Brüel & Kjær - Model Types 4825 and 4826 - Modal Exciters for Testing
With a force rating of 200 N (sine) and 400 N (sine) respectively, Types 4825 and 4826 are ideal for high-precision excitation of a variety of mechanical components in SISO and SIMO test setups on automotive structures, aerospace sub-structures, passenger car and truck body-in-white, engines, powertrain and drive train components. Also, it is ideal for demanding and uncompromised excitation of large and very large structures in MISO and MIMO test setups. The two modal exciters are available as stand-alone units - supplied only with the appropriate trunnion, blower and connecting cable - or as complete systems with matching power amplifiers.
- General mechanical mobility measurements
- Experimental modal analysis on most mechanical structures
- SISO, MISO, SIMO and MIMO modal testing applications
- Advanced structural dynamics investigations
- Structural damage detection
- Finite element model correlation
- Force rating 200 N sine (Type 4825) or 400 N sine (Type 4826)
- Wide frequency range
- Low stray magnetic field
- High force-to-weight ratio
- One inch peak-to-peak displacement for best low frequency excitation
- Compact construction enabling easy positioning/orientation relative to test object
Based on unique rare-earth neodymium magnet technology, Modal Exciters Types 4825 and 4826 feature extremely small physical dimensions relative to the force rating along with low total weight and a low-mass, high-rigidity, spring-suspended armature.
The low armature weight helps to ensure high-quality force measurements by minimising force drop-offs at the test specimen's resonance frequencies. Four upper radial flexures and four lower radial flexures, the latter providing an additional guide for best stabilisation, form a strong rectilinear guidance system which keeps the driver coil perfectly centered in the magnetic assembly's air gap. In the transverse directions and in torsion, the flexure system provides very high stiffness to counteract rotational movement of the test specimen. Also, through this configuration, the modal exciter can absorb high lateral forces without damage to the exciter's internal construction.
The 'hole-through' design makes it possible to use tension wire stingers or traditional push/pull stingers with the exciter. Easy and fast attachment of both types of stingers is achieved with the chuck nut assembly (for use with tension wire stingers) or with an M6 to 10–32 UNF threaded insert (for use with push/pull stingers).