Development of portable two-dimensional impact tester for sports surfaces

Abstract

This study aims to develop a portable two-dimensional impact tester for sports surfaces. In our previous studies, a two-dimensional impact tester was developed for laboratory use whose frame was fixed to the floor to counteract the horizontal reaction force. To investigate the relationship between surface properties and injuries, two-dimensional impact tests on the various installed fields are required. Additionally, to perform the two-dimensional impact tests on the installed fields without fixing the fields, the portable two-dimensional impact tester, which does not need to fix the fields, is required. This study added the dummy sensor unit to the previous two-dimensional impact tester to counteract the horizontal force. 60 kg impact weight was dropped from 55 mm on the center of the two sensor units with three initial impact angles. As a result, the vertical impact force became that of half of the previous impact tester with the same condition because the vertical impact was divided into two sensor units. Furthermore, the horizontal impact force is almost the same as the previous impact tester because the horizontal impact force of the sensor unit counteracts the impact force produced by the dummy sensor unit. The variance of horizontal maximum force increases with increasing the initial impact angle, although the variances of vertical maximum force decrease with increasing the initial impact angle. Obviously, the experiments' results from the portable two-dimensional impact tester show almost the same tendencies as the previous two-impact tester.