三跨缩比护栏系统冲击动力响应的有限元分析

建立了三跨缩比波形梁护栏系统受冲击荷载作用的有限元模型，运用LS-DY-NA3D有限元分析程序对护栏系统的冲击动力响应进行了有限元分析，得到了护栏系统各部件的瞬态变形过程，包括波形梁的弯曲、防阻块的挤压以及立柱的扭转和弯曲；给出了加载头冲击加速度初始急剧增长而后衰减到零的过程和速度逐渐降低直到反向的变化过程；分析了撞击过程中护栏系统的能量吸收特性，发现加载头的冲击能量主要转化为护栏系统各部分的内能和加载头的剩余动能，吸收能量的主要部件是防阻块和波形梁，将分析结果与实验结果进行对比，二者吻合很好，表明了模型的有效性。

Finite Element Analysis of Dynamic Response of Three-Span Scaled-Down Guardrail System Under Impact Loading

A finite element model of the three-span scaled-down W-beam guardrail established in this paper. The dynamic response of the guardrail system under the using the LS-DYNA finite element code, and the instantaneous deformation process system under impact loading is impact loading is analyzed by of each part is revealed, including the bending of the W-beam, the extruding of the blocks, the torsion and bending of the posts. Then, the variations of the acceleration and the velocity are investigated, showing that the impact acceleration of the loading head rapidly increases at the beginning and then gradually decreases to zero, while at the same time, the impact velocity gradually decreases to a reverse value. Moreover, the energy-absorbing characteristics of the guardrail system in the impact process are analyzed. It is found that the impact energy of the loading head mainly translates into the internal energy at each part of the guardrail system and the residual kinetic energy at the loading head, and that the blocks and the W-beams are the main parts absorbing energy. The analytical results are finally compared with the experimental ones and they are found to be consistent, thus revealing the validity of the proposed model.