Effect of damping on equivalent static load dynamic factor of air blast load

GENG Shaobo; LUO Gan; CHEN Jialong; ZHAO Zhou

doi:10.11883/bzycj-2021-0036

Volume 42 Issue 2

Feb. 2022

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GENG Shaobo, LUO Gan, CHEN Jialong, ZHAO Zhou. Effect of damping on equivalent static load dynamic factor of air blast load[J]. Explosion And Shock Waves, 2022, 42(2): 023201. doi: 10.11883/bzycj-2021-0036

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GENG Shaobo, LUO Gan, CHEN Jialong, ZHAO Zhou. Effect of damping on equivalent static load dynamic factor of air blast load[J]. Explosion And Shock Waves, 2022, 42(2): 023201. doi: 10.11883/bzycj-2021-0036

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Effect of damping on equivalent static load dynamic factor of air blast load

doi: 10.11883/bzycj-2021-0036

Department of Civil Engineering, North University of China, Taiyuan 030051, Shanxi, China

Received Date: 2021-01-23
Accepted Date: 2021-12-13
Rev Recd Date: 2021-06-08

Available Online: 2022-01-04

Publish Date: 2022-02-28

Abstract

Abstract

In order to examine the effect of damping on the equivalent static load dynamic factor of the air blast loading, the solutions of the elastoplastic displacement and ductility ratio were derived by the structural equivalent single degree of freedom (SDOF) method for the air blast loading. According to the relationship between the duration of the air blast loading and the duration required for the structural members to complete elastic vibration, the members are divided into two types: rigid members and flexible members. Twenty typical calculation cases, including damping ratios from 0.000 1 to 0.1 and ductility ratios from 1 to 4, were completed and compared with the dynamic factor formula results of the current blast resistant design code. The results show as follow. A ductility ratio less than 0.000 1 can be regarded as a state without damping. The relative error of the dynamic factor between the calculation results with a damping ratio of 0.01 and without damping is less than 2.08%. This relative error is so small that the damping effect with a damping ratio less than 0.01 can be ignored. The dynamic factor with a damping ratio of 0.05 is about 9.92% lower than the one without damping. This relative error is so great that considering the damping ratio will have obvious economic benefits for the blast resistant design when its value is greater than 0.05. Based on the elastic design, the calculation results from the current blast resistant code formula are in good agreement with those from the derived formula in this paper, and the value of the dynamic factor calculated from the code is between the results of damping ratios of 0.01 and 0.05. Furthermore, the current air blast resistant design code formula is more suitable for flexible structure systems. When the code formula is applied to calculate the dynamic factor of rigid members, there will be a large calculation error, which is more unfavorable for members with small damping.
- air blast loading,
- equivalent static load,
- equivalent single degree of freedom,
- dynamical factor,
- damping ratio

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References

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