Durability evaluation of a composite bogie frame with bow-shaped side beams

In the current study, the static structural safety and durability of two composite bogie frame models were evaluated using a finite element analysis. Prior to evaluation, the in-plane and out-of-plane mechanical properties of the base material were measured. The fatigue property was also measured to evaluate the durability of two composite bogie frames. Based on material data, the static structural safety was examined using the Tsai-Wu failure criterion under ten different loading conditions. Stress combination data were used to evaluate durability of two composite bogie frames. Analysis results indicate that the maximum Tsai-Wu failure indices of the two composite bogie frames under a twisting load were 0.48 and 0.57. Based on the durability evaluation using Goodman diagrams, all combined stress data of the two models were within the endurance limit. In the bogie frames with a side beam height of 50 mm, the side beam bottom area was the most affected region. The joint center area revealed higher mean stress and stress amplitude values in the bogie frames with a side beam height of 150 mm.     

The strength analysis and probabilistic design of a bogie frame with incomplete probabilistic information

Journal of Mechanical Science and Technology - A bogie frame is a key component of high-speed rail; higher requirements of the safety and stability of the bogie frame are put forward with the...     

电熔刚玉复合涂料在转K6型摇枕﹑侧架铸钢件上的应用

本文就转K6型摇枕、侧架铸钢件生产特点,试制电熔刚玉复合涂料,确定工艺参数,在转K6型摇枕、侧架应用,效果良好,并降低了生产成本。成功替代锆英粉涂料应用于转K6型摇枕、侧架。     

Experimental analysis of combined side weir-gate located on a straight channel

Flow measurement and control in open channel system for lateral flow is important to support the system management. The flow characteristics of combined side weir-gate are complicated due to changes in flow conditions along the side weir-gate section. Experimental investigation of the flow characteristics of both weir and sluice gates is crucial for predicting the flow through a combined side weir-gate structure. Although weir-gate structures are widely used for frontal flow in hydraulic structures, the same is not true for lateral flows. In this study, 650 laboratory tests were conducted to determine the flow characteristics of combined side weir-gate for subcritical flow, and the experimental results were analyzed to determine the effect of these characteristics and weir-gate geometry on discharge capacity. Interaction factor of combined side weir-gate is a function of the upstream Froude number, the ratio of gate opening to upstream flow depth, the ratio of distance between the top of the sluice gate and the weir crest to gate opening, the ratio of weir and gate length to upstream flow depth, and the ratio of weir and gate length to main channel width. Consequently, more discharge is passed through combined side weir-gate compared to side weir and sluice gates. The empirically derived equations for the discharge of combined side weir-gate show good compatibility with the experimental data.     

Static, dynamic, and buckling analysis of partial interaction composite members using Timoshenko's beam theory

The static, dynamic, and buckling behavior of partial interaction composite members is investigated in this paper by taking into account for the influences of rotary inertia and shear deformations. The governing differential equations obtained are very comprehensive, covering and extending the current models for the problems that are based on Euler–Bernoulli beam theory. The analytical solutions of the deflection are then found for the beam with uniformly distributing load under common boundary conditions. The free vibration and buckling behavior are also studied and the analytical expressions of the frequencies of the simply supported beam are obtained explicitly, as are the buckling loads. For other boundary conditions, the eigen-equations are transcendental and thus some numerical examples are presented to demonstrate the effects of the shear deformation and rotary inertia on the resonant frequencies and buckling loads.     

机车构架静强度及模态有限元分析

利用大型有限元分析软件ANSYS,对某新型机车转向架构架进行静强度及模态仿真计算,从理论上证明构架静强度足够,刚性满足要求,能保证构架良好的动态性能,为机车的可靠运行提供了保证。     

Experimental and numerical investigation of self-priming siphon side weir on a straight open channel

Siphons are basic and powerful hydraulic instruments which can be used as dam spillway or weir. In a siphon, atmospheric pressure pushes the water into the region of vacuum at the crest of the siphon, and then water falls towards the outlet of siphon. In this study, the siphon used as a side weir was investigated to determine hydrodynamic characteristics experimentally, theoretically and numerically. First, the flow properties of main channel were examined for subcritical flow condition. Then, the velocity and pressures distributions inside the siphon; finally the discharge performance of siphon side weir was determined comparatively, and the results were discussed.     

A study on comparisons of composite and conventional steel bogie frames

In this study, the dynamic characteristics of three different bogie configurations, a conventional Steel bogie (SB), a composite bogie without primary suspension (CB1), and a composite bogie with primary suspensions of conical rubber type (CB2), were compared. The CB1 shows the highest critical speed while the CB2 shows the lowest. The SB configuration showed the highest ride index value while the CB2 showed the lowest. Both of the composite configurations showed better ride comfort index than that of the steel configuration. The trend of the derailment index was opposite to that of the critical speed. In the derailment index measuring test, the CB1 bogie configuration had a 12.3 % higher derailment index than that of the SB. These results show good agreement in overall trends with the simulation results.     

机车转向架构架静强度设计方法

运用有限元技术对某机车转向架构架进行强度仿真计算及试验验证分析,以DF4D内燃机车转向架构架为例,详细介绍了客车转向架构架强度的分析方法,利用仿真计算与试验测试相结合的方法能较好地对构架静强度进行设计,为机车可靠运行提供理论依据.     

地铁车辆转向架构架有限元强度计算与分析

介绍了某改进型转向架构架的结构特征,建立了其有限元模型,根据标准UIC515-4/UIC615-4,计算了构架强度分析的主要载荷,并考虑了辅助载荷对疲劳强度的影响,确定了强度分析的工况,对静强度进行了计算与评定,用Goodman疲劳强度极限图对疲劳强度进行了评定,结果表明,该构架能够满足静强度及疲劳强度的要求.     

Design,performance analysis,and testing of a GFRP racetrack ring for a high-temperature superconducting motor with a flexible support rotor

Journal of Mechanical Science and Technology - A conceptual 20 MW high-temperature superconducting (HTS) motor (HTSM) with a novel glass-fiber reinforced plastic (GFRP) racetrack ring in the...     

Dynamic condition assessment of a cracked beam with the composite element model

Existing models of local damage in a beam element are usually formulated as a damage in a single element, and the coupling effect between adjacent damages is simply ignored. This coupling effect is larger in the case of a fine mesh of finite elements or when there is a high density of damage in the structure. This paper studies such effect from multiple cracks in a finite element in the dynamic analysis and local damage identification. The finite beam element is formulated using the composite element method [P. Zeng, Composite element method for vibration analysis of structure, Journal of Sound and Vibration 218 (1998) 619–696] with a one-member–one-element configuration with cracks where the interaction effect between cracks in the same element is automatically included. The accuracy and convergence speed of the proposed model in computation are compared with existing models and experimental results. The parameter of the Christides and Barr [One dimensional theory of cracked Bernoulli–Euler beams, International Journal of Mechanical Science 26 (1984) 639–648] crack model is found needing adjustment with the use of the proposed model. The response sensitivity-based approach of damage identification is then applied in the identification of single and multiple crack damages with both simulated and experimental data. Results obtained are found very accurate even under noisy environment.     

Theoretical research and experimental validation of elastic dynamic load spectra on bogie frame of high-speed train

When a train runs at high speeds, the external exciting frequencies approach the natural frequencies of bogie critical components, thereby inducing strong elastic vibrations. The present international reliability test evaluation standard and design criteria of bogie frames are all based on the quasi-static deformation hypothesis. Structural fatigue damage generated by structural elastic vibrations has not yet been included. In this paper, theoretical research and experimental validation are done on elastic dynamic load spectra on bogie frame of high-speed train. The construction of the load series that correspond to elastic dynamic deformation modes is studied. The simplified form of the load series is obtained. A theory of simplified dynamic load–time histories is then deduced. Measured data from the Beijing–Shanghai Dedicated Passenger Line are introduced to derive the simplified dynamic load–time histories. The simplified dynamic discrete load spectra of bogie frame are established. Based on the damage consistency criterion and a genetic algorithm, damage consistency calibration of the simplified dynamic load spectra is finally performed. The computed result proves that the simplified load series is reasonable. The calibrated damage that corresponds to the elastic dynamic discrete load spectra can cover the actual damage at the operating conditions. The calibrated damage satisfies the safety requirement of damage consistency criterion for bogie frame. This research is helpful for investigating the standardized load spectra of bogie frame of high-speed train.     

Collimation testing of laser beam with holographic optical elements

The shear elements in the shear interferometers of collimation test are commonly plane parallel plates or wedge plates of a small wedge angle. A new holographic shear element that acts as the wedge plate is proposed. The interferometer composed of holographic shear lenses has the advantages of high contrast fringes and adjustable shear amount. It posses the flexibility of altering the measurement sensitivity in a broad range, has more suitability and can meet different measuring requirements. Detailed analysis for the experimental configuration of this system is presented.     

Delamination behavior of L-shaped composite beam with manufacturing defects

Journal of Mechanical Science and Technology - Composite structures are more susceptible to manufacturing defects than conventional materials. Fiber misalignment, cracks, and voids are typical...     

The design and testing of a composite lower limb prosthesis

In unilateral lower limb prosthetic gait, the intact limb, together with the hip on the affected side, strive to compensate for the loss of the missing below-knee musculature. The resultant abnormal gait patterns can eventually lead to pathologies of the spine and other joints. The aim of this research was to design a trans-tibial dynamic elastic response (DER) prosthesis which could simulate the power generation and absorption properties of an intact foot and shank segments. A carbon fibre sickle-shaped prosthesis was developed in which the strain energy from the early part of the stride was stored, and was released again at the point of take-off, to simulate the action of the missing musculature. Stress analysis techniques were used in the design of the prosthesis, for the purposes of computing and maximizing the strain energy of the elements. A force transducer was designed into the prosthesis to verify the analysis. Video motion analyses of the prosthesis were carried out in order to determine the most appropriate shape that would reduce gait asymmetries. The research shows that biomechanical techniques, together with good engineering design and the selection of modern materials, can lead to a prosthesis which approaches the function of a natural foot.     

Design and testing of a hybrid polymeric electrostrictive/piezoelectric beam with bang–bang control

Electrostrictive materials, hard ceramics and soft polymers, have been used as precision actuators in many engineering applications. This study is to examine bang–bang control performance of a hybrid Plexiglas beam laminated with polymeric electrostrictive (RTV 270) actuator and piezoelectric polyvinylidene fluoride (PVDF) sensor layers using both analytical and experimental techniques. Material characteristics are calibrated via static testing first; a hybrid beam model is then fabricated and an experiment set-up, consisting of a bang–bang controller, high-voltage amplifier, data acquisition system and the hybrid beam system, is designed to evaluate vibration control characteristics (i.e., damping ratio estimation) of the hybrid beam subjected to various control conditions. Due to the quadratic behaviour of electrostrictive materials, the controller activates the electrostrictive actuator only in upward motion of the beam, with reference to signals generated from the piezoelectric sensor. Base on constitutive equations and dynamic/control characteristics, a mathematic hybrid beam model is also derived from the electrostrictive thin shell theory and its dynamic responses, based on the finite difference discretization, are simulated to predict damping ratios resulting from control forces induced by the electrostrictive actuators. Dynamic responses (with and without control) of the physical beam model are measured and compared with simulation results. Favourable comparison suggests that the mathematical model describes the experimental model very well and its application to other advanced structures can be proceeded.     

Effect of testing conditions on friction and wear of a polyetheretherketone-based composite

Friction and wear characteristics of a type of polyetheretherketone (PEEK)- based composite were evaluated under two different loading pressures and sliding speeds (P = 1.0 MPa, V = 1.0 m/s and P=2.0 Mpa, V=3.3 m/s). The material was in contact with steel surfaces of two different roughnesses (Ra=0.15 μm and Ra=0.33 μm). Interface temperature, coefficient offriction, depth wear rate, and specific wear rate of the polymer composite changed considerably with the PV value and the counterface roughness. The interface temperature increased with increasing PV value, whereas the friction coefficient decreased. The depth wear rate at the higher PV value was much higher than that at lower PV. In addition, the rougher counterface resulted in a higher friction coefficient, depth wear rate, and specific wear rate, when the PV value was fixed. The effect of counterface roughness on the specific wear rate at the higher PV value was smaller than that at the lower PV. Further variations in friction and wear with testing conditions are discussed along with the corresponding microscopic observations of the worn polymer surfaces and the polymer transferred counterfaces.     

Nonlinear saturation controller for vibration supersession of a nonlinear composite beam

In this paper, a study for nonlinear saturation controller (NSC) is presented that used to suppress the vibration amplitude of a structural dynamic model simulating nonlinear composite beam at simultaneous sub-harmonic and internal resonance excitation. The absorber exploits the saturation phenomenon that is known to occur in dynamical systems with quadratic non-linearities of the feedback gain and a two-to-one internal resonance. The analytical solution for the system and the nonlinear saturation controller are obtained using method of multiple time scales perturbation up to the second order approximation. All possible resonance cases were extracted at this approximation order and studied numerically. The stability of the system at the worst resonance case (Ω = 2ω _s and ω _s = 2ω _c ) is investigated using both frequency response equations and phase-plane trajectories. The effects of different parameters on the system and the controller are studied numerically. The effect of some types of controller on the system is investigated numerically. The simulation results are achieved using Matlab and Maple programs.     

Forced transverse vibration of composite sandwich beam with magnetorheological elastomer core

We studied, experimentally and numerically, the vibrational response of a magnetorheological elastomer sandwich beam, clampedfree, delimited by two skins aluminum 7075T6, first subjected to a variable magnetic field perpendicular to the skin of the beam, and second to a harmonic excitation by magnetic force applied at the free end. Our main objective was to predict the effect of the intensity of the current flowing through a coil on several dynamic factors. The maximum amplitude of resonance and the variation of the loss factor as a function of structural stiffness are adjusted simultaneously by the application of different magnetic fields. The results of both methods are compared.