{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,13]],"date-time":"2026-02-13T23:27:34Z","timestamp":1771025254906,"version":"3.50.1"},"reference-count":66,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2018,5,28]],"date-time":"2018-05-28T00:00:00Z","timestamp":1527465600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["51678322 and 51650110509"],"award-info":[{"award-number":["51678322 and 51650110509"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100002855","name":"Ministry of Science and Technology of the People's Republic of China","doi-asserted-by":"publisher","award":["2017YFC0703603"],"award-info":[{"award-number":["2017YFC0703603"]}],"id":[{"id":"10.13039\/501100002855","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Bolted spherical joints are widely used to form space steel structures. The stiffness and load capacity of the structures are affected by the looseness of bolted spherical joint connections in the structures. The looseness of the connections, which can be caused by fabrication error, low modeling accuracy, and \u201cfalse twist\u201d in the installation process, may negatively impact the load capacity of the structure and even lead to severe accidents. Furthermore, it is difficult to detect bolted spherical joint connection looseness from the outside since the bolts connect spheres with rods together from the inside. Active sensing methods are proposed in this paper to monitor the tightness status of the bolted spherical connection using piezoceramic transducers. A triangle-on-triangle offset grid composed of bolted spherical joints and steel tube bars was fabricated as the specimen and was used to validate the active sensing methods. Lead Zirconate Titanate (PZT) patches were used as sensors and actuators to monitor the bolted spherical joint tightness status. One PZT patch mounted on the central bolted sphere at the upper chord was used as an actuator to generate a stress wave. Another PZT patch mounted on the bar was used as a sensor to detect the propagated waves through the bolted spherical connection. The looseness of the connection can impact the energy of the stress wave propagated through the connection. The wavelet packet analysis and time reversal (TR) method were used to quantify the energy of the transmitted signal between the PZT patches by which the tightness status of the connection can be detected. In order to verify the effectiveness, repeatability, and consistency of the proposed methods, the experiments were repeated six times in different bolted spherical connection positions. The experimental results showed that the wavelet packet analysis and TR method are effective in detecting the tightness status of the connections. The proposed active monitoring method using PZT transducers can monitor the tightness levels of bolted spherical joint connections efficiently and shows its potential to guarantee the safety of space steel structures in construction and service.<\/jats:p>","DOI":"10.3390\/s18061727","type":"journal-article","created":{"date-parts":[[2018,5,29]],"date-time":"2018-05-29T02:58:18Z","timestamp":1527562698000},"page":"1727","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":71,"title":["Health Monitoring of Bolted Spherical Joint Connection Based on Active Sensing Technique Using Piezoceramic Transducers"],"prefix":"10.3390","volume":"18","author":[{"given":"Jing","family":"Xu","sequence":"first","affiliation":[{"name":"School of Civil Engineering, Qingdao University of Technology, Qingdao 266033, China"},{"name":"State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chenyu","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, University of Houston, Houston, TX 77004, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hongnan","family":"Li","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China"},{"name":"College of Civil Engineering, Shenyang Jianzhu University, Shenyang 110168, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chunwei","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Civil Engineering, Qingdao University of Technology, Qingdao 266033, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jiajia","family":"Hao","sequence":"additional","affiliation":[{"name":"School of Civil Engineering, Qingdao University of Technology, Qingdao 266033, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4081-0414","authenticated-orcid":false,"given":"Shuli","family":"Fan","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,5,28]]},"reference":[{"key":"ref_1","first-page":"53","article-title":"Study on influence caused by bolt-connection defect on mechanical properties of bolt-ball joint","volume":"49","author":"Wu","year":"2017","journal-title":"J. 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