Pre­cis­i­on Sen­sors for Struc­tu­ral Health Monitoring

New pre­cis­i­on sen­sors from the Chem­nitz-based elec­tro­nics com­pa­ny GEMAC sup­port the moni­to­ring of buil­dings and bridges. This solu­ti­on approach will be pre­sen­ted for the first time at the SPS/​IPC/​Drives trade fair (Hall 7, Stand 297), which will take place from 22 to 24 Novem­ber 2016 in Nuremberg.

In coöpe­ra­ti­on with Deut­sche Bahn, the GEMAC - Gesell­schaft für Mikro­elec­troni­k­an­wen­dung Chem­nitz mbH deve­lo­ps pre­cis­i­on sen­sors for the moni­to­ring of buil­dings and bridges. Up to now, two sen­sors have been deve­lo­ped: on the one hand, a sen­sor for high-pre­cis­i­on tilt mea­su­re­ment in the ran­ge of ±5° and, on the other hand, a sen­sor for pre­cise acce­le­ra­ti­on and dis­pla­ce­ment mea­su­re­ment. The first men­tio­ned sen­sor impres­ses with an accu­ra­cy of up to 0.001° and a reso­lu­ti­on of 0.0001°. The mea­su­ring ran­ge of the sen­sor for acce­le­ra­ti­on and dis­pla­ce­ment mea­su­re­ment is ±2 g, with a reso­lu­ti­on of 1 µg. As the­se sen­sors com­mu­ni­ca­te via a CAN inter­face, they are easy to wire and enable robust and inter­fe­rence-pro­of communication.

Initi­al field tests with pro­to­ty­pes were suc­cessful­ly car­ri­ed out in 2015. The­se sen­sors are then trans­fer­red to series pro­duc­tion. The aim is to deve­lop an out-of-the-box solu­ti­on. Howe­ver, much more data has to be coll­ec­ted on various structures.

The advan­ta­ge of distance mea­su­re­ments based on acce­le­ra­ti­on data is that no local refe­rence is requi­red. This opens up the pos­si­bi­li­ty of per­ma­nent moni­to­ring, espe­ci­al­ly for bridges. Howe­ver, a cali­bra­ti­on of the acce­le­ra­ti­on sen­sors at the instal­la­ti­on loca­ti­on is requi­red for dis­pla­ce­ment mea­su­re­ment. A limi­ta­ti­on of the distance mea­su­re­ment by means of acce­le­ra­ti­on is that the dou­ble inte­gra­ti­on of the acce­le­ra­ti­on data for obtai­ning the distance signal has to be car­ri­ed out sub­se­quent­ly for cer­tain time win­dows (e. g. the dura­ti­on of a train crossing) and can­not be car­ri­ed out in real time. Pre­vious approa­ches for the long-term mea­su­re­ment of a path using acce­le­ra­ti­on data and its dou­ble inte­gra­ti­on are not sui­ta­ble for the appli­ca­ti­on. By com­bi­ning acce­le­ra­ti­on and pre­cis­i­on tilt mea­su­re­ments, the posi­ti­on of bridges can now be moni­to­red over a long peri­od of time wit­hout any pro­blems. This opens up num­e­rous new appli­ca­ti­ons for the incli­na­ti­on and acce­le­ra­ti­on sen­sors of GEMAC in the field of struc­tu­ral health moni­to­ring. In addi­ti­on to dis­pla­ce­ment mea­su­re­ment, the­se acce­le­ra­ti­on sen­sors also offer the pos­si­bi­li­ty of mea­su­ring natu­ral fre­quen­cy up to 200 Hz.