高速公路波形梁护栏安全性评价

Safety evaluation of W-beam guardrail on freeway

针对交通安全设施标准修订后的设计需求,为实现中国高速公路改扩建中护栏安全性的快速评价,开展了波形梁护栏碰撞安全性评价研究。分别建立板厚4mm的新标准波形梁护栏有限元模型、板厚3mm的旧标准波形梁护栏有限元模型、土壤与立柱的约束作用模型和雪佛兰C2500整车有限元模型,对车体与护栏碰撞过程中可能接触的区域进行网格局部细化,利用实车试验验证了汽车-道路-护栏有限元仿真模型的准确性;分析不同护栏设计标准的差异,提出在旧标准栏板厚度3mm的波形梁护栏中增加中间立柱的改造方案;依据《高速公路护栏安全性能评价标准》(JTG/T F83-01—2004)进行碰撞仿真试验,采集有限元仿真中的护栏最大变形量、车身质心处加速度、车辆驶出角等参数,对比新、旧标准护栏和改造后护栏的安全性能,评价护栏改造方案的可行性。研究结果表明:仿真试验与实车试验的护栏最大动态变形量相对误差为2.8%,驶出角误差为1°,验证了所建立的汽车与护栏有限元模型的正确性;改造护栏模型碰撞后变形量为436mm,车体质心三向(X、Y、Z向)加速度均小于20g,且车辆驶出角小于12°,均在标准规定范围内,说明该改造方案具有可行性;采用三维非线性有限元仿真方法能够快速评价高速公路波形梁护栏的安全状况,提高了交通工程安全设施的设计效率。

In order to achieve rapid evaluation of guardrail safety in Chinese freeway reconstruction and expansion projects to meet the revised design requirements of traffic safety facilities standards, research on the W-beam guardrail collision safety evaluation was carried out. Finite element models with plate thickness of 4 mm for the new standard W-beam guardrail and the plate thickness of 3 mm for the old standard W-beam guardrail, the constraint model of soil and column, and the integrated finite element model of Chevrolet C2500 were established. Contact area in the collision of vehicle body and guardrail was locally refined by grid. The accuracy of finite element models for vehicle-road-guardrail was verified by real vehicle test. The difference of design standard for different guardrails was analyzed, and the improvement program of adding middle column for the old standard guardrail with plate thickness of 3 mm was put forward. According to the evaluation specification for highway safety barriers （JTG/T F83- 01--2004） ,the crash simulation test was conducted. The parameters of finite element simulation of the guardrail maximum deformation, accelerations of vehicle body centre of mass, the degree of vehicle driving-out were then acquired. The safety performance of the old and the new standard guardrail and revised guardrail was compared, and the feasibility of the improvement program was evaluated. The results show that the relative error of the maximum dynamic deformation is 2.8%, and the error of degree of vehicle driving-out is 1° by comparing simulation test and real vehicle test, which proves the accuracy of the established finite element model of vehicle and guardrail. The deformation of improved guardrail model after collision is 436 mm, the three-axis accelerations of vehicle body centre of mass are less than 20g, and the degree of vehicle driving-out is less than 12°, which are all within the standard range. Therefore, the improved design of guardrail is feasible. The three-dimensional nonlinear finite element simulation method can rapidly evaluate the safety performance of W-beam guardrail and improve the design efficiency of freeway safety facilities. 8 tabs, 6 figs, 19 refs.