Vibration is a vital field in physics, especially within the aeronautical industry, where precise vibration prediction is crucial to prevent structural failures and equipment damage. During the conceptual phase of aircraft design, the prediction of the vibrational environment is highly valu-able. This thesis examines the vibrational environment in an aircraft structure subjected to cavity oscillations caused by an internal weapon bay. The study uses the ESDU 18011 standard to model a continuous non-deterministic excitation resulting from these oscillations. The aims are to in-vestigate the necessary model fidelity to accurately capture the vibrational environment in the frequency range, to model and install damping mats to investigate the influence on the dynamical behaviour, and to examine the effect of equipment mounting on local vibration responses. The methodology begins with designing the downstream wall of the internal weapon bay to withstand fatigue and resonance due to increased sound pressure. This redesigned wall is then incorporated into the aircraft structure. Structural fidelity is assessed by implementing reinforcements, point masses, and fuel. The effects of damping mats on the vibrational environment are evaluated by modelling and mounting them. Furthermore, the study analyses the local impact of the mount-ing of the equipment on vibrations. The results show that high model fidelity is crucial near the internal weapon bay, a dense mesh is required to accurately capture the wave propagation for higher frequencies, damping mats influence the dynamic behaviour, and equipment mounting substantially decreases local vibrational amplitudes.