值状态的方法有很好的一致性。我们还表明，利用不同参数发现的子级联数量可以对时间演化和破碎程度相似的级联进行分类和分组。我们可以看到，随着子级联数量的增加，SIA 和空位的数量、簇中缺陷的百分比以及级联的体积都会减少。
{"title":"Identifying sub-cascades from the primary damage state of collision cascades","authors":"Utkarsh Bhardwaj and Manoj Warrier","doi":"10.1088/1361-651x/ad4b4b","DOIUrl":"https://doi.org/10.1088/1361-651x/ad4b4b","url":null,"abstract":"The morphology of a collision cascade is an important aspect in understanding the formation of defects and their distribution. While the number of sub-cascades is an essential parameter to describe the cascade morphology, the methods to compute this parameter are limited. We present a method to compute the number of sub-cascades from the primary damage state of the collision cascade. Existing methods analyze peak damage state or the end of ballistic phase to compute the number of sub-cascades which is not always available in collision cascade databases. We use density based clustering algorithm from unsupervised machine learning domain to identify the sub-cascades from the primary damage state. To validate the results of our method we first carry out a parameter sensitivity study of the existing algorithms. The study shows that the results are sensitive to input parameters and the choice of the time-frame analyzed. On a database of 100 collision cascades in W, we show that the method we propose, which analyzes primary damage state to predict number of sub-cascades, is in good agreement with the existing method that works on the peak state. We also show that the number of sub-cascades found with different parameters can be used to classify and group together the cascades that have similar time-evolution and fragmentation. It is seen that the number of SIA and vacancies, % defects in clusters and volume of the cascade, decrease with increase in the number of sub-cascades.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"18 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141169714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-13DOI: 10.1088/1361-651x/ad4576
Damien Tourret, Rouhollah Tavakoli, Adrian D Boccardo, Ahmed K Boukellal, Muzi Li and Jon Molina-Aldareguia
Bioresorbable Mg-based alloys with low density, low elastic modulus, and excellent biocompatibility are outstanding candidates for temporary orthopedic implants. Coincidentally, metal additive manufacturing (AM) is disrupting the biomedical sector by providing fast access to patient-customized implants. Due to the high cooling rates associated with fusion-based AM techniques, they are often described as rapid solidification processes. However, conclusive observations of rapid solidification in metal AM—attested by drastic microstructural changes induced by solute trapping, kinetic undercooling, or morphological transitions of the solid-liquid interface—are scarce. Here we study the formation of banded microstructures during laser powder-bed fusion (LPBF) of a biomedical-grade Magnesium-rare earth alloy, combining advanced characterization and state-of-the-art thermal and phase-field modeling. Our experiments unambiguously identify microstructures as the result of an oscillatory banding instability known from other rapid solidification processes. Our simulations confirm that LPBF-relevant solidification conditions strongly promote the development of banded microstructures in a Mg–Nd alloy. Simulations also allow us to peer into the sub-micrometer nanosecond-scale details of the solid–liquid interface evolution giving rise to the distinctive banded patterns. Since rapidly solidified Mg alloys may exhibit significantly different mechanical and corrosion response compared to their cast counterparts, the ability to predict the emergence of rapid solidification microstructures (and to correlate them with local solidification conditions) may open new pathways for the design of bioresorbable orthopedic implants, not only fitted geometrically to each patient, but also optimized with locally-tuned mechanical and corrosion properties.
可生物吸收的镁基合金具有低密度、低弹性模量和良好的生物相容性，是临时骨科植入物的理想候选材料。无独有偶，金属快速成型技术（AM）正在颠覆生物医学领域，为患者提供快速定制植入物。由于基于熔融的快速成型技术具有较高的冷却速度，因此通常被称为快速凝固工艺。然而，有关金属 AM 快速凝固的确凿观察结果却很少，这些观察结果表明，溶质截留、动力学过冷或固液界面形态转变会诱发微观结构的剧烈变化。在这里，我们结合先进的表征技术和最先进的热场与相场建模技术，研究了生物医学级镁稀土合金在激光粉末床熔融（LPBF）过程中形成的带状微结构。我们的实验明确确定了微结构是其他快速凝固过程中已知的振荡带状不稳定性的结果。我们的模拟证实，与 LPBF 相关的凝固条件强烈促进了 Mg-Nd 合金中带状微结构的发展。模拟还使我们能够窥探到导致独特带状图案的固液界面演变的亚微米纳秒级细节。由于快速凝固的镁合金与铸造的镁合金相比，在机械性能和腐蚀反应方面可能会有很大不同，因此预测快速凝固微结构的出现（并将其与局部凝固条件相关联）的能力可能会为生物可吸收骨科植入物的设计开辟新的途径。
{"title":"Emergence of rapid solidification microstructure in additive manufacturing of a Magnesium alloy","authors":"Damien Tourret, Rouhollah Tavakoli, Adrian D Boccardo, Ahmed K Boukellal, Muzi Li and Jon Molina-Aldareguia","doi":"10.1088/1361-651x/ad4576","DOIUrl":"https://doi.org/10.1088/1361-651x/ad4576","url":null,"abstract":"Bioresorbable Mg-based alloys with low density, low elastic modulus, and excellent biocompatibility are outstanding candidates for temporary orthopedic implants. Coincidentally, metal additive manufacturing (AM) is disrupting the biomedical sector by providing fast access to patient-customized implants. Due to the high cooling rates associated with fusion-based AM techniques, they are often described as rapid solidification processes. However, conclusive observations of rapid solidification in metal AM—attested by drastic microstructural changes induced by solute trapping, kinetic undercooling, or morphological transitions of the solid-liquid interface—are scarce. Here we study the formation of banded microstructures during laser powder-bed fusion (LPBF) of a biomedical-grade Magnesium-rare earth alloy, combining advanced characterization and state-of-the-art thermal and phase-field modeling. Our experiments unambiguously identify microstructures as the result of an oscillatory banding instability known from other rapid solidification processes. Our simulations confirm that LPBF-relevant solidification conditions strongly promote the development of banded microstructures in a Mg–Nd alloy. Simulations also allow us to peer into the sub-micrometer nanosecond-scale details of the solid–liquid interface evolution giving rise to the distinctive banded patterns. Since rapidly solidified Mg alloys may exhibit significantly different mechanical and corrosion response compared to their cast counterparts, the ability to predict the emergence of rapid solidification microstructures (and to correlate them with local solidification conditions) may open new pathways for the design of bioresorbable orthopedic implants, not only fitted geometrically to each patient, but also optimized with locally-tuned mechanical and corrosion properties.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"108 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140941986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-13DOI: 10.1088/1361-651x/ad4406
Rahul Jayakumar, T P D Rajan and Sivaraman Savithri
The metal casting process, which is one of the key drivers of the manufacturing industry, involves several physical phenomena occurring simultaneously like fluid flow, phase change, and heat transfer which affect the casting yield and quality. Casting process modeling involves numerical modeling of these phenomena on a computer. In recent decades, this has become an inevitable tool for foundry engineers to make defect-free castings. To expedite computational time graphics processing units (GPUs) are being increasingly used in the numerical modeling of heat transfer and fluid flow. Initially, in this work a CPU based implicit solver code is developed for solving the 3D unsteady energy equation including phase change numerically using finite volume method which predicts the thermal profile during solidification in the metal casting process in a completely filled mold. To address the computational bottleneck, which is identified as the linear algebraic solver based on the bi-conjugate gradient stabilized method, a GPU-based code is developed using Compute Unified Device Architecture toolkit and was implemented on the GPU. The CPU and GPU based codes are then validated against a commercial casting simulation code FLOW-3D CAST® for a simple casting part and against in-house experimental results for gravity die casting of a simple geometry. Parallel performance is analyzed for grid sizes ranging from 10 × 10 × 10 to 210 × 210 × 210 and for three time-step sizes. The performance of the GPU code based on occupancy and throughput is also investigated. The GPU code exhibits a maximum speedup of 308× compared to the CPU code for a grid size of 210 × 210 × 210 and a time-step size of 2 s.
{"title":"A GPU based accelerated solver for simulation of heat transfer during metal casting process","authors":"Rahul Jayakumar, T P D Rajan and Sivaraman Savithri","doi":"10.1088/1361-651x/ad4406","DOIUrl":"https://doi.org/10.1088/1361-651x/ad4406","url":null,"abstract":"The metal casting process, which is one of the key drivers of the manufacturing industry, involves several physical phenomena occurring simultaneously like fluid flow, phase change, and heat transfer which affect the casting yield and quality. Casting process modeling involves numerical modeling of these phenomena on a computer. In recent decades, this has become an inevitable tool for foundry engineers to make defect-free castings. To expedite computational time graphics processing units (GPUs) are being increasingly used in the numerical modeling of heat transfer and fluid flow. Initially, in this work a CPU based implicit solver code is developed for solving the 3D unsteady energy equation including phase change numerically using finite volume method which predicts the thermal profile during solidification in the metal casting process in a completely filled mold. To address the computational bottleneck, which is identified as the linear algebraic solver based on the bi-conjugate gradient stabilized method, a GPU-based code is developed using Compute Unified Device Architecture toolkit and was implemented on the GPU. The CPU and GPU based codes are then validated against a commercial casting simulation code FLOW-3D CAST® for a simple casting part and against in-house experimental results for gravity die casting of a simple geometry. Parallel performance is analyzed for grid sizes ranging from 10 × 10 × 10 to 210 × 210 × 210 and for three time-step sizes. The performance of the GPU code based on occupancy and throughput is also investigated. The GPU code exhibits a maximum speedup of 308× compared to the CPU code for a grid size of 210 × 210 × 210 and a time-step size of 2 s.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"26 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140935704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-12DOI: 10.1088/1361-651x/ad4405
Yanhui Yang, Boyan Zhang, Xiuquan Chen, Xiaoxuan Wang and Jingshi Sun
Through heat treatment experiments and numerical simulations, the effects of the heating temperature (1313–1423 K) and holding time (10–240 min) on the grain growth behavior of the extruded FGH96 alloy were investigated. A two-dimensional cellular automata (CA) model that considered the dissolution of the γ′ phase over time and the distribution characteristics with different sizes was developed to explore the grain growth behavior above the γ′ phase over-solution temperature (1423 K) and below the γ′ sub-solution temperature (1383 K), respectively. The results showed that the rate of grain growth of FGH96 alloy was obviously enhanced when the heating temperature exceeded 1363 K, which was mainly related to the dissolution of the γ′ phase, and the grain growth of FGH96 alloy mainly occurred during the initial stage of insulation. The grain growth model of the extruded FHG96 alloy could accurately predict the grain growth behavior, and the simulation results were in good agreement with the experimental results at over-solution temperature or sub-solution temperature. The effects of volume fraction and radius of γ′ phase on the grain growth behavior of FGH96 alloy were studied by simulating the grain growth behavior of FGH96 alloy under different sizes and volume fractions of γ′ phase. The results follow the Zener relation, and the coefficient n in the Zener relation was determined by fitting the simulation results.
{"title":"Modeling and simulation of grain growth for FGH96 superalloy using a developed cellular automaton model","authors":"Yanhui Yang, Boyan Zhang, Xiuquan Chen, Xiaoxuan Wang and Jingshi Sun","doi":"10.1088/1361-651x/ad4405","DOIUrl":"https://doi.org/10.1088/1361-651x/ad4405","url":null,"abstract":"Through heat treatment experiments and numerical simulations, the effects of the heating temperature (1313–1423 K) and holding time (10–240 min) on the grain growth behavior of the extruded FGH96 alloy were investigated. A two-dimensional cellular automata (CA) model that considered the dissolution of the γ′ phase over time and the distribution characteristics with different sizes was developed to explore the grain growth behavior above the γ′ phase over-solution temperature (1423 K) and below the γ′ sub-solution temperature (1383 K), respectively. The results showed that the rate of grain growth of FGH96 alloy was obviously enhanced when the heating temperature exceeded 1363 K, which was mainly related to the dissolution of the γ′ phase, and the grain growth of FGH96 alloy mainly occurred during the initial stage of insulation. The grain growth model of the extruded FHG96 alloy could accurately predict the grain growth behavior, and the simulation results were in good agreement with the experimental results at over-solution temperature or sub-solution temperature. The effects of volume fraction and radius of γ′ phase on the grain growth behavior of FGH96 alloy were studied by simulating the grain growth behavior of FGH96 alloy under different sizes and volume fractions of γ′ phase. The results follow the Zener relation, and the coefficient n in the Zener relation was determined by fitting the simulation results.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"62 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140930981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-12DOI: 10.1088/1361-651x/ad4575
Zbigniew Kozioł
Anharmonic inter-atomic potential , n > 1, has been used in molecular dynamics (MD) simulations of stress dynamics of FCC oriented crystal. The model of the chain of masses and springs is found as a convenient and accurate description of simulation results, with masses representing the crystallographic planes. The dynamics of oscillations of two planes is found analytically to be given by Euler’s beta functions, and its scaling with non-linearity parameter and amplitude of oscillations, or applied shear pressure is discussed on examples of time dependencies of displacements, velocities, and forces acting on masses (planes). The dynamics of stress penetration from the surface of the sample with multiply-planes (an anharmonic crystal) towards its interior is confirmed to be given exactly as a series of Bessel functions, when n = 2 (Schrödinger and Pater solutions). When n 2 the stress dynamics (wave propagation) in bulk material remains qualitatively of the same nature as in the harmonic case. In particular, results suggest that the quasi-linear relationship between frequency and the wave number is preserved. The speed of the transverse sound component, dependent on sound wave amplitude, is found to be a strongly decreasing function of n. The results are useful in the analysis of any MD simulations under pressure, as they help to understand the dynamics of pressure retarded effects, as well as help design the proper methodology of performing MD simulations in cases such as, for instance, studies of the dynamics of dislocations.
在分子动力学（MD）模拟 FCC 取向晶体的应力动力学时，使用了 n > 1 的非谐波原子间势。质点和弹簧链模型可以方便而准确地描述模拟结果，质点代表晶体平面。通过分析发现，两个平面的振荡动力学由欧拉贝塔函数给出，并根据作用在质点（平面）上的位移、速度和力的时间相关性实例，讨论了其与非线性参数和振荡振幅或外加剪切应力的比例关系。当 n = 2 时（薛定谔和帕特解），应力从具有多平面（谐波晶体）的样品表面向其内部渗透的动力学被证实完全是一系列贝塞尔函数。当 n = 2 时，块体材料中的应力动力学（波的传播）在性质上与谐波情况相同。特别是，结果表明频率与波数之间的准线性关系得以保留。横向声成分的速度与声波振幅有关，是 n 的强递减函数。这些结果有助于分析压力下的任何 MD 模拟，因为它们有助于理解压力迟滞效应的动力学，也有助于设计在诸如位错动力学研究等情况下执行 MD 模拟的适当方法。
{"title":"Dynamics of stress propagation in anharmonic crystals: MD simulations","authors":"Zbigniew Kozioł","doi":"10.1088/1361-651x/ad4575","DOIUrl":"https://doi.org/10.1088/1361-651x/ad4575","url":null,"abstract":"Anharmonic inter-atomic potential , n > 1, has been used in molecular dynamics (MD) simulations of stress dynamics of FCC oriented crystal. The model of the chain of masses and springs is found as a convenient and accurate description of simulation results, with masses representing the crystallographic planes. The dynamics of oscillations of two planes is found analytically to be given by Euler’s beta functions, and its scaling with non-linearity parameter and amplitude of oscillations, or applied shear pressure is discussed on examples of time dependencies of displacements, velocities, and forces acting on masses (planes). The dynamics of stress penetration from the surface of the sample with multiply-planes (an anharmonic crystal) towards its interior is confirmed to be given exactly as a series of Bessel functions, when n = 2 (Schrödinger and Pater solutions). When n 2 the stress dynamics (wave propagation) in bulk material remains qualitatively of the same nature as in the harmonic case. In particular, results suggest that the quasi-linear relationship between frequency and the wave number is preserved. The speed of the transverse sound component, dependent on sound wave amplitude, is found to be a strongly decreasing function of n. The results are useful in the analysis of any MD simulations under pressure, as they help to understand the dynamics of pressure retarded effects, as well as help design the proper methodology of performing MD simulations in cases such as, for instance, studies of the dynamics of dislocations.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"103 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-12DOI: 10.1088/1361-651x/ad461e
Yixiu Luo, Juan Wang, Luchao Sun and Jingyang Wang
Understanding the phononic origin of the infrared (IR) dielectric properties of yttria (Y2O3) and other rare-earth sesquioxides (RE2O3) is a fundamental task in the search of appropriate RE2O3 materials that serve particular IR optical applications. We herein investigate the IR dielectric properties of RE2O3 (RE = Y, Gd, Ho, Lu) using density functional theory-based phonon calculations and Lorentz oscillator model. The abundant IR-active optical phonon modes that are available for effective absorption of photons result in high reflectance of RE2O3, among which four IR-active modes originated from large distortions of REO6 octahedra are found to contribute dominantly to the phonon dielectric constants. Particularly, the present calculation method by considering one-phonon absorption process is demonstrated with good reliability in predicting the IR dielectric parameters of RE2O3 at the far-IR as well as the vicinity of mid-IR region, and the potential cutoff frequency/wavelength of its applicability is disclosed as characterized by the maximum frequency of IR-active longitudinal phonon modes. The results deepen the understanding on IR dielectric properties of RE2O3, and aid the computational design of materials with appropriate IR properties.
{"title":"Phononic origin of the infrared dielectric properties of RE2O3 (RE = Y, Gd, Ho, Lu) compounds","authors":"Yixiu Luo, Juan Wang, Luchao Sun and Jingyang Wang","doi":"10.1088/1361-651x/ad461e","DOIUrl":"https://doi.org/10.1088/1361-651x/ad461e","url":null,"abstract":"Understanding the phononic origin of the infrared (IR) dielectric properties of yttria (Y2O3) and other rare-earth sesquioxides (RE2O3) is a fundamental task in the search of appropriate RE2O3 materials that serve particular IR optical applications. We herein investigate the IR dielectric properties of RE2O3 (RE = Y, Gd, Ho, Lu) using density functional theory-based phonon calculations and Lorentz oscillator model. The abundant IR-active optical phonon modes that are available for effective absorption of photons result in high reflectance of RE2O3, among which four IR-active modes originated from large distortions of REO6 octahedra are found to contribute dominantly to the phonon dielectric constants. Particularly, the present calculation method by considering one-phonon absorption process is demonstrated with good reliability in predicting the IR dielectric parameters of RE2O3 at the far-IR as well as the vicinity of mid-IR region, and the potential cutoff frequency/wavelength of its applicability is disclosed as characterized by the maximum frequency of IR-active longitudinal phonon modes. The results deepen the understanding on IR dielectric properties of RE2O3, and aid the computational design of materials with appropriate IR properties.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"156 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-10DOI: 10.1088/1361-651x/ad44bd
Eric Abercrombie, J Gregory McDaniel
The current approach to modeling viscoelastic materials in most commercial finite element packages is based on the General Maxwell Model, which views these materials as combinations of spring and dashpot elements. However, the data can be incorporated more directly into a transient finite element study by direct interpolation of the relaxation function. This work explores a linear interpolation scheme to the inclusion of viscoelastic relaxation functions on an example problem. The results show several benefits over the General Maxwell Model for transient studies. Included in the analysis are displacement solutions utilizing both approaches, relaxation function error calculations for both approaches, and parametric runtime studies comparing speed of calculation. The variation in computational flop counts is considered and an argument is made for the preference of the proposed approach.
{"title":"Direct integration of measured viscoelastic relaxation data in time-domain finite element simulations","authors":"Eric Abercrombie, J Gregory McDaniel","doi":"10.1088/1361-651x/ad44bd","DOIUrl":"https://doi.org/10.1088/1361-651x/ad44bd","url":null,"abstract":"The current approach to modeling viscoelastic materials in most commercial finite element packages is based on the General Maxwell Model, which views these materials as combinations of spring and dashpot elements. However, the data can be incorporated more directly into a transient finite element study by direct interpolation of the relaxation function. This work explores a linear interpolation scheme to the inclusion of viscoelastic relaxation functions on an example problem. The results show several benefits over the General Maxwell Model for transient studies. Included in the analysis are displacement solutions utilizing both approaches, relaxation function error calculations for both approaches, and parametric runtime studies comparing speed of calculation. The variation in computational flop counts is considered and an argument is made for the preference of the proposed approach.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"8 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-09DOI: 10.1088/1361-651x/ad4407
Rahul Ghosh, Bhavana Sahu, Arjun Dey, Hari Krishna Thota, Karabi Das
Nowadays, anodic coating on additively manufactured (AM) or 3D printed Al–10Si–Mg alloy are used for various components in spacecraft such as antenna feeds, wave guides, structural brackets, collimators, thermal radiators etc. In this study, artificial neural network (ANN) and power law-based models are developed from experimental nanoindentation data for predicting elastic modulus and hardness of anodized AM Al–10Si–Mg at any desired loads. Data from nanoindentation experiments conducted on plan- and cross-sections of anodized coating on AM Al–10Si–Mg alloy was considered for modeling. Apart from nanomechanical properties, load and displacement curves were predicted using Python software from ANN and the Power law model of nanoindentation. It is observed that the ANN model of 50 mN nanoindentation experimental data can accurately predict the loading pattern at any desired load below 50 mN. Elastic modulus and hardness of anodized AM Al–10Si–Mg computed from ANN and the power law model of the unloading curve are also comparable with the values obtained from Weibull distribution analysis reported elsewhere. The derived models were also used to predict nanomechanical properties at 25 and 35 mN, for which no experimental data was available. The computed hardness of plan section of the anodic coating is 3.99 and 4.02 GPa for 25 and 35 mN, respectively. The computed hardness of cross-section of the anodic coating of is 7.16 and 6.61 GPa for 25 and 35 mN, respectively. Thus, the ANN and Power law model of nanoindentation can predict elastic modulus and hardness at different loads by conducting the minimum number of experiments. The novel approach to predict nanomechanical properties using ANN resulted in determining realistic and design specific data on hardness and modulus of the anodized coating on AM Al–10Si–Mg alloy.
如今，阳极涂层添加剂制造（AM）或三维打印的 Al-10Si-Mg 合金被用于航天器中的各种部件，如天线馈线、波导、结构支架、准直器、热辐射器等。本研究根据纳米压痕实验数据开发了基于人工神经网络（ANN）和幂律的模型，用于预测阳极氧化 AM Al-10Si-Mg 在任何所需载荷下的弹性模量和硬度。建模时考虑了对 AM Al-10Si-Mg 合金阳极氧化涂层的平面和横截面进行的纳米压痕实验数据。除纳米力学性能外，还使用 Python 软件根据 ANN 和纳米压痕幂律模型预测了载荷和位移曲线。据观察，50 毫牛顿纳米压痕实验数据的 ANN 模型可以准确预测 50 毫牛顿以下任何所需载荷的加载模式。根据 ANN 和卸载曲线的幂律模型计算出的阳极氧化 AM Al-10Si-Mg 的弹性模量和硬度值也与其他地方报道的通过 Weibull 分布分析获得的值相当。推导出的模型还用于预测 25 和 35 mN 条件下的纳米力学性能，因为没有这方面的实验数据。阳极涂层平面部分的计算硬度在 25 和 35 毫牛顿时分别为 3.99 和 4.02 GPa。阳极涂层横截面的计算硬度在 25 和 35 mN 条件下分别为 7.16 和 6.61 GPa。因此，纳米压痕的 ANN 和幂律模型可以通过进行最少的实验来预测不同载荷下的弹性模量和硬度。利用 ANN 预测纳米力学性能的新方法确定了 AM Al-10Si-Mg 合金阳极氧化涂层硬度和模量的现实和设计特定数据。
{"title":"Artificial neural network-based approach for prediction of nanomechanical properties of anodic coating on additively manufactured Al–10Si–Mg alloy","authors":"Rahul Ghosh, Bhavana Sahu, Arjun Dey, Hari Krishna Thota, Karabi Das","doi":"10.1088/1361-651x/ad4407","DOIUrl":"https://doi.org/10.1088/1361-651x/ad4407","url":null,"abstract":"Nowadays, anodic coating on additively manufactured (AM) or 3D printed Al–10Si–Mg alloy are used for various components in spacecraft such as antenna feeds, wave guides, structural brackets, collimators, thermal radiators etc. In this study, artificial neural network (ANN) and power law-based models are developed from experimental nanoindentation data for predicting elastic modulus and hardness of anodized AM Al–10Si–Mg at any desired loads. Data from nanoindentation experiments conducted on plan- and cross-sections of anodized coating on AM Al–10Si–Mg alloy was considered for modeling. Apart from nanomechanical properties, load and displacement curves were predicted using Python software from ANN and the Power law model of nanoindentation. It is observed that the ANN model of 50 mN nanoindentation experimental data can accurately predict the loading pattern at any desired load below 50 mN. Elastic modulus and hardness of anodized AM Al–10Si–Mg computed from ANN and the power law model of the unloading curve are also comparable with the values obtained from Weibull distribution analysis reported elsewhere. The derived models were also used to predict nanomechanical properties at 25 and 35 mN, for which no experimental data was available. The computed hardness of plan section of the anodic coating is 3.99 and 4.02 GPa for 25 and 35 mN, respectively. The computed hardness of cross-section of the anodic coating of is 7.16 and 6.61 GPa for 25 and 35 mN, respectively. Thus, the ANN and Power law model of nanoindentation can predict elastic modulus and hardness at different loads by conducting the minimum number of experiments. The novel approach to predict nanomechanical properties using ANN resulted in determining realistic and design specific data on hardness and modulus of the anodized coating on AM Al–10Si–Mg alloy.","PeriodicalId":18648,"journal":{"name":"Modelling and Simulation in Materials Science and Engineering","volume":"156 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140930983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：