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Example of experimental validation and calibration of a finite element model of a heavy vehicle

Szurgott P., Kwaśniewski L., Wekezer J. W.

Journal of KONES

2010

Vol. 17, No. 1

433-440

An example of the experimental validation ofafinite element model of a selected heavy vehicle is presented in the paper. A truck tractor with a three axle single drop lowboy trailer and the total weight of 20 tons was selected as a representative for the tests. The major goal of the conducted studies was to develop a well validated the numerical model of a heavy vehicle applicable for computer simulation of dynamic interaction between a vehicle and a bridge or road structure. Therefore, only several components of the vehicle, affecting the vehicle-road interaction, like wheels and the suspension systems, were modelled in detail. The rest of components were simplified and considered as rigid bodies. The finite element model included fully pneumatic tires and the suspension system modelled with discrete massless springs and dampers. Numerical analyzes were performed using the LS-DYNA computer code. The validation and calibration procedure proposed in the current paper was carried out in two steps. In the first one, some parameters such as material densities, thickness of selected elements, were modified to achieve the correct mass distribution in the model based on the measured axle loads. In the next step the stiffness and damping parameters of the suspension system were evaluated based on the results of the experimental tests. The spring and damping coefflcients at all axles were adjusted until the performance of the FE model closely matched that of the actual vehicle.

Retrofit analysis of Florida beam-and-post reinforced concrete bridge barriers

Wekezer J. W., Kreja I., Issa M.

Engineering Transactions

2002

Vol.50, iss.3

187-220

The major objective of the study was to evaluate crashworthiness of the existing Florida Beam-and-Post reinforced concrete bridge barriers. These barriers were first installed thirty years ago, they are still popular, and represent a significant investment in transportation infrastructure of the State. The major emphasis of the paper is focused on utilization of computational mechanics to improve safety of the existing reinforced concrete bridge rails. It presents results of analytical efforts to simulate crash impacts between a pickup truck and the Florida Beam-and-Post barrier. Computer calculations were performed using LS-DYNA, explicit, dynamic, 3-D finite element code. Finite element models of a 2000P Chevrolet pickup truck and the model of the bridge barrier were used to simulate test 3-11 per NCHRP Report 350. Computer simulations revealed severe snagging problems and provided input for a better understanding of the barrier response. Specific recommendations for a retrofit of the existing Florida Beam-and-Post barriers were provided. These recommendations include guidelines for new, proposed, safe reinforced concrete bridge barriers for consideration by transportation engineers.