Research on the correlation between the medium-weight impact test load and the design load of ship equipment

At present, there is a lack of research on the correlation between the impact design load specified in GJB1060.1-1991 and the test load corresponding to the test conditions specified in GJB150.18-1986 in China. Without a clear understanding of the severity of design loads and test loads, it is impossible to accurately guide the anti-shock design, evaluation and testing of ship equipment. Taking the medium-weight impact test specified in GJB150.18-1986 standard as the object, a multi-degree-of-freedom mass stiffness damping dynamic model is established. Aiming at the single-degree-of-freedom rigid installation equipment installed on the hull ( the equipment itself is assumed to be rigid ), the impact test load calculation under the standard conditions can be carried out. It can be found that there are upper and lower limits for the impact spectrum velocity of the test load anvil, the lower limit is about 1.75 m / s, and the upper limit is about 2.40 m / s, and the calculation formula of the impact test spectrum velocity is fitted. Through the DDAM method and the impact design spectrum value specified in GJB1060.1-1991, the impact design spectrum velocity calculated is compared with the impact test load, and the influence of equipment installation frequency, equipment quality and pendulum height on the design load and test load is analyzed. Based on the comparison results, overall, the impact design load is more severe than the test load. However, when the channel steel span is relatively large (greater than 90 cm) and the equipment installation frequency is relatively high (greater than 80 Hz), the impact test load may be more severe. In addition, the quantitative ratio between the velocity of the impact design spectrum and that of the impact test spectrum is provided.The research results prove the correlation between the impact design load and the test load, which can provide reference for the impact resistance design and test of the equipment and the revision of relevant standards.