Repeatability of a dynamic rollover test system
ABSTRACT Objective: The goal of this study was to characterize the rollover crash and to evaluate the repeatability of the Dynamic Rollover Test System (DRoTS) in terms of initial roof-to-ground contact conditions, vehicle kinematics, road reaction forces, and vehicle deformation. Methods: Four rollover crash tests were performed on 2 pairs of replicate vehicles (2 sedan tests and 2 compact multipurpose van [MPV] tests), instrumented with a custom inertial measurement unit to measure vehicle and global kinematics and string potentiometers to measure pillar deformation time histories. The road was instrumented with load cells to measure reaction loads and an optical encoder to measure road velocity. Laser scans of pre- and posttest vehicles were taken to provide detailed deformation maps. Results: Initial conditions were found to be repeatable, with the largest difference seen in drop height of 20 mm; roll rate, roll angle, pitch angle, road velocity, drop velocity, mass, and moment of inertia were all 7% different or less. Vehicle kinematics (roll rate, road speed, roll and pitch angle, global Z′ acceleration, and global Z′ velocity) were similar throughout the impact; however, differences were seen in the sedan tests because of a vehicle fixation problem and differences were seen in the MPV tests due to an increase in reaction forces during leading side impact likely caused by disparities in roll angle (3° difference) and mass properties (2.2% in moment of inertia [MOI], 53.5 mm difference in center of gravity [CG] location). Conclusions: Despite those issues, kinetic and deformation measures showed a high degree of repeatability, which is necessary for assessing injury risk in rollover because roof strength positively correlates with injury risk (Brumbelow 2009). Improvements of the test equipment and matching mass properties will ensure highly repeatable initial conditions, vehicle kinematics, kinetics, and deformations.
Relationship of the roof strength resistance with the displacement of top-end of A-pillar in CRIS test
This paper examines whether the displacement of A-pillar top-end of vehicle in CRIS (Controlled Rollover Impact System) is related to roof strength. Current roof strength tests are not relevant to current rollover accident trends because the test condition is quasi-static. The ADAMS model of the vehicle was developed in this paper to compare the results obtained in the different test condition. This model consists of deformable upper-body members (A/B/C- pillars, Roof-bows, Side roof-rails) and a rigid under-body. The collapse behavior is considered by computing the characteristics of deformable members. This model was used to simulate quasi-static roof crush test and CRIS rollover test. The roof crush test condition (quasi-static) was adopted in accordance with the IIHS test protocol. The CRIS rollover test condition is selected to represent the trip-over type rollover given that a dynamic test protocol has yet to be developed. L27 orthogonal array is adopted for the DOE (Design of Experiment) analysis. The results show that the dominant member affecting roof crush resistance differs from the dominant member in dynamic test. Hence, the dynamic test should be used to evaluate the roof strength of vehicles. Nonetheless, roof crush resistance remains the minimum requirement for ensuring driver and passenger safety in the event of a roll-over accident.
Handbook of environmental management and technology
Learn how to respond to the complex problems encountered in environmental management Highlighting all aspects of the spectrum of environmental control, this text provides a historical perspective on pollution problems and solutions, and offers an introduction to the specialized literature in this and related areas. It includes:* Introduction to the issues* Air pollution management issues* Water pollution management issues* Solid and radioactive waste management issues* Hazardous waste management issues* Pollution prevention* Additional environmental concerns and management considerations* New technologies and approaches* Risk-related topics* Recent developments* Appendices