Maintaining active safety performance through appropriate vehicle bumper refinishing: Case study for Korean minor damage repair standards

Abstract

The Korean government has established “minor damage repair standards” that require repair without replacement when vehicle bumpers can be repaired to reduce plastic bumper waste. However, when blind spot detection and lane change assist systems, active safety systems, are installed, there is a controversy over whether the standards can be applied to restore the minor damage bumper covers because the short-range radar sensor for them is located inside each corner of the rear bumper. Therefore, it is necessary to identify the difference between original and repair conditions to confirm the repair methods that can meet the government’s standards while maintaining the safety performance of the systems. The experiments were designed two sectors, most vehicle bumper cover repair methods were produced as test specimens which are used for static tests to compare with the new vehicle state, and based on the results, specimens needed field confirmation were prepared and dynamic tests were conducted. The microscopic performance difference of the safety systems according to the refinishing was determined by analyzing the dynamic test results using null-hypothesis significance testing and analysis of variance methods. The results of the tests showed that applying a filler to form the bumper surface does not cause performance problems if the radar signal transmission area of 10 m2 is avoided. In the case of paintwork on the radar signal area, two or three layers of paint did not show any difference from the manufacturer’s bumper, therefore paint layer scratches can be refinished up to twice. However, if metal-colored paint layers are three as a result of paintwork twice, the maximum detection angle performance is adversely affected. Through this study, new experimental methods were suggested for identifying the safety performance of advanced driver assistance systems when various repair methods are applied to the plastic bumper cover.