رفتار ساختاری از قاب واگن تخت کامپوزیت GFRP برای قطار شهری مترو تحت شرایط بار بحرانی

In order to replace a conventional steel bogie to a composite one, in this study, a GFRP composite bogie frame has been designed and manufactured to be applied to the bogie of urban subway trains. To evaluate the structural behavior, the compositebogie frame was manufactured using the autoclave curing method and tested under the critical load conditions; vertical loads andtwisting load. Through the test, the stresses at the connection region between a cross beam and a side beam and deflection weremeasured and used to assess the structural safety. Moreover, the stress and strain distribution for the whole bogie frame was evaluated through finite element analysis and compared with the experimental results.

The bogie of a railway vehicle sustains the weight of the car body, controls the wheel sets on straight and curved track, and absorbs the vibrations [1]. The weight of the bogie makes up approximately 37% of the total vehicle weight. Therefore, reducing the weight of the components making up the bogie system is essential for lightweight railway vehicle design. In particular, a bogie frame, which accounts for approximately 20% of the bogie weight, is intended to support heavy static and dynamic loads, such as the vertical load by the body of the vehicle, braking and accelerating load, twisting load induced by track twisting, and traction load. This is why it is common to produce bogie frames with solid steel (especially a freight bogie) or welded structures. Such bogie frames are rigid and heavy, weighing from 1 to 2 tons. They have to be equipped with suspension and damping systems to safeguard the comfort of passengers and to absorb vibrations due to the unevenness of the railway track on which the vehicles run. Usually, the bogie of urban subway trains is subjected to much more load variation than passenger trains due to passenger weight difference between the full weight condition during rush hour and the tare weight condition. The passenger weight difference of the urban subway train is in the range of 25tones to 30tones while in case of the In order to evaluate the fatigue limit of the 4-harness glass/epoxy composite, the fatigue test using specimen was conducted under the sinusoidal cyclic loading, R= -1 as shown in Fig. 2 (c) and the loading frequency of 5 Hz was selected to ignore temperature rise in the test specimen during the fatigue test [7]. Table 1 lists the material properties of the GEP224 glass/epoxy. The properties of the quadaxial glass fiber perform and the Airex® foam were referred from the data sheets supplied by the manufacturers.

In this study, the structural safety of a composite bogie frame was evaluated using the static test and the finite element analysis. In order to achieve these goals, the material properties such as the in-plane, the out-of plane and the fatigue limits were evaluated. Through the structural safety evaluation using the Goodman diagram, it was clear that the composite bogie frame was within the safe region. And, the maximum stress occurred at the strain gauge located on the joint region between that side beams and the cross beam. In addition, the overall stress distributions of the bogie frame were evaluated using the finite element analysis. Comparison of the experimental and the numerical results showed the similar trends.