Brake is a safety critical system for railway vehicles and brake failures have caused many catastrophic accidents in the history. Detailed accident investigation reports are available and National Transportation Safety Board (NTSB) also makes safety recommendations to Federal Railroad Administration and the industry. However, there is limited research on how to improve the brake safety from the perspective of design, system integration and safety analysis. In this paper, a framework for braking safety design and analysis is introduced, which includes four parts: failure alarming system, safety design, safety analysis and preventative maintenance. For failure alarming, according to the severity level, the failures will be notified to the operator, to Operation Control Center (OCC) or saved for the maintainer. For safety design, redundant design for fail-safe feature, automatic braking, brake release, weight control, ergonomics design for easy operation and maintenance are discussed and several application examples are illustrated. In the safety analysis section, Preliminary Hazard Analysis (PHA) as a semi-quantitative analysis, Failure Modes, Effects, and Criticality Analysis (FMECA) as a bottom-up method and Fault Tree Analysis as a top-down method are used. The hazards details, system assurance actions and closure references are recorded in the Hazard Tracking Log (HTL) to ensure all the safety related items are well tracked and documented. Preventative Maintenance (PM) which is regularly performed on the brake components to lessen the likelihood of failing is also discussed in combination with the reliability prediction and safety analysis for a balance of safety and economy. The safety design framework and principles introduced in this paper can also be applied into other railway systems, such as Propulsion, Signaling, Doors, etc. and may provide insights to similar industries such as automotive, energy and so on.

At present, the fire performance of vehicles is highly concerned in domestic and international rail transit market projects [1], where the fire performance of the vehicle’s underframe is a crucial factor that restricts the fire safety of the entire rail vehicle. How to improve the fire resistance of vehicle underframe structure has become the focus and difficulty of vehicle fire engineering [2]. This article introduces main international fireproof standards applicable for urban rail vehicles. Then, based on the typical underframe structures of urban rail vehicles stainless steel body, three refractory structure models on different underframe structures are established by using different fireproof insulation materials as underframe fillers. Moreover, fire resistance tests are conducted on samples of three underframe models to verify the effectiveness of those fire performance. As per the fire test results, the crucial indexes such as heat insulation, fire resistance, temperature rise curve, fire resistance time and material cost of different filler insulation materials are compared and summarized. Finally, the standardized and modular design specification is suggested on refractory underframe structures in urban rail vehicles.

Vibration suppression has been implemented for many years as a way for a building’s occupants to feel more comfortable in structures prone to horizontal swaying or vertical oscillation. Suppression of a structure’s natural vibrations becomes even more important when delicate work, like surgeries, will be performed within. The purpose of this experiment was to confirm the validity of a passive vibration suppression unit to reduce the vibration in a portable shelter floor where surgeries would take place. Impact tests were done to determine the natural frequency of the floor, and along with the weight of the floor, were used to calculate operating parameters for a tuned mass damper, or TMD. A TMD was then assembled and vibration suppression effects were tested at 4% of total floor mass, to confirm the viability of the design. Additionally, TMDs of 2%, 3%, 4%, and 5% of the mass of the floor and shaker combined were made so frequency sweep tests could be done. Finally, a cantilever beam TMD was made, to test effectiveness of an easily adjustable TMD variant. The produced TMDs are expected to reduce the time the floor is vibrating and reduce vibration of the floor by up to 60%, bringing oscillations within comfortable levels even at the floor’s natural frequency.

This paper introduced the design and research of spent resin conical dryer which was based on the analysis of the thermal decomposition characteristics of resins. The drying experiment of non-radioactive cation exchange resins and anion exchange resins was also carried out in this study. The result showed that the water content of resins reduced from about 55%(wt) to 8.5%(wt) and the volume reduction ration reached 2.17 with a drying end temperature of 90°C, which preliminarily verified the feasibility of the vacuum drying process and conical dryer device for treating radioactive spent resins.

A new approach to measure direct current (DC) using shape memory alloy (SMA) tuning piezo cantilever resonant frequency technique is proposed in this work. The proposed current sensor system is designed using an electrically insulated SMA wire surface mounted on the cantilever beam with piezoelectric actuator. The cantilever beam is maintained at resonance using a closed loop piezo resonator circuit and the current ‘I’ to be measured is given to the SMA wire. The current induced temperature change of the SMA wire produces a mechanical shape change and produces a stiffness change to the resonating cantilever beam. The shift in resonant frequency due to the stiffness change is measured, which is related to the input electrical current ‘I’ to the SMA wire. The key enabling concept of this proposed work is to alter the cantilever resonant frequency using the shape changing property of SMA wire with input unknown electric current. The analytical model of the current sensor system is derived and the results are compared with the experimental results. The SMA coupled with piezo actuator based resonant current sensing system is evaluated for the input current range of 0 to 0.5A. The proposed current sensing concept is simple and completely novel and it is found that it has very high sensitivity to current and result is piecewise linear.

Langasite (LGS) has attracted considerable attention from researchers as a potential substrate material for piezoelectric device applications due to its very good frequency stability and moderately large electromechanical coupling factors for acoustic wave devices. This paper presents a new determination of the second order elastic constants of LGS using acoustic wave velocities measured by a time-of-flight cross-correlation method. Two types of ultrasonic transducers have been used to generate longitudinal and shear bulk waves that propagate through cube-shaped specimens. The specimens and attached transducers are placed inside a temperature chamber to maintain a constant environmental temperature during the measurements. We present a full comparison between the new values determined here and those previously reported.

Rotary compressor has been widely used in room air conditioner. During development of the new compressor, the abrasion of bearings and the break of crankshaft frequently occurred. So it is very important to build a numerical method to estimate the reliability of the compressor. The rotor-journal bearing system is numerically solved as a dynamic nonlinear fluid-structure interaction problem in this paper. The finite element models of the rotor and bearing housings are built up by using the Timoshenko beam model. In order to get the oil film pressure of the journal bearing, Reynolds equation is solved by variation principle, and the finite element method is used to discrete the oil film. An iterative method based on the complimentary principle is used to solve the oil film force and the Reynolds boundary simultaneously. Through analysis, the abrasion position between the bearing and shaft is presented, and the bending tension stress shows the dangerous sections of the crankshaft. Through the distribution of the oil pressure, position of the screw oil groove, which is built on the inside of the bearing housing to supply the oil to lubricate the bearing, is determined. The proper position of the radial oil hole on shaft is decided by analysis of the bending tension stress.

Effects of bounce on particle transport, deposition and removal in turbulent channel flow are studied. The pseudo-spectral method is used to generate the instantaneous turbulent fluid velocity field by Direct Numerical Simulation (DNS) procedure. The particle equation of motion includes all the relevant hydrodynamic forces. In addition, simulation accounts for particle adhesion, resuspension and rebound processes. For particle bounce from the surface, the critical velocity is evaluated and is used in the analysis. Effects of bounce during particle-wall collisions on the deposition rate are also studied.

With the requirement of low noises in the airconditioner marketing, noise problems have been becoming an important task in the design of compressors. In this paper, the achievements of reducing compressor noises in our company are introduced and the impacts of outer and inner parts of the compressor, such as case’s thickness, foot’s shape and muffles, are discussed. Kinds of methods are used. Noise resources and the frequency of peak value are analyzed using theoretical calculation of professional software, such as CAE and SYSNOISE and phonometry of special instruments. On the basis, some modifications have been adopted. Finally the result of experiments shows that the noise of compressors reduces about 7 to 8 dBA.