# US 2014/0150526 A1 · Electrodynamic Modal Test Impactor System and Method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0150526 A1 - Document ID: US20140150526A1 - Status: Published application - Kind: A1 - Application number: 13/691,584 - Filed: 2012-11-30 - Published: 2014-06-05 - Earliest claimed: 2012-11-30 - Assignees: The Boeing Company - Inventors: Donald E. Powers; Jason C. Kiiskila - Web page: https://patentgrep.com/patent/US20140150526A1 ## CPC - G01M 7/08: Shock-testing - G01N 3/34: generated by mechanical means, e.g. hammer blows - G01N 29/045: {by imparting shocks to the workpiece and detecting the vibrations or the acoustic waves caused by the shocks (measuring resonant frequency G01H13/00; measuring strength properties by application of mechanical stress G01N3/00)} - G01N 29/12: by measuring frequency or resonance of acoustic waves {(measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00)} - G01N 3/30: by applying a single impulsive force, e.g. by falling weight - G01N 3/317: generated by electromagnetic means - G01N 2203/0039: Hammer or pendulum - G01N 2291/042: Wave modes - G01N 2291/2694: Wings or other aircraft parts - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract There is provided an electrodynamic modal test impactor system and method. The system has a controller device and an impactor assembly coupled to the controller device. The impactor assembly has a housing and a permanent magnet positioned within the housing. The impactor assembly further has a voice coil positioned within the housing in a magnetic gap of a magnetic yoke housing. The voice coil is driven by the controller device. The impactor assembly further has a drive shaft supported by two or more support elements. The drive shaft is attached to the voice coil and is driven by the voice coil. The impactor assembly further has a load cell attached to a free end of the drive shaft and a biasing device positioned within the magnetic yoke housing. ## Claims ### Claim 1 An electrodynamic modal test impactor system comprising: a controller device; an impactor assembly coupled to the controller device, the impactor assembly comprising: a housing; a permanent magnet positioned within the housing; a voice coil positioned within the housing in a magnetic gap of a magnetic yoke housing, the voice coil being driven by the controller device; a drive shaft supported by two or more support elements, the drive shaft attached to the voice coil and being driven by the voice coil; a load cell attached to a free end of the drive shaft; and, a biasing device positioned within the magnetic yoke housing. ### Claim 2 (depends on 1) The system of claim 1 wherein the controller device comprises an audio amplifier device. ### Claim 3 (depends on 1) The system of claim 1 wherein the housing comprises a first housing portion and a second housing portion, the first housing portion comprising a cap portion and a base portion, and the second housing portion comprising the magnetic yoke housing. ### Claim 4 (depends on 1) The system of claim 1 wherein the permanent magnet is coupled between a magnetic yoke base plate and a magnetic yoke center pole and is surrounded by a magnetic yoke outer pole, wherein the permanent magnet, the magnetic yoke base plate, the magnetic yoke center pole, and the magnetic yoke outer pole comprise a magnet assembly housed within the magnetic yoke housing. ### Claim 5 (depends on 1) The system of claim 1 wherein the voice coil comprises a winding wound around an exterior of an armature support, the winding comprising a wire having a gauge measurement of 30 gauge or greater. ### Claim 6 (depends on 1) The system of claim 1 wherein the voice coil has an armature support that is integrally machined with the drive shaft. ### Claim 7 (depends on 1) The system of claim 1 wherein the support elements comprise bushings each having an opening corresponding to an outer diameter of the drive shaft. ### Claim 8 (depends on 1) The system of claim 1 wherein the load cell is attached to an impact tip. ### Claim 9 (depends on 1) The system of claim 1 wherein an integral force measuring device comprising one or more strain gauges and one or more strain gauge wires is attached to the drive shaft and is used in place of the load cell, and an impact tip is attached directly to the free end of the drive shaft. ### Claim 10 (depends on 1) The system of claim 1 wherein the biasing device comprises two coil springs or two foam pieces. ### Claim 11 (depends on 1) The system of claim 1 further comprising a connector comprising a plurality of impact signal wires, the connector attached between the controller device and the impactor assembly. ### Claim 12 (depends on 1) The system of claim 1 further comprising an articulating mounting device on which the impactor assembly is mounted. ### Claim 13 (depends on 1) The system of claim 1 further comprising a computer device and/or processor unit to review and analyze electrodynamic modal impact test measurements measured with the system. ### Claim 14 An automated electrodynamic modal test impactor system comprising: an audio amplifier; an impactor assembly coupled to the audio amplifier via a plurality of impact signal wires, the impactor assembly comprising: a housing comprising a first housing portion and a second housing portion, the second housing portion comprising a magnetic yoke housing; a magnet assembly housed within the magnetic yoke housing, the magnet assembly comprising a permanent magnet coupled between a magnetic yoke base plate and a magnetic yoke center pole and surrounded by a magnetic yoke outer pole; a biasing device positioned within the magnetic yoke housing; a voice coil positioned within the housing in a magnetic gap of the magnetic yoke housing, the voice coil being driven by the audio amplifier; a drive shaft supported by two or more support elements, the drive shaft integrally machined to an armature support of the voice coil, the drive shaft being driven by the voice coil; a load cell attached to a free end of the drive shaft; and, an impact tip attached to the load cell; an articulating mounting device on which the impactor assembly is mounted; and, a computer device to review and analyze electrodynamic modal impact test measurements measured with the system. ### Claim 15 (depends on 14) The system of claim 14 wherein an integral force measuring device comprising one or more strain gauges and one or more strain gauge wires is attached to the drive shaft and is used in place of the load cell, and an impact tip is attached directly to the free end of the drive shaft. ### Claim 16 A method of performing electrodynamic modal impact tests, the method comprising the steps of: imparting short duration force impacts of between about 1 millisecond to about 10 milliseconds in duration on a structure being tested for dynamic modal response; centering a voice coil within a magnetic gap; biasing the voice coil and a drive shaft driven by the voice coil, in a quiescent position to provide a long outward stroke and a minimal inward stroke; and, measuring an impact force using a load cell attached to a free end of the drive shaft. ### Claim 17 (depends on 16) The method of claim 16 wherein biasing the voice coil and the drive shaft further comprises holding the voice coil and the drive shaft in the quiescent position with a biasing device comprising a coil spring or a foam piece. ### Claim 18 (depends on 16) The method of claim 16 wherein the measuring step comprises measuring greater than 100 pounds of impact force. ### Claim 19 (depends on 16) The method of claim 16 further comprising exciting the structure being tested at a frequency in a range of about 10 Hertz (Hz) to over 10 kiloHertz (kHz). ### Claim 20 (depends on 16) The method of claim 16 further comprising powering the voice coil with an electrical current in a range of about 0.1 amps (amperes) to about 10 amps (amperes).