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This paper deals with the problem of the sensitivity of strain gauge force sensors to bending moment which badly affects the measurement accuracy. The bending moment sensitivity can be caused by incorrect force sensor geometry, suboptimal arrangement of strain gauges, imprecise positioning of strain gauges during installation, variation of the strain gauges’ properties. In this study we investigate the effects of the strain gauges’ positioning errors and variation of their properties on the bending moment sensitivity for the case of a compression membrane force sensor having axis-symmetrical geometry. Firstly, we obtain the information about the sensor’s stress-strain state when it is loaded with compressive force and bending moment using Finite Element Analysis. The Finite Element Analysis results are used in conjunction with probabilistic modelling techniques for evaluation of the distribution of the bending moment sensitivity. The modelling results have shown that the distribution’s mean value is approximately zero due to the axis-symmetrical geometry of the force sensor. The standard deviation of the bending moment sensitivity depends on the number of strain gauges in the Wheatstone bridge and the gradient of the strain caused by bending moment in the areas where the strain gauges are installed. The proposed method of evaluating bending moment sensitivity can be applied to other kinds of parasitic loads and other types of strain gauge force sensors for minimizing the sensitivity to parasitic loads in single- and multi-axis strain gauge force sensors. [ABSTRACT FROM AUTHOR]

The first plastic deformations appearance and the limit state processes of the wide stripe pure bending were investigated by analytical and computer simulation methods. Steel wide stripe has been exposed in two cases of the pure bending use of freely supported and restrained beams. The bending moments of the cases of first plastic deformation and limit state of the stripe with corresponding values of external F forces and with q intensity uniformly distributed loads were determined. Statically undetermined restrained beam has been solved using the universal equation for the determination of the rotation angles of the beam crosssections.The computer simulation is implemented in the ABAQUS FEM software package. The values for Misses, main circumferential stresses and other components of stress-strain state are received for different q uniformly distributed loads for stripe. The Misses stresses are used for quantitative analysis of the first plastic deformations appearance and the limit state processes in the wide stripe. [ABSTRACT FROM AUTHOR]

The composite structures are extensively used for its high specific strength, structural stiffness and less weight. A composite beam comprises of concrete slab at the top with a steel beam of I shaped cross section beneath the slab. In this research a three dimensional composite beam is modelled to study the variation in thickness of concrete slab and steel section subjected to uniformly distributed load using finite element analysis. The support conditions of the structure are modelled as fixed beam on both the ends. Relative study is proposed on three different concrete slab thicknesses of 80,100 and 120mm respectively with steel I section beams. The parameters involves total deformation, maximum principal stress, shear stress, normal elastic strain and strain energy in the composite T beam at midspan are reported. It also attempt to conclude that the longitudinal compressive stresses in concrete slab had a non-uniform distribution of stresses along the cross section and it also produces positive bending moment. Shear stress across the sections must be checked to ensure that concrete components act compositely. [ABSTRACT FROM AUTHOR]

This project deals with the structural analysis of transport aircraft wing. A comparative analysis on Aluminium T6-2024 and carbon fiber reinforced composite materials is carried out to reduce the weight ratio in wing structure. As per the classical method of calculations, the ideal variables are choosed for a transport aircraft and then a 3-Dimensional model of the wing structure is designed by CATIA-V5 software and loads such as bending moments and shear force are calculated. The linear static analysis carried out using MSC Nastran and Patran, Patran is used for carrying out operations like importing the geometry, Finite element modeling, defining material properties, Loads and cross sectional properties of the structure whereas Nastran is used for as a solver When carrying out a linear static analysis, in the finite element method the stress and displacement of a wing structure is determined. By comparing the results it is found that CFRP have better mechanical properties than Aluminium T6-2024. [ABSTRACT FROM AUTHOR]

The methods of estimation of structural damage in operation of the aircraft on the example of analysis of the relationship between the spectra of the bending moment of the wing and the acceleration in mass center of the engine during takeoff and landing are discussed. The change in the reaction of the structure to perturbing effects is illustrated by theoretical calculation based on the model of a standard inelastic body. The state of the structure is estimated by the ratio of the spectra of the input effects and the reaction of the structure in certain time and frequency ranges. Their choice is determined by the mutual spectral characteristics and the coherence function of the compared processes. A measure of the state of the structure is the maximum values of the coefficient of transmission of disturbing effects to its controlled points. Taking into account the dependence on the takeoff and landing masses of the aircraft, changes in the magnitude and frequency of the transmission coefficient maxima will indicate the appearance of damage in the design. [ABSTRACT FROM AUTHOR]

Forming and wrinkling of composite textile reinforcements depends strongly of bending properties. The physics of bending of fibrous reinforcement is particular. Bending is related to the slip between the fibres. In addition the fibres are almost inextensible. Consequently the plate and shell standard approaches cannot be used. Numerical simulations of the forming can be done by introducing bending energy dependent on the bending moment and the curvature. In this way, it is possible to simulate wrinkles during shaping. To go further and simulate the overall deformation of the textile reinforcements in the thickness, a shell approach, different from the standard theories, is presented to correctly calculate the rotations of the normals of the textile reinforcement [ABSTRACT FROM AUTHOR]

When working on a Schr¨odinger equation, finding a general method which gives exact solution for all systems is nearly impossible. The superiorities of methods are discussed relative to each other have been examined in numerous studies [1–3]. But it is easy for the systems defined under certain conditions just like one dimensional harmonic oscillator. Simulating them in the analysis will be beneficial. In this work, we are trying to solve the univariate Schr¨odinger equation for our specially-defined system, exponentially anharmonic symmetric oscillator, by using approximation methods. Analyses show that, position variable, x ! 1 limit gives clues for the asymptotic behavior of the solution of the spectral equation of Hamilton operator. But in our work, we prefer to use a new proper function as a new coordinate instead of x to facilitate the analysis. This function defines actually a coordinate under certain conditions. We call this function definition as “Coordinate Axis Bending” or shortly “Coordinate Bending”[4, 5]. In the solution step, we try basis set of eigenfunctions of harmonic oscillator which is defined with the help of Hermite polynomials [6]. The recursive relation between the Hermite polynomials can simplify the computation of eigenvalue problem of our specified system. The numerical complications of overall computations lead us to use “Mathematical Fluctuation Theory” which approximates to an operator with the use of new matrix representations [7–10]. [ABSTRACT FROM AUTHOR]

This paper presents the problem of comparing the results of computer simulations with the results of laboratory tests. The subject of the study was the insert-type joint of scaffolding loaded with a bending moment. The research was carried out on the real elements of the scaffolding. Due to the complexity of the connection different friction coefficients and depths of wedge insertion were taken into account in the analysis. The aim of conducting the series of analyses was to determine the sensitivity of the model to the mentioned characteristics. Since laboratory tests were carried out on the real samples, there were no preparations of surface involved in the load transfer. This approach caused many problems with the clear definition of the nature of work of individual node elements during the load. The analysis consist of two stages: the stage in which the connection is defined (the wedge is inserted into the rosette), and the loading stage (the node is loaded by the bending moment). [ABSTRACT FROM AUTHOR]

A novel draw-bending testing method using a non-contact optical 3D deformation measuring system (ARAMIS®, GOM) was developed to investigate the deformation process of draw-bending. Furthermore, the accuracy of the fracture prediction based on a fracture criterion using the concept of forming limit stress was also investigated. The experimental apparatus is capable of applying draw-bending to a sheet specimen with a forming speed of 100 mm/s, which is comparable to those in real press forming operations. Specimens undergo bending-unbending under tension when passing over the die profile radius. The test materials is a 590MPa high-strength steel sheet. In order to evaluate the effect of the stress variation in the width direction of a specimen on the accuracy of the calculated draw-bending fracture stress σDB, the strain components on the upper surface of the specimen were measured using the ARAMIS® software. High-speed CMOS cameras were used to take synchronized images. The development of the strain field on the surface of the specimen was succssesfully measured. The σDB was calculated from the draw-bending force and the strain components at the moment immediately before fracture, and compared with the forming limit stress σPT measured for monotonic plane strain tension. It is concluded that the forming limit stress criterion is effective as a fracture criterion for the draw-bending of the test material. [ABSTRACT FROM AUTHOR]

In this paper, finite element software is used to simulate and analyze ECC beams. With the ratio of waterbinder, fiber content and the content of fly ash as variables, the initial cracking moments, the yield moments, the initial cracking deflections, and the yield deflections of the ECC beams are studied. The results show that the lower the waterbinder ratio is, the better the beam performance is; When the fiber content is 13kg/m3, the mechanical properties of the ECC beams are the lowest, and then strengthen; When the content of fly ash increase, the bending moment of the specimen beam becomes smaller and the deflection tends to increase, however the deflection of the fly ash decreases when the content of fly ash is higher than 1300kg/m3 in the initial cracking. According to the formula of ordinary concrete ultimate load capacity, the formula of yield capacity of ECC beam is deduced. [ABSTRACT FROM AUTHOR]

The paper presents a detailed analysis of the influence of the angle of phase shift on the fatigue life of specimens made of structural steel in the process of initiation and propagation of fatigue cracks. The modelling of calculated fatigue life was carried out using the modified model proposed by Gasiak and Rozumek. The results of fatigue life calculations obtained during the modelling process were compared to the results obtained by means of experimental tests. [ABSTRACT FROM AUTHOR]

Plastic crash of thin-walled circular tube section in three-point bending by circular tools is considered. Nonlinear elastic-plastic tube bending simulation is used with work hardening effect consideration. Critical tube curvature and toll reactions leading to plastic crash of the tube section are estimated using plastic hinges mechanism. Elastic-plastic bending moment versus curvature, critical curvature and toll reaction estimations, constrained by thin-walled tube plastic crash, are reasonably correlated with experiments. [ABSTRACT FROM AUTHOR]

In order to determination vertical deflections and rail bending moments the Winkler model (1867) is often used. This linear model neglects several conditions. For example, by using experimental results, it has been observed that there is a substantial increase in the maximum rail deflection and rail bending moment when considering the nonlinearity of the track support system. A deeper mathematical analysis of the models is necessary in order to obtain better methods for more accurate numerical solutions in the determination of deflections and rail bending moments. This paper is intended to be a small step in this direction. [ABSTRACT FROM AUTHOR]

In this study, in order to determine the effect of trench width (Bd) on the behavior of buried rigid pipes, a concrete pipe having an outside diameter of 150 cm and wall thickness (t) of 15 cm was analyzed using 2D PLAXIS finite element program. In the analyses, three different trench widths (Bd = 2.20 m, 3.40 m, and 4.40 m) were modeled. The results of the analyses indicated that, as the width of the trench increases, the axial force, shear force, bending moment, effective normal stress, and the earth load acting on the pipe increased. The variations of the loads acting on the pipe due to the increasing trench widths were also evaluated using the Marston load theory. When the loads calculated by the Marston Load Theory and the finite element analysis were compared with each other, it was seen that the Marston Load Theory resulted in slightly higher load values than the finite element analysis. On the other hand, for the two methods, the loads acting on the pipe increased with increasing trench width. [ABSTRACT FROM AUTHOR]

The buckling behavior of slender unreinforced masonry (URM) walls subjected to axial compression and out-of-plane lateral loads is investigated through a combined experimental and numerical homogenizedapproach. After a preliminary analysis performed on a unit cell meshed by means of elastic FEs and non-linear interfaces, macroscopic moment-curvature diagrams so obtained are implemented at a structural level, discretizing masonry by means of rigid triangular elements and non-linear interfaces. The non-linear incremental response of the structure is accounted for a specific quadratic programming routine. In parallel, a wide experimental campaign is conducted on walls in two way bending, with the double aim of both validating the numerical model and investigating the behavior of walls that may not be reduced to simple cantilevers or simply supported beams. Panels investigated are dry-joint in scale square walls simply supported at the base and on a vertical edge, exhibiting the classical Rondelet's mechanism. The results obtained are compared with those provided by the numerical model. [ABSTRACT FROM AUTHOR]

Typically, short range potential only depends on neighbouring atoms and its parameters function can be categorized into bond stretching, angle bending and bond rotation potential. In this paper, we present our work called Angle Bending (AB) potential, whereas AB potential is the extension of our previous work namely Bond Stretching (BS) potential. Basically, potential will tend to zero after truncated region, potential in specific region can be represented by different piecewise polynomial. We proposed the AB piecewise potential which is possible to solve a system involving three atoms. AB potential able to handle the potential of covalent bonds for three atoms as well as two atoms cases due to its degeneracy properties. Continuity for the piecewise polynomial has been enforced by coupling with penalty methods. There are still plenty of improvement spaces for this AB potential. The improvement for three atoms AB potential will be studied and further modified into torsional potential which are the ongoing current research. [ABSTRACT FROM AUTHOR]

Springback is an inevitable phenomenon in sheet metal forming, and many researches on its prediction and compensation method have been presented. The use of high-strength steels is now popular; therefore, the demand for effective springback compensation system is increasing. In this study, a novel approach of springback compensation is presented. The proposed framework consists of a springback solver and design system and optimization process. The springback solver is a finite element procedure in which the degenerated shell element is used instead of the typical shell element. This allows the designer to access directly to the resultant stresses such as the bending moment that is a major cause of springback. By our system, mechanically reasonable springback compensation is possible whereas the conventional compensation method only uses geometrical information that may lead to non-realistic solution. The authors have developed a system based on the proposed procedure to demonstrate the effectiveness of the presented strategy and applied it to some forming situations. In this paper, the overview of our approach and the latest progress is reported. [ABSTRACT FROM AUTHOR]

A theoretical study on the shape instability of a slightly deformed bubble encapsulated by a viscoelastic membrane in an ultrasound field is performed. The membrane effects of the inplane stress and the bending moment are incorporated into the traction jump condition at the bubble surface. The spherical motion of the bubble is numerically obtained by solving the Rayleigh-Plesset equation with the elastic stress. The deflection therefrom is linearized and expanded with respect to the Legendre polynomial. Two amplitudes for each shape mode are introduced because the membrane has mobility not only in the radial direction but also in the tangential direction. A simple expression for the natural frequency of shape mode is derived. Stability diagrams for the higherorder shape mode are mapped out in the phase space of driving amplitude versus driving frequency. The most unstable driving frequency is found to satisfy an integer multiple relationship with twice of the higher-order natural frequency. This finding is justified by a fact that the system with a boundary layer approximation is simplified into Mathieu's equation. Liquid viscosity plays an important role in the shape stability due to the vorticity generation on the deformed membrane. [ABSTRACT FROM AUTHOR]

This paper reports on bending-moment characteristics of heightwise/vertical crease of a corrugated fiberboard, a scored line of which is in parallel to the inner flute structure, and the effect of mechanical processing conditions on a failure phenomena of liner sheet scored by a rotary creaser. Regarding the dispersion and the variance of folding resistance, the creaser/pre-creaser gaps, the deviation of scored line from the inner flute apex, the diameter of creaser rolls and the effect of humidity on the material properties were experimentally investigated using a proto-type rotary creaser and a bending strength tester. [ABSTRACT FROM AUTHOR]

Experiments on force-deflection of bending of cantilevered thick multiwalled carbon nanotubes (MWCNTs) with varying forces, P, set up mainly to determine their effective Young's modulus, show that the nanotubes exhibit wavelike distortion or ripple on their inner arc and the strain energy deviates from the usual quadratic behavior for large deflection. Using a nonlinear relation between the bending moment and the bending curvature we have derived expressions for total deflection and strain energy with P and found that there is an upper bound on the load (Pmax) on a cantilevered thick MWCNT. We have calculated the value of Pmax and also the corresponding length of the cantilevered end portion of the tube where the rippling is observed. [ABSTRACT FROM AUTHOR]

In this paper, a method is proposed to analyse the seismic response of single piles under nonlinear soil condition. It is based on the Winkler foundation model formulated in the time domain, which makes use of p-y curves described by the Ramberg-Osgood relationship. The analyses are performed referring to a pile embedded in two-layer soil profiles with different sharp stiffness contrast. Italian seismic records are used as input motion. The calculated bending moments in the pile are compared to those obtained using other theoretical solutions. [ABSTRACT FROM AUTHOR]

The design of flexible earth retaining structures under seismic loading is a challenging geotechnical problem, the dynamic soil-structure interaction being of paramount importance for this kind of structures. Pseudo-static approaches are often adopted but do not allow a realistic assessment of the performance of the structure subjected to the seismic motions. The present paper illustrates a numerical parametric study aimed at estimating the influence of the dynamic soil-structure interaction in the design. A series of flexible earth retaining walls have been preliminary designed according to the requirements of Eurocode 7 and Eurocode 8—Part 5; their dynamic behaviour has been then evaluated by means of dynamic numerical simulations in terms of bending moments, accelerations and stress state. The results obtained from dynamic analyses have then been compared with those determined using the pseudo-static approach. [ABSTRACT FROM AUTHOR]

A new method for evaluating and compensating springback is presented. It is based on prediction of the change in curvature after springback by the mechanics of the elastic recovery. Starting from the nodal coordinates and the stress and strain distributions predicted by the FEM simulation at the beginning of springback, it first calculates the curvature and bending moments on the stamped sheet surface. Then, by modifying bending moment and curvature of sheet surface as well as process conditions it predicts an ideal sheet state at the beginning of springback. While predicting the ideal sheet state, it solves optimization problems to minimize springback defects with the aid of shape defect evaluation software named “NXT Defect Evaluator”. The springback process from this ideal state is expected to generate the desired shape. Therefore, the ideal sheet shape is helpful when designing compensational tools and renewing the FEM model. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

The grazing angle variability of bent elliptical microfocusing mirror with variable width mirror substrates was investigated. It has been shown that with properly adjusted bending moments, a bent elliptical microfocusing mirror optimized for certain optical configuration can be well used for a range of grazing incident angle. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Experiments have shown that the thickness of shear bands depends upon the mean particle size. These observations suggest that a proper continuum representation of granular behavior must be augmented in a manner that introduces a characteristic length scale. Such generalized continua include micro-polar continua (which involve couple-stress or higher-order stress) and strain-gradient material models. The paper presents the results of DEM simulations that test whether such micro-polar or strain-gradient effects are present in granular materials. The 2D simulation experiments were conducted as “flexure tests” of roughly square assemblies of circular particles. The platens along two opposite sides were rotated to produce a fiexural curvature of the assembly between these sides. Particles along the rotating sides were constrained to translate and rotate in conformity with the sides; whereas, interior particles were free to adjust their movements so that their local equilibrium was maintained. The constraining movements of the platen particles were produced by applying external forces and moments. By measuring incremental forces and moments, we compute the incremental bending moment on the particle assembly. This incremental moment is compared with that of a simple classical continuum. After being compressed to near the peak strength, the bending stiffness is significantly greater than would be computed from classical stiffness moduli. That is, at large strains, granular stiffness depends, in part, on the gradient of strain, not just the strain alone. The results are consistent with micro-polar media or with a strain gradient-dependent material. [ABSTRACT FROM AUTHOR]

We study a simple model of random folding of the triangular lattice. We model random folding process as writing creases randomly along the bonds of the triangular lattice. The end-to-end distance R, the bending energy E, the distribution function P(l) of the length of crease l are studied numerically. The distribution function P(l) shows power low behavior P(l) ∝ 1/l[sup 2.1∼2.3], irrespective of the types of dynamics and boundary condition, which remind us of the 'universal' power low of the noise emitted from the crumpled elastic sheets (E.M.Kramer and A.E.Lobkovsky, Phys. Rev.E53 (1996) 1465). [ABSTRACT FROM AUTHOR]