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Frontal crash for the large vehicle is less severe compared to the lightweight vehicle due to the height position of the driver compartment in the vehicle which sits well above the impact area in any accident involving a passenger vehicle. Due to this reason, most of the coachbuilder does not include crumple zone in their design as what the car’s manufacturer did. However, in the case of frontal collision between two large vehicles or with the rigid wall, the possibility of energy absorption of the structure is very low and the remaining energy will be transferred directly to the driver and occupants. In this respect, two prominent regulations for frontal impact, namely United Nation Economic Commission of Europe (UNECE) Regulation no. 29 and New Car Assessment Program (NCAP) is used to determine whether the structures are having enough strength to withstand the load produced by the impact. This paper deals with the finite element simulation of a frontal impact on bus superstructure by applying both of the regulations. Then, the results for both simulations are compared in terms of energy produced, structure deformations, maximum stress, and the corresponding plastic strains. It is found that the energy from the ECE R29 regulation is lower than NHTSA’s NCAP with 55 kJ and 142 kJ respectively. However, the deformation observed from R29 simulation, the front structures is severely deformed. Meanwhile, the structures in the NCAP simulation are still intact and the steering wheel structures are still not in contact with any body parts of the driver.

The mechanical properties of the thin sputtered copper layer on the SiO2-coated silicon substrate is needed as part of the requirements in quantifying the reliability of the Through-Silicon Via (TSV) interconnects. In this respect, two different Cu coating layers, each from the different sputtering process, are examined. A series of nanoindentation tests are performed on the Cu coating layer samples with indenter speeds ranging from 80 to 400 nm/s, and the indentation depths of 320 nm. The properties of elastic modulus, hardness and the hardening behavior of the Cu coating layers have been quantified. Results show that the coating with higher contamination of C at 8.41 wt. % displays a significant hardening and a peak load level, as reflected in the measured nanoindentation load-displacement curves. However, insignificant effect of the applied probe displacement speeds up to 400 nm/s on the resulting properties of the coating is registered. The Johnson-Cook constitutive equation adequately describes the strain rate-dependent hardening behavior of the Cu coating layer.

This paper deals with structural analysis of bus superstructure undergoes rollover event. Bus superstructure with varying beam profile size will undergo rollover simulations analysis. The purpose of this work is to analyze structural response of bus superstructure in terms of deformation, stress and strain under several loadings and constraining conditions. These rollover simulations were run according to United Nation Economic Commission of Europe Regulation 66 (UNECE R66). Validation procedure using simple box modeled undergoes rollover have been done to ensure the results are synchronized with real problem. An interaction with bus coach builder allows author acquired accurate bus superstructure dimensions before designing the mathematical model in finite element analysis software. Three full-scale bus superstructures mathematical model with difference cant-rail horizontal roof beam profile size was developed and the deformation of superstructure during and after rollover testing had been study. Analyses suggested that one of the contributing factors that lead to the failure of bus having rollover accident is cant-rail and roof structure profile size.

The risk of injuries and fatalities is severe when bus superstructure fails during rollover accidents. This study deals with two stages of analyses which are superstructure strength having rollover analysis and occupants kinematic analysis. The validation process by correlating the strain results obtained from simple box rollover and simulation process done. The inputs from validation process had been used for full-scale bus superstructure rollover. A complete bus structure was developed and simulation was done according to the United Nation Economic Commission of Europe (UNECE) regulation 66 by utilizing finite element analysis software. Injury to occupant at various locations was studied as well as comparison study between belt occupant and unbelted occupants by using the Mathematical Dynamic Model (MADYMO) software. Analysis suggested that superstructure strength and occupant kinematics consideration can reduce fatality and serious injury in bus rollover accident.