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Tsujie M.,Track Dynamics Laboratory | Akama M.,Vehicle and Bogie Parts Strength Laboratory | Namura A.,Track Dynamics Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) (Japan) | Year: 2011

Accurately analyzing the propagation of transverse cracking which causes rail failure is important to ensure train operation safety. Crack propagation until now has been analyzed using methods such as the Finite Element Method (FEM). These existing methods, however require the subdivision of meshes to be executed every time a crack is to be analyzed after new propagation. This paper proposes a crack propagation analysis method using the Boundary Node Method (BNM). The development of the BNM program for 3-D elastic analysis is presented here along with the results of some of its transverse crack propagation analyses. Source


Ujita Y.,Vehicle and Bogie Parts Strength Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2014

This evaluation deals with the structural design standard for rolling stock body structures from the viewpoint of the crashworthiness. Current Japanese Industrial Standard JIS E 7106 Code, which defines the minimum static loading conditions required to provide structural integrity of carbody structures for their normal operation, does not explicitly take the crashworthiness into account. Here, one of the detailed FE models for the end structures of EMUs, designed in accordance with the JIS E 7106 standard, was taken as an example, and numerical analysis was carried out under several irregular loading conditions such as the collision of end structures of intermediate rolling stock in a rake, caused by overriding or train set buckling occurring during train collision accidents. The results of the numerical analyses have shown some points that need to be resolved in terms of the strength of the super structures as well as draw gears around coupling devices. Source


Okino T.,Vehicle and Bogie Parts Strength Laboratory | Ujita Y.,Vehicle and Bogie Parts Strength Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2012

It is a regretful fact that fatal accidents sometimes still occur despite ongoing efforts to reduce accident risk and ensure the safety of railways. At the Amagasaki accident in April 2005, one carbody was severely damaged due to side impact. Static and dynamic compression tests were performed to evaluate the carbody side strength using full-size partial carbodies followed by FE analyses under the same loading conditions as in the empirical tests. The numerical results obtained by FE analyses were consistent with the empirical results in terms of the load-time characteristics as well as deformation of carbodies. A method was developed to evaluate the impact deformation behavior of a carbody subject to side loads by using FE analysis. Source


Makino K.,Vehicle and Bogie Parts Strength Laboratory | Sakamoto H.,Vehicle and Bogie Parts Strength Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2014

For railway axles, the wheel seat is periodically inspected by ultrasonic testing. When the ultrasonic axle inspection is performed while the wheels are mounted, the flaw echo height varies depending on the fitting condition. When the inspection is performed on an in-service axle, the echo height also varies under the influence of the bending load acting on the axle due to the car weight. In this study, the variation in echo height due to the contact pressure with a wheel was quantitatively evaluated by simulation of ultrasound propagation. Moreover, the echo-height variation during cyclic rotating bending in a full-sized wheelset was investigated experimentally by studying variation in normal stiffness at the axle-wheel interface. Source


Okino T.,Vehicle and Bogie Parts Strength Laboratory | Ujita Y.,Vehicle and Bogie Parts Strength Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) (Japan) | Year: 2010

When a railway vehicle overturns in an accident, the carbody cross section is likely to take on a parallelogram shape as a result of side impact, and the survival space for passengers and crew is reduced as a result. To secure the survival space available, an innerring structure can be formed by uniting sub-frames attached to the inside of the carbody as non-structural members. The authors performed strength tests and FE analysis to verify the possibility of improving carbody strength against loads from the side by creating such a ring structure. Source

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