Effect of Structural Thickness on the Failure Behavior of Door-Lock Systems Under Explosive Breaching
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Explosive breaching is widely used to rapidly disable door-lock systems in military and emergency operations. This study investigates the structural response and failure behavior of door-lock systems subjected to explosive breaching charges, using a combination of numerical simulations and experimental validation. A three-dimensional numerical model was developed using explicit dynamic analysis to simulate the interaction between a C4 explosive charge and a steel door-lock system. The influence of structural thickness was examined for three configurations (2 mm, 3 mm, and 4 mm). The results show that the explosive loading generates extremely high stress levels, with peak von Mises stress reaching approximately 600–700 MPa, which is significantly higher than the yield strength of CT3 steel (235 MPa). This leads to rapid plastic deformation and structural failure. Increasing the thickness of the door-lock system reduces both deformation and stress concentration; however, failure still occurs in all cases. The results indicate that thickness primarily affects the severity of damage rather than preventing failure under the given loading conditions. Experimental tests were conducted to evaluate detonation reliability and breaching effectiveness. The explosive charge was successfully initiated in all tests, and all door-lock systems were effectively destroyed, confirming the breaching capability of the proposed design. The experimental observations show good qualitative agreement with the numerical predictions. Overall, the study provides insight into the role of structural parameters in explosive breaching and demonstrates that increasing thickness improves resistance but does not eliminate failure.
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