Márcio Walber

NUMERICAL ANALYSIS OF AN INTERCITY BUS STRUCTURE: A SIMPLE UNIFILAR MODEL PROPOSAL TO ASSESS FRONTAL AND SEMIFRONTAL CRASH SCENARIOS

TO IMPROVE THE SAFETY OF THE INTERCITY BUS STRUCTURE AGAINST IMPACT SCENARIOS AND TO REDUCE THE INJURES AND DEATH IN TRAFFIC ACCIDENTS IT IS CRUCIAL IN A COUNTRY WITH CONTINENTAL DIMENSIONS LIKE BRAZIL, WHERE THE ROAD TRANSPORT MATRIX IS FUNDAMENTAL IN THE TRAFFIC OF PEOPLE AND GOODS. IN THIS CONTEXT IN THE PRESENT ARTICLE, A NUMERICAL MODEL OF AN INTERCITY BUS WAS BUILT WITH ELASTOPLASTIC BEAMS IMPLEMENTED IN A COMMERCIAL SOFTWARE LSDYNA. THIS MODEL WAS SUBMITTED TO DIFFERENT FRONTAL AND SEMI FRONTAL IMPACT CRASH SCENARIOS. WITH THIS MODEL WERE ANALYZED DIFFERENT ACCIDENTS WHICH HAPPENED IN THE BRAZILIAN HIGHWAYS, IT WAS ALSO SIMULATED A FRONTAL IMPACT TEST AND THE RESULTS OBTAINED WERE COMPARED WITH THE EXPERIMENTAL RESULTS. FINALLY THREE NUMERICAL APPROACHES WERE COMPARED, THEY ARE: A SIMPLE MODEL MADE WITH LUMPED MASSES AND NON-LINEAR SPRINGS SERIES CONNECTED, THE ELASTOPLASTIC BEAM MODEL AND THE CONVENTIONAL NON-LINEAR FINITE ELEMENT MODEL BUILT WITH SHELL ELEMENTS. THE DIFFERENT COMPARISONS CARRIED OUT LET US VALIDATE THE INTERCITY BUS MODEL CREATED USING ELASTOPLASTIC BEAM ELEMENTS AND PROPOSE TO USE THIS MODEL AS AN EFFECTIVE TOOL TO SEARCH FOR MORE EFFICIENT BUS STRUCTURAL CONFIGURATIONS AGAINST IMPACT SCENARIOS.

Evaluation of the seat fastening in the frame of a road bus submitted to frontal impact

The collective intercity transportation by bus is currently a mean of locomotion much sought after by people. Security in accidents is a very important factor that must be taken into account in design of bus body structure, being the evaluation of passenger safety of this type of vehicle is an important subject that should be checked, because in many accidents occur disconnection between seats and fastening members causing serious passengers injury, often fatal. This work aims at evaluation the behavior of frame fixing of seats of intercity bus bodies, submitted to the frontal impact situation in a rigid wall of 100% offset, through evaluation by finite element method (FEM). This study uses a numerical model corresponding to the body structure and chassis, developed through flexible beam elements, combining with shell elements for the structure of the seats and its fastening members, with the objective of not missing the essential aspects of the problem, allowing the solution with a reduced computational time. The numerical model of bus body and seat was impacted against a rigid wall at a speed of 8.89 m/s, being its validation according to the deceleration curve established by Regulation 80. Then it was gotten the Von Mises stress in fastening members of the seat structure in bus body. It is also presented a proposal to improve the fastening of the seat structure, comparing the results of the stress gotten in the two types fastening submitted to the frontal impact.

Evaluation of the Vibratory Effect Transmitted by Road Buses Bodyworks

The objective of this work is to evaluate the levels and vibratory effects that the passengers who use intermunicipal road buses are submitted. In the study, measurements of the accelerations produced in the vertical direction had been carried through according with norm ISO 2631, in two bus bodyworks, of different manufacturers, in a normal situation of use, in three points of it (frontal, central and back). With the measurements it was possible to point which are the places in the bodywork interior and the points in the seats that produce greater accelerations r.m.s. The results had been evaluated and compared with the curves values established for norm ISO 2631 in relation to health and comfort and in relation to fatigue, comparing the two tested bodyworks.