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This article presents the characteristics of four straw-filled beetle elytron plate (BEPsc) nonload-bearing walls, with their thermal and mechanical properties ascertained by the finite element method, focusing on structural parameters reported in previous studies and further optimized in this paper. The results are as follows: 1) The sequence of the four models' mechanical and thermal insulation properties with the reported structural parameters is given. The mechanical properties are mainly affected by the core layer's out-of-plane bending moment of inertia Ix. The insulation capability is mainly governed by the minimum cross section of the core concrete. Based on this result, a BEP with nonuniform cross-sectional honeycomb walls is proposed. 2) Further optimization is conducted on the two models with the weakest mechanical and thermal properties. The I-beam beetle elytron plate (IBEPsc) is proven most suitable for nonload-bearing walls. The potential for end-trabecular beetle elytron plate (EBEPsc) in hollow floors is expected. 3) As biomimetic models emerge constantly, it is of great significance to conduct parallel comparisons between new and old models to determine their performance levels and advantages. This paper provides an example for selecting suitable BEPs for applications and an inspiration for more work on screening outstanding biomimetic models. [ABSTRACT FROM AUTHOR]

The purpose of trucks is very diverse, but the main purpose is freight transportation. When cargos are transported, the truck's suspensions are heavily loaded, so failures also occur most often in the suspension elements. For axles of trailers - tubular construction failures occur, they crack. Axle failure investigations are required to determine the cause of the failure. The paper analyses three-axle truck trailer suspension. Axle failure analysis and axial deformation modelling were performed to determine trends and causes of truck trailer suspension axle failures. Different cases with axles of tubular construction with wall thicknesses of 9 and 11 mm were modelled. The paper presented visual failure analysis of truck trailers suspension axles and finite element modelling results of axle's deformation of different geometrical parameters. The results were discussed and conclusions were drawn. [ABSTRACT FROM AUTHOR]

This paper presents the state of the art report on available approaches to predicting the ultimate bearing capacity of two-layered soils. The article discusses three most popular methods, including the classical method, application of the finite element method and artificial neural network. Various approaches based on these three powerful tools are studied and their methodologies are discussed.

With the progressive promotion of BIM technology in collaborative design and engineering data management, there are large amounts of project information available for intelligent construction, engineering computation and design optimization. In the construction of subway station, BIM technology is still not mature and the engineering design is generally separate from the engineering safety evaluation. Thus, this paper proposed a technology that integrates BIM and numerical simulation (BIM-FEM/FDM integrated technology) to solve the problem of separation between engineering design and computation. A three-dimensional parametric modeling of subway station excavation was first carried out using the Revit® modeling software. Afterward, a FEM/FDM-process oriented data conversion interface was developed to extract and process the critical information from the parametric BIM model for numerical simulation. Then, under the impetus of an auto-simulation interface, the safety evaluation of subway station excavation was realized automatically and visualized graphically. The research of the BIM-FEM/FDM integrated technology presented in this paper has established a supporting platform to achieve the integration of BIM-based design and safety evaluation for subway station excavation. [ABSTRACT FROM AUTHOR]

This paper deals with the convergence and stability of Galerkin finite element method for a hyperbolic partial differential equations with piecewise continuous arguments of advanced type. First of all, we obtain the expression of analytic solution by the method of separation variable, then the sufficient conditions for stability are obtained. Semidiscrete and fully discrete schemes are derived by Galerkin finite element method, and their convergence are both analyzed in L²-norm. Moreover, the stability of the two schemes are investigated. The semidiscrete scheme can achieve unconditionally stability. The sufficient conditions of stability for fully discrete scheme are derived under which the analytic solution is asymptotically stable. Finally, some numerical experiments are presented to illustrate the theoretical results. [ABSTRACT FROM AUTHOR]

Prefabricated slab has been widely used in the global construction industry due to energy saving, environmental protection, and good economic advantages. In this paper, a new type of fully prefabricated staggered flip-down slab without cast-in-situ operation has been proposed. First, the experiments were carried out on the new slab. The structural performance of the new slab was compared with the cast-in-situ slabs and composite slabs of the same specification. The experimental results showed that the ultimate bearing capacity of the new slab meets the requirements for practical utilization. On this basis, an additional CFRP sheet could be pasted on the bottom initial seam between prefabricated slabs to enhance the integrity and prevent cracks. Then, the whole loading process of the slab was simulated, and the results were consistent with the experimental results. Finally, through experiments and parametric analysis, recommendations for improvement were put forward to enhance the mechanical properties of this kind of slab. [ABSTRACT FROM AUTHOR]

Gravity meters can be used to measure all effects that make up the Earth's gravity field. Many of these effects are caused by known sources such as the Earth's rotation, distance from the Earth's center, topographic relief, and tidal variation. Physical fields are the main component of many centuries of the paradigm of all of Earth Sciences. The changing gravitational field is very important subject of research in the scientific aspect and practical. This paper applies two analytical models to simplify the gravitation calculation, which are sphere and cone models. Examples and finite element applications for the two models are studied also and discussed. The results of this study reveal that the possibility of using the proposed method with using presented analytical, finite element and numerical models to estimate the better determination of the characteristics of the local gravity of natural and man-made objects of sizes up to several tens of kilometers. [ABSTRACT FROM AUTHOR]

The main structure of the Baishihu suspension bridge was connected to the anchor foundations by three main steel cables. The wooden pedestrian deck was fixed to the main steel cables using steel beams and was stabilized by two stabilizing cables. The stabilizing cables and bridge body were joined by 44 steel connecting rods. Therefore, the slope stability at the anchorage foundations of the main steel cables, as well as the performance monitoring and analysis of the main steel cables and stabilizing cables, are critical to the overall performance of the suspension bridge. This paper discusses the performance monitoring and analysis of the steel cable deflection and cable strength for this bridge, as well as the main considerations and results of the stability analysis of the bridge abutments and side slopes of the two banks. Water-level observation wells, inclinometers, and tiltmeters monitoring were used to record reference data for the analysis of the slope stability performance. Additionally, the three-dimensional dynamic analysis program VFIFE was used to analyze the deformation and motion of the bridge. The final steady-state results were used to compare the static design value and monitoring data. The dynamic response before the final steady state was also observed. [ABSTRACT FROM AUTHOR]

The stability of cable-net structures depends on the prestress of the system. Due to the large displacement and mutual effect of the cables, it is difficult to simulate the tensioning process and control the forming accuracy. The Backward Algorithm (BA) has been used to simulate the tensioning process. The traditional BA involves complicated and tedious matrix operations. In this paper, a new numerical method based on the Vector Form Intrinsic Finite Element (VFIFE) method is proposed for BA application. Moreover, the tensioning sequence of a complex cable-net structure is introduced. Subsequently, a new approach for BA application in the simulation of the tensioning process is presented, which combines the VFIFE approach and the notion of form-finding. Finally, a numerical example is simulated in detail and the results of different tensioning stages are analyzed to verify the feasibility of the proposed approach. This study provides a significant reference for improving the construction control and forming accuracy of complex prestressed cable-net structures. [ABSTRACT FROM AUTHOR]

Copyright of Science: Future of Lithuania / Mokslas: Lietuvos Ateitis is the property of Vilnius Gediminas Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Civil Engineering & Management is the property of Vilnius Gediminas Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Civil Engineering & Management is the property of Vilnius Gediminas Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents the blast responses of ultrahigh-performance concrete (UHPC) structural members obtained using finite element (FE) modelling. The FE model was developed using LS-DYNA with an explicit solver. In the FE simulation, the concrete damage model, which is a plasticity-based constitutive material model, was employed for the concrete material. The simulation results were verified against previous experimental results available in the literature and were shown to be in good agreement with the experimental results. In addition, the developed FE model was implemented in a parametric study by varying the blast weight charges. The numerical results for UHPC members were compared with those for conventional reinforced concrete (RC) members. The numerical responses, such as the maximum deflections, deflected shapes, and damage patterns, of the UHPC members subjected to blast loading were significantly better performance than those of the RC members as a result of the high strength and ductile capacity of UHPC. [ABSTRACT FROM AUTHOR]

This article presents an analytical approach for calculating web stiffeners in thin-walled columns. A novel method is introduced, which treats each bending point in the cross-section web as a separate stiffener. The advantages of this calculation method are discussed, highlighting its increased versatility in designing cross-section geometry. The load-bearing strength of axially compressed thin-walled closed cross-section columns, calculated using this method, is compared to analytical calculations based on the Eurocode 3-1-3 methodology and to the finite element method analysis. Calculation results of columns with cross-sections including shallow web stiffeners were up to 9.22% less conservative when compared to the Eurocode 3-1-3 methodology. The results demonstrate great compliance of the proposed method for column crosssections with deep stiffeners. Finite element method (FEM) analysis was performed to verify the calculated load bearing strengths of the columns according to both calculation methodologies. FEM analysis confirmed the reliance of the calculated results and showed, that the load bearing strengths calculated using the newly presented methodology were ranging from 88.77% to 97.86% of load bearing strength calculated using finite element method. These results proved, that the proposed method provides an accurate load bearing strength of thin-walled columns with web stiffeners. [ABSTRACT FROM AUTHOR]

This paper establishes a Finite Element (FE) model of a rigid barrier impact of a single vehicle constructed from carbon steel, stainless steel, and aluminum alloy, which are three typical materials used in metro vehicle car body structures. The different responses of the three materials during the collision are compared. According to the energy absorption, velocity, deformation and collision force flow characteristics of each vehicle, the relationship between the energy absorption ratio of the vehicle body and the energy absorption ratio of its key components is proposed. Based on the collision force flow distribution proportion of each component, the causes of the key components' deformation are analysed in detail. The internal relationship between the deformation, energy absorption and impact force of the key components involved in a car body collision is elucidated. By determining the characteristic parameters describing the vehicle's dynamic stiffness, a metro vehicle frontal impact model using lumped parameters is established that provides a simple and efficient conceptual design method for railway train safety design. These research results can be used to guide the design of railway trains for structural crashworthiness. [ABSTRACT FROM AUTHOR]

Paper explores some aspects of 3D modeling of ‘aircraft cable’ as mostly used sling wire rope. First, the 1×19 stainless steel core of ‘aircraft cable’ was investigated. The analysis was carried out by finite element method based computer program. The software used allowed two different types of contacts, including friction. The sling wire rope core was subjected to two different types of axial loading. The obtained results were compared with the solutions calculated from the literature (Costello 2012). Finally, using the advanced modeling techniques, the parametric 3D model of 7×19 ‘aircraft cable’ was analyzed using finite element method, in order to provide a better understanding and, hence, prediction, of the mechanical behavior of the sling wire ropes in lifting processes. [ABSTRACT FROM AUTHOR]

The purpose of trucks is very diverse, but the main purpose is freight transportation. When cargos are transported, the truck’s suspensions are heavily loaded, so failures also occur most often in the suspension elements. For axles of trailers – tubular construction failures occur, they crack. Axle failure investigations are required to determine the cause of the failure. The paper analyses three-axle truck trailer suspension. Axle failure analysis and axial deformation modelling were performed to determine trends and causes of truck trailer suspension axle failures. Different cases with axles of tubular construction with wall thicknesses of 9 and 11 mm were modelled. The paper presented visual failure analysis of truck trailers suspension axles and finite element modelling results of axle’s deformation of different geometrical parameters. The results were discussed and conclusions were drawn. First published online 21 May 2021

For the last decades, fully erected container cranes have been delivered to a customer site by ships. On one hand, using this method of transportation is very attractive due to its cost and time savings. However, on the other hand, being exposed to cycling loads from the ship motions during the sea voyage, the crane structure accumulates fatigue damage. Using the accumulated fatigue damage parameter, the crane transportation could be associated with the amount of the working cycles the crane could have worked out during its normal operating at the customer site. In the presenting paper the research for the real case of a new crane voyage from China to Ukraine has been done. [ABSTRACT FROM AUTHOR]

The behaviour of standard bolted steel connections submitted to monotonic loads, through the use of numerical models, is presented in the current paper. The bolted connections allow speed up constructive processes in an increasingly competitive and globalized world in which the costs are a decisive factor in the development of a project. The use of computational tools in the analysis of bolted connections becomes determinant, mainly for new solutions or solutions less explored in terms of design codes. Throughout the years, bolted connections have been suffering transformations resulting from research activities performed by many authors. Rivets have been replaced by bolts, the main achievement being the pre-stressed bolts. Methodologies based on finite element analyses were proposed for double shear bolted connection. The non-linear behaviour of these connections is investigated and their performances are compared. In the numerical modelling of the bolted connection, linear elastic and elastoplastic analyzes reveal that there are two slip levels associated with local non-linearities caused by the contact pairs, which vary with clamping stresses. [ABSTRACT FROM PUBLISHER]

The present paper shows the vibrational characterization tests of a clay brick heritage construction from XIX century, the Nossa Senhora das Dores Church, placed in Sobral, Brazil. In this study the calibration of the 3D finite element numerical model of the church was performed through ambient vibrational testing using the first three natural frequencies identified. The obtained results, namely the natural frequencies identified, and the calibrated model intends to give a contribute for understanding of the structural behavior of the Brazilian heritage constructions, and introduces relevant information for be used for safety assessment of the church along the time. [ABSTRACT FROM PUBLISHER]

New advances in top-down construction are developing with the construction of supertall buildings in China. This study presents a finite element analysis for high-rise structural construction with a top-down method (TDM) considering complex environmental conditions. Based on this analysis model, the forces and the deformation of the diaphragm wall, beams, and soldier piles at various stages of construction are computed. Taking a super high-rise building with a 5-story basement in Nanjing as an example, the reliability and accuracy of the model is verified by comparing the measured and simulated results of displacement and stress values at various locations. The research results reveal the relationship between excavation depth, soil settlement and pile displacement, which is convenient for finding the optimal construction critical surface. It lays a foundation for the study of the critical height of the subsequent construction and facilitates the prediction of the weak link in the process. At present, this project is under construction, so this study has reference value for subsequent construction projects. [ABSTRACT FROM AUTHOR]

This paper describes the use of data mining tools for predicting the non-linear layer moduli of asphalt road pavement structures based on the deflection profiles obtained from non-destructive deflection testing. The deflected shape of the pavement under vehicular loading is predominantly a function of the thickness of the pavement layers, the moduli of individual layers, and the magnitude of the load. The process of inverse analysis, more commonly referred to as ‘backcalculation’, is used to estimate the elastic (Young's) moduli of individual pavement layers based upon surface deflections. A comprehensive synthetic database of pavement response solutions was generated using an advanced non-linear pavement finite-element program. To overcome the limitations associated with conventional pavement moduli backcalculation, data mining tools such as support vector machines, neural networks, decision trees, and meta-algorithms like bagging were used to conduct asphalt pavement inverse analysis. The results successfully demonstrated the utility of such data mining tools for real-time non-destructive pavement analysis. [ABSTRACT FROM PUBLISHER]

Copyright of Science: Future of Lithuania / Mokslas: Lietuvos Ateitis is the property of Vilnius Gediminas Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Civil Engineering & Management is the property of Vilnius Gediminas Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

During the service life of a pavement, it is oft en required to conduct Non-destructive tests (NDTs) to evaluate its structural condition and bearing capacity and to detect damage resulting from the repeated traffic and environmental loading. Among several currently used NDT methods, the Falling Weight Deflectometer (FWD) is the most commonly used pavement NDT method applied by many transportation agencies all over the world. Non-destructive testing of pavements using FWD is typically accompanied by the prediction of the Young's modulus of each layer of the pavement structure through an inverse analysis of the acquired FWD deflection data. The predicted pavement layer modulus is both an indicator of the structural condition of the layer as well as a required input for conducting mechanistic-based pavement structural analysis and design. Numerous methodologies have been proposed for backcalculating the mechanical properties of pavement structures from NDT data. This paper discusses the development of an Adaptive-Network-based Fuzzy Inference System (ANFIS) combined with Finite Element Modeling (FEM) for the inverse analysis of the multi-layered flexible pavement structures subjected to dynamic loading. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Civil Engineering & Management is the property of Vilnius Gediminas Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Science: Future of Lithuania / Mokslas: Lietuvos Ateitis is the property of Vilnius Gediminas Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The seismic response of the large-space underground structure (LSUS) is significantly influenced by the physical properties of the surrounding soil media, while the soil owns a strong spatial variability. This study proposes a seismic response analysis process of the soil-LSUS interaction system is proposed, which can consider the characteristic of the spatially distributed soil properties. The proposed process begins with establishing the spatially random field model of the soil properties using the improved latent space method. Then, the model is calibrated based on the real data and Bayesian approach, and the realization of the random field is accomplished. Further, the soil-LSUS interaction finite element (FE) model is established, which incorporating the soil physical properties generated from the random field. Finally, the nonlinear time-history analysis of the soil-LSUS interaction FE model is conducted. As an illustration of the proposed process, a typical LSUS located in Guangzhou is selected as an example, and the seismic mitigation measure which the lead-filled steel tube damper (LFSTD) is installed between the intermediate column and the top beam is adopted for the LSUS. The influence of the spatial variability of soil properties on the seismic mitigation effect of the LSUS is investigated. Results indicate that the spatial variability of the soil properties can cause a minor influence on the force and deformation of the intermediate column and the energy dissipation ratio between the LFSTD and structure, while it can bring a significant influence on the maximum deformation and force and the shape of the hysteresis loop of the LFSTD. [ABSTRACT FROM AUTHOR]

Steel I-shaped beams with web openings of shapes like hexagonal, circular and rectangular at regular intervals have been used since last 60–70 years. Therefore aim of this paper is to examine the behaviour of steel I-beams with rectangular web openings by performinganexperimental and parametric study. A parametric study based on finite element analysis consists of effect of fillet radius, aspect ratio of rectangular openings, stiffeners position around the openings and effect of positions of openings on load carrying capacities of steel beam with rectangular web openings was carried out by using a commercial finite element software ANSYS v.12. An overall study of such type of beam was carried out and results shows that rectangular openings having fillet radius either 2 times thickness of web or 25 mm (whichever is minimum), aspect ratio of 1.6 and reinforcement either in the form of horizontal or vertical stiffeners around the web openings found to be very effective. The fillet radius and stiffeners also affect the stress distribution around the corner regions of openings. Load carrying capacities of perforated beams are almost equal to plain-webbed beams, when openings are placed within middle two-third(neutral zone) of the span. [ABSTRACT FROM AUTHOR]

Copyright of Science: Future of Lithuania / Mokslas: Lietuvos Ateitis is the property of Vilnius Gediminas Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The authors studied the influence of metro loads on the destruction of nearby buildings and construction structures with the help of BIM technologies in order to eliminate the human factor at the design stage. In the study, numerical modeling was carried out using the LIRA-SAPR software package, and dynamic loadings were set by the time integration technique. The suggested technique involved a nonlinear dynamic analysis conducted considering the time factor; the parameters of the stress-strain state (displacement, force, stress) were determined at each moment of exposure, changing the rigid characteristics of the building structures. The authors conducted a structural assessment of an unfinished construction facility, considering the vibrodynamic loads of the metro. Numerous models were adopted as the structural designs of buildings that consider various impact factors, such as nonlinear soil behavior and permanent action and the nature of dynamic loads. The comparison with experimental data confirmed the theoretical and computational parts of the developed technique. The study determined the vibrodynamic impact of the metro on the construction structures. Verification of the developed methodology based on BIM technologies was carried out by comparing the results of numerical experiments with the results of subsequent full-scale vibration tests. [ABSTRACT FROM AUTHOR]

Real-world optimization problems are ubiquitous across scientific domains, and many engineering challenges can be reimagined as optimization problems with relative ease. Consequently, researchers have focused on developing optimizers to tackle these challenges. The Snake Optimizer (SO) is an effective tool for solving complex optimization problems, drawing inspiration from snake patterns. However, the original SO requires the specification of six specific parameters to operate efficiently. In response to this, enhanced snake optimizers, namely ESO1 and ESO2, were developed in this study. In contrast to the original SO, ESO1 and ESO2 rely on a single set of parameters determined through sensitivity analysis when solving mathematical functions. This streamlined approach simplifies the application of ESOs for users dealing with optimization problems. ESO1 employs a logistic map to initialize populations, while ESO2 further refines ESO1 by integrating a Lévy flight to simulate snake movements during food searches. These enhanced optimizers were compared against the standard SO and 12 other established optimization methods to assess their performance. ESO1 significantly outperforms other algorithms in 15, 16, 13, 15, 21, 16, 24, 16, 19, 18, 13, 15, and 22 out of 24 mathematical functions. Similarly, ESO2 outperforms them in 16, 17, 18, 22, 23, 23, 24, 20, 19, 20, 17, 22, and 23 functions. Moreover, ESO1 and ESO2 were applied to solve complex structural optimization problems, where they outperformed existing methods. Notably, ESO2 generated solutions that were, on average, 1.16%, 0.70%, 2.34%, 3.68%, and 6.71% lighter than those produced by SO, and 0.79%, 0.54%, 1.28%, 1.70%, and 1.60% lighter than those of ESO1 for respective problems. This study pioneers the mathematical evaluation of ESOs and their integration with the finite element method for structural weight design optimization, establishing ESO2 as an effective tool for solving engineering problems. [ABSTRACT FROM AUTHOR]

Copyright of Science: Future of Lithuania / Mokslas: Lietuvos Ateitis is the property of Vilnius Gediminas Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Science: Future of Lithuania / Mokslas: Lietuvos Ateitis is the property of Vilnius Gediminas Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Science: Future of Lithuania / Mokslas: Lietuvos Ateitis is the property of Vilnius Gediminas Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Science: Future of Lithuania / Mokslas: Lietuvos Ateitis is the property of Vilnius Gediminas Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Civil Engineering & Management is the property of Vilnius Gediminas Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents application of the Principal Component Analysis method for analysis of geometry of biological objects and computation of three dimensional anthropometric database. In this work as the biological objects the fifteen human femur bones were used. The geometry of each bone was obtained by using 3D structural light scanner. For PCA analysis all objects have to be described with the same FEM mesh. To achieve this, the modified fluid registration was used. PCA decomposes the set of 3D objects into mean geometry and individual features (empirical modes) describing deviations from mean value. In this paper the mean shape and features of real bones were presented and discussed. [ABSTRACT FROM AUTHOR]

Confidence intervals provide a way of reporting an estimate of a population quantile along with some information about the precision of estimates. Some procedures that may be used to obtain estimates of confidence intervals for quantiles in a finite population (most of which are based on resampling) are compared in the paper. A simulation study, based on two different artificial populations, is performed and comparisons of the estimation methods proposed for confidence intervals of population quantiles are made. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Civil Engineering & Management is the property of Vilnius Gediminas Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We have investigated and calculated the distribution of electromagnetic fields and forces induced by a three- phase axially-symmetric system of electric current with six electrodes in a cylinder of a finite length [1, 3]. In this paper the alternating current is fed to each of nine discrete circular conductors-electrodes, which are placed on the internal wall of the cylinder. This new mathematical model describes a real device [7], which transforms electric energy into heat. The viscous incompressible flow of weakly electroconductive liquid-electrolyte is obtained by the finite-difference method, using the monotonous vector finite difference schemes. The average axially-symmetric motion of electrolyte and vortex distribution in a cylinder has been considered. The dependence of electromagnetic forces and velocity distribution at the inlet of the cylinder is investigated in the case of: 1) the vortex formation from the Lorentz force inside the cylinder by the electrode, 2) the vortex-breakdown from the swirl velocity at the inlet of the cylinder. [ABSTRACT FROM AUTHOR]

The article presents the results of the numerical analysis of the asymmetrical one-pylon suspension bridge builtin rigid cables. The models for the suspension bridge with the cables of different rigidity are analyzed by comparing vertical displacements, bending moments and strains in the structural members of the bridge. The numerical analysis was performed by examining the bridge under symmetrical and asymmetrical loading and different erection methods. The stress-strain state of a single asymmetrical pylon with the cables of different rigidity and the rational relationship between cable rigidity and girder stiffness has been established. [ABSTRACT FROM AUTHOR]

Prestressed stayed compression members are frequently required as very slender load-bearing structural components by both investors and architects. Behavior of these members depends on their geometrical and material properties, prestressing and boundary conditions. In the paper are discussed respective critical buckling loads and post-buckling paths with regards to 2D and 3D GMNIA (geometrically and materially nonlinear analysis with imperfections) using ANSYS software. Former tests and recent detailed analyses of other authors are commented with respect to the 3D analysis, level of imperfections, boundary conditions at central crossarm (fixed or sliding stays) and nonlinear stainless steel material. [ABSTRACT FROM AUTHOR]

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Gear pumps are widely used in transport machines not only in hydraulic drive systems, but also in lubrication and fuel systems. A positive displacement pump converts mechanical energy into pressure energy stored in the liquid, which it transports to the hydraulic cylinder or motor. The efficiency of this process depends on the efficiency of the system components, including the efficiency of the pump, which depends on the amount of internal leakage through the gaps between the high and low pressure sides. The larger the gaps, the lower the volumetric efficiency. This article presents an investigations of impact of pump deformations on circumferential gap height. The article presents a three-dimensional model of an external gear pump using Finite Element Method (FEM) during operating conditions. The model reflects pumping operation at discharge pressures up to 32 MPa and it was validated against strain measurements of pump casing. The simulation results indicate that the pump casing becomes deformed due to pressure, causing a significant increase in the height of the circumferential gap. The increase of the discharge pressure from 8 to 32 MPa causes more than twofold local increase in the height of the circumferential gap. The obtained results indicate that for the correct modelling of the flow generated by gear pumps, it is necessary to consider the change in the size of the gaps resulting from the deformation of the pump. [ABSTRACT FROM AUTHOR]

The paper deals with the strength analysis of structural devices(platform bridges) that fasten cars to a car carrier frame. Theloads of all bridges are evaluated along with the indication ofthe areas of load concentration. The paper presents a brief structuraldescription of platform bridges, including their drawingsperformed with the help of SolidWorks software. The bridgeloads have been analyzed applying Ansys software. Accordingto the results of computer simulation of the loads, dangerousstructural areas of the bridges have been identified. While makingattempts to solve the established structural problems of suchcar carriers, suggestions for their structural improvement havebeen put forward, and computer simulation of loads and stressspread have been performed. The paper ends with conclusionsand suggestions. Santrauka Straipsnyje atliekamas automobilio tvirtinimo prie automobilvežio rėmo konstrukcinio elemento (platformos tiltelio) stipruminis tyrimas. Nustatoma tiltelį veikianti apkrova bei apkrovos koncentracijos vietos. Straipsnyje trumpai aprašomi tiltelio konstrukciniai elementai ir, naudojant „SolidWorks“ programinį paketą, braižomas pats tiltelis. Tiltelio konstrukciją veikiančios apkrovos tiriamos „Ansys“ programiniu paketu. Pagal atlikto apkrovų modeliavimo rezultatus patvirtinamos pavojingos konstrukcinės tiltelio zonos. Siekiant išspręsti nustatytą konstrukcinę automobilvežio platformos elemento problemą, pasiūlytas konstrukcijos tobulinimas, atliktas šios konstrukcijos apkrovų ir įtempimų pasiskirstymo modeliavimas. Formuluojamos išvados bei pasiūlymai. Reikšminiai žodžiai: automobilvežis, rėminė konstrukcija, platformos tiltelis, baigtinių elementų metodas, apkrova, įtempimas.

The article examines an algorithm used for processing the results of laboratory tests when experimental data was obtained in the aerodynamic tunnel. The paper deals with information when data about pressure distribution on the surfaces of a designed building are recalculated into wind loads required for calculating a virtual model for the finite element method. Due to differences in methodology between experimental airflow testing in the aerodynamic tunnel and the simulation of wind loads for a complex facility referring to the finite element method, the proposed investigations are actual while taking into account the current design codes and climatology conditions for an individual site. A review of similar problems, design conditions, the principles of the conducted experiment, a concept of the algorithm, basic assumptions and some results are briefly described in the paper. The final conclusions and recommendations can help with choosing the right solution during such calculations. Santrauka Straipsnyje nagrinėjamas laboratorinio bandymo rezultatų apdorojimo algoritmas, kai aerodinaminiame tunelyje gauti eksperimentiniai duomenys apie oro slėgio pasiskirstymą ant pastato maketo paviršių perskaičiuojami šio vėjo apkrovas, reikalingas baigtinių elementų metodo virtualiajam modeliui skaičiuoti. Duomenu perkėlimo uždavinys yra aktualus, nes laboratorinių tyrimų metodika ir priemonės iš esmės skiriasi nuo skaitinio modeliavimo baigtiniais elementais eigos ir principų, kai atsižvelgiama šių realiai projektuojamo statinio vietovės klimatologines sąlygas ir galiojančių projektavimo normų reikalavimus. Straipsnyje apžvelgta eksperimento duomenų apdorojimo problematika, nagrinejama konkretaus statinio konstrukcijų skaičiavimo situacija, aptarti pagrindiniai laboratorinio aerodinaminio bandymo principai, paaiškintas duomenų perkėlimo inžinerinis algoritmas bei esmines prielaidos, pasirinktinai pateikti rezultatai uždavinio sprendimui vaizduoti. Baigiamosios išvados ir siūlymai pades rasti tinkamiausius sprendinius kuriant panašaus pobūdžio algoritmus. Reikšminiai žodžiai: perskaičiavimo algoritmas, vėjo inžinerija, sudėtingas statinys, aerodinaminiai bandymai, baigtinių elementų metodas

This paper deals with a theoretical and a numerical analysis of local stability of web of tapered beams subjected to a pure bending moment. A standard FEM code COSMOS/M has been used for a numerical estimation of a critical load multiplier. It has been assumed that the critical stress of the web of tapered beam could be calculated in an analogous way as for uniform member just with an additional correction factor αb.w. A large number of simulations carried out within a wide range of the ratios of second moments of area allowed to determine the proper values of that factor. In the paper there was investigated the influence of steel grade, relative slenderness and beam's ends cross‐section moments of inertia ratio to the local stability of web of the tapered beam subjected to pure bending. Santrauka Straipsnyje aprašyti teoriniai ir skaitmeniniai grynai lenkiamu trapeciniu siju sieneles vietinio pastovumo tyrimai. Kritinis apkrovos daugiklis gautas baigtiniu elementu metodo programa COSMOS/M. Atlikus teorinius tyrimus nustatyta, kad trapecines sijos sieneles vietini pastovuma galima apskaičiuoti kaip pastovaus skerspjūvio sijai naudojant papildoma koeficienta . Atlikus skaitinius eksperimentus kintant sijos galu skerspjūvio inercijos momentu santykiui, gautos tikslios šio koeficiento reikšmes. Straipsnyje nagrineta plieno klases, sijos sieneles salyginio liaunio ir sijos galu skerspjūvio inercijos momentu santykio itaka grynai lenkiamai trapecinei sijai. First Published Online: 24 Jun 2011 Reikšminiai žodžiai: vietinis sieneles pastovumas, grynai lenkiama trapecine sija, baigtiniu elementu metodas, kritiniai sieneles itempiai

There are many methods to calculate castellated steel beams; however, neither of these methods determines the rational cross‐section selection. Selecting the rational cross‐section induces a significant reduction in the quantity of steel. A new algorithm for selecting the rational dimensions of the castellated beams is presented in this paper. In future works it may be adopted and used for design. 12 m long beams, web thickness 6–12 mm and web depth 500–1000 mm are analysed in this paper. Opening size used varies from half of the web depth to the total web depth minus 100 mm. The chosen cross‐sectional area of two flanges is equal to the cross‐sectional area of the web. The thickness of the flanges is twice as big as the thickness of the web. The finite element method was used for geometrical and physical non‐linear analysis of the castellated beams under a uniformly distributed load. The upper flanges of the beams are restrained out of the plane. The results are presented in relevant charts. Santrauka Yra ne viena sijų su perforuotąja sienele skaičiavimo teorija, tačiau nė viena iš jų nenurodo, kaip parinkti racionalius tokių sijų skerspjūvio matmenis. Jeigu sijos su perforuotąja sienele skerspjūvio matmenys būtų parinkti racionalūs, galima būtų sutaupyti nemažai plieno tokioms sijoms gaminti. Buvo analizuotos sijos, kurių ilgis 12 m ir sienelės storis 6−12 mm, o aukštis 500−1 000 mm. Perforacijos skersmuo buvo parinktas nuo pusės sienelės aukščio iki sienelės aukščio atėmus 100 mm. Dviejų lentynų plotas buvo parinktas lygus sienelės plotui, o lentynų storis lygus dviem sienelės storiams. Analizuotos sijos buvo dviatramės, apkrautos tolygiai išskirstytąja apkrova, jų viršutinės lentynos buvo suvaržytos iš plokštumos. Sijos skaičiuotos baigtinių elementų metodu geometriškai ir fiziškai netiesiškai. Išanalizavus šias sijas, skaičiavimo rezultatai buvo pateikti grafikų pavidalu. First Published Online: 14 Oct 2010 Reikšminiai žodžiai: sija su perforuotąja sienele, perforacija, perforacijos forma, perforacijos skersmuo, racionalus aukštis, baigtinių elementų metodas, ribinė apkrova.