74 J. Paripovic and R. L. Mayes Fig. 6.1 (a) MATV Finite Element Model Cutaway, (b) MATV Hardware in a Test Setup, (c) target accelerometer locations in large end of the cone 6.2 Introduction and Background The instrumented Removable Component from the Box Assembly and Removable Component (BARC) was the structure of interest in a previous MATV acoustic test and the measured data was recorded and is used as the ‘truth’ field data for this investigation. Here, we use this field data of as the target control on a 6DOF shaker table. The Removable Component (RC) is a base mounted component. The BARC has been a structure of interest for many in the modeling, analytical, and experimental field [5, 6, 7, 8]. The Removable Component (RC) was mounted inside a Modal Analysis Test Vehicle (MATV) and subjected to a 147 dB acoustic “field” test using an acoustic horn in a reverberant chamber at the Institute of Sound and Vibration Research Consulting facility at the University of Southampton. Developed at the Atomic Weapons Establishment (AWE), the MATV is constructed of a conical composite aluminum shell with a foam filled steel pipe in the axial center, as seen in see Fig. 6.1a. Additionally, the MATV consists an aluminum cover plate which is used to close off the larger end, and an aluminum component plate at the top of the steel pipe where the RC mounts to. This whole MATV structure has a mass of 47 kg. To simulate a free-free boundary condition, bungee cords were used to suspend the MATV during the acoustic test, which is shown in Fig. 6.1b. Fourteen internal target control accelerometers were used. The four triaxial accelerometers used are shown in Fig. 6.1c. Here, the focus is on whether the field could be replicated in a MIMO 6-DOF environment and use Nodes 1–4 (triaxial accelerometers on the RC) for the response control. The next section describes the 6-DOF lab environment test conducted to simulate the MATV acoustic test. In this case, we consider the MATV field test data as the ‘truth’ data and use it as the target control. 6.3 Experimental Results and Discussion A nominally identical RC [8] was instrumented using the same 4 triaxial accelerometers (Nodes 1–4) at the same locations and was mounted to the Team Tensor 900 6-DOF shaker. This shaker has 12 servos – 2 on each side of the plate and 4 below the shaker head. Two different adapter plates were used to accommodate the same mounting configuration as the IMMAT test. Nine additional accelerometers were used on the base plate, 4 on the sides on the plate and 4 equidistant on the top surface of the base plate and an additional one in the center, see Fig. 6.2. Two different tests were conducted using this configuration. First, a response control scheme using the Spectral Dynamics MIMO random controller was implemented to control the original 4 nodes (12 responses) to the measured MATV acoustic
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