Rain erosion may cause substantial damage to aircrafts during supersonic flight. Such event is investigated here via high-speed waterjet impact on composite laminates. An experimental setup is developed to produce waterjets with the speed up to 700m/s and a finite element model of the waterjet-composite impact event is established. The consistency of experiment and simulation results validates the adopted numerical methods. The distribution of the water-hammer pressure is non-uniform and the maximum pressure occurs near the contact periphery when the water is about to eject laterally. After a high-speed (300∼560m/s) waterjet impacts a composite laminate, the impacted surface depression is observed, and the typical surface damage presents a central region with no visible surface damage surrounded by a faded “failure ring” with resin removal, matrix cracking and minor fiber fracture. Delamination occurs at the interfaces of adjacent layers with unequal dimensions and longitudinal matrix cracking appears on the back surface. Both the velocity and the diameter of waterjets are crucial factors on CFRP damage extents. Water-hammer pressure, the stagnation pressure and propagation of stress waves are failure mechanisms for most matrix damage in CFRP impacted by waterjets.

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Predicting the spatial distribution of direct economic losses from typhoon storm surge disasters is crucial for supporting emergency response efforts. Using case-based reasoning, we developed a preliminary method for completing predictions about the impact of typhoon storm surge disasters for multiple coastal regions. We proposed retrieval, reuse, and revision algorithms to predict the following effects of a typhoon storm surge disaster: total direct economic losses and their grades, the affected regions, and individual direct economic losses and their grades in each affected region. We tested 33 such disaster cases using the developed method, and the predicted results were as follows. In about 70% of the cases, all recorded affected regions were predicted; the grades of the total direct economic losses were accurate in over 70% of the cases; in 63% of the cases, the grades of direct economic losses in each affected region were partly accurate, and they were all accurate in 30% of the cases. These promising results suggest that the proposed method can support disaster managers to respond adequately to typhoon storm surge disasters for multiple coastal regions.@en

In China, storm surge disasters cause severe damages in coastal regions. One of the most critical tasks is to predict affected regions and their relative damage levels to support decision-making. This study develops a two-stage retrieval model to search the most similar past disaster case to complete prediction. Based on spatial attributes of cases, the top-ranking past cases with a similar location to the target case are selected. Among these past cases, the most similar past case is selected by disaster attribute similarities. Three typical storm surge case studies have been used and implemented into this proposed model, and the results show that all the most affected regions can be predicted. The proposed model simplifies the prediction process and updates results quickly. This study provides valuable information for the government to make real-time response plans.@en