## 2 Description of the Systems Under Investigation and Experimental Setups
The BARC system was fixed using four screws at the base of the system in a 5\({}^{\prime\prime}\) by 2\({}^{\prime\prime}\) rectangular pattern, as depicted in Figure 4. Spacers were used between the base of the BARC and the testing fixture to accurately represent the dynamical response of the systems [26]. The first testing that was conducted on the systems was a free vibration test, which is considered to find the dominant frequencies of each system. Each BARC structure was impacted in the Y-direction with a modal impact hammer with a soft blue tip. Selecting the correct tip is crucial for impact testing, as the tip affects the measurements being taken during testing [31]. Each impact test occurred in the same spot, using as close to the same  
Figure 2: Accelerometers’ locations on the BARC system. amount of force as possible to account for uncertainties within the experiment. The setup for this test can be found in Figure 5.  
Once impact testing was conducted, random vibration testing was then performed on each system. In order to conduct the random testing, a slip-table setup was assembled, as pictured in Figure 6. The BARC system was fixed to the slip-table using four screws at the base in a manner similar to Figure 4. Like impact testing, spacers were used at the base of the BARC between the baseplate and the slip-table. To excite the system, a singer was used to attach the shaker to the slip-table. Something to keep in mind when using a singer is that, although the goal of singer use is to decouple the shaker from the test article, it is not possible to achieve this perfectly. Previous studies have been conducted on minimizing the effects of the stinger, and these variables were considered when conducting experimental testing [32]. Pseudorandom excitation is considered since the interest for this test is in the  
Figure 4: BARC base hole pattern. Figure 5: The impact testing setup for the BARC system. Figure 2.0 Alternating screw pattern for the removable component. nonlinear characteristics of the BARC assembly. Unlike other random vibration techniques, pseudorandom excitation does not average out nonlinear responses but does come with the cost of losing accuracy with response frequencies [33]. It should be mentioned that this technique is used to qualitatively explore the dynamics of the systems for the considered frequency range with a particular focus on the first few modes of vibrations. The goal of random testing is to determine trends within the data by taking samples over a wide frequency range. These trends can be more easily viewed by dividing the output response by the input signal. Examples of the trends that are expected include nonlinear hardening, softening, or damping. After finalizing random vibration testing, harmonic excitation tests were then performed on each assembly. Harmonic testing allows for an ample focus on a narrow set of frequencies to find trends in the experimental data more accurately. After finding the first mode of vibration through previous testing, a frequency range of 7.5 Hz on either side of the peak was tested, for a total of 15 Hz over the course of each experiment. Harmonic testing consisted of an up-sweep utilizing a step size of 0.1 Hz, held for 15 s each step, making sure steady-state responses are accomplished. Due to the length of each test, only the first mode of each assembly is considered. The testing setup for both random and harmonic testing is presented in Figure 2.1  
The Central-Cut Width Influence on the Linear Characteristics of the BARC System: Computational Analysis  
To begin the study, finite element analysis was performed on the systems using 3 DExperience ABAQUS software. This allowed for a general understanding of the system's reactions to various excitations and would give a favorable understanding of the initial dynamics of the systems prior to experimentation. In the literature, researchers typically do not consider the influence of the accelerometer within simulations. [PERSON] et al.