# US 8,569,928 B2 · Method for influencing, damping, or suppressing mechanical vibrations occurring during operation in a turbomachine blade, a turbomachine blade useful for carrying out the method, and a piezoelectric damping element > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,569,928 B2 - Document ID: US8569928B2 - Status: Granted - Kind: B2 - Application number: 13/298,726 - Filed: 2011-11-17 - Published: 2012-05-24 - Granted: 2013-10-29 - Earliest claimed: 2010-11-24 - Assignees: ALSTOM Technology Ltd - Applicants: Jaroslaw Leszek Szwedowicz; Wolfgang Kappis; Lars Panning; Sebastian Marc Schwarzendahl; Marcus Neubauer; Andreas Hohl; Jörg Wallaschek - Inventors: Jaroslaw Leszek Szwedowicz; Wolfgang Kappis; Lars Panning; Sebastian Marc Schwarzendahl; Marcus Neubauer; Andreas Hohl; Jörg Wallaschek - Web page: https://patentgrep.com/patent/US8569928B2 ## CPC - F01D 5/16: for counteracting blade vibration - F01D 25/06: for preventing blade vibration (means on blade-carrying members or blades F01D5/00) - F04D 29/324: {Blades} - F04D 29/668: {damping or preventing mechanical vibrations} - F16F 15/005: {using electro- or magnetostrictive actuation means (generating of mechanical vibrations operating with electrostriction B06B1/06, with magnetostriction B06B1/08; vehicle suspension arrangements characterised by use of piezoelectric elements B60G17/01941; piezoelectric, electrostrictive and magnetostrictive devices per se H10N30/00)} - F05D 2260/96: Preventing, counteracting or reducing vibration or noise - Y02E 10/72: Wind turbines with rotation axis in wind direction - Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract In a method for influencing, in particular damping or suppressing, mechanical vibrations occurring during operation in a turbomachine blade (10), the mechanical vibratory energy of the turbomachine blade (10) is first converted into electrical energy and the electrical energy generated is then converted into heat loss. Effective damping which can be used especially simply and in a versatile way is achieved in that the piezoelectric effect is used in order to convert mechanical vibratory energy into electrical energy. ## Claims ### Claim 1 A method for suppressing mechanical vibrations occurring during operation in a turbomachine blade, the method comprising: forming a cavity in the turbomachine blade configured and arranged to receive at least one piezoelectric damping element; installing at least one piezoelectric damping element firmly in the turbomachine blade, including inserting the at least one piezoelectric damping element into the cavity and firmly coupling the piezoelectric damping element to the turbomachine blade; converting mechanical vibratory energy of the turbomachine blade into electrical energy; piezoelectrically converting said electrical energy into heat loss, wherein piezoelectrically converting comprises deforming said at least one piezoelectric damping element as a result of the mechanical vibrations of the turbomachine blade and generating an electrical voltage; and wherein converting said electrical energy comprises ohmically losing heat from the generated electrical voltage in a connected electrical network. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein: said electrical network comprises a shunt including a series connection of an inductance and an ohmic resistance; the piezoelectric damping element comprises a capacitance including a piezo body arranged between electrodes; and further comprising tuning a resonant frequency of an oscillatory circuit formed by said electrical network to a mechanical vibration to be damped of the turbomachine blade. ### Claim 3 (depends on 2) The method as claimed in claim 2, further comprising: measuring and evaluating electrical oscillations in the piezoelectric damping element to determine and monitor the mechanical vibrations in the turbomachine blade. ### Claim 4 (depends on 1) The method as claimed in claim 1, wherein coupling comprises forming a materially integral connection or mechanical bracing. ### Claim 5 (depends on 1) The method as claimed in claim 1, wherein the turbomachine blade comprises a turbine blade. ### Claim 6 A turbomachine blade comprising: a blade leaf; a cavity in the blade leaf; at least one piezoelectric damping element installed firmly in the blade leaf; wherein the at least one piezoelectric damping element is positioned in said cavity. ### Claim 7 (depends on 6) The turbomachine blade as claimed in claim 6, wherein said blade comprises a turbine blade. ### Claim 8 (depends on 6) The turbomachine blade as claimed in claim 6, wherein the at least one piezoelectric damping element comprises a piezo element and an electrical network connected to the piezo element. ### Claim 9 (depends on 8) The turbomachine blade as claimed in claim 8, wherein the electrical network comprises a shunt containing an ohmic resistance connected to electrically dampen the piezo element. ### Claim 10 (depends on 9) The turbomachine blade as claimed in claim 9, wherein the electrical network or the shunt comprises a series connection comprising said ohmic resistance and an inductance. ### Claim 11 (depends on 9) The turbomachine blade as claimed in claim 9, wherein the electrical network or the shunt comprises a coil. ### Claim 12 (depends on 8) The turbomachine blade as claimed in claim 8, wherein the piezo element comprises a stack of piezo bodies and electrodes. ### Claim 13 (depends on 6) The turbomachine blade as claimed in claim 6, further comprising: a dedicated casing surrounding the at least one piezoelectric damping element. ### Claim 14 (depends on 13) The turbomachine blade as claimed in claim 13, wherein the dedicated casing comprises an upper subcasing and a lower subcasing. ### Claim 15 (depends on 6) The turbomachine blade as claimed in claim 6, wherein the at least one piezoelectric damping element is firmly coupled to the blade leaf. ### Claim 16 (depends on 6) The turbomachine blade as claimed in claim 6, wherein the at least one piezoelectric damping element is coupled to the blade leaf with a materially integral connection or by mechanical bracing. ### Claim 17 (depends on 6) The turbomachine blade as claimed in claim 6, wherein the at least one piezoelectric damping element comprises a plurality of piezoelectric damping elements arranged in and distributed over the blade leaf. ### Claim 18 (depends on 6) The turbomachine blade as claimed in claim 6, further comprising: a measuring device configured and arranged to receive and evaluate signals occurring at the piezoelectric damping element; wherein the at least one piezoelectric damping element is wirelessly connected to the measuring device. ### Claim 19 (depends on 8) The turbomachine blade as claimed in claim 8, wherein the electrical network comprises a time-variable resistance.