Crashworthiness Analysis And Optimization Of Car Body In Small Overlap Frontal Oblique Impact Of Two Cars

With the rapid development of China's economy and automobile industry in recent years,the domestic automobile quantity is increasing year by year,and resulting number of road traffic accidents has been staying at a high level.According to statistics,automobile frontal impact took up the highest proportion in all types of traffic accidents,while the traffic accident investigations supported by IIHS showed that small overlap impact accounted roughly for 24% of the total quantity of automobile frontal impact accidents,being about four times as many as the number of the front full width collision.Besides,statistics from NHTSA suggested that the occupants' injury rate in an oblique collision of two cars is obviously higher.Therefore,more and more attention has been paid to the problem of small overlap frontal oblique impact of cars.To evaluate the crashworthiness of passenger cars in a small overlap frontal oblique impact accident,a verified finite element model of two colliding SUV cars of same type was developed by using Hyper Works and LS-DYNA software.Through simulating several impact conditions of 25% overlap,the influences of collision angle and velocity on the crashworthiness of two car bodies were analyzed based on four evaluation indexes i.e.two cars' maximum acceleration at the bottom of left B-pillar,maximum bending angle on the upper part of left A-pillar,dash panel intrusion and car-body deformations within 120 ms.After the worst crashworthiness condition of car-body structure was determined and studied,some measures to improve the crashworthiness of cars were suggested.The results show as follows: 1)In the situations where both the velocities of two cars are 56 km/h and collision angle is separately at 0°,15°,30° and 45°,the crashworthiness of inserting car and inserted car have their worst performance respectively at 0° and 15°.2)Compared with inserting car,the crashworthiness of inserted car is obviously worse when collision angle is at 15° and better when at 30° and 45°.3)While collision angle is at 15° and two cars' relative collision velocity increases from 96 km/h to 112 km/h,the crashworthiness of both inserting car and inserted car will deteriorate sharply,for their data of the above first three indexes respectively raise 26%,28%,32% and 72%,80%,33%.4)In the optimal design of car body structure,the worst crashworthiness condition can be chosen for the pointed optimization of the top beam,longitudinal beam and threshold beam of cars.