{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T21:13:36Z","timestamp":1792790016520,"version":"4.5.0"},"reference-count":25,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T00:00:00Z","timestamp":1791244800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006041","name":"Innovate UK","doi-asserted-by":"publisher","award":["10022433"],"award-info":[{"award-number":["10022433"]}],"id":[{"id":"10.13039\/501100006041","id-type":"DOI","asserted-by":"publisher"}]},{"award":["10022433"],"award-info":[{"award-number":["10022433"]}],"id":[{"id":"https:\/\/ror.org\/05ar5fy68","id-type":"ROR","asserted-by":"publisher"}]},{"name":"University of Bath","id":[{"id":"https:\/\/ror.org\/002h8g185","id-type":"ROR","asserted-by":"crossref"}]},{"id":[{"id":"https:\/\/ror.org\/002h8g185","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This study investigates fluid-mechanical interfaces (FMIs) for transmitting pressure oscillations in a hydraulic fluid to a piezoelectric stack, with the aim of supporting self-powered sensing and energy harvesting in hydraulic systems. A hydraulic test rig was employed in which a pump, switching valve, pressure sensors, and a piezoelectric stack were coupled through stainless-steel diaphragms of varying thickness (0.10 to 0.80 mm, 48 mm diameter). The effect of maximum pump pressure (20\u201350 bar) and valve switching frequency (1\u201350 Hz) on force transmission was evaluated, and diaphragm integrity was assessed after testing. The results demonstrate that diaphragm thickness strongly influences transmissivity under cyclic hydraulic loading. For the stainless-steel diaphragms tested, a low thickness of 0.25 mm provided a favourable balance between safety and force transmission, performing essentially as well as the thinnest 0.10 mm diaphragm while offering improved mechanical robustness. Thicker diaphragms up to 0.80 mm remained viable for sensing applications where maximal transmissivity is less critical. The findings suggest that FMI geometry can be tuned to improve energy transfer to embedded transducers while maintaining hydraulic integrity. Further work is needed to assess long-term durability under extended cyclic loading and to adapt the design for higher-pressure applications.<\/jats:p>","DOI":"10.3390\/s26196302","type":"journal-article","created":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T08:06:47Z","timestamp":1791274007000},"page":"6302","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Investigation of Fluid-Mechanical Interfaces (FMIs) for the Transmission of Oscillations in Hydraulic Fluid"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8427-5914","authenticated-orcid":false,"given":"Lorenzo","family":"Giunta","sequence":"first","affiliation":[{"name":"Department of Mechanical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"}]},{"given":"Jingqi","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"software","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2901-3388","authenticated-orcid":false,"given":"Min","family":"Pan","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"resources","vocabulary":"credit"}]},{"given":"Vimal","family":"Dhokia","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5880-9131","authenticated-orcid":false,"given":"Chris","family":"Bowen","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"validation","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"}]},{"given":"James","family":"Roscow","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,10,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2103185","DOI":"10.1002\/aenm.202103185","article-title":"Hydraulic Pressure Ripple Energy Harvesting: Structures, Materials, and Applications","volume":"12","author":"Xiao","year":"2022","journal-title":"Adv. Energy Mater."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Aranda, J.J., Bader, S., and Oelmann, B. (2021). Self-Powered Wireless Sensor Using a Pressure Fluctuation Energy Harvester. Sensors, 21.","DOI":"10.3390\/s21041546"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1109\/MPEL.2023.3271199","article-title":"Industrial Adoption of Energy Harvesting: Challenges and Opportunities","volume":"10","author":"Becker","year":"2023","journal-title":"IEEE Power Electron. Mag."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"728","DOI":"10.1002\/ett.2529","article-title":"Energy harvesting technologies for low-power electronics","volume":"23","author":"Alvarado","year":"2012","journal-title":"Trans. Emerg. Telecommun. Technol."},{"key":"ref_5","unstructured":"Becker, T., Borjesson, V., Cetinkaya, O., Chen, B., Colomer-Farrarons, J., Duffy, M., Elefsiniotis, A., Govoni, L., Hadas, Z., and Hayes, M. (2025, January 14). Energy Harvesting for a Green Internet of Things. Available online: https:\/\/www.psma.com\/technical-forums\/energy-harvesting\/whitepaper."},{"key":"ref_6","first-page":"853481","article-title":"Piezoelectric Energy Harvesting Devices: An Alternative Energy Source for Wireless Sensors","volume":"2012","author":"Nechibvute","year":"2012","journal-title":"Smart Mater. Res."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Kottapalli, A.G.P., Tao, K., Sengupta, D., and Triantafyllou, M.S. (2019). Self-Powered and Soft Polymer MEMS\/NEMS Devices, Springer. [1st ed.].","DOI":"10.1007\/978-3-030-05554-7"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"106976","DOI":"10.1016\/j.mssp.2022.106976","article-title":"Porous dielectric materials based wearable capacitance pressure sensors for vital signs monitoring: A review","volume":"151","author":"Chittibabu","year":"2022","journal-title":"Mater. Sci. Semicond. Process."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"3883","DOI":"10.1002\/ese3.784","article-title":"Multi-source ambient energy harvester based on RF and thermal energy: Design, testing, and IoT application","volume":"8","author":"Bakytbekov","year":"2020","journal-title":"Energy Sci. Eng."},{"key":"ref_10","first-page":"667","article-title":"Electromagnetic Energy Harvester Interface Design for Wearable Applications","volume":"65","author":"Wang","year":"2018","journal-title":"IEEE Trans. Circuits Syst. II Express Briefs"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"746","DOI":"10.1039\/C9NA00790C","article-title":"A highly reliable, impervious and sustainable triboelectric nanogenerator as a zero-power consuming active pressure sensor","volume":"2","author":"Vivekananthan","year":"2020","journal-title":"Nanoscale Adv."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"104011","DOI":"10.1088\/0964-1726\/23\/10\/104011","article-title":"Power performance improvements for high pressure ripple energy harvesting","volume":"23","author":"Erturk","year":"2014","journal-title":"Smart Mater. Struct."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"116097","DOI":"10.1016\/j.oceaneng.2023.116097","article-title":"Design, simulation and experiment for a piezoelectric energy harvester based on fluid pressure pulsation in water hydraulic system","volume":"288","author":"Shi","year":"2023","journal-title":"Ocean Eng."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"128287","DOI":"10.1016\/j.energy.2023.128287","article-title":"Experimental and simulation study of a hydraulic piezoelectric energy harvester under different connection modes","volume":"281","author":"Shi","year":"2023","journal-title":"Energy"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Sob, P.B., and Pita, M. (2020, January 20\u201322). Simulation and theoretical Analyses of the Impact of Velocity, Pressure and Kinetic Energy during Damping in a Shock absorber. Proceedings of the 2020 IEEE 11th International Conference on Mechanical and Intelligent Manufacturing Technologies (ICMIMT), Cape Town, South Africa.","DOI":"10.1109\/ICMIMT49010.2020.9041170"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1016\/j.sna.2019.01.022","article-title":"A space-coiling resonator for improved energy harvesting in fluid power systems","volume":"291","author":"Aranda","year":"2019","journal-title":"Sens. Actuators A Phys."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Cao, D.-X., Duan, X.-J., Guo, X.-Y., and Lai, S.-K. (2020). Design and performance enhancement of a force-amplified piezoelectric stack energy harvester under pressure fluctuations in hydraulic pipeline systems. Sens. Actuators A Phys., 309.","DOI":"10.1016\/j.sna.2020.112031"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"106938","DOI":"10.1016\/j.nanoen.2022.106938","article-title":"Recent progress and development of interface integrated circuits for piezoelectric energy harvesting","volume":"94","author":"Li","year":"2022","journal-title":"Nano Energy"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"107013","DOI":"10.1016\/j.ymssp.2020.107013","article-title":"Modelling of the circular edge-clamped interface of a hydraulic pressure energy harvester to determine power, efficiency and bandwidth","volume":"146","author":"Xiao","year":"2021","journal-title":"Mech. Syst. Signal Process."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2705","DOI":"10.1109\/TIM.2018.2828701","article-title":"An Apparatus for the Performance Estimation of Pressure Fluctuation Energy Harvesters","volume":"67","author":"Aranda","year":"2018","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2200096","DOI":"10.1002\/ente.202200096","article-title":"Design and Experimental Investigation of a Novel Piezoelectric Energy Harvester in Pneumatic System","volume":"10","author":"Yang","year":"2022","journal-title":"Energy Technol."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Ko, Y., Yu, S.M., and Bilton, A.M. (2019, January 11\u201314). Modelling and experimental validation of a controllable energy harvester for pressure regulation. Proceedings of the ASME 2019 International Mechanical Engineering Congress and Exposition, Salt Lake City, UT, USA.","DOI":"10.1115\/IMECE2019-11514"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"2993","DOI":"10.1017\/pds.2024.303","article-title":"A review of hydraulic energy harvester designs \u2013 current practice and future improvements","volume":"4","author":"Giunta","year":"2024","journal-title":"Proc. Des. Soc."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"10721","DOI":"10.1080\/15376494.2023.2295383","article-title":"Improving piezoelectric energy harvesting performance through mechanical stiffness matching","volume":"31","author":"Kurt","year":"2023","journal-title":"Mech. Adv. Mater. Struct."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"101396","DOI":"10.1016\/j.mtener.2023.101396","article-title":"A comprehensive energy flow model for piezoelectric energy harvesters: Understanding the relationships between material properties and power output","volume":"37","author":"Li","year":"2023","journal-title":"Mater. Today Energy"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/19\/6302\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T04:11:37Z","timestamp":1791432697000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/19\/6302"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,10,6]]},"references-count":25,"journal-issue":{"issue":"19","published-online":{"date-parts":[[2026,10]]}},"alternative-id":["s26196302"],"URL":"https:\/\/doi.org\/10.3390\/s26196302","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,10,6]]}}}