Failure assessment of shipboard equipment subjected to underwater explosions

During combat, naval vessels may be subjected to underwater explosions that impart shock loading onto the ship structure, its subsystems, equipment, and crew. This violent shock loading can cause considerable damage and even failure of critical components, potentially rendering vital systems inoperable and the ship unable to perform its mission. To prevent unwanted failure, shipboard equipment must be assessed for shock hardness to ensure survivability. To this end, a set of failure criteria were developed related to functional failure. These criteria are based on the dynamic response of the equipment such that they can be applied to any loading condition regardless of the support structure configuration or location within the ship system. To evaluate the developed functional failure criteria, a series of computer simulations were performed using standard shock platform and ship models with a proposed simple equipment model representing the functional failure. The developed failure criteria were based on the threshold values for the peak velocity response and the critical change in displacement. The numerical study provided good validation of the proposed failure criteria. Additionally, simplified equipment models were presented as options for increasing the computational efficiency of modeling equipment installed in large complex structures such as ships.