Failure and detachment path of impulsively loaded plates

Abstract

The deformation and detachment path of simply-supported and fully clamped mild steel quadrangular plates subjected to impulsive blast loads are investigated numerically. A comprehensive failure model that incorporates two competing mechanisms of damage due to ductile and shear failure is employed to simulate the progression of tearing within the plate. The stress triaxiality dependent Modified Mohr-Coulomb (MMC) fracture criterion is implemented in a finite element model, and experimental tensile and shear tests were carried out to calibrate the material parameters. The direction of crack propagation along the clamped plate support and the residual length are predicted for a wide range of impulse intensity, reproducing the failure modes observed experimentally. Furthermore, the developed model highlights the different failure mechanisms that occur in simply-supported plates, similar to those of panels subjected to localised blast loadings. Parametric studies are performed to establish dimensionless failure maps and investigate the influence of plate topology and boundary conditions on the dynamic response, for both square and rectangular geometries, thus offering an effective support for the design of impulsively loaded plates for advanced engineering applications.

Confined blast loading of steel plates with and without pre-formed holes

“…Notice that the numerical prediction of failure behaviour is dependent upon the value of failure strain, i.e. a greater value of ¯ f would delay the onset of fracture as shown previously in the work of [9,43].…”

“…5; whereas the results predicted using a 16 × 16 mm 2 mesh indicates a different fracture behaviour. It is hardly surprising that the predictions for damage evolution is mesh-dependent -due to the stress singularities at the sharp corner of the square holes -as was previously noted in [9,[43][44][45]. Using a different failure criterion based on critical plastic work, Aune et al [2], too, found that the predicted damage evolution of the air-blast loaded ductile plate with square holes also depends upon the mesh size.…”

“…In the current work, instead of circumventing the stress singularity problem with artificial numerical treatment [9] or adopting a more complex damage model [43], the mesh size is calibrated against the experimental results following [2]. Since only the 4 × 4 mm 2 mesh (shown in Fig.…”