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LS-DYNA Wall Blast Analysis

A large global civil infrastructure company is responsible for designing buildings which are required to withstand specific blast loads.  The company needed a way to estimate the thickness of the concrete walls and the amount of rebar required to contain the blast.  They knew that standard, implicit, finite element software codes could not do the job because they cannot accurately simulate the short-duration stress and shock waves that result from blast loads.

With many years of experience analyzing these phenomena, CAE Associates was asked to create models of the building walls and to predict reaction forces, deflection, and damage caused by different blast loads.  The ANSYS/LS-Dyna explicit finite element code was used to model the blast event because it includes complex concrete material models and has the ability to accurately simulate shock and stress wave propagation during short-duration transient events.  ANSYS macros were created in order to automate the process of generating the geometry and mesh, including the embedded steel rebar.

Blast load pressure histories were applied to the external surfaces of the walls.  Deflection, reaction force, and damage results were used to determine the need for additional wall thickness and rebar.  The client used the finite element analysis results to determine the ductility ratios and support rotations, and to compare these against allowable design limits.

CAE Associates delivered the FEA results and models in time to ensure the client was able to meet the aggressive schedule goals imposed on them.  CAE Associates also followed through with extra support to help them use the finite element models to evaluate additional configurations.