In this thesis the responses of railway vehicles during a collision accident have been systematically analysed. The main objective is to mitigate the injury severity by means of reasonable measures to prevent the collided vehicles from derailment. This research work has been carried out by using MBS software SIMPACK.
Two collision scenarios from the standard EN 15227 have been adopted in this thesis as designed collision scenarios. Besides that, according to the analysis of collision accidents it points out the collisions between two freight trains, especially on curves, deserve to be taken into account. Therefore, this collision scenario has been designed and involved in this thesis.
Collision simulations between two railway multiple units have been carried out in Chapter 5 to explore the causes of overriding phenomenon. Computer simulations demonstrate there are many contributory factors to the overriding collision. In addition to the initial vertical offset described in the standard EN 15227, vehicle pitching motion has great influence to the overriding collision. This pitching motion is also affected by some important factors, such as collision mass, pitching frequency and height of the centre of gravity above the rail level. Compared to the factor of collision mass, overriding phenomenon is more sensitive to the variations in pitching frequency and height of the centre of gravity.
What¿s more, in order to prevent the crashed train units from overriding, anti-climber devices have been recommended. The maximal vertical constraint force is critical to determine the behaviour of anti-climber devices. According to the simulation results, 200 kN is required for the combined anti-climber devices (100 kN for each side anti-climber) to constrain the vertical relative motion between the crashed train units.
The derailment of collided city tram has been analysed in Chapter 6. The corner collision scenario defined in the standard EN 15227 has been adopted. Simulation results indicate this collision scenario is mainly focused on the structure deformation and collision energy absorption. Due to the large impact angle (45°), it is unlikely for a city tram to comply with this scenario without derailment. In order to avoid derailment the maximum impact angle has been recommended to decrease to 25°. Besides that, computer simulations demonstrate that there are many contributing factors to the derailment phenomenon of collided city tram. Compared to the factor of impact point position, the derailment phenomenon is more sensitive to the variations in impact angle, mass of loaded passengers and friction coefficient.
Two measures have been proposed to prevent the collided city tram from derailment. One is using secondary lateral dampers to absorb the collision energy. Another is increasing the lateral stiffness of secondary springs as well as lateral clearance to store the collision energy in the suspension. It has been validated by collision simulation with these measures the safety against derailment can be improved.
Curve collisions between two freight trains have been simulated in Chapter 7. Simulation results demonstrate that from the point of view of safety against derailment the bogie wagon Rmms 662 has better behaviour than the 2-axle wagon Kls 442. In addition, it is pointed out that there are many contributory factors to the responses of freight wagons during a collision, such as curve radius, loading mass, height of centre of gravity of car body, etc. The derailment phenomenon is less likely to occur, when freight trains are collided on a curve with larger radius. Besides that, the characteristics of freight wagons, such as large axle load, low centre of gravity of car body and appropriate static strength, are favourable for the collided wagons to reduce the risk of derailment.