Proposal for systematic studies of active suspension failures in rail vehicles

Abstract

Application of active suspensions in high-speed passenger trains is gradually getting more and more common. Active suspensions are primarily aimed at improving ride comfort, wear or stability. Failure of these systems may not only just deteriorate the performance but it may also put vehicle safety at risk. There are not many studies that explain how a thorough study proving safety of active suspension should be performed. Therefore, initiating this type of study is necessary for not only preventing incidences but also for assuring acceptance of active suspension by rail vehicle operators and authorities. This study proposes a flowchart for systematic studies of active suspension failures in rail vehicles. The flowchart steps are solidified by using failure mode and effects analysis and fault tree analysis techniques and also acceptance criteria from the EN14363 standard. Furthermore, six failure modes are introduced which are very general and their use can be extended to other studies of active suspension failure. In the last section of the paper, the proposed flowchart is put into practice through four failure examples of active vertical suspension.

Fault-tolerant design and evaluation for a railway bogie active steering system

“…Although different actuation technologies have various principles and components, their failure modes can be grouped in a limited number of categories which are weak depending on the actual implementation of the steering system. References [6,13] summarise failure modes of actuation systems and the categorisation proposed in the two works is, to a large extent, consistent, as summarised in Table 5. The table applies all kinds of actuator technologies, but 'Jamming' is intrinsically related to a fault in the ball screw and therefore shall be considered only for EMAs.…”

“…The specially designed valve and circuit make the actuator fail-safe when inverse steering takes place [12]. A latest seminal work by Qazizadeh proposed a systematic method [13] where the classic Failure Mode and Effect Analysis (FMEA), Failure Tree Analysis (FTA) and standard EN 14363 for the acceptance of running characteristics of railway vehicles are combined to assess the impacts of failure on active secondary suspension.…”

Fault-Tolerant Analysis for Active Steering Actuation System Applied on Conventional Bogie Vehicle

“…In the background of active suspension system, if a frequent failure mode of actuation system has a severe impact on safety and is difficult to detect, the system needs to be improved in the design process to avoid this failure mode, for instance implementing redundant structures. A seminal work presented in Reference [5] adopted the RPN value to study the failures of active suspension for the first time. Following this work, we propose a quantitative method to assess the PRN value where the severity is focused upon as is introduced in Section 2.2.…”

“…Each sub-structure, such as hydraulic actuator, valve, piping network, controller could have various failure mechanisms leading to the malfunction of actuation system. In spite of the complex failure causes, the failure modes could be summarized into limited items as is studied in Reference [5]. In this paper, we considered three typical failure modes: Maximum force, Zero force and Harmonic excitation.…”

An Extended FMEA Model Based on Cumulative Prospect Theory and Type-2 Intuitionistic Fuzzy VIKOR for the Railway Train Risk Prioritization

“…As a kind of reliability analysis and risk management technique, failure mode and effect analysis (FMEA) has been widely used in rail traffic risk analysis [ 1 , 2 ]. In practice, the risk prioritization of every failure mode can be obtained by a risk priority number (RPN) through three risk factors of occurrence (O), severity (S) and detection (D).…”