Development of technological principles of technical control of bus bodies during operation based on passive safety conditions

Abstract

The object of this study is the permissible limits of aging of bus bodies during operation and the formation of appropriate recommendations to control them based on the conditions of compliance of the body with passive safety rules. According to the current method, the new model of the bus is checked for compliance with passive safety by a destructive method. However, during operation, the physical and mechanical properties of the body deteriorate until the moment of non-compliance with the requirements of passive safety. Therefore, the principles of technical control of bus bodies under the conditions of passive safety by non-destructive methods, the implementation of which became possible during the operation of buses, have been developed. 3 implementation options have been proposed. In the first variant, visual control is complemented by a measuring tool – an ultrasonic thickness gauge for measuring the thickness of the frame pipes. This method has not previously been used in the certification of vehicles. The second option involves checking the mechanical properties during repairs on a breaking machine. It is proved that during the restoration repairs of buses, the endurance limit of the steel elements of the body frame is reduced by 1.14–3.33 times. In the third variant, the methodology for modeling and calculating the stressed-strained state of the body was improved based on the method of finite elements, taking into account the effects of corrosion and fatigue strength of the metal of the frame. When modeling, the deformation of the body racks exceeded the permissible values by 1.5–2.0 times. This non-destructive method makes it possible to check the bus for compliance with passive safety requirements during operation, which was previously impossible. The scope of practical application is the introduction of research results into the real practice of operating buses at the legislative level. The results are suitable for monitoring the technical condition of buses by non-destructive methods during operation

Predictive Assessment of Bus Body Life in the Matlab Simulink Software Environment

“…One way to overcome such difficulties may be to study the durability of the frame-type buses, as well. Such an approach is used in work [3]. However, here only compliance with UN Rule No.…”

“…The accuracy and maximum approximation to the real operation of simulation modelling is ensured by taking into account the suspension failures of the bus. Unlike [3], which proposes determining the compliance of the body with UN ECE Regulation No. 66 [5] during operation, the prognostic assessment of the bus body's durability in the Matlab Simulink software environment allows predicting the bus body's durability at the design stage.…”

Devising an approach to assessing the durability of bus body on a frame chassis

“…Part of the methodology of the cited work [1] is suitable for determining the durability of the bus body on the frame chassis since the main force structure of the body, described in [1], is concentrated in the lower part of the body but needs to be improved taking into account the features of the frame operation [1]. In [3], simulation of the bus on the frame chassis was carried out when tipping to the side, which made it possible to determine the compliance of the bus with Rules No. 66 of the UNECE [4].…”

“…In [3], the bus was inspected during operation, where the deformation of the body frame racks was de termined. However, the degradation of the frame material in work [3] was not taken into account and the comparative calculation of the bus frame and frame was not carried out. In [5], the authors report a procedure of simulation for the compliance of the bus with Rules No.…”