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This paper put forward a mine location algorithm based on multiple linear regression, which using only simple RSSI value to get a higher location accuracy under long narrow and sensitive mine environment. General RSSI measurement method and its drawbacks are discussed in the paper. In order to acquire smaller location error, we filtered some abnormal RSSI data through Gaussian filter method. And we deduced regression equation according to multiple linear regression principle. Combined with training sample, we got their regression parameter. We did relevant location experiment again in the same environment---40m long and narrow bomb shelter which may imitate mine tunnel to a great extent, which shows that the total errors are limited in 3m and 75% errors are less than 2m. What’s more, it can be extended to infinite measuring range with the same set regression coefficient in similar environment.

Compare with the Rayleigh wave method, ultrasonic creeping waves critically technique for surface and subsurface defects nondestructive measurement for has the prominent advantage, which not sensitive to surface roughness in coarse-grained materials such as austenitic steel, In this paper, the propagation characteristics and beam profiles of the creeping probe were investigated using finite difference method and measured experimentally. The finite difference numerical model for reflection arc part of the IIW block was established. Through the numerical analysis, wavefront snapshots of the creeping wave propagated in the IIW block are very clear to illustrate the mechanism, and the directivity characteristic of the main beam is obtained. The creeping wave sound characteristics were observed using the dynamical photoelastic experimental method. The beam profiles of the creeping wave probe was measured on the IIW block, the experimental measurement results and the numerical analysis are in good agreement. The results are really significant to design an efficient producer for the surface and sub-surface defects detection based on the ultrasonic creeping wave method.In this paper, a numerical modeling of contact conical transducers is discussed in conjunction with wave propagation analyses by a finite difference method (FDM). Although transducers are the devices to convert electrical energy into mechanical energy and vice versa, attention in this paper is paid mostly to the study of characteristics and parameters of cones and wedges influencing their performance. Cones and wedges inserted between an ultrasonic transducer and the specimen provide the transducer with enhanced capability for point or line contact with the specimen. We study the effect of the dimensions, shape and aperture on the frequency response and the angle of incidence of the wave. Through the testing transducer modeling, some conclusions have been drawn from the analysis, which is useful to as the guideline and criteria for an optimum conical wedge design.

In this paper, the kinematic analysis on a 3-DOF Delta parallel mechanism was carried out and the relationship models between the end cell output motions and the master arms input parameters were established. The forward and inverse solutions to position, velocity and acceleration were deduced and then verified by simulation, the curves that gotten by calculation and simulation were smooth, and no mutations or jumps appeared. In the meantime, based on the kinematic analysis, the impact of Jacobian matrix on the manipulator singular configuration was discussed, and the maneuverability in the reachable space was obtain quantitatively, meanwhile, the value of cond(C(Jv)) was located in the acceptable range, which approached to the isotropic value, so, the theory basis for optimal design was provided. The methods and conclusions in this paper are helpful to the design and control of 3-DOF Delta parallel mechanism.

In this paper the anti-plane moving crack in a functionally-graded material is studied by the analytical method. First the governing equations for a functionally-graded material are obtained using a Fourier cosine integral transform. Then the dual integral equations for moving crack are established according to the mixed boundary value conditions. It is shown that the dual integral equations can be reduced to the Fredholm integral equation of the second kind. Numerical results shown in the present paper indicate that the non-homogeneity of material has an important influence on the dynamic stress intensity factor.

The aim of this paper is to construct an image recongnition system based on Gabor wavelets for infrared image. An enhanced representation of the Gabor wavelets is proposed, in which the properties of Gaussian mask in Gabor wavelets is developed to enhance the envelope function, and simultaneously the parameters of the filter based on Gabor wavelets is designed depengding on the frequency response of the training images. Some experiments including infrared image recognitions are given. The good performances are verified through using the proposed scheme in this paper.

Aiming at the present gait instable walking-aid, a low cost walking-aid research platform is designed in this paper. The paper developed a dynamic walking aids mechanical design process which based on the study of body's gait stability and motion parameters, analyzed the structural design of the walking aids in ergonomic principles. Furthermore, based on the ZMP gait stability theory, adopting a composed design/integrated optimization gait planning method to program the gait of normal walkers and wearers. Adjusting the ankle joint to the rear foot and the trajectory of the hip’ abscissa is integrated to modify the actual ZMP trajectory to the ideal ZMP trajectory. The proposed composed design/integrated optimization method greatly simplifies the programming process and provides a good experiment platform for walking aid teaching and scientific research.

In this paper, static mechanical characteristics for some epoxy/hemp composites are studied. By using the tensile test, the static mechanical characteristics are determined, such as: breaking strength, yield stress, Young modulus and breaking elongation. There is also determined the standard deviation. Then, by using some known theories, there is validated the static Young modulus.

In this paper, we will compare the methods of solving with explicit or implicit finite difference of the partial differential equations that define the mechanical models of hydrodynamics movements, thermodynamics or those that define the vibration movements with the ones that use integral transforms. By applying the Laplace and Fourier transforms, finite in sine or cosine, depending on the boundary conditions of the real physical problem, it leads to the algebraic approach of the problem, which reduces the difficulty of solving partial differential equations. The errors obtained for the solution of partial differential equations using different methods are within the standard norms. However, in terms of calculus precision, the use of integral transforms is more advantageous.

In this paper, we proposed the numerical solution of Volterra integro-differential equations of the second kind using Improved Runge-Kutta method of order three and four with 2 stages and 4 stages, respectively. The improved Runge-kutta method is considered as two-step numerical method for solving the ordinary differential equation part and the integral operator in Volterra integro-differential equation is approximated using quadrature rule and Lagrange interpolation polynomials. To illustrate the efficiency of proposed methods, the test problems are carried out and the numerical results are compared with existing third and fourth order classical Runge-Kutta method with 3 and 4 stages, respectively. The numerical results showed that the Improved Runge-Kutta method by achieving the higher accuracy performed better results than existing methods.

Efficient surrogate modelling of computer models (herein defined as simulators) becomes of increasing importance as more complex simulators and non-deterministic methods, such as Monte Carlo simulations, are utilised. This is especially true in large multidimensional design spaces. In order for these technologies to be feasible in an early design stage context, the surrogate model (oremulator) must create an accurate prediction of the simulator in the proposed design space. Gaussian Processes (GPs) are a powerful non-parametric Bayesian approach that can be used as emulators. The probabilistic framework means that predictive distributions are inferred, providing an understanding of the uncertainty introduced by replacing the simulator with an emulator, known as code uncertainty. An issue with GPs is that they have a computational complexity of O(N3) (where N is the number of data points), which can be reduced to O(NM2) by using various sparse approximations, calculated from a subset of inducing points (where M is the number of inducing points). This paper explores the use of sparse Gaussian process emulators as a computationally efficient method for creating surrogate models of structural dynamics simulators. Discussions on the performance of these methods are presented along with comments regarding key applications to the early design stage.

This paper presents a computer software application (using the Maple programming language) together with numerical applications which allow the determination of the pressure drop uniformly distributed in the pipes with circular-eccentric section, which appears in the case of critical transition flow subdomain I.

This paper uses the Analytic Hierarchy Process to optimize the PESTEL analysis. The scenario: pre-construction and assembly factors of huge civil engineering construction projects. Several managers use too many criteria to evaluate large projects. It suggests that there may be few important criteria that summarize the manager's preference. To demonstrate the feasibility of the proposed hypothesis, the authors prepared a qualitative and exploratory study. Conclusions are based on the judgment of an expert interviewed. As expected, the hypothesis was considered plausible. Two main criteria corresponded to 71% of the expert's preference. The result resembles a Pareto distribution.

The method of the synthesis of multi-channel decentralized variable structure system for the control of quadrotor spatial motion is developed in this paper. The control law based on the formation of the sliding mode in the separate subsystems of each coordinates control is formed. Each subsystem includes two loops for Cartesian coordinates and relevant Euler angles control. The conditions of the existence of stable sliding mode are obtained. These conditions take into account essential dynamic reciprocal effect between all control channels. The application of proposed control law provides high control quality and maximal fast-action at any variations of the quadrotor parameters within given ranges. This control law does not require the identification of changing object parameters. Efficiency of synthesized control system is confirmed by numerical simulation results. The control system can be realized in the real time by simple technical means.

Natural phenomena can be modelled adequately precise with differential equations. An example of such phenomena is diffusion. All differential equations with partial derivatives, of two variables and of the second order, which model the diffusion are parabolic with simple solutions. This simple solution is: erf(x), exponential functions or power series. Adding new differential terms requires the use of more complicated functions, some degenerated, modified or confluent, of real or imaginary variables. This functions are: Bessel, Kummer, Whittaker, Hermite, hyper-geometrical or Heun. The benefit of using these functions lies in greater clarity and precision in mathematical expression. Modelling methods by change-of-variable and function, adding new differential terms and transformations of special functions increase modelling possibilities of convective diffusion in different environments using differential equations. The paper presents a novel approach to diffusion modelling for dry corrosion.

During their use, optical fibers are subject to harsh installation and environmental conditions. To evaluate more precisely the lifetime of an optical fiber, it is necessary to study the mechanical behavior of optical fibers under extreme conditions, in particular under mechanical and thermal stress.This paper presents the results of new silica optical fibers aged in hot water between 20°C and 70°C and subjected to mechanical static bending stresses from 3 GPa to 3.5 GPa. Thermal dependence of the time to failure was observed. This dependence can be described by the Arrhenius model, where the activation energy is one of the main physical characteristic.

In Computational Fluid Dynamics (CFD) we have to deal with various types of phenomena with strong discontinuities at different length scales like turbulence or hypersonic flows. It is essential that the numerical techniques must provide accurate approximation to calculate the time and space-derivatives. This paper focuses on the behavior of the solution of some known numerical schemes in comparison with analytical solution provided here for the first time, applied on one-dimensional conservation law with different fluxes and non-usual different initial conditions. The results are very interesting in the sense that methods which report very good results on classical tests schemes were not able to accurately predict solutions that admit discontinuities and sharp gradients inside.

The paper deals with eigenvalues excited-state energy eigenvalues and wave-function of a particle under harmonics oscillator asymmetric potential using numerical shooting method. The numerical shooting method is generally regarded as one of the most efficient methods that give very accurate results because it integrates the Schrodinger equation directly, though in the numerical sense. If the value of parameter μ is small the energy eigenvalues of single particle will large and the parameter μ large the energy eigenvalues of single particle will small.

The current paper investigates on the creep behavior of 12Cr-Mo-W-0.25V heat resistant steel base on the long-term stress relaxation test data. It is shows that the stress relaxation curve can be divided into 2 stages: the high stress stage has higher apparent activation volume of 79~350 b3 and the low stress stage is 35~78 b3. Besides, the Helmholtz free energy at the high stress stage is 827~1034 kJ/mol which is higher than 210~252 kJ/mol of the low stress stage. Taking both apparent activation volume and activation energy into account, it is assumed that the high stress stage is mainly controlled by dislocation slip and the low stress stage is more related to diffusion.

This paper presents about generating elemental stiffness matrix for quadrilateral elements in closed form solution method for application on vehicle analysis which is convenient and simple as long as Jacobian is matrix of constant. The interpolation function of the field variable to be found can integrate explicitly once for all, which gives the constant universal matrices A, B and C. Therefore, stiffness matrix is no longer integration of the given functional, it is simple calculation of universal matrices and local co-ordinates of the element. So time taken for generation of element stiffness can be reduced considerably compared to Gauss numerical integration method. For effective use of quadrilateral elements hybrid grid generation is recommended that contains all interior element edges are parallel to each other (rectangle or square elements) and outer boundary elements are quadrilaterals with distortion. So in the Proposed method, the closed form and Gauss numerical method is used explicitly for interior elements and outer elements respectively. The time efficiency of proposed method is compared with conventional Gauss quadrature that is used for entire domain. It is found that the proposed method is much efficient than Gauss Quadrature.

The modulus of elasticity is an important property of any structural member or machine component. It has a vital role in designing the structural components or machine components for their specific use. This paper discusses evaluation of modulus of elasticity of cantilever beams made out of Self-Compacting Concrete (SCC) using a structural dynamic approach – the free vibration test. The concept of free flexural vibration essentially involves setting up a specimen (beam) into ‘free vibration’ by imparting an initial condition, such that the specimen vibrates in its fundamental natural frequency. The digital data were stored using an efficient data acquisition system (Daisy lab version 5 software) and processed using Fast Fourier Transformation (FFT) (Acceleration v/s Time). The fundamental natural frequencies thus obtained were used to evaluate dynamic modulus of elasticity of SCC specimens using well established basic equations of structural dynamics. The study revealed that the dynamic modulus of elasticity for the cantilever beams were equal to the initial tangent modulus obtained by conventional compresso-meter method as per ASTM C 469-02. Moreover, the free vibration tests exhibited high consistency and repeatability. This technique can be of potential use as Non-Destructive Testing (NDT) for monitoring the health of in situ structures or machine components.

WSN’s practical application has high level of spontaneity in positioning information and is susceptible to the outside interference, which may lead to the reduction of positioning accuracy. This paper studies Gauss distribution function, the single sensor batch estimate fusion theory and RSSI positioning technique based on the design of the CC2430/1 wireless sensor network positioning system hardware and puts forward a kind of positioning algorithm of WSN based on the Gauss distribution function and batch estimation fusion theory. The algorithm first uses Gauss model to analyse RSSI, reject RSSI value of a small probability event through the Gauss model, and then applies single sensor batch estimation fusion theory to estimate in batches the fushion theory’s calculation of the RSSI value of high probability events as the RSSI value of the final positioning operation. Experiments show that using this algorithm, the positioning precision of the system can be improved to be within 0.5 meters.

Impulse facilities generate transient high-velocity gas flows for ground testing in aerodynamics. The expansion tube is the facility type with the highest performance capability in terms of total flow enthalpy and total pressure, and is particularly useful for studies of atmospheric re-entry, chemical kinetics, scramjet flight and supersonic combustion. In operation, a thin film diaphragm that initially partitions two tube sections is required to rupture under the force of a shock-wave. Fragmented pieces are accelerated with the flow and can damage test models and instrumentation, and the rupture process itself affects flow properties. It has been proposed to replace the diaphragm with a fast open valve that clears the tube prior to shock arrival. This paper investigates the effect of early valve opening on the test flow.An inviscid, axisymmetric model was created using Eilmer3, a compressible CFD solver developed at the University of Queensland. Early valve opening was simulated at varying times for instantaneous diaphragm removal. The result was the formation of a secondary shock and expansion wave. The primary shockwave reaches the test section at a higher velocity due to passing through the expansion wave, creating a faster, higher-pressure test flow, but also higher temperature, leading to substantially reduced Mach number. The interactions with the secondary waves were found to cause unsteadiness in test flow properties.

This paper presents an analysis into the computational results for modelling of a two degree-of-freedom nonlinear vibrating structure. Fast Fourier Transformations, Short Time Fourier Transformations, Hilbert Transformations and wavelets are used to model this system. These techniques aim to locate and quantify the nonlinear behaviour of the system. Coulomb friction was detected with a number of these techniques, however other nonlinearities could not be detected. From the analysis conducted, improved computational methods are necessary for the detection of nonlinearities.

This paper is concerned with the accurate prediction of parasitic drag due to excrescences introduced by structural repairs to aircraft wings and fuselage. Numerical computations are carried out to quantify the effect of isolated surface excrescences in a turbulent boundary layer on a flat plate. Both step excrescence in 2-D domain and wall-mounted hexahedron in 3-D domain are considered in the investigation. Various approaches for calculating drag coefficient increments for wing repair plates are presented. Menter's Shear Stress Transport (SST k-ω) turbulence model is employed here for its accurate prediction of aeronautics flows at typical repair locations with strong adverse pressure gradients and separation. Solutions are obtained via a high-order numerical scheme and an implicit time-marching approach on a multi-block structured mesh. A grid resolution study was carried out to confirm the accuracy of the computations. From the results curves are drawn showing the variation of parasitic drag components for a range of controlled speed (Mach 0.1 to 0.8), local Reynolds number (104 to 107) and the height of excrescence (y+=102 to 104).

This paper presents the vibration test method of the elastic modulus of glulam beams. Under the condition of simply supported, the elastic modulus of glulam beams is tested based on the vibration method. Compared with the static modulus tested by static load test and the natural frequency tested by finite element method, vibration-based detection method is proved to be feasible and accurate in measuring the elastic modulus of glued laminated beams.

The computational fluid dynamics solver Eilmer has proven useful to The University of Queensland’s Centre for Hypersonics for its ability to simulate high-speed compressible flows. In Eilmer, turbulence is modelled using Wilcox’s 2006 k-ω model. While the turbulence model implementation has been validated for two-dimensional and axisymmetric flows, validation is required for three-dimensional flows. The present paper describes the progress of the validation of the k-ω turbulence model for two three-dimensional test cases. A case featuring Mach 4.5 air flow over a flat plate produced results that correlated with previous numerical results within 4%. A second case featuring the injection of Mach 1 air into a Mach 4 air cross-flow produced results indicating that the code successfully captured the main flow features.

Understanding the effects of unsteady flows is a critical area of hypersonic research. This paper presents a comparison of experimental results and analytical tools commonly used for the prediction of fluid structure interactions: Piston theory, Van Dyke’s theory, and Unsteady Shock Expansion theory. The investigation is carried out with a wedge-nosed flat-plate airfoil with pitching degree-of-freedom at Mach 6 flow conditions.High-speed Schlieren video is used to extract data about airfoil pitching motion and the unsteady shock structure. These data are compared to predictions from the various methods giving insight into their capability to correctly predict surface pressure and the resulting pitching motion at a reduced frequency, k=6.3×10-3. Contrary to expectations for this quasi-steady flow regime, the analysis of the shock structure shows hysteresis, indicating additional viscous interactions.

In this paper, an effective approach to couple finite elements (FEs) with discrete elements (DEs) is presented. The proposed approach conforms to displacement compatibility condition at the interface between FEs and DEs, and this constraint is enforced by the Lagrange multiplier method. The coupling system is solved by the Gauss-Seidel iteration strategy and the incompatibility of degrees of freedom between FEs and DEs can be effectively addressed. Two numerical examples are employed for validation and the effectiveness of the proposed approach is also demonstrated via comparison with other numerical methods.

Customary conservation law of energy is commonly derived using first-order Taylor series, which is only valid for situation of linear changes in the flow of energy in control volume. It is shown that using high-order Taylor series will approximate non-linear changes in the flow of energy but in fact some error remains. We used fractional Taylor series which exactly represent non-linear flow of energy in control volume. By replacing the customary integer-order Taylor series approximation with the fractional-order Taylor series approximation, limitation of the linear flow of energy in the control volume and the restriction that the control volume must be infinitesimal is omitted. The innovation of this paper is we show that as long as the order of fractional differentiation is equal with flow power-law, the fractional conservation law of energy will be exact and it can be used for fluid in a porous medium.

Wake and heat transfer characteristics around a heated circular cylinder were studied numerically in this paper. Heat transfer from a heated cylinder to the freestream flow was in mixed convection regime, with the free convection-bouyancy driven flow in opposite direction to the forced convection-main flow. Numerical simulations were performed for three Reynolds numbers of 100, 135 and 200, with the Richardson (Ri = Gr/Re2) numbers varied from 0 to 1. Results showed that buoyancy force significantly altered wake formation behind the heated cylinder, further resulted in increasing drag and decreasing Nusselt number.

The paper presents a new reduced-order multiple observer which can achieve the finite-time reconstruction of the system’s state associated to a multiple-model. This observer is a combination of a reduced-order observer and a full-order multiple observer. The design of the new observer involves the usage of the Lyapunov theory, the solving of a linear matriceal inequality, and a variables’ change. The steps of the design procedure have been software implemented in order to validate the new reduced-order multiple observer for the case of an aircraft motion during landing.

Plate is one of the most common structural elements, which appears in a wide range of applications: steel bridges, blast-resistance door, and armored vehicles. In this paper, the behavior of steel plates under blast loading was studied through numerical approaches using LS DYNA and then the results were compared with the experiment results obtained from existing literatures. The study of a clamped square plate exposed to blast loading in three distinct stand-off distances. Three different methods of modeling blast loading were used, namely: empirical blast method, arbitrary Lagrangian Eulerian (ALE) method, and coupling of Lagrangian and Eulerian method. The empirical blast method was deployed by using key card *LOAD_BLAST in LS-DYNA. In ALE method, Langrangian and Eulerian solution were combined in the same model and the fluid-structure interaction (FSI) handled by coupling algorithm. In coupling method, the engineering load blast in LS-DYNA (*LOAD_BLAST_ENHANCED) was coupled with the ALE solver. In terms of central deflection and computational time, the coupling method appeared to be the best method which is very time-effective and showed a good correlation with the experiment data.

This paper deals with the formulation of the dimensionally homogeneous extended Jacobian matrix, which is an important issue for the performance analysis of f degrees-of-freedom (f ≤6) parallel manipulators having coupled rotational and translational motions. By using the f independent coordinates to define the permitted motions and (6-f) independent coordinates to define the restricted motions of the moving platform, the 6×6 dimensionally homogeneous extended Jacobian matrix is derived for non-redundant parallel manipulators. The conditioning number of the parallel manipulators is computed to evaluate the homogeneous extended Jacobian matrix, the homogeneous actuation wrench matrix, and the homogeneous constraint wrench matrix to evaluate the performance of the parallel manipulators. By using these indices, the closeness of a pose to different singularities can be detected. An illustrative example with the 3-RPS parallel manipulator is provided to highlight the effectiveness of the approach and the proposed indices.

This paper presents the theoretical characteristics of elastohydrodynamic lubrication (EHL) in point contact under steady operating conditions of ball bearing thrust bearing. The numerical simulations employed a finite different method, Newton Raphson method and multigrid method to solve the modified Reynolds equation with a Non-Newtonian fluid. The general numerical schemes are implemented to investigate the profile of pressure and film thickness, with varying applied loads viscosity of lubricants and speeds. The results show that the applied load has significant effect on the film thickness profile. The contact is increase area but film thickness decrease as the applied load increase. The minimum film thickness and friction coefficient both increase significantly as viscosity of lubricant is increased. The increasing of surface velocity, the film thickness increase but film pressure decrease.

For MEMS (Micro-Electro-Mechanical System) inertial sensor low precision, high noise and the characteristics of the gyroscope error accumulating, this paper designed a kind of yaw angle measuring system based on EKF (Extended Kalman Filter) by STM32 microcontroller and MEMS sensor. The EKF applys the attitude angle quaternion as the filter state variable, the angular rate as the filter time update. And application of the carrier location's gravitational field and geomagnetic data, complete filter measurement update, suppress divergent attitude error, obtain high accuracy and reliability of the attitude angle (pitch angle, roll angle, yaw angle) data. Experimental results show that the practical application of error control heading within ± 1º, with high practical value.

This study is focused on experimental investigation of a selected type of brazed plate heat exchanger (PHEx). The main aim of the paper was to experimentally check the ability of nanofluids to enhance the performance of PHEx. A typical water-Al2O3 nanofluid was tested and compared to that of the base fluid, i.e. water. Nanoparticles were tested at the concentration of 0.1% and 1% by weight. Impact of the 1 day and 3 days break of operation of the tested PHEx on its performance was of particular interest. Pressure drop in all runs was measured as well. The Wilson approach was applied in order to estimate heat transfer coefficients for the PHEx passages. It was observed, that addition of nanoparticles resulted in deterioration of an overall heat transfer coefficient for the selected PHEx and tested conditions, i.e. temperature range and Reynolds number. Moreover, substantial increase of pressure drop was recorded after each break of operation of the tested PHEx.

An article is about mechanical effect of the physic-mechanical material properties on the radial pressure in the compression chamber during the compacting process of wood. Some general methods that describe the transformation process of axial pressure into the radial pressure are shown, As well as the mathematical or experimental methods specifying dependencies and physical conditions. Mathematical finite element method in this area is very useful, but rarely used. Common problems using FEM are the proper definition of the physical material properties in a particular stage of compaction. Material properties are greatly influenced by a number of factors such as moisture, fraction size, chemical composition, current temperature, radial macro structure, axial macrostructure, current pressure and others. The chamber material and the manufacturing processes or the state of wear has an impact on the physical conditions. In terms of tensile elastic deformations, these complex effects reflect and can be merged into several properties. The conversion of axial to radial pressure indicates that some properties of the compacted material have a major impact on the process, such as friction between material and chamber, elastic modulus and Poisson's ratio. The geometry of the pressing chamber also has a significant impact. This paper does not deal so much with the pressing chamber geometry but more so with the characteristics embodied in experimentally measurable quantities. The measurement of these properties in combination with the application of FEM methods proves to be a highly progressive method for understanding the compaction process and the engineering design of compaction machines for the production of briquettes and pellets. The article urges further examination and measurement of a wider range of material properties in the densification process.

This paper investigates the mechanical behaviour of three-dimensional beams subjected to thermal stresses.The temperature field is obtained by exactly solving Fourier's heat conduction equation and, as classically done by a staggered solution approach, it is considered as an external load within the mechanical analysis.Several higher-order beam models are derived thanks to a compact notation for the a-priori approximation of the displacement field upon the cross-section.The governing differential equations and boundary conditions are obtained in a compact nuclearform using the Principle of Virtual Displacement.The final form does not depend upon the order of approximation of the displacement fieldover the cross-section (this latter being a free parameter of the proposed modelling approach).The obtained problem is solved by means of two strong form solutions: an analytical Navier-type solution andpoint collocation (using Wendland's radial basis functions).Isotropic, functionally graded and laminated beams are considered.Results are validated towards three-dimensional FEM solution obtained by ANSYS.The proposed models yield accurate results characterised by smooth stresses thanks to the used solution methods.Furthermore, computational costs are very attractive when compared to the reference three-dimensional solutions.

The paper presents research of shrinkage of the cement paste. The tested specimens wereprepared eight years ago from Portland cement CEM II and water. The observation was focused onthe evolution of creep in long time and for very old material. The material properties like a compressionstrength and Modulus of elasticity were observed according with the creep.

A numerical analysis for masonry columns is presented in this paper. The behavior and character of deformation of compressed unreinforced masonry columns is investigated and compared with the deformation of masonry columns reinforced by FRP wrapping. The experimental program is part of a research project NAKI [1]. Both, the bricks and the mortar are modeled as 3D continuum and to the interface between these two materials a non-linear contact law is assigned. The contact between reinforcement and masonry support is considered as perfectly-adherent. Two different cases are simulated - the ratio of Young ́s modulus of brick and Young’s modulus of mortar is 5:1, respectively 1:5. For all simulations the commercial software package ABAQUS was used and the obtained numerical results are discussed.

Non-destructive methods for detection and measurement of residual stresses (RS) have been increasingly used in the last few years. The paper outlines the capability of Barkhausen noise analysis (BNA) for evaluation of real structure changes and RS on cross-section of welds due to welding of ferromagnetic plates compared with X-ray diffraction (XRD). The purpose of this study is to evaluate the RS distribution of specimens joined using by high power diode laser and metal active gas (MAG) welding that can be used for quantitative analysis of macro and micro level RS separately. The principal advantages of BNA over XRD as a tool for RS analysis and real structure characterisation are that it is mobile, faster with more facile carrying out and hence BNA is frequently used for continuous monitoring of RS in industrial processes.

In this paper we will build some new and original composite sandwich bars reinforced with two and four layers of carbon fiber (in the upper and lower sides), with the core made of polypropylene honeycomb. For these sandwich bars, we will use the next experimental setup: we will clamp them at one end and we will leave the other free. Using an accelerometer, we will record the eigenfrequencies. Bu using the eigenfrequencies values and the Euler-Bernoulli theory, there is established a procedure to determine the bars flexural rigidity and dynamic Young modulus. We will consider the bars as having 320 and 350 mm free lengths. We will highlight how the two extra carbon fiber layers will influence the flexural rigidity values and the dynamic Young modulus.

In this paper a pumping systems for deep extraction is simulated using SolidWorks and ADAMS. The elastic displacement of a point on the flexible moving cable is analyzed. The dynamics of the system is characterized with phase plane, Poincaré maps, and Lyapunov exponents. The Lyapunovexponents represent the dynamic stability of the system. The largest Lyapunov exponents for three different angular velocity show the chaotic motion of the system

During oil wellbore drilling processes, filter cake is formed on the sidewalls of the well hole due to filtration of drilling fluid particles. The filter cake is crucial to the drilling process, since it helps to maintain the wellbore hole, protects the drilling bit from jamming and facilitates the subsequent phases of the well development. The most important parameter for filter cake formation is its thickness and its variation due to drilling conditions. In this paper, the drilling fluid particles filtration process was simulated at conditions mimicking deep wellbore drilling. The drilling fluid was simulated as a non-Newtonian two-phase fluid of liquid and particles, utilizing an Eulerian-Eulerian approach. The model successfully predicted a filter cake thickness which agrees well with measurements and previous CFD work.

This paper presents an economic model based on graph theory to optimize the execution order for automotive products on the manufacturing lines served by robots, so that the total manufacturing cost is minimized. The starting point is a representation of the range of automotive products with similar design attributes but with different construction requirements (material, tolerances, production volume). This representation is distinguished by a directed graph G = (X, Γ) consisting of the set X of nodes (products) and the set Γ of arcs (paths with minimal cost). In terms of mathematical optimization problem is solved by determining the minimum length Hamiltonian path in the graph, using the algorithm of Foulkes. The length of a path is obtained by adding the numbers associated with that path arcs. The model can be applied to other extreme transportation issues CIM type, such as: transportation network modeling; determining minimum distances; median problem (placing checkpoints); multi-product maximum flow problem.

This paper presents a design methodology for the heading control system of an unmanned airship. Since the aircraft motion depends both on deterministic command signals required for tracking a desired path and on random exogenous inputs modelling the wind influence, a mixed H2/H-infinity type method have been chosen for the design of the automatic flight control. Moreover, due to the fact that the vehicle dynamics at straight and level flight is different from the model at level turning flight, a stochastic Markovian model with two states is adopted to simulate these two situations. A design methodology for a state-feedback controller with Markov jumps is presented. The theoretical developments are illustrated by numerical comparative results indicating the benefits of proposed optimal design approach.

This paper presents a detailed CFD analysis of an H-type Darrieus VAWT of 1.5 kW. Menter's SST turbulence model was used in a pressure-based, transient solver in order to obtain both the global and the detailed flow parameters of the turbine at its design point TSR. Due to the sensitivity of the case itself, a low Reynolds number as well as a curvature and rotation correction were added to the baseline turbulence model. The airfoil of the turbine was chosen following a classical drag polar screening and evaluation, with particular care to the angles of attack beyond the stalling angle. Results indicate that the NACA 0021 was an optimal choice for this case and that the global parameters are close to the classical theory at design point. Further work may include 3D LES or DES of the flow in order to obtain even more details regarding the vorticity structures developing along within the turbine.

In this paper, the influences of magnetic field and porous space of peristaltic flow of a Newtonian fluid in the tapered channel are studied. Flow analysis is also discussed in the presence of heat transfer. A model of wall-induced fluid flow within an infinite tapered channel having symmetric wall displacements and phase difference is developed. Expressions of dimensionless stream function and temperature are obtained analytically by employing long wavelength and low Reynolds number assumptions. The effects of various emerging parameters on the flow characteristics are shown and discussed with the help of graphs. It has been found that The geometric parameters likes, non-uniform parameter, amplitudes and phase difference control the fluid transport phenomena.

This paper investigates the performance and characteristics of saw tooth shape micro channel in the theoretical level. If the conduct area of the nano fluid increases the heat transfer also increases. The performance curve has drawn Reynolds number against nusselt number, heat transfer co efficient. Pressure drop plays an important role in this device. If pressure drop is high the heat transfer increases. The result in this experiment shows clearly that the heat transfer is optimized.

This paper is to explore the measure of isotropy applied to a 2-DOF revolute spherical serial manipulator. A revolute spherical serial manipulator means that the directions of rotation of the manipulator are intersecting. This manipulator arm will be used for carrying microscope camera as part of the 2-hand master-slave operation with force reflection system for miniature task operation in order to enhance view of vision. The data of the dexterity measure are collected from the computer simulation based on invert kinematics and Jacobian of the manipulator. The results revealed that the design solution of the manipulator has high measure of isotropy for prescribe paths. This result is to confirm that the manipulator can move with in the design workspace smoothly.