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Mechanical joints are commonly required in structures made of fiber metal laminate (FML), which pose a threat due to multi-site stress concentrations at rivet or bolt holes. Thus, for a reasonably designed FML joint, it is essential to characterize the failure mechanism of multiple-hole FML, however, little information about this has been found in open literature. In the present work, influences of hole arrangement and loading strategy (on-axis or off-axis) on the failure mechanism of multiple-hole FML were investigated, by performing finite element analyses and energy dissipation analyses with elastoplastic progressive damage models that took curing stress into account. Six types of specimens with holes arranged in parallel and staggered forms were designed, whose geometrical parameters were in strict accordance with those specified for composites joints. It indicated that the stress distribution, gross/net notched strength, critical fracture path, and damage evaluation process were only slightly influenced by the hole number and hole arrangement. On the other hand, they were strongly influenced by the loading strategy, due to the transition of failure domination. Results presented here can provide evidence for introducing design regulations of composite joints into the more hybrid FML, and for reasonably determining its multiple-hole strength merely based on the sing-hole specimen.

Modal performance of micro-perforated sandwich beams with honeycomb-corrugation hybrid cores was investigated. Finite element methods and modal analysis techniques have been used to predict their vibration characteristics (i.e. their natural frequencies and mode shapes). It is shown that the natural frequencies of sandwich beam with micro-perforation are slightly lower than those of corresponding order of sandwich beam without micro-perforation based on the experimental and three-dimensional finite element calculated results. To reveal the effect of micro-perforation diameters on the natural frequencies of sandwich beams, a dimensionless frequency parameter ϖ was proposed. The results demonstrate that the frequency parameter of sandwich panels decrease near-linearly with the increase of micro-perforation ratio. In addition, the frequency parameter ϖ is sensitive not to such parameters as the face sheet thickness ratio, the slenderness ratio of corrugated member and the relative density of filling honeycomb, but to the configuration of micro-perforation.

In order to explore the static contact problem between the rolling element and raceway of the elastic composite cylindrical roller bearing based on the locomotive wheel set, the mechanical analysis of the new type bearing of the locomotive wheel set is carried out by using the numerical simulation method and the theoretical analysis method. The contact stress, contact half width, contact displacement and contact stress of the elastic composite cylindrical roller bearing under the load of locomotive wheel pair are analyzed by finite element method The results show that: the contact displacement and contact half width of the elastic composite cylindrical rolling element applied to locomotive wheel set increase with the increase of filling degree; the contact stress and equivalent stress have minimum values with the increase of filling degree, and the minimum values change regularly. Compared with the solid cylindrical roller bearing, the elastic composite cylindrical roller bearing has obvious advantages in contact stress. Reasonable filling degree can reduce the contact stress and improve the "edge effect".

Based on the previous research on the ECCRB, this paper deeply analyzes the working load-bearing mechanism of the wheel set, studies the influence of the ECCRB on the wheel set from the perspective of comprehensive stress and stiffness, deeply analyzes the deep hole structure design of the ECCRB with specific size and type that can meet the working requirements of the wheel set, and deeply analyzes the wheel set based on locomotive In this paper, the bending stress of the ECCRB of locomotive wheelset axle box is analyzed, and the working reliability of the ECCRB based on the locomotive wheel set is analyzed. The above research and analysis are comprehensive, which has important practical significance for the application of ECCRB in locomotive wheel set.

The stiffness performance of bearing plays a key role in the normal operation of Electric Multiple Unit. Elastic composite cylindrical roller bearing (hereinafter referred to as elastic bearing) is a new type of bearing which can improve stress concentration and comprehensive performance. By means of theoretical analysis, the complex load distribution of emu's axle box is determined, the new bearing and ordinary bearing are analyzed by means of numerical analysis, and the stiffness and maximum equivalent stress of the two bearings are calculated by taking the pre-load and the number of rollers as variables. The results show that the stiffness and maximum equivalent stress of new bearing and ordinary bearing increase with the increase of preload. As the number of rolling bodies increases, the stiffness increases but the maximum equivalent stress decreases. Considering the comprehensive fatigue failure, the elastic bearing has obvious advantages in static stiffness compared with ordinary cylindrical roller bearing.

This article experimentally studies the seismic behavior of reinforced concrete frames with buckling-restrained steel plate shear walls. The buckling-restrained steel plate shear wall is connected to adjacent reinforced concrete beams alone by an embedded steel connector in the beams (two-side connection). This is to avoid the force transfer between the shear wall and adjacent columns with a four-side connection. Four specimens of two-story and one-bay reinforced concrete frames with buckling-restrained steel plate shear walls are designed and tested under monotonic and cyclic loads. Finite element analyses are also conducted to further investigate the advantages of buckling-restrained steel plate shear walls by comparing the behavior of reinforced concrete frames with and without buckling-restrained steel plate shear walls. The results show that the presence of buckling-restrained steel plate shear wall can not only enhance the stiffness and load-bearing capacity but also improve the ductility and energy...

Elastic composite cylindrical roller bearing is a kind of new bearing. In view of its structural particularity, explicit dynamics finite element model of elastic composite cylindrical roller bearing is established by utilizing ABAQUS/EXPLICIT. Dynamic responses of elastic composite cylindrical roller bearing are analyzed and response analysis is compared under different radial loads and rotation speeds. Dynamic responses of elastic composite cylindrical roller bearing are analyzed and response analysis is compared under different radial loads and rotation speeds. Results show that rolling and holder lag in rotation is as being compared to inner ring. The motion processes of all the holder, inner ring and roller have certain periodicity. Fluctuation amplitude of inner ring displacement increases with load. Response increases with rotation speed when amplification decreases. Analysis results can offer beneficial reference for further research on dynamic characteristics of elastic composite cylindrical roller bearing.

This paper proposes a practical engineering method about calculating the natural frequency and modes of high aspect ratio wing. The process of discretizing and parameterizing the three-dimensional model of high aspect ratio wing is described in two steps. The first step is to simplify the model according to the thin-walled mechanics and engineering beam theory. Then the stiffness matrix and mass matrix is established by calculating the distribution of the wing’s stiffness and mass. After putting the matrixes into the calculating program based on method of matrix iteration, the natural frequencies and modes of the wing are given out. Comparison of the results with the FEM and the experiment data is made and it is revealed that the deviation is acceptable, which proves this method’s feasibility.

Based on ANSYS, a finite elements method study is conducted on couple fields of fixed tube-sheet heat exchanger. On the basis on the calculating results, the paper tries to analyze and evaluate the reliability and parameter sensitivity of the couple field of fixed tube-sheet heat exchanger, so as to present references for the reliable design on the intensity of mechanical equipments.

This research investigates an axial flux singlerotor single-stator asynchronous motor (AFAM) with aluminum and copper cage windings. In order to avoid using die casting of the rotor cage winding an open rotor slot structure was implemented. In future, this technique allows using copper cage winding avoiding critically high temperature treatment as in the die casting processing of copper material. However, an open slot structure leads to a large equivalent air gap length. Therefore, semi-magnetic wedges should be used to reduce the effect of open slots and consequently to improve the machine performance. The paper aims to investigate the feasibility of using open slot rotor structure (for avoiding die casting) and impact of semi-magnetic wedges to eliminate negative effects of open slots. The results were mainly obtained by 2D finite element method (FEM) simulations. Measurement results of mechanical performance of the prototype (with aluminum cage winding) given in the paper prove the simulated results.

A new structure design method of elastic composite cylindrical roller bearing is proposed, in which PTFE is embedded into a hollow cylindrical rolling element, according to the principle of creative combinations and through innovation research on cylindrical roller bearing structure. In order to systematically investigate the inner wall bending stress of the rolling element in elastic composite cylindrical roller bearing, finite element analysis on different elastic composite cylindrical rolling elements was conducted. The results show that, the bending stress of the elastic composite cylindrical rolling increases along with the increase of hollowness with the same filling material. The bending stress of the elastic composite cylindrical rolling element decreases along with the increase of the elasticity modulus of the material under the same physical dimension. Under the same load, on hollow cylindrical rolling element, the maximum bending-tensile stress values of the elastic composite cylindrical rolling element after material filling at 0° and 180° are 8.2% and 9.5%, respectively, lower than those of the deep cavity hollow cylindrical rolling element. In addition, the maximum bending-compressive stress value at 90° is decreased by 6.1%.

A payload structure is joined by rivets, which are potential weakness in random vibrations and thus require safety examination. Based on the general finite element software ANSYS®, a 3D whole-local finite element model of payload structure was established. The strength evaluation method is determined for rivets through a determinate transient dynamics analysis and related experiment under half sine impulse load. A Power Spectral Density (PSD) analysis is carried out and the rivets under random vibration environment were analyzed. The results of the random vibration analysis show that the design scheme of rivets is feasible.

The study investigates piezoelectric harvesting efficiency of BTO microstructures with different structural configurations for electromechanical nanogenerators using FEM simulation. The effects of different BTO structures in same cross-section area are simulated, including the lengths, the heights, array numbers, shapes and harmonic response. The results show that a single-bulk structure of piezoelectric BTO produces less harvesting energy than an array structure in same cross-section area. The harvesting voltages increase with array number increasing. However, the energy harvesting obviously decreases when the array number is over 33. There has lager energy harvesting with a small ratio (Rh) that defined a diameter of BTO cylinder devided by a height of BTO cylinder. In addition, the piezoelectric harvesting based on BTO arrays with a zigzag layer has higher harvesting efficiency.

In the framework of the actual structure of projects and inevitably there are some uncertainties. Interval finite element method can effectively function to define the scope and provide a strict mathematical sense, the results of the calculations, and finite element method for interval data can be expressed uncertainty. In this paper, the theoretical calculation of interval finite element of a layer rigid frame structure, compared the simulation results with the combination of ANSYS modeling, Numerical analysis of examples from the results of the theoretical value and the true value of the error between the results of a very small can be proved that the interval finite element theory and method for frame structures is very applicable.

In this paper three-way double-layer space grids structure is assumed as equivalent sandwich plate, and has been analyzed by the non-traditional theory of plate with three generalized displacements, in which shearing deformation is considered. Based upon the split rigidity method, static analysis and natural vibration analysis of three-way double-layer space grids structure has been studied. The formulas for calculating internal forces, displacement as well as natural vibration frequency are given out. The comparison with finite element method and equivalent sandwich plate method shows that the formulas in this paper are not only simpler than other simplified methods but also of high accuracy.

Rehabilitated steel moment connections differentiate from newly erected and strengthened ones in that the connections are subject to initial loading during the rehabilitation process. In this circumstance, significant stress redistribution will take place. Therefore, the design method for a newly erected and strengthened connection is not applicable. This paper investigates cover-plate rehabilitation. Finite element analysis was conducted to simulate the rehabilitation process with initial loading. The moment distributions between the cover plates and the original connections take the different initial loading into account. A revised design procedure for rehabilitation process using cover plates is proposed.

The dynamic response of saturated asphalt pavement subjected to moving vehicle load is studied. Based on the porous media theory, a three-dimensional finite element model is developed and the temporal and spatial distribution of three directional stresses and strains are calculated in saturated pavement and compared with those in dry condition. The results show obvious difference between saturated and dry asphalt pavement, especially in asphalt layer.

The combined effect of moisture and dynamic loading on asphalt mixtures has been recognized as one of the main causes of premature deterioration of flexible pavements. Based on porous medium theory, the asphalt mixture is regard as saturated porous material, and a three-dimensional finite element model is established to investigate dynamic response of two typical asphalt pavement structures, which are the semi-rigid asphalt pavement and the semi-rigid asphalt pavement with flexible base course. Then the spatial and temporal distribution of stress, strain and pore fluid pressure of the two structures are calculated, respectively. Analysis results show the superiority of semi-rigid asphalt pavement structure with flexible base course to the semi-rigid asphalt pavement in aspect of moisture resistance capability.

For current semiconductor technology, interfacial crack in stacked thin films of Cu/low-k damascene integration is a critical reliability issue that needs to be urgently resolved. In addition to the measurement of 4-point bending test, how to precisely estimate the adhesion energy between dissimilar films through simulation, based on fracture mechanics is important while designing robust interconnect structures as well as developing next-generation low-k materials. Distinct from the former studies, this research proposes a novel tie-release crack prediction technique based on finite element calculations in order to consider the stress-induced impacts on the thermo-mechanical reliability of the microelectronic package with a low-k chip during the different cracking length of film interfaces. To ensure the correctness and feasibility of the presented technique, a plastic ball array (PBGA) package with stacked Cu/low-k interconnects is implemented as test vehicle to validate actual testing data of experiments and evaluate the variation of interfacial cracking energy while silicon chip becomes thinner. Through the combination of J-integral approach with the technique of global–local sub-modeling, all the predicted results for the forgoing referred cases reveal a good agreement with the physical behaviors of devices. Therefore, it can be concluded that the proposed methodology is highly reliable in estimating the occurrence opportunities of interfacial crack.

Space infrared sensor must be assembled on a small satellite platform, so its whole mass and structure dimensions are strictly restricted by the satellite platform. The mechanical structure must be compacted, light, handy and reliable. Task of space infrared sensor structure system is to integrate each parts of system and provide a stable and reliable work platform for the whole body. The transfer functions of flexible object and base are analyzed by using mechanical impedance method and compared with stiffness models. It indicates that space infrared sensor must be considered the flexible body influence for transfer function on some certain conditions. Using second order Krylov method expresses multi-DOF flexible substructure, which combines with modal synthesis method to model and analyze two substructures connecting with springs and dampers. Compared with direct FEM arithmetic, it can improve the calculation efficiency and handle variable-rate stiffness and damping model or complex stiffness model of flexible connection, which is cannot do for common commercial FEM software.

Mass concrete temperature cracking is an important problem of concrete foundation safety in civil engineering projects, which exists from construction process of concrete foundation to operation period. This paper introduces the simulation method of mass concrete temperature cracking propagation process by Finite Element Method(FEM). With the concrete heat conduction problem, an example to study concrete surface cracks of the whole process of pouring concrete caused by temperature changes and discussed how concrete cracking process brought from temperature decrease is simulated by FEM. The results show that the finite element method can effectively simulate the development of concrete block cracks under temperature stress. The calculation result accord the cracks distribution law of mass concrete blocks in the uniform temperature drop and the basis of strong constraints.

This paper describes a finite element method for simulating migration of interfaces (e.g. phase and grain boundaries) in materials. The method is built on a classical theory. Each individual grain is in an equilibrium state; interface tension and bulk phase chemical potential constitute the free energy. An interface migrates—as atoms break from one grain, cross the interface, and attach to the other grain—at a velocity proportional to the free energy reduction per unit volume of atoms crossing the interface. We express this theory in a weak statement, model the interfaces with finite elements, and update nodal positions incrementally. The variations of the free energy, associated with the virtual motions of the nodes, define the generalized forces. The weak statement connects the generalized forces and the nodal velocities with a viscosity matrix. The method takes into account large interface shape changes, interface tension anisotropy, and non-equilibrium triple junctions (if present). We illustrate the method with examples including grooving on a polycrystal surface, grain growth in a thin film, and facet formation of a single crystal particle.

Bamboo has many good features, is an ideal material for the construction industry. The numerical simulation of multi-layer seismic frame structure of bamboo by hand shows that, for re-bamboo wood columns, typical of the two failure modes for the transverse deformation is too large can not continue to load and top of the fibers in the lateral pressure exploded, bamboo column can be restored in the unloaded more than 80% of deformation, has excellent elastic recovery, bamboo can withstand the load beam is actually controlled by the stiffness, not strength.

In this paper, the dynamic interaction between soil and a cooling tower is analysed using a hybrid method that combines a finite element method and a boundary element method. The dynamic behavior of the soil half-space is investigated in detail. The effect of soil-structure interaction on the gust responses of draught column-supported hyperbolic cooling towers is estimated, and a comparison is made between these numerical results and their counterparts obtained under a full-scale test.

By means of the established deterministic combination of numerical and physical model for nonlinear wave propagation, the adaptability of regular and irregular wave propagation are verified under the condition of nonlinear strength and different water depth. In the combined model, a triangular finite element model based on modified Boussinesq equations is applied for wave computation, and a 2D piston-type wavemeker and the associated control system is adopted in physical wave generation. It is shown from various simulation and experiment results of wave propagation that the results at the boundary between numerical and physical model, whether regular or irregular wave, match extremely very well. The combined model is effective for establishing the deterministic combination with numerical and physical model. Furthermore, the conclusion that the nonlinear error of the combined model increases with the increase of relative water depth can be easily drawn, according to the analysis of the simulation error trend.

In the present paper the analysis of the static soil-structure interaction is presented by use of a coupling method combining a finite element method with a boundary element method. The new coupling method is a so-called semianalytical one. Particular emphasis is placed on the interaction between soil and hyperbolic cooling tower. Numerical results show that the effect of the static interaction on the response of the tower structure can be neglected.

Publisher Summary In the chapter, three-way double-layer space grids with circular shape are assumed as an equivalent sandwich plate and are analyzed by the non-traditional theory of plate with three generalized displacements, in which shear deformation is considered. Based on the split rigidity method, the static analysis and the free vibration analysis of three-way double-layer space grids with circular shape are discussed in the chapter. The calculating formulas for deflection and fundamental frequency are also provided in the chapter. Comparison with the results of the finite element method (FEM) shows that as a simplified method, the method in the chapter is very accurate. So it can be used in the analysis and the preliminary design of three-way double-layer space grids with circular shape for practical engineering. It can also be used to verify results of the finite element method in general.