Comparison of CPX systems with Round Robin Test

摘要

The CPX method (ISO/CD 11819-2) is regularly used for assessing the acoustic quality ofroad surface within the frame work of checking with compliance to contract requirementsand conformity-of-production. The reproducibility of the test procedure is investigatedwith a Round Robin test in which 7 operators of CPX systems, coming from Belgium,Denmark, Germany and Netherlands, participated. All systems were constructed as twowheeled trailers, both with and without enclosure.All systems performed tests with three different tyre sets. One of them was a referenceset that was used by all systems. Tests were done on a series of five different road surfaces,comprising of dense, semi open and porous types.The analysis of the variances observed in the test results (ANOVA) learned that therepeatability of the test procedure (one standard deviation) is about 0.4 dB. Thereproducibility of the system without the effect of differences in tyre properties is about0.6 dB. When the variation in tyre properties is included a standard deviation of 0.8 dBresulted. These test results corroborate the estimated uncertainty given by the ISO/CD11819-2.