Page 44 - libroBrevetti

Department of Engineering, ICT and Technologies for Energy and Transport Patent Title Radial force transducer, in pĂƌƟcular for rotaƟnŐ shĂŌ’s. Ref. CNR 10305 Assignee(s): CNR CNR InsƟƚute: INSEAN Main Inventor: Fabrizio Ortolani Countries: IT Priority date: 28/03/2014 Abstract Radial forces measurement on ƌŽƚĂƟnŐ shĂŌ is ŽŌĞn a ĐŚĂůůĞŶŐĞ͘ The use of strain ŐĂƵŐĞƐ mounted directly on the shĂŌ requires the use of slip rinŐs or a radio link in order to power the system and acquire data. Moreover underwater ĂƉƉůŝĐĂƟŽŶƐ or into a dirty environment are even more diĸcult to achieve. Object of the present invenƟon is a custom pass thru-hole, strain ŐĂƵŐes based, biaxial force transducer able to quĂŶƟfy radial forces acƟŶŐ on a rotĂƟŶŐ shĂŌ͘ It is desiŐned to be mounted as shĂŌ͛s frame and it converts shĂŌ’s deŇecƟŽŶƐ into forces measure usinŐ sensŝƟve plates equipped with strain ŐauŐes. Moreover, scalability and sensŝƟvity can be chanŐĞd in a wide raŶŐĞ just modifyŝŶŐ main body dimensions or sensiƟve parts’ thickness. Background The ĮƌƐt purpose of the transducer is ŐŽŝŶŐ to be the measure of lateral forces ĂĐƟŶŐ on propellers durinŐ model test. Usually the measure of propeller’s transversal loads are performed usinŐ dedicated instruments, that allow to study only the propeller, in so called “open water“ tests. Thus, the propeller is separated from the vehicle so hull’s contribuƟŽŶƐ or ŝŶƚĞƌĂĐƟŽŶƐ are modeled only in thĞŽƌĞƟĐĂů ŵĂƚŚĞŵĂƟĐĂl sŝŵƵůĂƟŽns. Technology The transducer’s ŽƉĞƌĂƟŶŐ principle is the conversion of the ĚĞŇeĐƟŽn of ƐĞŶƐŝƟve beams, caused by forces on the shĂŌ, into a voltaŐĞ siŐnal usinŐ strain ŐauŐes sensors. The transducer is composed of independent structures, machined in order to decouple the force’s components and eliminate eīects due to beŶĚŝŶŐ moments. Advantages and ApplicaƟons UsŝŶŐ this transducer is possible to perform measurements in a real opeƌĂƟǀe ĐŽŶĚŝƟon, workŝŶŐ both as a frame and as meĂƐƵƌŝŶŐ device. Other apƉůŝĐĂƟŽŶs would be turbine or airfoil test into ǁŝŶĚͬĐĂǀŝƚĂƟon tunnel, measurements of loads on structures/equipments that foresee the use of loaded rods or shĂŌƐ, as auƚŽŵĂƟŽn and control system, auƚŽŵŽƟve monitorinŐ or R&D preliminary and prototypinŐ measurements. Development stage A prototype is beinŐ developed and calibrated. Recently, a test session on full experimental setup - that is the transducer mounted on a vessel model’s shĂŌ line - in order to measure bearinŐ loads durinŐ free runninŐ maneuverinŐ tests, has been performed and experimental data and results are ŐoinŐ to be presented in succeedinŐ papers. 35