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Concrete-filled steel tubular (CFST) structures are well known to possess high strength and ductility. CFST members are used under complex stress states, such as beam–columns, piers, caissons, or other foundation components. Recommendations for the design and construction of concrete-filled steel tubular (CFST) structures were published in 1997 and revised in 2008 in Japan. In the recommendations, calculation methods for the axial strength and flexural strength of CFST columns were established on the basis of experimental results of more than 400 specimens; however, the test results of the columns that failed in shear referred to only 12 specimens in the recommendations. It is necessary to accumulate experimental data on the shear strengths and behaviors of CFST columns. Tests and analyses have been carried out on eight circular CFST column specimens with a shear span ratio of 0.75. The diameter-to-thickness ratio of the steel tube is approximately 34. The shearing capacities of the tests were underestimated by over 20% errors using the calculation method of the CFST Recommendations in Japan. The load versus deformation relations obtained by the tests were well traced by 3D-FEM analysis. The shearing capacities were estimated as an average of 12% errors using 3D-FEM analysis. [ABSTRACT FROM AUTHOR]

The magnetic flux in a permanent magnet transverse flux generator (PMTFG) is three-dimensional (3D), therefore, its efficacy is evaluated using 3D magnetic field analysis. Although the 3D finite-element method (FEM) is highly accurate and reliable for machine simulation, it requires a long computation time, which is crucial when it is to be used in an iterative optimization process. Therefore, an alternative to 3D-FEM is required as a rapid and accurate analytical technique. This paper presents an analytical model for PMTFG analysis using winding function method. To obtain the air gap MMF distribution, the excitation magneto-motive force (MMF) and the turn function are determined based on certain assumptions. The magnetizing inductance, flux density, and back-electro-magneto-motive force of the winding are then determined. To assess the accuracy of the proposed method, the analytically calculated parameters of the generator are compared to those obtained by a 3D-FEM. The presented method requires significantly shorter computation time than the 3D-FEM with comparable accuracy.

Bolt nut connections are essential elements and widely used in industry. The authors have verified that introducing a slight pitch difference between the bolt and the nut may improve the anti-loosening performance and fatigue life of the bolt nut connections. Besides, the effect of residual torque of pitch difference bolt-nut connections on the loosening resistance performance was discussed. In this study, the Junker loosening test was investigated experimentally and analytically to confirm the anti-loosening performance of pitch difference bolt nut connections directly. The FEA results are in good agreement with the experiments. It is confirmed that, for pitch difference bolt nut connections, the threads contact status is different from the common bolt nut connections, and the torque between the thread contact surface friction is the main reason of anti-loosening performance improvement of the pitch difference bolt nut connections. In addition, the results showed that if the pitch difference is large enough, the nut loosening angle equals the tightening angle for each vibration, and nut loosening does not occur. If the pitch difference is relatively small but just large enough to provide a prevailing torque, with increasing of the vibrations number of the nut, the loosening speed decreases gradually and finally the clamping force remains steady, which means the bolt nut connections retain anti-loosening performance to some extent. [ABSTRACT FROM AUTHOR]

In this study, we consider the numerical solution of convection‐diffusion typed equations defined in 3‐D domain using the finite element method (FEM) with the stabilized version in order to fill the gap in literature on this area in the sense of different applications. The formulation processed is performed step by step. For this purpose, we started with FEM formulation of the 3‐D Laplace equation. Then, the obtained formulation is extended to the convection‐diffusion equation with standard Galerkin FEM. In order to solve the stability problems for the convection dominated case, the most popular stabilized formulation known as the streamline upwind Petrov‐Galerkin (SUPG) type stabilization method is considered. As a further step, obtained stabilized formulation is used in the solutions of the MHD equations by transforming the coupled system of differential equations to the decoupled convection‐diffusion type equations defined on different 3‐D domains. For the comparison purpose, MHD equations are also formulated with finite volume method (FVM). Obtained numerical results are displayed in terms of a table and figures as the 2‐D slices of the 3‐D plots in order to visualize the effect and accuracy of the proposed numerical scheme over the different test problems. [ABSTRACT FROM AUTHOR]

Hybrid excitation motor is a combination of permanent magnet motor and electric excitation motor, which can flexibly adjust the air gap magnetic field. At present, the traditional silicon steel sheet core material is widely used, but this material limits the further reduction of stator iron loss. In this paper, a new type of hybrid excitation synchronous motor with modular stator structure based on amorphous alloy material is proposed. The design power is 1kW, and the speed is 3000rpm. By placing the armature winding and electric excitation winding in the stator slot, the slip ring and brush are avoided, and the reliability of the motor is improved. The rotor adopts staggered magnetic pole structure, which has strong flux adjusting ability. The core loss is greatly reduced by using amorphous alloy. Firstly, the structure and working principle of the new motor are given; Secondly, the size parameters of the motor are given, and the principle of flux adjustment is verified and analyzed by three-dimensional finite element(3D-FEM); Finally, through theoretical analysis of the influence factors of the magnetic adjustment ability and 3D-FEM finite element computation, the flux adjustment ability and the torque lifting at low speed are verified, and the advantages of the motor are verified.

In this paper, a flexible piezoelectric micromachined ultrasonic transducer (PMUT) based on Scandium (Sc)-doped Aluminum Nitride (AlN) film was designed and modeled by the three-dimensional finite element method (3D-FEM). The resonant frequency of 218.1 kHz was reported. It was noticeable that a high effective electromechanical coupling coefficient (k2eff) of 1.45% was obtained when a combination of a flexible PI and a thin Si layer was used as the PMUT supporting structure layer. Compared with a pure Si supporting layer counterpart, the coupling coefficient had been improved by 110.68%. Additionally, the increase of Sc doping concentration in AlN film further enhanced the device electromechanical coupling coefficient and resulted in an improvement for transmitting/receiving sensitivity of the proposed flexible PMUT. When the doping concentration of Sc reached 30%, the emission sensitivity was as large as 1.721 μm/V, which was 2.86 times greater than that of conventional AlN film-based PMUT. The receiving sensitivity was found to be 2.11 V/KPa, which was as high as 1.23 times the performance of an undoped device. Furthermore, the bending simulation result showed that the proposed flexible PMUT device can maintain a good mechanical stability when the bending radius is greater than 1.5 mm. The simulation of sound field characteristics demonstrated that the flexible PMUT based on AlScN could receive stable sound pressure signals under the bending radius of 1.5 cm. [ABSTRACT FROM AUTHOR]

Permanent deformation (rutting) is an important disturbing failure on flexible road pavements. This phenomenon appears on the flexible pavement as longitudinal depressions, and it is a consequence of the degradation of materials under high traffic loading based on consolidation/densification, surface wear, plastic/shear flow, and mechanical deformation. Hence, the rutting phenomenon depends on the accumulation of permanent deformations on pavement surfaces subjected to repeated wheel loads. In recent years, several studies have confirmed that the service life of asphalt pavements can be increased by using geosynthetics between or within layers because of the improved mechanical properties. The aim of this paper is to present the results of the 3D-finite element (FE) simulations and the development of the rutting phenomenon in a traditional flexible pavement and a reinforced one, both subjected to a cyclic load. Through Abaqus/CAE software, a road section reinforced by a geogrid was analyzed and compared with a traditional road section to investigate the advantages given by the geosynthetic completely embedded at two-thirds of the asphalt concrete layer (AC) in terms of permanent deformations. The results show the capability of the proposed FE study, that uses the plasticity model of Drucker-Prager for unbound materials combined with the simple creep law to model HMA layers to predict the permanent deformation distribution. [ABSTRACT FROM AUTHOR]

The mechanical properties of concrete and steels are likely to deteriorate depending on the environmental conditions defined by the geographic location of infrastructures in civil engineering. In this field, external bonding of FRP plates or sheets is one of the most popular methods for strengthening reinforced concrete structures. This paper focuses on the application of three-dimensional finite element method (3D-FEM) in order to study the effect of some parameter on the failure by delamination of repaired cracked concrete beams in the first part. In the second part, we focused to study the effects of adding of steel fiber in concrete and its volume fraction on the load-deflection response of concrete. The level of ultimate load is examined of patched and unpatched concrete beams. The results also showed that the flexural-deflection response vary with volume fractions of fibers compared to witness beam (without reinforcement). The effects of the loading magnitude, crack initiation, mechanical properties and geometrical parameters were highlighted.

In this paper, a flexible piezoelectric micromachined ultrasonic transducer (PMUT) based on Scandium (Sc)-doped Aluminum Nitride (AlN) film was designed and modeled by the three-dimensional finite element method (3D-FEM). The resonant frequency of 218.1 kHz was reported. It was noticeable that a high effective electromechanical coupling coefficient (k2eff) of 1.45% was obtained when a combination of a flexible PI and a thin Si layer was used as the PMUT supporting structure layer. Compared with a pure Si supporting layer counterpart, the coupling coefficient had been improved by 110.68%. Additionally, the increase of Sc doping concentration in AlN film further enhanced the device electromechanical coupling coefficient and resulted in an improvement for transmitting/receiving sensitivity of the proposed flexible PMUT. When the doping concentration of Sc reached 30%, the emission sensitivity was as large as 1.721 μm/V, which was 2.86 times greater than that of conventional AlN film-based PMUT. The receiving sensitivity was found to be 2.11 V/KPa, which was as high as 1.23 times the performance of an undoped device. Furthermore, the bending simulation result showed that the proposed flexible PMUT device can maintain a good mechanical stability when the bending radius is greater than 1.5 mm. The simulation of sound field characteristics demonstrated that the flexible PMUT based on AlScN could receive stable sound pressure signals under the bending radius of 1.5 cm.

In industrial fields, the bolt-nut connection is widely used and unitized as an important machine component. In the previous studies, a bolt-nut connection with slight pitch difference was considered towards realizing anti-loosening performance and high fatigue strength through axisymmetric finite element method (FEM) as well as experiment. Also by applying three-dimensional FEM, the nut screwing process was analyzed to obtain the prevailing torque Tp confirming anti-loosening performance. In this study, the tightening and untightening processes after the nut touched the clamped body are analyzed through 3D FEM as well as experiment. The FEM results are in good agreement with the experimental results. The clamping force and tightening torque relationship under the pitch difference is compared to the normal nut. Then, the behaviors of the pitch difference nut in tightening and untightening process is discussed by varying the pitch difference. For the normal nut, the equation of clamping force and tightening torque relation in the untightening process is clarified by FEM. Since the nut untightening property after the nut tightening is more important to prevent the nut self-loosening, the loosening resistance torque TRu is newly defined in this process. It is found that with increasing the pitch difference the loosening resistance torque TRu increases. The large loosening resistance torque TRu suggests that the pitch difference nuts have good anti-loosening performance.

Titanium alloys are used as an aerospace material due to their inherent properties such as high strength to weight ratio, corrosion, and fracture resistance. However, the low conductivity and reactivity towards plastic deformation causes these materials to be difficult to cut category. The prediction of various parameters like chip formation and actual cutting forces are important factors for better machinability which involves lot of resources. To overcome such issues, this work proposes three-dimensional FE approach to simulate the machinability behavior of Ti-6Al-4V especially on conventional turning. The impact of cutting speed and feed rate on the cutting force, thrust force, feed force and surface roughness were analyzed experimentally for various conditions. The predicted machining forces showed strong correlation with the experimental results and the effective von mises stress were examined. [ABSTRACT FROM AUTHOR]

The objective of this article is to study how the stator step skewing method can lead to the reduction of the cogging torque of a transverse‐flux permanent‐magnet (TFPM) machine with flux concentrators. Three structures are analysed and compared in terms of their influence of the skewed displacement on the cogging torque using the three‐dimensional finite element method (3D‐FEM). Thereafter, to validate the FEM results, cogging torque is calculated by applying a Schwarz–Christoffel (SC) conformal mapping. To apply this transformation, the 3D TFPM generator structure with axially magnetised permanent magnets (PMs) is converted into a 2D structure with radially magnetised PMs and the cogging torque of the machine is predicted using both the analytical method and 3D‐FEM. The accuracy of the approach is demonstrated by the adequate agreement between the results obtained through this SC mapping and those of the 3D‐FEM. In addition, two 100 W prototyped TFPM machines are designed, simulated, manufactured and tested to validate the effects of the step‐skewed stator yoke on the predicted cogging torque and back‐EMF. [ABSTRACT FROM AUTHOR]

This paper suggests using a combination of steel and fiber-reinforced polymer (FRP) reinforcements to introduce sustainable reinforced concrete moment-resisting frames (RC-MRFs) characterized by damage-controlled seismic performance, cost-effectiveness, and postearthquake recoverability. The aim of this study is twofold. First, according to a predefined seismic performance of RC-MRFs, this study introduces the optimum replacement ratio of the longitudinal FRP reinforcement of FRP RC-MRFs with steel bars. Second, this study investigates the application of FRP-steel reinforcement details to alleviate damage in the plastic-hinge zones of the beams. A detailed three-dimensional finite-element model (3D-FEM) of an RC-MRF is developed and validated against the experimental results of a large-scale, two-bay, two and half story MRF entirely reinforced with FRP rebars and stirrups. Results indicate that compared with FRP RC-MRFs, for a replacement ratio of FRP reinforcement ≤42%, the serviceability state of the proposed steel–FRP RC-MRFs is characterized by a controlled deformability, and the ultimate state is characterized by an acceptable residual lateral strength ensuring safe exit of the structure from its functionality. Furthermore, when steel reinforcements are only provided at the ends of the beams, the frame lateral deformability is based on the development of two sequential plastic hinges at each end of the beams, leading to higher deformability and lower damage levels. [ABSTRACT FROM AUTHOR]

The mechanical properties of concrete and steels are likely to deteriorate depending on the environmental conditions defined by the geographic location of infrastructures in civil engineering. In this field, external bonding of FRP plates or sheets is one of the most popular methods for strengthening reinforced concrete structures. This paper focuses on the application of three-dimensional finite element method (3D-FEM) in order to study the effect of some parameter on the failure by delamination of repaired cracked concrete beams in the first part. In the second part, we focused to study the effects of adding of steel fiber in concrete and its volume fraction on the load-deflection response of concrete. The level of ultimate load is examined of patched and unpatched concrete beams. The results also showed that the flexural-deflection response vary with volume fractions of fibers compared to witness beam (without reinforcement). The effects of the loading magnitude, crack initiation, mechanical properties and geometrical parameters were highlighted. [ABSTRACT FROM AUTHOR]

In this study, the effect of adding of new stator and rotor slots on cogging torque of a transverse‐flux permanent‐magnet (TFPM) machine with flux concentrators is studied. To reduce the cogging torque, the widths and the positions of the slots of concern are improved through three‐dimensional finite element method (3D‐FEM). After that, to validate the 3D‐FEM results, cogging torque is determined by applying a Schwarz–Christoffel (SC) conformal mapping. To apply this transformation, the 3D TFPM structure with axially magnetised PM is converted into a 2D structure with radially magnetised PMs and cogging torque of the machine is predicted using both the analytical method and 3D‐FEM. The agreement in the obtained results through this SC mapping and the 3D‐FEM method is the indicative of the accuracy of the efforts. [ABSTRACT FROM AUTHOR]

In this study, the development of a 3D Finite Element (FE) model for the turning of AISI-D3 with ceramic tooling is presented, with respect to four levels of cutting speed, feed, and depth of cut. The Taguchi method was employed in order to create the orthogonal array according to the variables involved in the study, reducing this way the number of the required simulation runs. Moreover, the possibility of developing a prediction model based on well-established statistical tools such as the Response Surface Methodology (RSM) and the Analysis of Variance (ANOVA) was examined, in order to further investigate the relationship between the cutting speed, feed, and depth of cut, as well as their influence on the produced force components. The findings of this study point out an increased correlation between the experimental results and the simulated ones, with a relative error below 10% for most tests. Similarly, the values derived from the developed statistical model indicate a strong agreement with the equivalent numerical values due to the verified adequacy of the statistical model.

The transient stress in a single-lap, adhesively bonded composite-titanium joints subjected to solid projectile impact is analyzed using the three-dimensional finite element method. This method is constructed based on the progressive failure features of the composite adherend and the elastic-plastic property of the titanium adherend and adhesive. The effects of the thickness and overlap length of the adhesive layer, the solid projectile size and its velocity, and the strain-rate effect on the dynamic stress of the joints are examined. It is shown that the stress evolution with certain amplitude exists in the joint. During the impact process, compressive stress concentration is imparted at the point of the contact. Furthermore, experiments are carried out for measuring the strain responses of the adhesively bonded joints. A fairly good agreement is observed between the numerical and measured results. [ABSTRACT FROM AUTHOR]

The shortcomings of the machining analytical and empirical models in combination with the industry demands have to be fulfilled. A three-dimensional finite element modeling (FEM) introduces an attractive alternative to bridge the gap between pure empirical and fundamental scientific quantities, and fulfill the industry needs. However, the challenging aspects which hinder the successful adoption of FEM in the machining sector of manufacturing industry have to be solved first. One of the greatest challenges is the identification of the correct set of machining simulation input parameters. This study presents a new methodology to inversely calculate the input parameters when simulating the machining of standard duplex EN 1.4462 and super duplex EN 1.4410 stainless steels. JMatPro software is first used to model elastic–viscoplastic and physical work material behavior. In order to effectively obtain an optimum set of inversely identified friction coefficients, thermal contact conductance, Cockcroft–Latham critical damage value, percentage reduction in flow stress, and Taylor–Quinney coefficient, Taguchi-VIKOR coupled with Firefly Algorithm Neural Network System is applied. The optimization procedure effectively minimizes the overall differences between the experimentally measured performances such as cutting forces, tool nose temperature and chip thickness, and the numerically obtained ones at any specified cutting condition. The optimum set of input parameter is verified and used for the next step of 3D-FEM application. In the next stage of the study, design of experiments, numerical simulations, and fuzzy rule modeling approaches are employed to optimize types of chip breaker, insert shapes, process conditions, cutting parameters, and tool orientation angles based on many important performances. Through this study, not only a new methodology in defining the optimal set of controllable parameters for turning simulations is introduced, but also the optimum set of process input variables for turning duplex stainless steels is defined.

This study focused on the investigation of influencing factors on behaviour of piled raft foundation in Bangkok subsoil. To evaluate the possibility of implementing this system in Bangkok subsoil condition, this research performed the consolidation analysis of piled raft foundation systems for low-rise (8- storey) and high-rise (25-storey) buildings with basement levels in clay soil, using coupled three-dimensional (3D) mechanical and hydraulic numerical model. The soils are modelled with Hardening Soil model and Mohr-Coulomb model. Evaluations of piled raft foundation, i.e., the load sharing ratio of piles, settlement behaviours in the foundation system are performed. The parametric study on the effect of raft depth, and load carried by piles of piled raft was done. The consolidation had a strong influence on the load carried by piles of the piled raft foundation in Bangkok. The load shared by piles can increase by up to 12% and 6% for low rise and high-rise buildings, respectively due to the consolidation effect. Therefore, the design of the piled raft foundation system in Bangkok subsoil essentially consider the consolidation effect. [ABSTRACT FROM AUTHOR]

In the present study, the chemo-thermal modeling of time-dependent hydration phenomenon of the recycled-aggregate-based mortar and natural-aggregate-based mortar has been achieved via the modified Arrhenius’ law and 3D finite element analyses. The experimental measurements about the heat release rate and total hydration heat have been taken into account for the numerical experiments later on. The numerical results confirm that hydration gradient across the cement paste matrix is disturbed by the existence of aggregates during the hydration process for both mortars. The gap spaces between cement paste and aggregates at Interfacial Transition Zone (ITZ) have been studied via Replica Method. However, the comparison among the numerical and experimental findings reveals that the numerical solutions provide different outcomes at ITZ for recycling mortar specimens. This matter substantiates that the modified Arrhenius’ law cannot be applied to the recycling mortar hydration modeling and needs to be revised to take into account the additional considerations pertaining to the thermo-chemically activated reactions through the recycled aggregates including cement pastes at very early age. Some fresh routes in the analytical and numerical modeling of the recycled-sand-based mortars are discussed. [ABSTRACT FROM AUTHOR]

The magnetic field produced by a rotor with alternating magnetic poles in a magnetic fluid hydrostatic bearing is numerically evaluated. There has been used a 3D program based on the finite element method (3D-FEM).

• Beam-like specimens were innovated for long fibrous polymeric composite (LFPC). • The matrix crack approach is suitable for predicting LFPC real fracture toughness. • Flexural and fracture behaviors of functionally graded (FG) LFPC were measured. • Beam-like specimen of the fracture toughness test for FG-LFPC was innovated. • FG-LFPC showed superior flexural and fracture behaviors over conventional LFPC. From the early seventies of the twenty-centenary until now, polymeric composite materials (PCMs) have been a tremendous development in structural engineering applications such as decks and beams of bridges. However, most of the specifications still used only plate-like specimens (breadth ≫ depth) rather than beam-like specimens (depth ≫ breadth). The present work has studied the flexural and fracture behaviors of beam-like specimens made of conventional and functionally graded (FG) PCMs. The three patterns: linear, non-linear, and stepwise/layered FG-PCMs, resulting from the distribution of fiber through the depth, were manufactured from long glass fibers reinforced epoxy. A three-dimensional finite element method was employed to demonstrate the progressive damage process of smooth and matrix-cracked specimens. The present results showed that the FG-PCM beams have higher flexural strength and fracture toughness values for the same fiber volume fraction than those of the conventional beams. In the case of long fiber PCMs, the matrix cracked specimens withstand a higher applied load than the through-thickness (common) cracked specimens confirming that the fracture toughness measured from the common cracked specimens is not applicable. The fracture toughness of PCMs depends on the type of test and the specimen geometry. Numerical predictions showed good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

In the present paper, the micro-dilatation theory or void elasticity is extended to both large displacement and large dilatation. Firstly, the deformation gradient tensor has been freshly defined by means of the matrix exponential function. The newly defined relation for the deformation gradient has painstakingly investigated for the uniqueness, decomposition issues as well as objectivity and isotropy considerations. The relation of the displacement gradient and deformation gradient tensor is brought via the matrix logarithm function. The micro-dilatation theory constitutive laws are derived using the thermodynamic principles under the zero-centrosymmetric, weakly-centrosymmetric and fully-centrosymmetric cases. These cases have been derived and scrutinized by the numerical experiments. To achieve this assignment, the basic loadings are taken into account, e.g. the hydrostatic loading, simple traction and shear. Some conclusions and outlook pertaining to the above-mentioned cases and variable bulk density have thereafter discussed. [ABSTRACT FROM AUTHOR]

The shortcomings of the machining analytical and empirical models in combination with the industry demands have to be fulfilled. A three-dimensional finite element modeling (FEM) introduces an attractive alternative to bridge the gap between pure empirical and fundamental scientific quantities, and fulfill the industry needs. However, the challenging aspects which hinder the successful adoption of FEM in the machining sector of manufacturing industry have to be solved first. One of the greatest challenges is the identification of the correct set of machining simulation input parameters. This study presents a new methodology to inversely calculate the input parameters when simulating the machining of standard duplex EN 1.4462 and super duplex EN 1.4410 stainless steels. JMatPro software is first used to model elastic–viscoplastic and physical work material behavior. In order to effectively obtain an optimum set of inversely identified friction coefficients, thermal contact conductance, Cockcroft–Latham critical damage value, percentage reduction in flow stress, and Taylor–Quinney coefficient, Taguchi-VIKOR coupled with Firefly Algorithm Neural Network System is applied. The optimization procedure effectively minimizes the overall differences between the experimentally measured performances such as cutting forces, tool nose temperature and chip thickness, and the numerically obtained ones at any specified cutting condition. The optimum set of input parameter is verified and used for the next step of 3D-FEM application. In the next stage of the study, design of experiments, numerical simulations, and fuzzy rule modeling approaches are employed to optimize types of chip breaker, insert shapes, process conditions, cutting parameters, and tool orientation angles based on many important performances. Through this study, not only a new methodology in defining the optimal set of controllable parameters for turning simulations is introduced, but also the optimum set of process input variables for turning duplex stainless steels is defined. [ABSTRACT FROM AUTHOR]

Three Dimensional Finite Element Method (3D-FEM) has been used to model the deviatoric stress field in a forsterite aggregate with a sandwich geometry: two forsterite cubes aligned in the same crystallographic orientation (the 'breads') sandwich a third forsterite cube (the 'filling'), which might have an identical or different crystallographic orientation. The results show that there is no von Mises stress in the forsterite sandwich if the sandwiching and sandwiched forsterite cubes are aligned in the same crystallographic orientation. If the crystallographic orientations are different, however, von Mises stress and heterogeneous stress distribution occur both along the boundary and in the forsterite cubes. For the investigated P- T conditions (up to 6.4 GPa and 500°C), the resulted deviatoric stress is much lower than the yield strength of forsterite, so that higher P, higher T, or other means to create higher deviatoric stress is necessary, in order to constrain the yielding behavior of forsterite. [ABSTRACT FROM AUTHOR]

Numerical and experimental investigations were carried out in order to reduce the forming load and defects for non-axisymmetrical complex components. The component with intricate shape and V-type high ribs was widely used as key load-bearing structures. Single-step integral loading with different billet shapes and two-step local loading schemes were used to simulate the forming process and study the metal flow laws. Forming processes of preforming and finisher were analyzed to predict the detail characteristics of material flow using the 3D finite element method models. The simulated results showed that the two-step local loading schemes significantly reduced the forming load and improved the metal filling formability without defects, the required forming load obviously lower than single-step integral. The occurrences of defects, forming loads, and velocity vector distributions were studied and a suitable preform and corresponding die designs were obtained. The experimental results also showed that the component could meet the requirements of dimensional accuracy and mechanical properties. [ABSTRACT FROM AUTHOR]

Highlights: [•] A novel two-layer 6/4 three-phase switched reluctance motor/generator is proposed. [•] It has two magnetically independent stator/rotor sets with field coil between them. [•] It works in both motoring and generating modes, which leads to hybrid operation. [Copyright &y& Elsevier]

Airgap leakage flux coefficient is one of the main parameters which must be given ahead of time when performing initial designs or getting performance results by magnetic circuit analysis for any kinds of electrical machines. Three -dimensional finite element method (3D-FEM) is the most reliable one to obtain the accurate leakage flux coefficient for axial-flux permanent magnet (AFPM) motor which definitely takes a much long time and is not advantageous to the motor's initial and optimal design. By constituting the accurate lumped-parameter magnetic circuit (LPMC) model and computing the resultant magnetic reluctances, the analytical formula of the leakage flux coefficient of AFPM is given which is verified by 3DFEM and the prototyped AFPM experiment. [ABSTRACT FROM AUTHOR]

The maximum torque values in computer analysis and experiment in the switched reluctance motor (SRM), having competitive torque density and efficiency with respect to the rare-earth permanent magnet motor employed in the 2009 Toyota Prius, have been compared. The SRM is highly saturated to provide the maximum torque for a short time; thus, the torque value tends to have considerable error of 15% even in the 3D FEM analysis with respect to experimental result because of the incomplete material setting. A comparison of the flux-linkage and current is also provided for consideration. The results of the 2D-FEM and 3D-FEM analysis as well as a test machine are presented. The maximum torque in the 3D-FEM analysis is shown to be within errors of 5.0% with respect to that in the test machine. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, the method of size effect was used to describe the hierarchical multi-scale behavior of trabecular human bone using micro-CT image. The micro-CT images extracted from a 98-year old male patient were used to provide the 3D-model of cancellous bone, which involves one of the most complex natural pore network. The non-linear or so-called geometrically exact Cosserat elasticity including Augmented Lagrangian–Eulerian (ALE) method has been used to handle the multi-scale behavior of trabecular human bone involving size effect in explicit manner. We have chosen the conformal energy density within micro-randomness issue in which the heterogeneous deformations at small scales are inherently sustained. [Copyright &y& Elsevier]

Abstract: In the present study, the micro-dilatation theory has been investigated. The analytical investigations on the penalized cases using a novel total energy density concept have been achieved via quadratic, affine and linear vector-to-vector and vector-to-scalar mappings. The total energy density has divided into four counterparts which are explicitly linked into the constitutive parameters. This novel energy density concept leads to four explicit constitutive laws. By taking advantage of the strongly ellipticity for the total strain energy density, a freshly defined coupling number was introduced. This issue yields two interesting outcomes, the first one is that the micro-dilatation coupling modulus β is bounded β 2 < Kξ and negative (β < 0) and the second one is that the pore pressure must be less than a specific threshold (P 2 < φ 2 Kξ). As a matter of fact, the micro-dilatation theory holds a rigorous restriction on the pore-fluid pressure comparing to Biot''s theory in which there is no restriction. We have analytically scrutinized the case limits and particularly bulk (case1) and conformal case (case2) in which the heterogeneous deformations occur. The numerical simulations of the micro-dilatation theory have been brought afterwards using Galerkin FEM under an Augmented Lagrangian–Eulerian (ALE) setting. The aforementioned numerical simulations substantiate that one can obtain the physically acceptable results for moderate and low coupling numbers. Based upon these results about the micro-dilatation theory some new routes in determining the micro-dilatation theory constants have been triggered. [Copyright &y& Elsevier]

Abstract: Recent theoretical studies of the literature are concerned by the hollow sphere or spheroid (confocal) problems with orthotropic Hill type matrix. They have been developed in the framework of the limit analysis kinematical approach by using very simple trial velocity fields. The present Note provides, through numerical upper and lower bounds, a rigorous assessment of the approximate criteria derived in these theoretical works. To this end, existing static 3D codes for a von Mises matrix have been easily extended to the orthotropic case. Conversely, instead of the non-obvious extension of the existing kinematic codes, a new original mixed approach has been elaborated on the basis of the plane strain structure formulation earlier developed by F. Pastor (2007). Indeed, such a formulation does not need the expressions of the unit dissipated powers. Interestingly, it delivers a numerical code better conditioned and notably more rapid than the previous one, while preserving the rigorous upper bound character of the corresponding numerical results. The efficiency of the whole approach is first demonstrated through comparisons of the results to the analytical upper bounds of Benzerga and Besson (2001) or Monchiet et al. (2008) in the case of spherical voids in the Hill matrix. Moreover, we provide upper and lower bounds results for the hollow spheroid with the Hill matrix which are compared to those of Monchiet et al. (2008). [Copyright &y& Elsevier]

Abstract: This paper presents the results of centrifugal model tests and three-dimensional elasto-plastic finite element analyses carried out to clarify the effects of the ring-cut method on the restraint of the ground settlements ahead of a tunnel face. A model tunnel is excavated in a soft ground by a robot under a centrifugal loading state, and the ground settlements are measured during the progress of the face by a picture analysis system with high accuracy. The settlements generated by the full-face excavation method are compared with those generated by the ring-cut method for two kinds of grounds with different mechanical properties. The maximum settlement caused by the ring-cut method becomes about 36% of that caused by the full-face excavation method for the ground with low strength and about 58% for the ground with high strength. Considerations regarding these phenomena are given by conducting three-dimensional elasto-plastic finite element analyses. [Copyright &y& Elsevier]

Abstract: A non-linear Cosserat theory involving the Arbitrary Lagrangian–Eulerian (ALE) method has been introduced into the brittle isotropic materials (amorphous glass and cement mortar) using the Modified Brazilian Disk (MBD) under an uni-axial compressive loading. These numerical experiments shed light on the nature of the Cosserat-based media and material moduli determination which are difficult to acquire using the most well-known experimental viewpoints. By using the identical micro-rotation constants , the Cosserat moduli reduce to only four constants for the 3D cases. According to the results obtained in this paper, the present methodology substantiates that the Cosserat theory would be readily applied to the wide range of materials from the full amorphous materials to the heterogeneous materials by changing the length scale parameter. Some fresh routes and new outlooks are discussed afterwards. [ABSTRACT FROM AUTHOR]

Abstract: An analytical study using the nonlinear finite-element method was conducted for reinforced concrete shear wall tests under cyclic loading to estimate the damage from the aspect of energy consumption. First, the validity of the analytical method was confirmed by studying the load–displacement relationship, the condition of the cracking, and a comparison between the total strain energy of the analysis and the loaded energy of the test. Next, the distribution of the energy consumption was investigated, and the division between rebars and concrete was studied. It was determined that energy consumption is an effective method for estimating damage of shear walls. [Copyright &y& Elsevier]

In this paper, we report our numerical study on the effect of the step-coverage structure on the parasitic capacitances in the LC cell. We analyzed the capacitances of the TN mode LC cell by using the 3D-FEM numerical simulator, TechWiz LCD. In order to calculate the parasitic capacitance, we employed the finite element method (FEM) and the energy method. In the case of the capacitances between the data line and the gate line, we found that the capacitance of the planarized structure is about 2.7 times as large as the capacitance of structure generated with the step-coverage. Our theoretical study revealed that an accurate structure generation is very critical to exactly calculate the parasitic capacitance. [ABSTRACT FROM AUTHOR]

Abstract: Integral structures have benefits compared to riveted structures, but they offer lower damage tolerance. This investigation analysed possible decrease of crack growth in integral structures by means of design analysis on stringer cross-sections. For this purpose the finite element analysis (FEA) was applied. First the reliability of FEA was proven by comparing calculated crack growth rates (CGR) to test results. Since CGR in linear elastic fracture mechanics is controlled by the stress intensity factors (SIF), different cross-sections were analysed. These configurations were evaluated regarding their crack turning behaviour (T-stress). The SIF was reduced about 18%. Crack turning is more probable when the crack is far away from stringer. [Copyright &y& Elsevier]