大跨连续刚构桥-船撞击动力响应研究

以某高速公路新建连续刚构桥为工程背景，采用非线性有限元分析方法，通过大型通用非线性有限元程序LS-DYNA建立全桥有限元模型和1 000 t船舶模型，对船-桥碰撞动力过程进行模拟，以确定船-桥碰撞过程中碰撞力的大小，并将有限元计算结果与规范经验公式进行比较。结果表明：船-桥碰撞过程中，船艏发生较大变形，吸收大部分的能量，将动能转化为势能；碰撞过程具有明显的非线性波动特征；各个规范经验公式计算的船撞力差异较大，且规范经验公式具有一定的局限性，有限元分析法能完整再现船-桥碰撞结构内部动力学过程，弥补规范经验公式的不足。     

Seabed collision emergency decision-making of AUV based on safety domain model北大核心CSCD

［Objectives］To ensure safety and prevent seabed collisions in complex unknown underwater environments, this study proposes a seabed safety domain model and tiered emergency response strategies. ［Methods］A vertical motion simulation model is established and verified by surpassing the test results, then used to calculate the active and passive safety domain distance of an autonomous underwater vehicle (AUV), thereby establishing a seabed safety domain model. An AUV emergency control system and emergency strategies are then built on the basis of the dynamic safety domain model. The trim and distance from the seabed of the AUV are used to calculate the current and future risk factors. Based on the weighted sum, the comprehensive risk factor is employed to provide the AUV with emergency response strategies.［Results］Lake tests with the AUV sailing at a fixed depth and height show a strong dependency of the comprehensive risk coefficient on seabed height when it is close to the boundary of the AUV's active safety domain. In the opposite case, there is a weak dependency of the comprehensive risk coefficient on seabed height. The results show that the proposed AUV emergency control system can reduce emergency false alarms caused by frequently changing riverbed heights and sailing altitudes close to the seabed. In such cases, reasonable emergency strategies can be realized under complex rough terrain.［Conclusions］The AUV seabed safety domain model and tiered emergency response strategies based on vertical motion equations proposed herein can be applied to evaluate seabed collision risk in various cases. Finally, this paper provides emergency response strategies to avoid seabed collision accidents, which can enhance the safety of AUV navigation. © 2023 Chinese Journal of Ship Research. All rights reserved.