Reducing Experimental Modal Survey Measurement Errors

MB Dynamics, Inc. announced the global market introduction of its Lateral Excitation Stand.

The MB Dynamics Lateral Excitation Stand can be used to help reduce measurement errors which can arise during experimental modal surveys. It does so, by offering versatile modal exciter suspension and support, as well as by applying force to a test structure in one of two unique ways: either horizontally, into the side of a test structure; or, obliquely, beneath a test structure. The stand further allows exact modal exciter positioning, in either horizontal or vertical direction, while still accommodating a maximum suspended load of up to 60 kg.

Designed by 40-year global industry experts in experimental modal analysis, the stand offers seamless compatibility with MB Dynamics’ own industry best-selling MODAL 50A and MODAL 110 exciter systems, of which more than 1,300 remain successfully installed in the field. The main structural parts of the Lateral Excitation Stand are constructed of a lightweight, durable, and rugged aluminum, while its rubber-footed adjustable steel legs offer added stability.

The Lateral Excitation Stand may also be used in combination with tensioned piano wire or compression stingers to help reduce measurement errors arising from unmeasured transverse forces. This, given that tension-only stingers can be used to apply axial forces without the typical sideloads which can otherwise contaminate measured data. When a piano wire stinger is properly suspended via four supplied turnbuckles, it connects to a test item’s force sensor via the modal exciter’s through-hole and corresponding base, along with any required inertial masses. The piano wire stinger then wraps around a pulley. Any required static preload force is applied via a small hand winch, with a series of quarter-turn handles used to secure the lateral arm and pulley. A low gear-ratio hand crank facilitates easy vertical adjustments of the suspended stinger over a range of 305 mm to 1415 mm. Upon application of sufficient static preload forces, as to exceed dynamic force, the piano wire stinger is secured by tightening the Dumore Chuck within the exciter’s moving element. As the Lateral Excitation Stand allows the modal exciter to be set atop its lateral arm and rotated more precisely about its trunnion base, the MODAL 50A or MODAL 110 exciter system can therefore provide excitation at virtually any angle, with up to a 300 mm horizontal adjustment rate, and with exciter motion properly isolated from the test stand.

Typical applications for the MB Dynamics Lateral Excitation Stand include virtually any experimental modal survey application incorporating the company’s own MODAL 50A and MODAL 110 exciter systems. These include, though may not be limited to, aircraft and automotive testing, civil engineering, power generation, and test & measurement applications. For more information about the new Lateral Excitation Stand, or MODAL 50A and MODAL 110 exciter systems, please visit MB Dynamics.