Wireless Sensors for Measuring Main Kinematic Parameters in Dynamic Tests Involving Intense Impacts

This study presents the development of two types of wireless sensor systems, one based on high-speed cameras and the other on high-capacity MEMS accelerometers. These sensors are intended for application in two experimental tests related to the ongoing SHELTER project aiming at developing a seismic shelter to protect human lives. In the first test, a half-scaled masonry building accommodating a half-scaled shelter on its top will be led to collapse over a shaking table for assessing the SHELTER impact accelerations during the building collapse. The second test type consists of free-fall of the SHELTER structure, supplied with a safety chair and a crash test dummy, to evaluate the shock accelerations on the human body. These damaging tests would not allow using the wired sensors often used in dynamic tests. Consequently, four wireless accelerometer sets containing two ±200 g accelerometers in the horizontal axes and one ±500 g accelerometer for the vertical direction were considered. In the building collapse test, these accelerometers will be installed in the half-scale shelter (four corners). In the free-fall tests, the accelerometers will be located in the shelter (three corners) and on the safety chair to hand out the large instant acceleration. Complementary measurements will be performed based on high-speed cameras and a large set of “optical + infrared” targets. These targets will be bonded to the under-studied model components in both tests. All sensors and targets were prepared and assembled in LNEC, where the shaking table test will be performed, and the sensor calibrations were carried out.