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Simulations of progressive failure of cable barrier

Ratul D Sarmah, University of Nebraska - Lincoln

Abstract

Perimeter security cable barriers are widely used by various government agencies all over the world to defeat threat vehicle penetration. Any new barrier design requires validation prior to implementation. Full-scale vehicular crash tests for validations are costly, while validation through finite element (FE) crash simulations are time consuming and requires specialized skills. Based on full-scale crash tests, an innovative and simple algorithm has been developed in this research to model the progressive failure of perimeter security cable barrier. ^ A different approach from the conventional FE method was developed in an attempt to reduce computer runtime. The entire event is divided into small time-steps of 0.5 milliseconds or less. Vehicle is modeled as an assembly of three-dimensional (3D) rigid and deformable parts made of solid and shell elements, connected by inelastic truss members. Stiffness of solid and shell elements are ignored. Nonlinear structural responses due to the inelastic material effect and large deformation of these truss members were taken into account. A method was developed to compute inertial tensors from vehicle solid elements and cargo loads. A 3D contact algorithm was developed to identify contacts between multiple faces and multiple vertices of multiple bodies. For a cable barrier, a 3D vehicle model interacts with a 3D cable barrier model during a time step, resulting in deformation of the cables and contact forces. In order to have an efficient simulation, only the predominant failure modes observed in the crash tests are modeled. Elasto-plastic deformation of cables, posts and vehicle are considered in the algorithm. For a particular crash scenario with known anchor parameters, a method was developed to estimate the energy dissipated in the post-soil interaction based on standard empirical equations, available crash tests and published literatures. Estimated energy dissipated is then included in each time step during the simulation. ^ The simulation model developed has been validated against three perimeter security cable barrier crash tests. This user-friendly cable barrier model, displaying simulation results graphically, can be used to provide realistic parameters for a perimeter security cable barrier design within less than 10 minutes of simulation runtime. ^

Subject Area

Engineering, Civil

Recommended Citation

Sarmah, Ratul D, "Simulations of progressive failure of cable barrier" (2008). ETD collection for University of Nebraska - Lincoln. AAI3309210.
http://digitalcommons.unl.edu/dissertations/AAI3309210

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