Emergency Ambulance Service is considered an important part of the emergency medical chain which employs a vehicle for quick transporting the patients or injured people to the hospital.  It must also provide safety for both patients and medical operators inside the ambulance. The structure of a cabin must be strong, but whereas the door is not part of the main structure of the cabin, it cannot be overlooked as it could protect people from splashing out of the vehicle in the event of a rollover accident. One of the major problem facing ambulance manufacturers today is that the door lock latch is loosened during driving, thus affecting security. Fault Tree Analysis (FTA) was used to analyze the problem and it showed that the main causes for the loosen door locks during driving resulted from the permanent deformation of the structure of the door caused by insufficient bending stiffness. The permanent deflection of the door is therefore unable to properly lock the lock on the door latch and the door can open by itself.           

An investigation of the structure of the ambulance door revealed that the door was produced by using a folded aluminum sheet as a door structure with all parts mounted by rivet nuts and spot welding and angle steel added to improve the flexural rigidity of the door.  This manufactured part might find problems during usage; for example, since the structure is heavy but it has insufficient flexural rigidity, thus causing looseness between the internal parts of the door structure. In addition, production time and production costs are quite high and the part is not readily repaired.            

Therefore, the researchers has developed a prototype of the side door and rear door of the ambulance to obtain prototypes with higher flexural rigidity, ensuring no permanent deformation during use. It could help lower production costs by reducing the number of components that are complex but insignificant on stiffness and functionality and increase the use of common parts of the door assembly.