Papers by Keyword: Lattice

Abstract: This study aimed to smelt high-entropy alloys (HEAs) composed of inexpensive and commonly available metallic elements using iron-based alloys, ligatures, and commercially pure metals, and to investigate their phase structure and heat-resistance. High-entropy alloys of the FeNiCrCuAl system were smelted in air using an induction furnace with a crucible lined with rammed neutral aluminum and magnesium oxides. The elements Fe, Ni, Cr, Cu, and Al were introduced via high-alloy cast iron, stainless steel grade GX10CrNiMn-18-9-1 (1.4541), industrial-grade low-carbon ferrochrome (FeCr70C1), binary Cu-33Al ligature, tough-pitch copper, and semi-finished nickel. Samples of the investigated alloys were prepared using lost foam and sand mold casting methods. Microstructural analysis revealed the presence of rounded dendritic branches, copper-rich interdendritic regions, and high-chromium carbides. The phase composition of the as-cast FeNiCrCuAl alloys consisted of multiple phases: solid solutions with a BCC structure ordered in the B2 type, an FCC structure, and complex carbides (FeCr)₇C₃. High-entropy alloys of the FeNiCrCuAl system, with increased aluminum and chromium content, can significantly outperform standard heat-resistant stainless steels in terms of oxidation resistance indicators – surface oxidation rate, and oxidation stability at 900°C and 1000°C. The specific oxidation of the high-entropy alloy FeNiCrCuAl, which contains at least 18 at. % chromium, was 0.1627 mg/cm² after a 4-hour exposure at 1000 °C. Under the same conditions, the specific oxidation of X2CrNi19-11 stainless steel (1.4306) was 0.6689 mg/cm².

Abstract: Metamaterials have emerged as promising candidates for protective structures due to their lightweight design and energy absorption capabilities. While various lattice-based architectures have been explored, further research is needed to optimize their dynamic response and computational modeling. Recent studies highlight the superior strength-to-weight ratios of lattice metamaterials over traditional foams, yet challenges remain in balancing predictive accuracy and computational efficiency.This study introduces novel computational frameworks for the design and analysis of deterministic, hybrid, and stochastic lattice architectures. Using finite element models, different unit cell configurations are evaluated under dynamic loading, comparing beam-based models for efficiency with 3D solid models for accuracy. A comparative assessment with foam materials further examines energy absorption performance.The framework developed in this study provides a versatile tool for the automatic generation and analysis of lattice structures. Moreover, this study provides critical insights into lattice topology, computational trade-offs, and impact resistance.

Abstract: Lattice models established themselves as a powerful tool to simulate fracture processes in cementitious materials such as concrete. The paper presents the main features of this method, together with the advancements in the modeling of fracture of concrete materials. A historical perspective is also given, highlighting advantages and drawbacks of the existing fracture mechanics theories and numerical methods.

Abstract: Influence of silver chloride synthesis conditions on its heat of sublimation after ultra-violet irradiation was explored. It was determined that silver chloride synthesized in excess of silver ions after irradiation was characterized by heat of sublimation about 6813 J/g, which meant that the original value increased in ~ 1.8 times. At the same time silver chloride synthesized in excess of chloride ions was characterized by decrease in value of heat of sublimation by ~ 2 times. Growth of heat of sublimation of silver chloride with excess of silver ions is connected with energy expenditure on sublimation due to decrease in proportion of surface which is not covered with silver. Reduction of heat of sublimation of silver chloride with excess of chloride ions is explained by absence of silver solid surface film and catalytic effect of silver klasters formed during the process of irradiation.

Abstract: The auxetic lattices are structures, which have the negative Poisson’s ratio. When material has negative Poisson’s ratio, has also auxetic properties - during process of stretching, are made wider and during compressing are made narrower. This structures are cellular and negative Poisson’s ratio is depending on the geometry of single auxetic cell. When geometry of the cell is slightly changed also Poisson’s ratio is different. Auxetics have attracted attention of researchers because of their superior dynamic properties. The lattice auxetic structures at one of their natural frequencies exhibit the deformed geometry. It’s can be exploit as resonance to optimization of the power required for the occurrence localized deformations. The dynamic behavior of auxetic and their transmission of the vibration, which is circumscribed by the parameter VTL (Vibration Transmission Loss) will be analyzed in this article.

Abstract: Block Data Transmission Systems (BDTS) are used in high speed wireless communication systems with time dispersive channel characteristics. Since Maximum Likelihood Block Detection (MLBD) requires huge amount of computation, Sphere Detection (SD) technique has been introduced as an alternative. This paper proposes an A_n Lattice Sphere Detection (A_nLSD) technique for detection in block data transmission systems (BDTS). The A_n lattice structure offers more dense constellation points than the customary Z_n lattice in SD technique. Thus, the proposed A_nLSD uses A_n lattice generator matrix as the channel matrix, and uses the Gram matrix which is obtained from the generator matrix as part of the detection process. Simulation results show that the proposed A_nLSD performs very close to the Exhaustive search (ES) using block size of 20 bits. It is also performing better than the other renowned methods tested under a channel with spectral nulls. The proposed A_nLSD technique offers significant reduction in term of objective functions evaluation as compared to the other renowned methods.

Abstract: The failure of a discrete elastic-damage axial system is investigated using both a discrete and anequivalent continuum approach. The discrete damage mechanics (DDM) approach is based on amicrostructured model composed of a series of periodic elastic-damage springs (axial DDM latticesystem). Such a damage discrete system can be associated with the finite difference formulation of aContinuum Damage Mechanics (CDM) evolution problem.The nonlocal CDM models considered in this paper are mainly built from a continualizationprocedure applied to centered finite difference schemes. A comparison of the discrete and thecontinuous problems for the chains shows the effectiveness of the new micromechanics-basednonlocal Continuum Damage modeling, especially for capturing scale effects.

Abstract: Cellular ceramics are attracting material solutions for high temperature applications because of their outstanding properties. SiC cellular ceramics in particular withstand harsh environments at high temperatures for long operating times and are particularly resistant to thermal shock. Ceramic foams though, being random fragile structures, comprise properties which are rather scattered and difficult to engineer. This presentation shows how finite element analysis is used to study the effect of morphological features on ceramic foams in respect of their mechanical properties. Mean morphological parameters, obtained by X-ray computed tomography (XCT) on a commercially available SiSiC foam produced by the replica method, were used to generate a set of lattices in which one parameter was varied at a time. Starting from this approach, further work was then dedicated to optimize their properties. Polymeric lattices and foams, in which some characteristics were digitally modified learning from the optimization work were, produced by 3D printing and ceramized via the replica method. Both foams and lattices were then mechanically tested. Results show that some features such as strut shape and cell stretching affect the mechanical behavior of ceramic foams.

Abstract: Frequent closed itemsets play an important role in pruning redundant rules fast. A lot of algorithms for mining FCI by vertical data formats have been developed. Previous methods often consume more memory for storage Bit-Vectors and the time for computing the intersection among Bit-Vectors. In this paper, it uses Dynamic Binary Group for compress the database and generates DBG-lattice for mining FCI. Advantages of this method are fast computing the support and the intersection of two DBGs. Experimental results show the efficient of this method in both the mining time and memory usage.

Abstract: Nonlinear finite element parameters analysis on the lattice type steel pipe concrete wind turbine tower, it shows the entire process of load bearing, failure mode and ultimate bearing capacity, researches on the influence law of aspect ratio, form of tower webs, tower diameter to thickness ratio and web member stiffness to tower column stiffness ratio on the ultimate bearing capacity and tower failure mode. The finite element analysis results shows that the tower aspect ratio λ, the diameter-thickness ratio γ of tower columns and the increase of stiffness ratio β between web members and tower columns has great influence on ultimate bearing capacity and failure mode, while the form of webs has small influence on that. with the increase of tower aspect ratio λ, the decrease of diameter-thickness ratio γ of tower columns and the increase of stiffness ratio β between web members and tower columns, the ultimate bearing capacity of this kind of latticed towers increase, the failure mode changed from Web local buckling to The combined damage of Web local buckling and the tension tower yield. This paper suggests that in the design of wind turbulent generator tower, the tower aspect ratio λ should be best controlled at 1/9, the bottom layers of this kind of tower should best use the re-divided web members, and other web member forms used on above layers, the diameter-thickness ratio γ of tower column should be taken less than 30, and the stiffness ratio β between webs and columns should be controlled less than 0.05 in order to avoid damage occurring on the tower columns earlier than the webs. The results can provide evidence for the engineering design.