Research on fragmentation impact of marine steel based on peridynamic
In order to study the relevant response mode of marine steel under the impact of fragments generated by non-contact explosion,and better improve the ability of ship hull to resist the impact of fragments,Based on the peridynamic method,the working condition of marine steel impacted by cube fragments is studied.Firstly,the damage number index was improved by combining the peridynamic theory,and a cubic fragment impact model of marine steel was established,which was in line with the marine steel material specification;secondly,the physical impact test and peridynamic numerical simula-tion are carried out for the marine steel under the condition of being impacted by cube fragments with different velocities and impact modes.The failure modes of steel plates under various conditions are analyzed through the optimized damage dia-gram after numerical simulation and the failure diagram after physical impact test.At the same time,the stress diagram of marine steel after penetration failure is selected for the stress change analysis of each penetration stage;finally,the non di-mensional method combined with linear regression method is used to analyze the rule of critical penetration velocity of mar-ine steel impacted by fragments;in terms of the impact degree of fragments on marine steel,the damage degree of steel plate under the condition of cube fragments impacting on marine steel with edges is 44.6％and 29.9％higher than that under the condition of surface and sharp angle impact respectively.In the study of the rule of the influence of the critical penetration velocity of fragments,the empirical formulas of the critical penetration velocity of cube fragments impacting steel plates with edges,surfaces and sharp corners with error rate less than 4％are obtained respectively.Under the same conditions,it is con-cluded that the critical penetration velocity required for the impact of cube fragments on marine steel with edges is the min-imum.The numerical simulation of fragment impact on marine steel using this peridynamic method has high applicability and accuracy.When analyzing the strength of marine steel plates,attention should be paid to the study of the working condi-tion of cube fragments impacting steel plates with edges.
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