Blast Performance Evaluation of Structural Components under Very Near Explosion.

The single-degree-of-freedom (SDOF) analysis with elastic-plastic resistance is often used for design of protective structures subjected to blast loads. Several documents such as UFC 3-340-02 present design charts for the maximum responses of the elasticplastic SDOF system. The SDOF design charts are available for far-field detonations but seldom for near-field detonations of high explosive in free air, noting that the focus of security design is the near-field. Further, the assumption of uniformly distributed load for the SDOF analysis may not be appropriate for the near-field detonations where blast pressure distribution varies significantly with distance and angle of incidence. In this paper, to resolve these issues, updated SDOF design charts including the response to the nearfield detonations are suggested based on numerical calculations. These generated charts are verified with comparison to UFC 3-340- 02 predictions and finite element analysis results of steel components. The recommendations and limitations for the utility of the SDOF design charts for blast assessment of steel components are provided with an emphasis on the near-field detonations. [ABSTRACT FROM AUTHOR]