{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,17]],"date-time":"2026-04-17T23:51:14Z","timestamp":1776469874464,"version":"3.51.2"},"reference-count":34,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2020,6,19]],"date-time":"2020-06-19T00:00:00Z","timestamp":1592524800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"KAKENHI of Japan Society for the Promotion of Science","award":["16H03134"],"award-info":[{"award-number":["16H03134"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Measurement of the internal stress and strain distributions within soft materials is necessary in the field of skin contact safety. However, conventional interactive force sensors cannot efficiently obtain or estimate these distributions. Herein, a shear strain sensor system consisting of distributed built-in piezoelectric polyvinylidene fluoride (PVDF) polymer films was developed to measure the internal shear strain field of a soft material. A shear strain sensing model was mathematically established, based on the piezoelectricity and mechanical behavior of a bending cantilever beam, to explain the sensing principle. An experiment in three-dimensional measurement of the shear strain distribution within an artificial skin was designed and conducted to assess the sensitivity of the sensing model. This sensor system could visualize the shear strain field and was sensitive to different contact conditions. The measurement results agreed well with the results of numerical simulation of the substrate, based on contact mechanics. The proposed sensor system was confirmed to provide a new sensing method for the field of shape analysis. The sensor system can be applied to develop sufficiently sensitive electronic skin and can significantly contribute to skin damage analysis and skin contact safety assessment.<\/jats:p>","DOI":"10.3390\/s20123484","type":"journal-article","created":{"date-parts":[[2020,6,19]],"date-time":"2020-06-19T12:19:55Z","timestamp":1592569195000},"page":"3484","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":14,"title":["Measurement of Shear Strain Field in a Soft Material Using a Sensor System Consisting of Distributed Piezoelectric Polymer Film"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1317-482X","authenticated-orcid":false,"given":"Fengyu","family":"Li","sequence":"first","affiliation":[{"name":"Department of Mechanical Systems Engineering, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yasuhiro","family":"Akiyama","sequence":"additional","affiliation":[{"name":"Department of Mechanical Systems Engineering, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xianglong","family":"Wan","sequence":"additional","affiliation":[{"name":"Department of Mechanical Systems Engineering, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shogo","family":"Okamoto","sequence":"additional","affiliation":[{"name":"Department of Mechanical Systems Engineering, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yoji","family":"Yamada","sequence":"additional","affiliation":[{"name":"Department of Mechanical Systems Engineering, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,6,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Hassan, P., Verma, G., and Ganguly, R. (2011). Soft materials-properties and applications. Functional Materials: Preparation, Processing and Applications, Elsevier.","DOI":"10.1016\/B978-0-12-385142-0.00001-5"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"133","DOI":"10.1007\/s11249-017-0916-7","article-title":"Characteristics of Dummy Skin Contact Mechanics During Developing Process of Skin Abrasion Trauma","volume":"65","author":"Mao","year":"2017","journal-title":"Tribol. Lett."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Bashir, S.J., and Chew, A.L. (2016). Mechanical injury to the skin. Rook\u2019s Textbook of Dermatology, John Wiley & Sons, Ltd.. [9th ed.].","DOI":"10.1002\/9781118441213.rtd0124"},{"key":"ref_4","first-page":"214","article-title":"Skin response to mechanical stress: Adaptation rather than breakdown-a review of the literature","volume":"32","author":"Sanders","year":"1995","journal-title":"J. Rehabil. Res. Dev."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1750114","DOI":"10.1142\/S0219519417501147","article-title":"Investigation of skin laceration threshold under a specific condition: Blade penetration test on porcine skin","volume":"17","author":"Ito","year":"2017","journal-title":"J. Mech. Med. Biol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"784","DOI":"10.1109\/TNSRE.2015.2464719","article-title":"Measurement of contact behavior including slippage of cuff when using wearable physical assistant robot","volume":"24","author":"Akiyama","year":"2015","journal-title":"IEEE Trans. Neural Syst. Rehabil. Eng."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"680","DOI":"10.1080\/01691864.2017.1318716","article-title":"Safety verification method for preventing friction blisters during utilization of physical assistant robots","volume":"31","author":"Mao","year":"2017","journal-title":"Adv. Robot."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"327","DOI":"10.1111\/j.1365-2133.1955.tb12657.x","article-title":"Experimental friction blisters","volume":"67","author":"Naylor","year":"1955","journal-title":"Br. J. Dermatol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1111\/j.1365-2133.1955.tb12729.x","article-title":"The skin surface and friction","volume":"67","author":"Naylor","year":"1955","journal-title":"Br. J. Dermatol."},{"key":"ref_10","unstructured":"Jacobs, T., and Virk, G.S. (2014, January 2\u20133). ISO 13482-The new safety standard for personal care robots. Proceedings of the ISR\/Robotik 2014 41st International Symposium on Robotics, Munich, Germany."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"472","DOI":"10.1136\/bmj.332.7539.472","article-title":"Pressure ulcers","volume":"332","author":"Grey","year":"2006","journal-title":"BMJ"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1315","DOI":"10.1080\/01691864.2015.1055799","article-title":"Interaction forces beneath cuffs of physical assistant robots and their motion-based estimation","volume":"29","author":"Akiyama","year":"2015","journal-title":"Adv. Robot."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Ozioko, O., Karipoth, P., Hersh, M., and Dahiya, R. (2020). Wearable Assistive Tactile Communication Interface based on Integrated Touch Sensors and Actuators. IEEE Trans. Neural Syst. Rehabil. Eng.","DOI":"10.1109\/TNSRE.2020.2986222"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/TRO.2009.2033627","article-title":"Tactile sensing\u2014from humans to humanoids","volume":"26","author":"Dahiya","year":"2009","journal-title":"IEEE Trans. Robot."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Yao, K., Kaboli, M., and Cheng, G. (2017, January 15\u201317). Tactile-based object center of mass exploration and discrimination. Proceedings of the 2017 IEEE-RAS 17th International Conference on Humanoid Robotics (Humanoids), Birmingham, UK.","DOI":"10.1109\/HUMANOIDS.2017.8246975"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1850001","DOI":"10.1142\/S0219843618500019","article-title":"Active tactile transfer learning for object discrimination in an unstructured environment using multimodal robotic skin","volume":"15","author":"Kaboli","year":"2018","journal-title":"Int. J. Humanoid Robot."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Feng, D., Kaboli, M., and Cheng, G. (2018). Active prior tactile knowledge transfer for learning tactual properties of new objects. Sensors, 18.","DOI":"10.3390\/s18020634"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1123","DOI":"10.1016\/j.mechatronics.2011.04.003","article-title":"Measuring human\u2013robot interaction on wearable robots: A distributed approach","volume":"21","author":"Lenzi","year":"2011","journal-title":"Mechatronics"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"295","DOI":"10.1016\/j.sna.2005.09.023","article-title":"A shear stress sensor for tactile sensing with the piezoresistive cantilever standing in elastic material","volume":"127","author":"Noda","year":"2006","journal-title":"Sens. Actuators A Phys."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Shih, B., Shah, D., Li, J., Thuruthel, T.G., Park, Y.L., Iida, F., Bao, Z., Kramer-Bottiglio, R., and Tolley, M.T. (2020). Electronic skins and machine learning for intelligent soft robots. Sci. Robot., 5.","DOI":"10.1126\/scirobotics.aaz9239"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1359","DOI":"10.1080\/01691864.2015.1095653","article-title":"New materials and advances in making electronic skin for interactive robots","volume":"29","author":"Yogeswaran","year":"2015","journal-title":"Adv. Robot."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Luo, M., Liu, D., and Luo, H. (2016). Real-time deflection monitoring for milling of a thin-walled workpiece by using PVDF thin-film sensors with a cantilevered beam as a case study. Sensors, 16.","DOI":"10.3390\/s16091470"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"2539","DOI":"10.1109\/TUFFC.2011.2117","article-title":"Polyvinylidene fluoride film sensors in collocated feedback structural control: Application for suppressing impact-induced disturbances","volume":"58","author":"Ma","year":"2011","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"48","DOI":"10.1016\/j.sna.2007.04.002","article-title":"Pressure sensor from a PVDF film","volume":"142","author":"Shirinov","year":"2008","journal-title":"Sens. Actuators A Phys."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"384","DOI":"10.1109\/JSEN.2008.917483","article-title":"A PVDF-based deformation and motion sensor: Modeling and experiments","volume":"8","author":"Yi","year":"2008","journal-title":"IEEE Sens. J."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1109\/TMECH.2007.915064","article-title":"A piezo-sensor-based \u201csmart tire\u201d system for mobile robots and vehicles","volume":"13","author":"Yi","year":"2008","journal-title":"IEEE\/ASME Trans. Mechatron."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Li, F., Akiyama, Y., Wan, X., Yamada, Y., and Okamoto, S. (2019, January 15\u201318). Shear Stress Sensor for Soft Material with Built-In Piezoelectric Polymer Films. Proceedings of the 2019 IEEE 8th Global Conference on Consumer Electronics (GCCE), Osaka, Japan.","DOI":"10.1109\/GCCE46687.2019.9015395"},{"key":"ref_28","unstructured":"Specialties, M. (2020, June 19). Piezo Film Sensors Technical Manual. Available online: https:\/\/www.sparkfun.com\/datasheets\/Sensors\/Flex\/MSI-techman.pdf."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"246","DOI":"10.1106\/8BFB-GC8P-XQ47-YCQ0","article-title":"Fundamental understanding of piezoelectric strain sensors","volume":"11","author":"Sirohi","year":"2000","journal-title":"J. Intell. Mater. Syst. Struct."},{"key":"ref_30","unstructured":"Beer, F.P., Johnston, R., Dewolf, J., and Mazurek, D. (1981). Mechanics of Materials, McGraw-Hill."},{"key":"ref_31","unstructured":"Timo\u0161enko, S.P., and Goodier, J.N. (1951). Theory of Elasticity, McGraw-Hill."},{"key":"ref_32","unstructured":"Johnson, K.L., and Johnson, K.L. (1987). Contact Mechanics, Cambridge University Press."},{"key":"ref_33","unstructured":"Kengo, Y., and Yoji, Y. (2014). Development of Specialized Dummy Coating for Viscoelasticity of Skin for Dummy for Safety Tests. [Graduation Thesis, Nagoya University]."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Akiyama, Y., Yamada, Y., Ito, K., Oda, S., Okamoto, S., and Hara, S. (2012, January 9\u201313). Test method for contact safety assessment of a wearable robot-analysis of load caused by a misalignment of the knee joint. Proceedings of the 2012 IEEE RO-MAN: The 21st IEEE International Symposium on Robot and Human Interactive Communication, Paris, France.","DOI":"10.1109\/ROMAN.2012.6343807"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/12\/3484\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:41:05Z","timestamp":1760175665000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/12\/3484"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,6,19]]},"references-count":34,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2020,6]]}},"alternative-id":["s20123484"],"URL":"https:\/\/doi.org\/10.3390\/s20123484","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,6,19]]}}}