Electrodynamic Modal Test Impactor System and Method

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.

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.