Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Entire DC Network
Viscoplastic Cap Model For Soils Under High Strain Rate Loading, Xiaoli Tong, Christopher Tuan
Viscoplastic Cap Model For Soils Under High Strain Rate Loading, Xiaoli Tong, Christopher Tuan
Christopher Y. Tuan
A viscoplastic cap model of the Perzyna type was developed for simulating high strain rate behaviors of soils. An associative viscous flow rule was used to represent time-dependent soil behaviors. The viscoplastic cap model was validated against experimental data from static and dynamic soil tests. The model was also compared with soil behaviors under creep and stress relaxation with good agreement. However, the model was unable to represent tertiary creep where strain softening became significant. The model was subsequently integrated into LS-DYNA for finite-element simulations of high strain rate behaviors of sandy and clayey soils in explosive tests. The significance …
Development Of Kansas Guardrail To Bridgerail Transition Designs Using Barrier Vii, Christopher Tuan, Edward Post, Syed Atuallah, J. Brewer
Development Of Kansas Guardrail To Bridgerail Transition Designs Using Barrier Vii, Christopher Tuan, Edward Post, Syed Atuallah, J. Brewer
Christopher Y. Tuan
BARRIER VII computer code was used to evaluate the dynamic performance of five Kansas guardrail-to-bridgerail transition designs. The simulation results were compared with those of two FHWA-approved transition designs. The test vehicle model was a 4,500-lb, 1977 Plymouth impacting the barriers at 60 mph with an approach angle of 25 deg. The vehicle-crushing properties and guardrail-post stiffness had been validated using full-scale vehicle crash test data before the simulations were conducted. A methodology for wheel-snagging prediction was also proposed and validated against available test data. It was shown that reliable simulation results could be obtained if the input parameters for …
Progressive Failure Simulation Of Security Cable Barriers, Christopher Tuan, Ratul Sarmah, Alexander Tuan, Ching-Sheng Kao, Q. Li
Progressive Failure Simulation Of Security Cable Barriers, Christopher Tuan, Ratul Sarmah, Alexander Tuan, Ching-Sheng Kao, Q. Li
Christopher Y. Tuan
Perimeter security cable barriers are widely used by various agencies all over the world to defeat threat vehicle penetration. New barrier designs require crash test validation prior to implementation. Full-scale vehicular crash tests are costly, whereas designs via finite element simulations are time consuming and require specialized skills. Based on full-scale crash tests, an innovative and simple algorithm has been developed to model the progressive failure of security cable barriers. A multi-body approach based on the first principles of physics was developed to substantially reduce computer runtime. The solution algorithm uses a large number of small time steps. Nonlinear vehicle …