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The collapse factor is a significant parameter in the framework of the safety assessment and economical design of ductile structures. This fact draws attention to the necessity of a careful assessment of the limit analysis approaches. The kinematics in these structures arises in fact from the actual rotation of the plastic hinges under axial force and bending moment. It can be shown that it is possible to obtain a reliable tool capable of competing with computationally expensive methodologies. The application of the methods of limit analysis involves a simplified and idealised model of the structure and, notwithstanding the fact that hundreds of papers have been devoted to the topic, some consequences of apparently unimportant simplifications still seem to have not been properly and firmly highlighted. This paper investigates the ultimate load and collapse modes of steel frames under combined vertical and horizontal forces through limit analysis.

Designing structures with frequency constraints is an important task in aerospace engineering. Aerodynamic loading, gust loading, and engine vibrations all impart dynamic loads upon an airframe. To avoid structural resonance and excessive vibration, the natural frequencies of the structure must be shifted away from the frequency range of any dynamic loads. Care must also be taken to ensure that the modal frequencies of a structure do not coalesce, which can lead to dramatic structural failure. So far in industry, no aircraft lifting surfaces are designed from the ground up with frequency optimisation as the primary goal. This paper will explore computational methods for achieving this task.This paper will present a topology optimisation algorithm employing the Solid Isotropic Microstructure with Penalisation (SIMP) method for the design of an optimal aircraft wing structure for rejection of frequency excitation.

This paper presents an experimental work about the design of a truss roof for a long-spanbuilding. This study makes use of an innovative hybrid truss that has been developed in a parallelstudy. The project presented herein shows the direct application of the technology on an existingbuilding, emphasizing its feasibility, potentiality and functionality. The paper highlights thecharacteristic of adaptability to both newly designed buildings and existing ones. Starting from thetruss prototype, different shape configurations that the technology allows are hypothesized. Thefinal roof shape is selected based on study aiming at optimizing the elements sections.

The cable-stayed bridge at the inner ring road in Prague in the Czech Republic was put into operation in 1997. The longest bridge span is supported by fourteen cable-stay pairs and next fourteen ones are symmetrically situated on the other side of the pylon. The cable-stays in the ten longest cable-stay pairs are tied together since the bridge construction to prevent vibrations of individual cables caused by wind. The experiment described in the paper was carried out because the large amplitudes of vibrations (about fifteen centimetres) were observed visually on some medium-length cable-stays in April 2015. The experimental analysis was focused on the nine day long continual observation of the selected six cable-stays vibrations during the standard bridge operational state. The analysis of probable causes and the recommended measures to reduce observed large vibrations are mentioned in the paper.

Machined product quality depends on its dimension and surface quality. The dimension quality depends on machine tool accuracy while the surface quality depends on machining system stiffness. A low machining system stiffness will shift spindle shaft-tool resonance frequencies to low frequencies. When one of these frequencies coincides with spindle rotational speed or its harmonics, chatter will be generated which in turn worsen the workpiece surface roughness. In addition to increasing machining system stiffness, chatter can be eliminated by decreasing the axial depth of cut as well. Maximum axial depth at certain spindle rotational speed which will not generate chatter is called as chatter threshold. A diagram describing chatter thresholds for certain range of spindle rotational speed is called as a SLD (stability lobe diagram). The diagram is very useful for selecting a maximum depth of cut at certain rotational speed in order to obtain chatter-free machining process. The SLD can be generated theoretically or experimentally. The theoretical one is fast and cheap but it is not guaranteed to be correct. On the other hand, although the experimental one will produce exact values but it is long, cumbersome and expensive, because for certain rotational speed many machining with different axial depth of cut must be conducted until chatter threshold is reached. The same process is then repeated for other rotational speeds. This paper deals with a new method in determining the chatter threshold or SLD experimentally, by using inclined workpiece, by which it only needs one time machining-test for each rotational speed. In this method, during machining process, chatter occurrence is detected by using accelerometer and validated by its surface roughness afterwards. It is shown in this paper that the new method works well for machining aluminium workpiece in vertical machining center.

Slab-column structures used in design and construction work are one of the typical kinds of structures used in building industry. The emergence of factors unexpected at the designing stage can lead to collapse of the structures. The paper presents experimental investigations of the central field of the continuous floor. The research was conducted on a nine-field slab with dimensions 9300×9300×100 mm. The aim of the research was to observe the behaviour of the experimental model in the time when excessive load is exerted. The model was prepared using high ductility steel (εuk>7.5%) in order to determine the possibility to induce tensile membrane action. The paper presents basic geometrical and material data, the research methodology, the description of the system of loading, the description of the measurement system, and the obtained measurement results. The last part summarizes the conducted investigations.

Published paper on modelling of propeller turbine blade and runner is not commonly found, especially those using Autodesk Inventor. One of them is titled CAD Modelling of Axial Turbine Blade using Autodesk Inventor. However, the road taken is quite complicated and should be repeated from the beginning whenever new geometrical characteristics of a new axial propeller turbine will be modelled. Currently, Autodesk Inventor has introduced the new tool that help sketching the spline lines either in 2D plane or 3D space simplifying the task of 3D modelling of propeller turbine blade, called Equation Curve. The Equation Curve tool requires the codes for creating the spline lines. To create the codes, two sources have been used: NACA report no. 460 and modelling methodology proposed by Milos in his paper. In NACA report no. 460, it is explained that NACA 4 Digit Series is created by combining mean line with the thickness variation curve of Gottingen 398 and Clark Y. This airfoil has 4 different lines with their own equation. The equations can be used for sketching in 2D plane. However, the solid model of the runner blade is formed from the airfoils in cylindrical surface. Then, as explained by Milos in his paper, the procedure is as follows: sketch the airfoil in 2D plane that is the tangent of cylindrical surface, move the airfoil to its center, rotate to its stagger angle, and project it to cylindrical surface. The result of this process will be the equations of lines in 3D space. Transform them to the Inventor codes. Input these codes to 3D Equation Curve tool to create the 4 lines for each cylindrical surface section of blade. Making the solid model of runner the following step is required: use loft command to create blade surfaces, use the stitch command to solidify, use the pattern command to create other blades, create hub, and lastly combine blades and hub. The solid model of the runner then is tested by simulating it using ANSYS Fluent. The hydraulic efficiency of the model is 85%.

This paper deals with a problem of earthquake of the cylindrical tank. During the seismic event, the load acts in one direction only, i.e. in the direction of earthquake. This load imposes a non-symmetrical loading of a structure. At seismic load of structure of cylindrical tank was used accelerogram. In final part of the paper some crucial results are presented both in a graphical and numerical way.

The present paper proves the feasibility of a semi-automatic control system of high frequency ultrasound for welded plastic pipes, by ultrasonic methods. The paper presents the main existing types of plastic materials, the technological joining possibilities, the problems that may occur in welding and control and the reasoning of the chosen examination method. The theoretical size of the reference ultrasonic parameters for the propagation of ultrasounds through the flawless juncture. The samples were welded using electro fusion (EF) under different working conditions. The samples were assessed circumferentially, every 10 degrees, on different working frequencies. A semi-automatic control system was designed and developed. For the optimal working frequency, a set of 10 measurements was done, in similar working conditions, on the automatic control stand, in order to test the systems’ capability and the results’ repeatability. The measured values were compared with the limits considered to be admissible using Shewhart statistic control charts.

The presented paper introduces the application of the Electronic Speckle Pattern Interferometry (ESPI) technique for measurements of contours of strains and stresses on 3-D surfaces. The paper focuses on three selected applications. Firstly, the methodology for determining the Poisson ratio of a material from tensile tests is described. Secondly, results of calibration verification of a biaxial extensometer used for measurements of shear strain in comparison with the ESPI measurements are presented. Finally, the experimental analysis of stresses in welds is discussed. As mentioned in the paper, the method is very useful for material testing, as well as for measurements on structural parts in service.

This paper is focused on the assessment of serviceability of the footbridge structure, which has been excited by pedestrians and vandals. The three dimensional FE model of the footbridge structure was created for the necessities of theoretical modal analysis. Computed mode shapes and natural frequencies were subsequently used for the forced vibration analysis as an input files into MATLAB code. Results obtained by the theoretical analysis were compared with the experimental results. At the end of this paper, the comfort criterion of crossing pedestrians has been evaluated.

Biomechanics is the science that uses mechanical equations in studying biological structures such as bones, muscles, ligaments, joints and other body structures. It is important in understanding the mechanism of injury to the cervical spine (C1-C7) and head bones. We developed a mathematical approach to mechanical behavior of cervical vertebrae and inter-vertebral discs, in terms of laboratory testing. The paper presents the mathematical model based on Lagrange equations for a frontal impact testing head-neck system. The steps for the solving these equations are exposed in the paper. These studies were combined with FEA and dynamic analysis for determination of constants,parameters, forces and functional relations. Results and conclusions were analyzed in the final of the paper.

This paper deals with an experimental analysis of hard rubber dynamic tests under finite torsion deformations. The experimental test rig was designed and composed for torsion loading of rubber under defined amplitudes, frequencies and temperatures. The present paper brings an amplitude-temperature analysis of isoprene-butadiene rubber ascertained by the use of the test rig. The mathematical rheological model of rubber was designed for phenomenological description and parametric identification of rubber.

Submitted paper is focused on dynamic analysis of the footbridge structure, which is represented by the simply supported beam. The continuous beam model was discretized by the FEM to MDOF system and loaded by pedestrians, walking across the structure. Three states of loading are considered in this paper. Firstly, it is the mathematical description of pedestrian's ordinary traffic, where each pedestrian is randomly generated by the Monte Carlo method. Secondly, the movement of single pedestrian, simplified by viscoelastic models, is introduced. Thirdly, the DLF model of stochastic vandals is investigated as well.

In this paper is presented a new mathematical model which is intended to simulate the hysteretic phenomenon of SERB-C Romanian friction device for damping and dissipation of earthquake energy used for buildings. These devices have unusual shape of force-displacement loop which can be simulated with our new model which represents a specific adaptation of the well known Bouc-Wen hysteretic model. The purpose of this analytical simulation is to determine a relation for the hysteretic loop which was obtained by experimental tests performed by the authors. The mathematical model presented in this paper can be used in computational simulation of a building protected with these types of devices, in order to determine the anti-seismic performances of a Romanian friction building protection system.

The paper deals with nonlinear phenomena that occurs during vibration of nuclear fuel rod (FR). The FR is considered as a system consisting of two impact-interacting subsystems FR cladding (zircalloy tube) and fuel pellets stack placed inside FR cladding. Between both subsystems, there is a small radial clearance. The FR is bottom-end-fixed, and at eight equidistant levels, the FR cladding is supported by spacer grids (SG). Both subsystems are modelled by means of finite element method for one-dimensional Euler-Bernoulli continua. During fuel assembly (FA) motion caused by pressure pulsations of the coolant, the FR vibrates and impacts can possibly occur between FR cladding and fuel pellets stack. The paper focuses on qualitative change of vibration with change of bifurcation parameters clearance between FR cladding and fuel pellets stack and stiffness of spacer grids cells. The change of vibration quality is shown by extremes of relative radial displacements of both continua in discretization nodes and by phase trajectories. Dependence of impact motion on modal properties of both subsystems is shown.

Energy consumption of buildings is increasing steadily and occupying approximately 30-40% of total energy use. It is important to predict heating and cooling loads of a building in the initial stage of design to find out optimal solutions among various design options, as well as in the operating stage after the building has been completed for energy efficient operation. In this paper, an artificial neural network model has been developed to predict heating and cooling loads of a building based on simulation data for building energy performance. The input variables include relative compactness, surface area, wall area, roof area, overall height, orientation, glazing area, and glazing area distribution of a building, and the output variables include heating load (HL) and cooling load (CL) of the building. The simulation data used for training are the data published in the literature for various 768 residential buildings. ANNs have a merit in estimating output values for given input values satisfactorily, but it has a limitation in acquiring the effects of input variables individually. In order to analyze the effects of the variables, we used a method for design of experiment and conducted ANOVA analysis. The sensitivities of individual variables have been investigated and the most energy efficient solution has been estimated under given conditions. Discussions are included in the paper regarding the variables affecting heating load and cooling load significantly and the effects on heating and cooling loads of residential buildings.

Aim of this paper is to show modern lightweight structures based on tensegrity systems. Principles of tensegrity structures and cable domes are shown. Last part of this paper is demonstrated how to join simple tensegrity prisms to tensegrity slabs. These structures are very interesting from architectonical point of view, they are made from fully recyclable material – steel and consumption of material is very low. Tensegrity structures have a great potential of the development of modern civil engineering.

In this paper the authors present the results of theoretical and experimental research in order to optimize suspension rigidity in case of Daewoo Nubira vehicle. The paper presents the mathematical model obtained by assimilating car with a dynamic system with 5 rigid solids with elastic and viscous linking between them. Theoretical results obtained based on this model and the experimental results are presented, and it is presented a solution to optimize suspension in order to remove the negative effects observed driving on gravel runways or damaged runaways. Theoretical results, compared with the experimental ones, allow us to say that it is possible to optimize suspension by analyzing specific parameters equivalent mathematical model.

This paper deals with the use of classical experimental technique of photoelasticity as well as modern one – digital image correlation by stress analysis. Both mentioned methods were used to compare the corresponding stress fields obtained on a sample with stress concentrators loaded by bending. The paper contains the basic principle of photoelasticity, methodology of static analysis with polariscope and briefly describes the measurement with low-speed digital image correlation system. Taking into account that the used correlation system does not allow to evaluated stress fields, calculation and visualization of stress fields were realized in program Q-STRESS v.1.0 developed at the authors department.

The electric base load of milling machine tools has a high share of the machine’s total energy consumption. An approach to decrease the energy demand per workpiece is to shorten the machining time by raising the material removal rate. The maximum feed depends on the tool’s wear resistance while the maximum depth of cut is often limited by the chatter stability of the machine. In this paper active damping is used to damp chatter vibrations, which leads to a higher depth of cut. To evaluate the decrease of energy consumption for any workpiece, a modeling methodology for the energy demand of machine tools was developed, which is presented in this paper. The methodology is able to estimate the energy requirements of the spindle during cutting, of the feed drives, of the auxiliary equipment and of the base load. The numerical results were experimentally validated by different 2.5D machining processes, with good agreement between the simulation model and the experimental results. Therefore, the proposed methodology can be used effectively for calculating the total energy required for the machining of any workpiece. In addition, the structural dynamics of the machine tool, the active damping system and the cutting process were modeled in order to simulate the chatter stability. This enables a straightforward determination of the optimum cutting parameters as well as a comparison of different milling part programs, both in terms of the energy demand. Furthermore, it is possible to evaluate the energy conservation by active damping and to point out for which cutting processes active damping is useful.

The paper is thematically connected with paper making machines. This type of the machine is equipped with a head which has a flexible slice lip for skimming the pulp applied to produce the paper. The definition of geometric features of the slice lip is a key issue. The slice lip should be made of material which is resistant to external factors, and designers want to obtain a high flexibility of this element. It is possible to get a high flexibility by forming a proper shape of the slice lip. The paper presents the proposal of dimensionless geometric indicators which combine basic geometric parameters of the slice lip. These indicators are the following: indicator of the cross-section, indicator of the length and indicator of the length of the transverse notch. FEM strength analyses were done – the aim of these analyses was the determination of the stress state and maximum deflection of the slice lip. The authors have analysed the slice lip with holes for mounting the actuators and the slice lip and with transverse notches for increasing its flexibility. The results were presented in the form of graphs.

The works [1, 2] present the values of the force and moment of friction needed to disassemble the axisymmetric connection with oval and three-angular shape of cross-section of the shaft. These works additionally show the variable values of the Mises stresses and contact pressures. This paper presents research which is a continuation of the research program on the evaluation of the influence of cross-section deviations, radial deviations, and their compilations on the value of the contact area in the connection. The limited contact area has a decisive impact on functional and operational parameters of the connection. Point contact between the shaft and the hole is the reason of the reduction of load transmission. The paper concerns the connection between the shaft with four-angular shape of cross-section with the deviation Tw = 13 μm and the hub with the nominal roudness. The authors have proved the occurrence of variable values of the force and moment of friction during disassembling of the connection. The authors have also showed the occurrence of variable values of the reduced stresses and contact pressures.

This paper presents the calculation of dynamic parameters of virtual prototype of mechanism, which function is the correct tensioning of wedge belt of belt gear. Sudden release of tensioning device usually occurs during the assembly process, large impact forces which form have destructive effect on the device. A part of the paper will be the analysis of input parameters for solution by function Impact. Impact effects will be solved with flexibility of chosen member of the mechanism in mind. The solution will be realized in the environment of software MSC.ADAMS and ANSYS.

This paper indicates the difference between the strengthened reinforced high performance concrete beams and the normal reinforced high performance concrete beams. This paper shows the cyclic behaviour of the two types of beams. Experimental investigations were carried out on reinforced High Performance Concrete (HPC) beams of size 150 mm × 250 mm × 3000 mm under both static loading and cyclic loading separately under four point bending. It was observed that the trend in behaviour of the load-deflection curve of the beams was showing the same trend of normal reinforced concrete beams under static loading. In static loading the strain energy absorbed by the beams were observed to be the same as calculated with the area under the load-deflection curve. Other beam was tested under cyclic load separately. The load applied was 35% of static ultimate load which was uniform throughout the fatigue testing of the beams. It was observed that the deflections were increased with the number of cycles. Some of the beams were strengthened by different types and thickness of the GFRP sheets. It was also observed that the strengthened beams withstood more number of cycles than normal HPC beams. The paper presents in detail the experimental investigations conducted on beams and pertinent conclusions drawn therefrom.

In this paper the authors present some of the results of research on the behavior of high entropy alloys used in ballistic protection structures. Bullet impact testing methodology and results on layered Ballistic Packages that incorporate high entropy alloys (HEA) are presented. The paper details the technological processes used to improve the mechanical characteristics of Ballistic Packages. The optimization of the high entropy alloy based layered ballistic composite structures is also investigated. Testing methodology of ballistic boxes, the special heat treatment processes, the homogenization and the artificial aging of high entropy alloys, designed and applied during scientific research; represent the novelties of the article. Ballistic Packages are layered structures which include combinations of the following materials: HEA, armored steel, ceramic plates and laminated polyamide fibers arranged in a predetermined order depending on the constructive version. Ballistic Boxes behavior was investigated by ballistic experimental methods and numerical simulation methods. For the numerical simulation a FEM with an explicit numerical code was used. The numerical and test results are consistent in underling the ballistic protection effectiveness of the investigated configuration.

The aim of this paper is to provide a solution for easy calculations of reinforced concrete with biaxial bending cross-section. The paper presents in an orderly manner basic definitions related to the discussed topics, to the extent necessary to understand the discussed issues. As a result of the computational analysis dozens of sections with biaxial bending, there was developed a table and a chart containing the correction factor for bending moments, allowing to obtain the correct bearing capacity of cross-section, subjected to biaxial bending. This work presents proposition for a new, own calculation method of such cross-section. Calculations were made according to PN-EN 1992-1-1:2008, Eurocode 2, Design of concrete structures. Part 1-1: General rules and rules for buildings, using algorithms based on simplified methods. According to carried out calculations, cross-section dimensioning compressed with biaxial eccentricities separately on each side and values of bending moments should be increased to maintain cross-section's bearing capacity. The coefficient K scaling moments was determined as a function of eccentricity ey. With the increase of eccentricity, the coefficient K decreases.

The aim of this paper is finite element presentation for vibration response of the intelligent structure (consisting peizoeectric members) and modification of the response. The active element consists of a piezoelectric ceramic actuator stack, a force transducer and mechanical interfaces. An integral plus double-integral force controller is designed to suppress vibration of the truss. In this paper, in order to find the best piezoelectric operator’s location in spatial truss and optimizing the performance of the member by changing the property of the members, an algorithm is presented to achieve desired natural frequency. Therefore, finite element method of spatial truss is extracted. The results are admitted by ANSYS software. At the end, an example to show the application of the relations is given.

Casing design is one of the most important parts of the well planning in the oil and gas industry. Various factors affecting the casing material needs to be considered by the drilling engineers. Wells partaking in thermal oil recovery processes undergo extreme temperature variation and this induces high thermal stresses in the casings. Therefore, forecasting the material behavior and checking for failure mechanisms becomes highly important. This paper uses Finite Element Methods to analyze the behavior two of the frequently used materials for casing - J55 and L80 steels. Modeling the casing and application of boundary conditions are performed through Ansys Workbench. Effect of steam injection pressure and temperature on the materials is presented in this work, indicating the possibilities of failure during heating cycle. The change in diameter of the casing body due to axial restriction is also presented. This paper aims to draw special attention towards the casing design in high temperature conditions of the well.

A new fatigue life simulation analysis method for spot weld joints is proposed which considers the fatigue crack propagation from the point of fracture mechanics. The traditional fatigue simulation analysis methods for spot weld joints are mainly LBF method based on force and LMS method based on stress, while there exist some issues such as the prediction accuracy is not high, modeling and computational efficiency is low. A modular spot weld model is adopted in this paper, the node forces and moments around the spot weld are extracted through the finite element analysis, then a average stress intensity factor through the crack propagation path is calculated as the evaluation parameter of fatigue life. Shear fatigue test is designed for spot weld joints with two high strength steel materials (HSLA340GI and DP600GI) and four different thicknesses, then double logarithmic regression analysis is implemented between the average stress intensity factor and the fatigue life data of spot weld joints, then a matching curve is obtained as the fatigue life prediction curve for spot welds. Comparative analysis of prediction accuracy is implemented for these three methods, the results show that the prediction accuracy of fatigue simulation method for spot weld joints in this paper is higher than traditional LBF and LMS methods.

An experimental investigation was presented in this paper on reinforced concrete box beams subjected to shear, torsion, and bending moment strengthened by carbon fiber reinforced polymer (CFRP). Eight box beams were cast and separated into two groups according to two different torque-to-shear and torque-to-bending moment ratios. Three box beams from each group strengthened by CFRP in different configurations and one control box beam were tested. The main parameters of this experiment were the different ratios and configurations, including U-jacket layers and U-jacket strips with or without longitudinal strips. The cracking and failure mode, effect of wrapping configuration, torsional capacity, and behavior of the different torque-to-shear and torque-to-bending moment ratios were studied in the paper.

Flexure hinge is the most basic compliant structure, the compliance is one of the important performance parameter. The structure characteristics is analysed and the new method used for calculating the compliance is performed in this paper. Based on the structure characteristics analysis of the right circle, corner filleted and elliptical flexure hinge (symmetric and non-symmetric), half flexure hinges are analysed and the compliance formulas are given by selecting the reasonable integral variable. The combined compliance formulas of 12 kinds flexure hinge (simple, hybrid (symmetric,non-symmetric)) are obtained by half different types of flexure hinge being combined. The right circular flexure hinge, right circular elliptical hybrid flexure hinge and non-symmetric elliptical flexure hinge are selected and their compliance are calculated with the formulas in this paper and in literatures, which results indiceted the validity and correctness of the combined compliance method.

With the increase in acts of terrorism, the effects of the explosion on structures has become highly topical. The aim of the paper is an analysis of various approaches to determine the response of blast loaded reinforced concrete pillar. Homemade ANFO (Ammonium nitrate + fuel oil) explosive will be a reference explosive. Such type of explosives is the most used one in terroristic attacks. The paper will be focused on the analysis of the blast wave, based on the experimental tests, and dynamic analysis of a structure under such load.

This paper explicitly highlights the failure analysis and study of thin walled composite beams (multi-cell and multi-tapered) in cantilever configurations when subjected to constrained torsional load, using MSC Patran / Nastran finite element package. Initially, the verification of the model was done with the analytical results in order to ensure the model accuracy. All the multi-tapered beams under examination are composed of closed section and three cell configuration with twisting moment applied at the free end. There is a vivid description of all the effects of different composite material and various stacking sequences on the margin of safety and failure loads. This paper also verifies the influence of various geometrical configurations (Beam lengths, tapered angles and point of variation of tapered angles) of beams on the failure loads. This paper would help in the wing design phase of modern agile and high speed aircraft in which multi-cell closed cross section beams are integral part.

This paper presents results of personal research concerning designing a new construction in the form of axially symmetric ducts, characterized by a complex construction of the carrying wall. These ducts were designed so that in the carrying wall they have a specified number of micro canals, in which additional cables can be placed. This paper presents research results of selected mechanical properties of the products, the values of force required to achieve a deformation of 3%, useful to calculating the peripheral stiffness of the construction. The research results allowed to determine the range of change of thinning possibility of the wall of the product in relation to the volume of the material and the mathematical function depicting the outline of the duct in cross-section.

In this paper, the analysis results of the imitative grounding systems consisting of 4 mesh grid with rods are presented by using the Finite Element Method (FEM) and field test. This combined grid with multiple rods configuration was installed by previous researchers [4] and the resistance value is obtained under steady state. The FEM simulations were conducted and the resistance value and electric field profile are obtained. Comparison study in terms of its resistance value is performed between FEM and at steady state, and further analysis of the grounding systems using FEM is presented and discussed in this paper.

This is Part-1 of the two-part paper in considering the effect of cambered airfoil blades on self-starting of vertical axis wind turbine. Part 1 reports the numerical studies on self-starting of vertical axis wind turbine with comparative studies involving NACA 0012 and cambered airfoil NACA 4415. Part 2 of the paper deals with numerical studies of NACA 0018 and cambered air foil NACA 63415. Darrieus type VAWT is attracting many researchers attention for its inherent advantages and its diversified applications. However, a disadvantage is when the rotor is stationary, no net rotational forces arises, even at high-wind speed. The principal advantage of the vertical axis format is their ability to accept wind from any direction without yawing mechanism. However, self-starting capability is the major drawbacks. Moreover, literatures based on computational analysis involving the cambered airfoil are few only. The objective of this present study is to select the suitable airfoil blades on self-starting of VAWT at low-Reynolds number. The numerical studies are carried out to identify self-starting capability of the airfoil using CFD analysis by studying the flow field over the vertical axis wind turbine blades. The commercial CFD code, ANSYS CFX 13.0© was used for the present studies. Initially, the flow over NACA 0012 was simulated and analyzed for different angles of attacks and similarly carried out for NACA 4415. The contours of static pressure distribution and velocity as well as the force and torque were obtained. Even though the lift force for cambered airfoil NACA 4415 is higher, based on the torque values of the above blade profiles, asymmetrical airfoil NACA 0012 is found to be appropriate for self-starring of VAWT.

In the present paper, the Preisach model of hysteresis is extended to structural analysis of trusses damaged under cyclic loading in plastic range. Parameters for the Preisach model of cyclic plasticity are obtained from uniaxial loading experiment. Damage, as a consequence of micro cracks appearance due to alternating loading in plastic domain, is modeled using brittle elements according to Preisach procedure. Results of this research are compared with the already existing in the literature. In the paper examples of trusses under various cyclic loadings are presented. Applied Mechanics and Materials

The function of the fan is to reduce heat in the radiator where hot cooling liquid is circulated. The radiator fan blades are made up of various materials nowadays and the legacy material used is steel. This paper presents the static analysis of the radiator fan and at the outcome we analyze the failure of the entire blade taking into design consideration. The analysis of the radiator fan is executed to different types of materials to check and evaluate the material and process conditions which withstand the dynamic and structural loads. In the paper design of the blade is done through reverse engineering. The static analysis is done using ANSYS where the 3D solid model of the radiator fan is considered for structural analysis. The various loads and properties and applied through the entire length of the radiator fan. The analysis leads us to proposal of suitable material to withstand all the loads. The Fiber Reinforced Plastic (FRP) material is tested and considered.

Spur gear is used to transfer rotary motion between parallel shafts. The simplicity in its design is one of the advantages of the spur gear. However higher frictional force that is accumulated on the gear teeth will influence the spur gear performance. Many previous papers elaborated extensively on the contact stress in the spur gear but few of them gave the details on how friction affects the gear teeth. There are insufficient frictional effect data in the gear and thus should be regarded as an important research parameter. In this paper, the contact stress of spur gear has been evaluated with and without friction by employing the Hertz theory, AGMA standard and finite element method (FEM). The frictionless contact stress result has been validated with both the theoretical methods with minimum deviation. Frictional coefficient range of 0.0 to 0.3 was selected and the corresponding contact stress is directly proportional to the friction coefficient. The work also involves the variation of face width of the gear set under the influence of friction. The contact stress of spur gear was found to be inversely proportional to the face width.

For an arch rib of concrete filled steel tube (CFST) erected by cable-stayed cantilever method, the construction control becomes increasingly difficult along with the erection of rib segments, owing to more system transformation, and higher degrees of static indeterminacy. First, for the problems usually occurred in the process of ribs erection, this paper presented a line-shape control principle that is “erecting higher, remaining stationary”. Secondly, based on analysis of the merits and demerits of common methods for cable forces calculation, and according to the principle of “remaining stationary”, a new calculation method for cable forces was proposed. At last, based on an X-style CFST railway arch bridge with a span of 360m, this paper compared the cable forces calculated by the new method with the actual tensioned forces, analyzed the variation of segments displacement in the process of erection, and discussed the influence of prearranged height on weld width. The control principle and the calculation method for cable forces presented in this paper have been proved effective, by the line-shape data measured after the closure of arch ribs, which may provide valuable reference for the construction control of similar CFST arch bridges.

The paper deals with some selected methods for essential reliability measures estimation. Results for polymer composites are presented. The polymer composites were placed in various climatic environments and stressed with thermal and humidity load. These climate simulated accelerated influence of operational environment which the composites percept in service operation. After these stresses mechanical strength tests were performed. Outcomes of these mechanical tests were used for reliability characteristic estimations. For assessment of reliability measures several statistical tests were used. In this paper we present fundamental reliability measures of composites which were obtained during environment accelerated tests as basic research results.

The LVL-concrete composite (LCC) structure is a hybrid in system which the LVL member is well connected to the concrete slab by a connector to produce composite action. Various types of connector with different stiffness and shear capacity are available in the market currently. The stiffness of the connector is identified through the push-out experiment. The notch connections for LVL concrete composite beams have higher stiffness and strength compared to mechanical fasteners. This paper discusses the experimental results of symmetrical push-out tests on 3 different types of connector, 150mm rectangular notch with 10mm diameter screw, 100mm rectangular notch with 8mm diameter screw and 100mm triangular notch with 8mm diameter screw. The experimental test was shear push out to failure and the type of failure was discussed. The 150mm rectangular notch was found to be strongest among all and low cost. The 100mm rectangular notch was found to be slightly stiffer than 100mm triangular notch but 100mm triangular notch is easier to construct with only 2 cut. The maximum strength and stiffness at ultimate limit states and serviceability limit states of each type of connection were discussed in this paper.

In this paper, a reinforce concrete inner supporting of tunnel working well is taken as the research object. Based on the result of field monitoring and numerical simulation, the change rules of axial force of inner-supporting are analyzed. By the method of field monitoring, the force condition of reinforced concrete inner-supporting can be understand. By the method of numerical simulation, the finite element model of reinforced concrete inner-supporting can be modeled by ABAQUS. The results show that, the error of measured values and design values is caused by the sensitivity of vibrating wire sensor, temperature and the shrinkage of concrete. This paper can provide a reference for similar measurement projects, whose measured values much larger than design values.

This paper deals with the determination of eigenfrequencies of high steel cylindrical storage tank. The eigenfrequencies have been determined for empty tank and also for the tank with fluid. Water levels varied in the range from 10 cm to 80 cm, with the step 10 cm. The task was solved by 3D computing model. The results were verified by the tests made on real structure in scale 1:1. Total dimensions, a material, the description of created computing model, applied loads, the descriptions of measuring devices and the tests are mentioned here. Obtained results and future plans are discussed at the end of the paper.

Now the most pressing and to end unresolved question is the determination of the design parameters for the base in the conditions of formation of karst deformations. Foundation calculations made on the basis of forecasting karst manifestations sizes and the likelihood of their formation at the base of the designed construction. In paper presented the grillage calculation scheme. We calculated the grillage with four bays for four cases: excluding karst collapse, taking into account the collapse of a single support, taking into account the collapse under two not adjacent supports and taking into account the collapse at two adjacent supports. In paper presents the diagrams of bending moments and shear forces.

The paper deals with the designing and analysing of concrete structures. A particular attention is paid to a multi-segment slab made from reinforced concrete. The purpose of the paper is to evaluate, in a non-linear analysis, impacts of input parameters of the concrete on the real load-carrying capacity of the ceiling which has been designed originally in DeMKP. FEM software applications have been used in the analysis. This is an in-house application DeMKP for designing the systems in line with standardised procedures. Another software is ATENA Science which can be used for non-linear analyses.

The Kevlar is an organic high crystalline fiber belonging to the aromatic polyamide family extensively used for its strength. Kevlar fiber posses high cut resistance and flame resistance, hence they have a wide range of application in ballistic and defense[2]. This paper investigates how K-149 behaves mechanically under sudden high velocity impact, it also shows which types of Kevlar grade hold the maximum impact stiffness capacity. In addition it also predicts the stress induced on the specimen at the time of impact. The ballistic impact object considered as 9mm standard size bullet used in short gun. The assumed velocity for these cases is 650m/s. The specimens K-149 & k-49 taken to be rectangle with the standard size 50 mm x 50 mm. The computational analysis done on Kevlar 49 & 149 and the results have been compared with the help of the pictorial representation of post processing abaqus results and the best ballistic material can be chosen. This paper also provided the recommended research data to fill the technology gap in defense material science.

This paper deals with a problem of eigenfrequencies of filled cylindrical tank rested on elastic foundation. For an ANSYS analysis of eigenfrequencies some numerical models of gravel subgrade are used and finally results got by these models are compared. In final part of the paper some crucial results are presented both in a graphical and numerical way.

Paper discusses the implementation of sectional analysis in a custom program developed by authors. The program is devoted to nonlinear analysis of reinforced concrete frames. Analysis consists of two interrelated iterative procedures, global frame analysis and sectional analysis. The latter works with the discretized cross section into finite number of concrete fibres and reinforcement layers. Each fibre is analysed separately to determine axial stresses on them. However, equilibrium and compatibility requirements are satisfied for the cross section as a whole. For determination of stresses on fibres is used Disturbed Stress Field Theory (DSFM) model. Paper summarizes the concept of the global and sectional analysis and DSFM. Finally it shows the proposed implementation of cross section discretization for the sectional analysis in respect with consideration of the cover layer if the concrete.