Numerical Simulation of Force Enhancement by Cellular Material under Blast Load

Abstract

The cause of force enhancement phenomenon when using cellular material, such as metal foam, for blast protection is discussed using both finite element method (FEM) and analytical method. Finite element (FE) models of cellular material under blast load are presented, in which the blast load is modeled by CONWEP blast function and the cellular material is modeled by the homogenized modeling method and the multiunit-cell modeling method. A one-dimensional analytical model is also presented for comparison purpose. Utilizing these models, an aluminum foam bar under blast load is simulated and the mechanism of both force attenuation and enhancement are depicted. The relationship between blast load intensity and the length of the foam bar is analyzed based on the simulation. It is found that the time of momentum transfer between the compacted foam bar and the protected structure is very short compared to the total time of the blast event, which causes force enhancement. Corresponding countermeasures are proposed based on this finding. The study will not only provide new modeling methods for the simulation of cellular material subjected to blast load but will also be beneficial to understand the mechanisms of force attenuation and enhancement, so as to seek for countermeasures.

Prediction of Crushing Response for Metal Hexagonal Honeycomb under Quasi‐Static Loading

“…e commercial finite element codes can simulate the entire deformation process of honeycombs with various cell specifications [26][27][28][29][30]. However, the theoretical expressions can give a direct prediction and can be employed when no computer is available [15].…”

Blasting demolition of steel structure using linear cumulative cutting technology

“…Gao et al 9 used the millisecond blasting scheme and the shaped cutting blasting scheme of main rebar of overpass bridge to control blasting vibration, blasting flying rock, bridge body shock vibration during blasting. Qi et al 10 analyzed the relationship between blast load intensity and the length of the foam bar based on the simulation and found that the time of momentum transfer between the compacted foam bar and the protected structure is very short compared to the total time of the blast event, which causes force enhancement. Chen and Zhang 11 found that the maximal equivalent stress and strain increase positively with the particle peak velocity, structures have a danger frequency band, and structural damage increases with duration.…”

Experimental Study of the Effectiveness of Sacrificial Cladding Using Polymeric Foams as Crushable Core with a Simply Supported Steel Beam

“…Considerable research has been conducted on the study of protective structures aiming at reducing the transmitted pressure to the main structure. Sacrificial cladding structures receive a lot of attention [1][2][3][4][5][6][7][8][9][10]. They consist of a crushable core between the main structure and a front plate.…”

“…They consist of a crushable core between the main structure and a front plate. The core material is often a cellular solid allowing large plastic deformation under relatively low constant stress (plateau stress, which is the average stress of the plastic region of the stress-strain curve of the crushable core) [1][2][3][4][5][6][7][8][11][12][13]. In order to control the magnitude of the transmitted pressure to the main structure and to guarantee an optimal design of the sacrificial cladding, the study of the effectiveness and the determination of the absorption capacity of a given sacrificial cladding configuration is needed.…”