Finite element analysis of stiffened plates subject to low velocity impact

• Main Author: Ong, Timothy Jia Jun
• Other Authors: Chai Gin Boay
• Format: Final Year Project
• Language: English
• Published: 2017
• Subjects: DRNTU::Engineering::Aeronautical engineering
• Online Access: http://hdl.handle.net/10356/71640
• Institution: Nanyang Technological University

The structural impact response resulting from dropped objects impact is of major concern in the offshore and marine industries as such impacts may result in fatalities or excessive damage to the overall structure. While much work has been done on stiffened metal plates subjected to low velocity impact, most of them focused on the projectile and the main part of the plate. Little has been done to study the effects of the stiffeners on the plates’ impact response. This report presents the numerical investigations of stiffened plates subjected to low velocity impact. Several numerical models were created based on the experiment setup in “Dropped Objects’ Plugging Capacity of Steel Plates: An Experimental Investigation” [1]. These models were built using various assumptions and their results were compared and analysed to identify the one with the best balance of efficiency and accuracy. The models were also validated against the published experimental results and were found to produce accurate numerical predictions. Parametric studies were subsequently conducted. The numerical results showed that plates with thin stiffeners are more robust against impact damage as compared to unstiffened plates. However, this robustness decreases as the stiffener thickness increases. In addition, the energy required for plugging failure increases towards a static value as the stiffeners are positioned closer to the plate centre. Lastly, plugging / tearing failure occurs more easily as the location of impact approaches the plate supports. This effect, however, can be reduced by allowing the plates to shift during the impact process. Recommendations, based on findings from the parametric studies, were also given to assist in the design of a robust stiffened plate.