An overview of two vibration laboratories at Brigham Young University

A virtual tour will be given of two research laboratories at Brigham Young University. In the first laboratory, an experimental apparatus for measuring the internal damping of thin beams will be shown. Here, a beam specimen is placed in a vacuum chamber. After pulling a vacuum, the beam is excited with an automatic force hammer and the response is measured with a single-point laser vibrometer. The velocity data is recorded using a data acquisition system controlled with a custom python script. In the second laboratory, three types of tests will be highlighted. In the first, several small shakers are used to study methods for reproducing the vibration environments that components experience in launch vehicles, and this is compared with traditional, single-axis testing. The second type of experiment is used to characterize structures with weak nonlinearities. The structures are excited impulsively and accelerometers are used to measure the effective natural frequency and damping. This is used to characterize structures with bolted or riveted joints as well as additively manufactured beams with pockets of unfused powder. Finally, an apparatus for inferring the stress in the Achilles tendon is demonstrated. Waves are excited in the tendon and the wave speed is measured by calculating the time delay between two accelerometers that are pressed on the surface of the skin.