INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND MANUFACTURING Vol. 13, No. 5, pp. 723-730 MAY 2012 / 723 DOI: 10.1007/s12541-012-0094-3 1. Introduction A reduction in the structural weight of one large component usually triggers positive synergy effects for other parts. For example, a reduction of the mass of a railway car body could leads to weight savings in the traction system, suspension, brakes and other subsystems. A reduced total weight of railway vehicles means less wear on the rails, wheels, and bearings, which would require less maintenance. 1-4 Composite materials have been used in a wide range of applications in structural design due to their superior mechanical properties over conventional materials. 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. 5 The weight of the bogie makes up approximately 37% of the whole vehicle weight. Therefore, reducing the weight of the components making up the bogie system is essential for a lightweight design of a railway vehicle. 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 commonplace to produce the bogie frame with steel plate (especially a freight bogie) or welded structures. Such bogie frames are heavy, ranging from 1 ton to 2 tons, and rigid and have to be equipped with suspension and damping systems in order to safeguard the comfort of the passengers of the vehicle and absorb vibrations due to the irregularities of the railway track on which the vehicle runs. There have been few attempts to develop the bogie frame using composite materials. Geuenich and Leo, et al. 6-8 built the world’s first bogie frame made of glass fiber reinforced plastics (GFRP). They targeted the bogie frame of a passenger train. The use of composite elements for the frame of the bogies gave a weight reduction of approximately 25%, enabling minimization of power capacity, energy consumption, and wear. Maurin et al. 9 assessed the mechanical reliability of the side beam of a composite-based bogie frame using a FBG sensor. They noted that the ultimate load of the composite side beam before the first failure appeared to be greater than 350 kN. The objective of the present work is to design, analyze, fabricate and testing of a GFRP side beam. The composite side beam was manufactured using two different method; autoclave curing method and resin transfer moulding method (RTM). It is targeted to replace a welded steel side beam for urban subway trains with the corresponding composite beam. Because of high elastic Manufacturing and Structural Behavior Evaluation of Composite Side Beams Using Autoclave Curing and Resin Transfer Moulding Method Jung-Seok Kim 1,# and Woo-Geun Lee 2 1 Railroad Structural Research Department, Korea Railroad Research Institute, 374-1, Woulam-dong, Uiwang-si, Gyeonggi-do, Korea, 437-050 2 Railway System Engineering, University of Science & Technology, 176 Gajeong-dong, Yuseong-gu, Deajeon, Korea, 305-350 # Corresponding Author / E-mail: jskim@krri.re.kr, TEL: +82-31-460-5663, FAX: +82-31-460-5289 KEYWORDS: Composite bogie, Bogie frame, Side beam, Subway In this study, in order to replace the conventional steel bogie with a composite bogie, a composite side beam made of glass/epoxy was developed to be used in the bogie frame of an urban subway train. The composite side beam was manufactured using two different manufacturing method; autoclave curing method and resin transfer moulding method (RTM). And, then, they were tested under a vertical load of 140 kN to evaluate the structural behavior. Moreover, the stress and strain distribution was evaluated with the finite element method and compared with the experiment. The maximum deflections of the two side beam were 7.74 mm and 8.25 mm, respectively. The side beam made by RTM appeared a little softer than the autoclave cured one due to the lower fiber volume fraction. Through the parametric study for the different design parameters, it was known that the variation of the side beam height appeared to be strongest effect to deflection. Manuscript received: March 15, 2011 / Accepted: December 8, 2011 © KSPE and Springer 2012