Shape Of Structuring Element Research Articles

ON AN OPTIMIZATION PROBLEM FOR A PRESTRESSED PLATE WITH VARIABLE STIFFNESS

Most studies in the field of optimization problems in the mechanics of the deformable solid body are aimed at finding the optimal shape of structural elements, which most often leads to the search for the optimal distributions of geometric characteristics for the considered objects in order to ensure reducing the objects? weight and improve their strength characteristics. At the same time, with the advent of modern materials with variable physical and mechanical properties, new relevant branches arose in the optimization problems, as well as the inverse problems on the reconstruction of non-uniform variable characteristics. In this study, the problem of steady-state oscillations of a prestressed inhomogeneous round elastic plate in an axisymmetric formulation is considered. Variational and weak problem statements are presented. The case of free oscillations of a plate simply supported along the contour is investigated; it is shown that the eigenvalue problem is self-adjoint and quite definite. The problem of finding the optimal distribution of the plates? elastic modulus and the corresponding oscillation shape in order to maximize the first natural frequency is considered. An isoperimetric condition for the variable stiffness function is proposed. Based on the Rayleigh energy ratio, the minimum principle for the first eigenvalue and the corresponding eigenfunctionis formulated. On the basis of the variational principle, using the constructed Rayleigh ratio, the optimality condition is formulated, and an explicit representation is obtained for the functions of the optimal oscillation shape and optimal stiffness, taking into account the initial radial stretching or compression of the plate. The range of possible values for the initial stress is determined. The results of solving the problem via constructing optimal inhomogeneity laws for the stiffness function in the class of smooth functions in the considered range of changes in initial stresses are obtained and analyzed.

Finite element, analytical, artificial neural network models for carbon fibre reinforced polymer confined concrete filled steel columns with elliptical cross sections

In the present era of architecture, different cross-sectional shapes of structural concrete elements have been utilized. However, this change in shape has a significant effect on load-carrying capacity. To restore this, the use of column confinements with elliptical sections has gained attention. This paper aim to investigate the effect of elliptical shape sections of confined concrete reinforced with Carbon Fiber Reinforced Polymer (CFRP) and steel tube on axial load-carrying capacity. This study is achieved using following tools Finite Element (FE) in Abaqus and Artificial Neural Networks (ANN) modeling. The study involved a 500-mm-high column with three sets of aspect ratios: 1.0, 1.5, and 2.0. In each aspect ratio, three different layers of CFRP were used, i.e., .167, .334, and .501-mm. Analytical results showed that with the increase in aspect ratio from 1 to 2, there is a decrease in ultimate axial load of about 23.2% on average. In addition, the combined confining pressure of steel tube and CFRP increases with a decrease in dilation angle as the number of CFRP layers increases. The failure mode for the column with a large aspect ratio is local buckling at its mid-height along the minor axis. The result showed a good correlation between FE and experimental results of ultimate stress and strains, with a mean squared error of 2.27 and .001, respectively. Moreover, ANN and analytical models showed a delightful correlation of R2 of .97 for stress models and .88 for strain models, respectively. The elliptical concrete section of the column confined with steel tubes can be adopted for a new architectural type of construction; however, with more than three aspect ratios, the wrapping of the section with CFRP jackets is highly recommended.

Analysis of the functional state of flanged joints

This article discusses related aspects of the formation and provision of the functional quality of the load-bearing elements of frame systems. The subject of the study is the analysis of the state of steel structures with the possible manifestation of violations of the shape of structural elements in flanged joints. The formation and provision of the functional qualities of metal structures and their connections is carried out at all main stages of the life cycle. The scientific hypothesis consists in the assumption that the analysis of the parameters of the stress-strain state in metal structures, characterized by the presence of deviations from the established indicators of functional quality, contributes to an accurate assessment of the parameters of the state and service life. The conditions and circumstances characterizing the possibility of loss of functional qualities of flanged joints of steel structures are determined. A block diagram of the analysis of risks associated with manifestations of the shrinkage distortion of flanges, which reduce the operational reliability of steel structures, has been developed. It is advisable to supplement the methodological basis for the development of design solutions for steel structure units with a forecast (modeling) of the state and operational suitability of a flange connection in the presence of shrinkage distortion of flanges. The results of the analysis of possible states of loss of bearing capacity using a predictive model will contribute to the development of rational parameters of labor intensity and material consumption of manufacturing flanges of steel structures.

Performative Structural Design Optimization: Generative Algorithm for a Preliminary Study of a Voided Beam

In the world of structural design, in most cases, there is a need to control the shape of structural elements and—at the same time—the performance that each one can achieve. With the evolution of structural analysis tools, nowadays it is possible not only to have an immediate investigation of the structure’s performance, but also to search for the best shape by imposing geometric constraints. The aim of this paper is to present an innovative methodology called the performative structural design optimization (PSDO) method, based on the use of algorithm-aided design (AAD). The proposed approach deals with an emptied voided beam; starting from the parameterization of a large-span beam, the search method for the most performing shape is accomplished by multi-objective evolutionary algorithms (MOEAs). The obtained results are characterized by a double optimization: the structure achieved by the hypervolume estimation algorithm for multi-objective optimization (HypE Reduction) (OCTOPUS) represents the starting shape for the application of form-finding, giving so the possibility to obtain different feasible solutions from a single study and to choose the best one in terms of structural behavior.

AESTHETIC PROBLEMS OF AUTOMOBILE MULTI-LEVEL TRANSPORT INTERCHANGES

The aesthetic qualities of the artificial environment are influenced by all types of buildings that form it. This fully applies to this type of construction, such as multi-level road interchanges. The practice of building such structures shows that architects do not always pay enough attention to the appearance of transport facilities, shifting all the responsibility to engineers. The consequence of this approach is a decrease in the aesthetic qualities of the urban environment.
 The nature of transport facilities changed depending on the development of economic and engineering capabilities of society, as well as the types of transport for which the fault was built.
 In the case of using traditional building materials - natural stone or brick, buildings structurally and architecturally acquired features formed in ancient times. In reinforced concrete viaducts, the supports less visually overlap the natural environment. The arched structure, with its transition from the surfaces of the supports to the arch, creates the compositional integrity of the viaduct, and increasing the number of bearing supports, and their metric location, increases the role of supports in the overall composition . A small number of supports showed that the viaduct can be a structure that does not visually "cut" the surrounding landscape, does not interfere with its view and perception.
 We have a slightly different situation with such transport facilities as multi-level car interchanges. The solution is horizontal planar composition. A multi-level denouement is a set of viaducts that intersect at different levels. Unlike a classic viaduct, a multi-level interchange is not a complete compositional whole. Due to the complex spatial construction of the multilevel solution, the location of the supports is perceived as chaotic and not subject to a single compositional plan. We are not talking about the aesthetic qualities of such an environment.
 The history of viaduct construction has shown the importance of the shape of supports in the formation of aesthetic qualities of transport facilities. The search for expressive, attractive forms of support in architectural objects has long been given much attention. This process did not stop the whole history of architecture and construction. It continues in modern architecture. Giving supports more complex shapes than square and rectangular, improves their appearance, visually reduces the size. There are options for applying three-dimensional decor on the surface of large supports. The search for the shape of supports and other structural elements of multilevel transport interchanges can diversify and make recognizable structures of this type. In order to improve the appearance of multilevel transport interchanges, other means can be used - landscaping, color and others. In the future, with the advent of new materials, it may be possible to create the supporting supports of the trestle transparent. This will radically change their appearance. The forest of supports will become less noticeable, and overpasses will create the impression of soaring in the air.
 Changing approaches to the appearance of multilevel transport interchanges, increasing the variety of architectural and compositional solutions based on the achievements of modern engineering and materials science will create them full-fledged, in terms of aesthetic qualities, elements of the urban environment.

Entropy-Driven Morphological Top-Hat Transformation for Infrared Small Target Detection

Infrared small target detection is a key technique in an infrared system. In the past decade, many methods have concentrated on traditional top-hat transformation, which relies on the hand-crafted shape and value of structural elements. However, these methods are inevitably challenged by the following two aspects: first, the structural elements cannot suppress heavy clutter because the construction of structural elements is always according to the prior information of the target and unable to consider the feature of clutter. Second, adaptively extracting sufficient local feature information for background suppression is hard for the structural element. In this article, we propose an entropy-driven top-hat transformation with guided filter kernel for considering the features of both the clutters and background. First, we propose an entropy-driven top-hat transformation method with our proposed local mean entropy, which can be used to suppress clutter according to the local complex degree of clutter. Then, an adaptive structural element based on a guided filter kernel is further exploited to capture the local feature information of image for background suppression. Finally, an adaptive threshold is combined with our algorithm to achieve target detection in image sequences. The experimental results show that the proposed algorithm is not only robust for suppressing different kinds of backgrounds but can also obtain a higher value of the signal-to-clutter ratio gain and detection accuracy compared with some popular traditional baseline methods and related top-hat methods.

Utilization of Waste Materials in Structural Members: A Review

More development approaches more litter, more litter makes natural worries of harmful danger. The use of litter materials for future new products would be a cost-effective and realistic solution to this problem, reducing the tremendous pressure on the country's landfills. Reusing litter as development materials save regular assets, saves energy, diminishes strong waste, brings down air and water contamination, and brings down ozone-depleting substance outflows. The development area can start to recognize and benefit from the advantages of using trash and repurposed materials. Acceptable litter, reused and reusable materials, and strategies have all been explored in numerous studies. Due to the scarcity and rising expense of raw materials, the use of shattered tiles, bones, glass, plastic, seeds, and coconut shell in structural components is becoming more popular. Compression, water absorption, hardness, shape, size, and soundness of structural elements made of litter material will be tested in this study. A comparison of all test findings of structural elements formed of litter materials with conventional structural members will be done to break down present practices in the building industry in regard to litter use and reused materials. This study provides an early knowledge of the practice's current strengths and flaws in order to assist the construction industry in formulating appropriate policies governing the use of trash and reused materials as development materials.

Progressive collapse analysis of a bulk carrier hull girder under longitudinal vertical bending moment considering cracking damage

Existence of crack causes reduction of the load carrying capacity of ship hull structural elements and eventually reduces the hull girder strength. Previous numerical and semi-analytical studies by the same authors revealed that in addition to the value of ultimate strength, the deflection shape and plastic collapse mechanism of ship hull structural elements will change due to existence of cracking damage. In this paper results from previous studies are used to investigate the way cracks affect ultimate longitudinal strength of ship hull girder. Progressive collapse analysis of an ISSC2000 bulk carrier is carried out to estimate its ultimate strength considering existence of cracking damages at different locations of the hull girder; namely bottom, double bottom, side and deck structures. For this reason, HULLST software which is based on Smith's method was modified to be able to model specific cracks anywhere in the ship hull girder. Results show that the way cracking damage effects the ultimate strength of the ship depends highly on the ship's collapse modes in hogging and sagging conditions as well as behavior of the ship structural elements.

Effect of Quasi-Continuous Equal-Channel Angular Pressing on Structure and Properties of Ti-Ni Shape Memory Alloys

The effect of equal-channel angular pressing (ECAP) in quasi-continuous mode on the structure formation and mechanical and functional properties of a near-equiatomic Ti-Ni shape memory alloy (SMA) was studied in this work. ECAP with channel intersection angles of 110° and 120° was carried out at a temperature of 350-450 °C for 2-7 passes. Optimum deformation temperatures of ECAP in quasi-continuous mode are determined as 400 °C for ECAP with a channel intersection angle of 120° and 450 °C for 110°. ECAP with a channel intersection angle of 110° at a temperature of 450 °C yields high values of strength (yield stress σy = 1,090 MPa, ultimate tensile strength σв = 1,150 MPa) and functional (maximum value of completely recoverable strain of 7.5% after ECAP and 8.4% after the addition of post-deformation annealing (PDA) at 400 °C for 1 h) characteristics. With the increase in the deformation temperature of quasi-continuous ECAP with a channel intersection angle of 110° from 350 to 450 °C, structure-morphological transformation in Ti-Ni SMA occurs. The shape of structural elements (grains and subgrains) changes from elongated to equiaxed; the size of the structural elements increases from less than 100 nm to 100-250 nm.

Non-linear optimization of frames with variable section stiffness of columns using Genetic Algorithm

Recently, in structural engineering, many main elements in structural systems such as columns or girders are designed with variable cross-section for certain purposes. In addition, in order to determine the appropriate sizes or suitable shapes of structural elements for optimal volume of material under the effect of certain loading or with the given sizes of elements the structures can be subjected maximum loading, it is required to studied the optimization problem. This paper presents the non-linear weight optimization problem of frames with variable section stiffness of columns according to the strength, stiffness and stability criteria with the help of finite element method. The non-linear optimization problem is solved by the Genetic Algorithm. The calculation procedure of non-linear optimization of plane frames with variable section stiffness of columns is established and implemented using Matlab calculation programming software. From the results of numerical examples, the conclusions and recommendations will be proposed.

Evaluation of ForestPA for VHR RS image classification using spectral and superpixel-guided morphological profiles

ABSTRACT In very high resolution (VHR) remote sensing (RS) classification tasks, conventional pixel-based contextual information extraction methods such as morphological profiles (MPs), extended MPs (EMPs) and MPs with partial reconstruction (MPPR) with limited numbers, sizes and shapes of structural elements (SEs) cannot perfectly match all sizes and shapes of the objects in an image. To overcome such limitation, we introduce novel spatial feature extractors, namely, the superpixel-guided morphological profiles (SPMPs), where the superpixels are used as SEs in opening by reconstruction and closing by reconstruction operations. Moreover, to avoid possible side effects from unusual maximum and minimum values within superpixels, the mean pixel value of superpixels is adopted (SPMPsM). Additionally, new decision forest based on penalizing the attributes in previous trees, the ForestPA is introduced and evaluated through a comparative investigation on three VHR multi-/hyperspectral RS image classification tasks. Support vector machine and benchmark ensemble classifiers, including bagging, AdaBoost, MultiBoost, ExtraTrees, Random Forest and Rotation Forest, are adopted. The experimental results confirm the effectiveness and superior performances of the proposed SPMPs and SPMPsM relative to those of the MPs and MPPR. Moreover, ForestPA outperforms only bagging and is not suitable for learning from large numbers of samples with high dimensionality from the computational efficiency and classification accuracy perspective.

Automatic fracture\u2013vug identification and extraction from electric imaging logging data based on path morphology

We present a path morphology method to separate total rock pore space into matrix, fractures and vugs and derive their pore structure spectrum. Thus, we can achieve fine pore evaluation in fracture–vug reservoirs based on electric imaging logging data. We automatically identify and extract fracture–vug information from the electric imaging images by adopting a path morphological operator that remains flexible enough to fit rectilinear and slightly curved structures because they are independent of the structuring element shape. The Otsu method was used to extract fracture–vug information from the background noise caused by the matrix. To accommodate the differences in scale and form of the different target regions, including fracture and vug path, operators with different lengths were selected for their recognition and extraction at the corresponding scale. Polynomial and elliptic functions are used to fit the extracted fractures and vugs, respectively, and the fracture–vug parameters are deduced from the fitted edge. Finally, test examples of numerical simulation data and several measured well data have been provided for the verification of the effectiveness and adaptability of the path morphology method in the application of electric imaging logging data processing. This also provides algorithm support for the fine evaluation of fracture–vug reservoirs.

Morphological Filter-Assisted Ensemble Empirical Mode Decomposition

In the ensemble empirical mode decomposition (EEMD) algorithm, different realizations of white noise are added to the original signal as dyadic filter banks to overcome the mode mixing problems of empirical mode decomposition (EMD). However, not all the components in white noise are necessary, and the superfluous components will introduce additional mode mixing problems. To address this problem, morphological filter-assisted ensemble empirical mode decomposition (MF-EEMD) was proposed in this paper. First, a new method for determining the structuring element shape and size was proposed to improve the adaptive ability of morphological filter (MF). Then, the adaptive MF was introduced into EMD to remove the superfluous white noise components to improve the decomposition results. Based on the contributions of MF in a single EMD process, the MF-EEMD was proposed by combining EEMD with MF to suppress the mode mixing problems. Finally, an analog signal and a measured signal were used to verify the feasibility of MF-EEMD. The results show that MF-EEMD significantly mitigates the mode mixing problems and achieves a higher decomposition efficiency compared to that of EEMD.

Electronic, dielectric, and optical properties of photonic crystals composed of TiO2 nanoparticles three-dimensional arrays: the first principles calculations

Opal photonic crystals (PCs), composed of TiO2 nanoparticles, three-dimensional array were simulated. This paper shows how electronic, dielectric, and optical properties of such PCs depend on the shape of structural elements, their polymorphic modifications, and the parameters of their stacking in the body’s space of metastructure.

Morphological Operation Method for Eggs Identification in Gonad Ultrasound Image for Mahseer’s Fish (Tor Tombroides)

This paper describes an approach based on morphological operation for identifying the eggs in Mahseer’s gonad ultrasound image. In the context of breeding and seed production of Mahseer species, understanding and control of the Mahseer gonad maturation level have given strong interest for scientific and commercial purposes. From the studies, this Mahseer’s fish have different stage and size of eggs at the same time. Therefore, to identify the eggs in the gonad ultrasound image, an appropriate method is required. Morphological operation dilation and erosion with the structuring element shape is applied in this paper. In between these two operators, morphological reconstruction that includes filling the hole and clearing the border are also applied to the image. This method is essential for eliminating the egg sac because only the eggs region in the gonad will be processed. The proposed method also have been compared with the other research paper method. The result shows that the proposed method effectively identify the eggs in the gonad ultrasound image compared with the other research paper method. To our knowledge, this is the first report on the use of the morphological operation method in the gonad ultrasound image of Mahseer’s fish.

Resolving compactness index of pores and solid phase elements in sandy and silt loamy soils

Soil structure is expressed by the size, shape, and arrangement of structural elements. Shape indices of pores and solid phase elements along with the physical soil parameters allow for thorough evaluation of soil structure. Therefore, the aim of the research was the analysis of properties of an index of shape – a compactness index CMP=(16area)/perimeter2 – of pore (“pore c-s”) and solid phase element cross-sections (“solid c-s”) ≥100pix2 (0.045mm2) of 4 soils. CMP was calculated via image analysis of resin-impregnated soil blocks prepared from intact soil specimens. The morphometric parameters of the objects assigned to selected CMP classes (≤0.2, the lowest compactness; 0.201–0.4; 0.401–0.6; 0.601–0.8; 0.801–1; 1.001–1.2; >1.2, the highest compactness) were compared via 2-way ANOVA for two horizons (A, C) and two textures (sand, silt loam). The usability of CMP in the description of soil structure was then tested. Moreover, the relations of the morphometric parameters of the objects in CMP classes and soil physical and chemical properties (total organic carbon TOC; bulk and particle density; texture; field water capacity FWC; field air capacity FAC; available water capacity AWC; air permeability at −15kPa lgFAP; saturated hydraulic conductivity lgKS) were examined by way of single and multiple linear regressions. For pore and solid c-s of CMP>0.2 their number, area, and average areas in CMP classes decreased with increasing CMP value. The distributions of pore and solid c-s among CMP classes depended on soil texture and structure (aggregate, non-aggregate), allowing for the diagnosis of soil structure status and change. Number and area of objects in CMP classes showed numerous strong relations (R2>0.7) to the soil physical and chemical parameters for the studied soil textures and horizons. The relations differed for pore and solid c-s and depended also on the object shape (spread, compact or very compact). The average areas of the compact and very compact pore and solid c-s increased with the increase of clay and silt content and the decrease of sand content. The number of pore c-s of CMP>0.2 was related to the texture or particle density. On the other hand, the number of solid c-s of CMP>0.2, and the average area of the most spread solid c-s were related to TOC and bulk density. FWC and AWC increased with the decrease of the number of mainly compact and very compact pore c-s by the decrease of the average area of the most spread solid c-s. Both water capacities increased with the increasing average areas of pore c-s of CMP>0.2 and the average areas of the compact and very compact solid c-s. FAC increased with the increase of the number of the compact and very compact pore c-s. lgKS increased with the increase of the number and area of mostly compact and very compact pore c-s. lgFAP increased with the area and the average area of the majority of pore classes and some of the relations were also controlled by the number of pore c-s and the average area of the most spread solid c-s. The study showed moreover that CMP increased with the decreasing size of the objects when measured via computer-aided image analysis. Small cross-sections revealed usually larger CMP values, and large cross-sections were more often classified as irregular or spread. Therefore the analysis of shape of soil structural elements should encompass a wide range of element sizes in relation to the image resolution to obtain the unbiased shape distributions.

Structure of the Cu2Se compound produced by different methods

Copper-selenide (Cu2Se) samples are produced by mechanochemical synthesis and compaction by spark plasma sintering and hot pressing. The structure and phase composition of the samples before and after heat treatment are studied by the X-ray diffraction technique and electron microscopy. The character of changes in the shape and size of structural elements of the samples is shown. Variations in the phase composition of copper selenide in the temperature range from 25 to 500°C are studied in situ.

Measuring structure deformations of a composite glider by optical means with on-ground and in-flight testing

In aeronautical research experimental data sets of high quality are essential to verify and improve simulation algorithms. For this reason the experimental techniques need to be constantly refined. The shape, movement or deformation of structural aircraft elements can be measured implicitly in multiple ways; however, only optical, correlation-based techniques are able to deliver direct high-order and spatial results. In this paper two different optical metrologies are used for on-ground preparation and the actual execution of in-flight wing deformation measurements on a PW-6U glider. Firstly, the commercial PONTOS system is used for static tests on the ground and for wind tunnel investigations to successfully certify an experimental sensor pod mounted on top of the test bed fuselage. Secondly, a modification of the glider is necessary to implement the optical method named image pattern correlation technique (IPCT), which has been developed by the German Aerospace Center DLR. This scientific technology uses a stereoscopic camera set-up placed inside the experimental pod and a stochastic dot matrix applied to the area of interest on the glider wing to measure the deformation of the upper wing surface in-flight. The flight test installation, including the preparation, is described and results are presented briefly. Focussing on the compensation for typical error sources, the paper concludes with a recommended procedure to enhance the data processing for better results. Within the presented project IPCT has been developed and optimized for a new type of test bed. Adapted to the special requirements of the glider, the IPCT measurements were able to deliver a valuable wing deformation data base which now can be used to improve corresponding numerical models and simulations.

A COMPARATIVE STUDY ON MECHANICAL PROPERTIES OF SCC BY PARTIAL REPLACEMENT OF CEMENT WITH FLY ASH AND GGBS WITH THE USE OF GLASS FIBERS

Concrete is a versatile material that can be used for construction of all kinds or shapes of structural elements. Self Compacting Concrete (SCC) was developed by the Japan researchers in the year 1989. SCC is a special type of concrete that is competent or capable to flow and consolidate under its own weight without any segregation and bleeding between the reinforcing bars. SCC is one of the widely used types of concrete in the current world because it makes the work easier and it does not bleed at the joints of the moulds. In this work, an attempt has been made to prepare a high strength SCC of grade M60 by partially replacing the cement content with the untreated industrial byproducts like fly ash & ground granulated blast furnace slag (GGBS) and also by replacing 100% of natural sand with manufactured sand (M.Sand). With the use of these industrial byproducts, it results in an eco-friendly environment and also solves the problem of its disposal. The present work deals with the comparative study on mechanical properties like compressive strength, split tensile strength and flexural strength of SCC for various percentages of powder contents with the use of glass fibers at 0%, 0.1% & 0.2% to the total volume of the concrete mix. In this study two types SCC mixes were prepared namely, Conventional SCC in which cement content was replaced by 30% with fly ash and Triple blended SCC in which cement content was reduced to 50% & the rest of the cement content was replaced with fly ash & GGBS by 25% each. The specimens are casted, cured & tested for the required number of days.

РАСЧЕТ ВЫНУЖДЕННЫХ КОЛЕБАНИЙ СТЕРЖНЕВЫХ СИСТЕМ МЕТОДОМ КОНЕЧНЫХ ЭЛЕМЕНТОВ С ПРИМЕНЕНИЕМ ДИНАМИЧЕСКОГО КОНЕЧНОГО ЭЛЕМЕНТА

The analysis of forced vibrations of frameworks using finite element method is considered. The dynamic finite element, the base functions of which represent exact dynamic shapes of structural elements, is used for system discretization. The assessment of errors as a result of classic FEM application is given. The efficiency of application of dynamic finite element for analysis of forced vibrations and dynamic stress-deformed state of structures is shown.