Requirements for Crash Performance and Technological Innovations of Two-Wave W-Beam Guardrail Panels for Highways

The guardrail panels and posts are the main structural components of the two-wave corrugated beam guardrail on highways. To analyze the impact of variations in structural parameters on the crash performance of the corrugated beam guardrail, a vehicle-guardrail collision dynamic model was established based on the dynamic explicit finite element method and LS-DYNA software. The thickness of the guardrail panels and posts were taken as design variables, with each design variable considering four levels. Crash simulation tests were conducted for eight groups of different structural parameter combinations of the corrugated beam guardrail, and the calculation results for each working condition were analyzed. The results show that the combination of a panel thickness of 3.5mm and a post thickness of 4.5mm, as well as the combination where both the panel and post thickness are 4.0mm, meet the guardrail crash performance requirements. Compared to the current standards for corrugated beam guardrails, these two combinations save 12.5% and 11.2% in material costs, respectively. Malicious accidents may occur when vehicles collide with round-headed and ground-anchored ends, hence a finite element model of vehicle collision with the ends was established. The safety evaluation of the ends was conducted from both side and frontal collision perspectives, analyzing accident shapes and causes to provide suggestions for the development of new ends. The research results indicate that during frontal collisions with round-headed ends, accidents may occur where the two-wave corrugated beam guardrail penetrates the vehicle body; during frontal collisions with ground-anchored ends, accidents such as rollover or even tumbling may happen; during side collisions with round-headed ends, vehicles may crash through the guardrail; and during side collisions with ground-anchored ends, vehicles may vault over the guardrail. An analysis of the accident shapes concluded that the small area and immobility of the round-headed ends are the main reasons for the corrugated beam panel penetrating the vehicle body, while the inability of the posts to fall over is a primary reason for excessive vehicle acceleration. Insufficient anchoring force of the ends is the main reason for vehicles crashing through the guardrail, while the vehicle climbing onto the ground-anchored ends is the main cause of rollovers. It is suggested that the newly developed type of corrugated beam guardrail ends should be able to move along the two-wave corrugated beam guardrail, with the posts connected to the ends able to fall over, while also providing sufficient restraining force for standard sections. The newly developed type of corrugated beam guardrail ends based on this foundation has already been applied in practical engineering. To reduce casualties caused by collisions with the ends of the two-wave corrugated beam guardrail on highways, existing guardrail ends are prone to severe accidents such as the penetration of the corrugated beam panel into the vehicle body and rollovers. Referencing relevant domestic and international standards and based on traffic flow characteristics in China, collision test conditions and evaluation standards for the corrugated beam guardrail ends are proposed. A combination of finite element simulation and full-scale vehicle collision tests was used to develop a new type of corrugated beam guardrail end that meets usage requirements. Through finite element analysis, the working performance and principles of each component of the ends were studied, and the conditions for full-scale vehicle collision tests were determined, followed by structural optimization. Full-scale vehicle collision tests validated that the newly developed type of corrugated beam guardrail ends can effectively prevent the occurrence of corrugated beam penetration into the vehicle body and rollovers, thereby protecting occupant safety while also providing sufficient restraining force for standard section guardrails to ensure their normal protective capability and meet related evaluation standards. Calculation results indicate that the newly developed corrugated beam guardrail ends utilize coiled corrugated beams to absorb the vehicle's kinetic energy, effectively preventing the occurrence of beam penetration into the vehicle body and rollover accidents, with the vehicle's center of gravity acceleration being less than 20g, thus protecting occupant safety while also providing sufficient restraining force for standard section guardrails to ensure their normal protective capability. The guardrail ends meet evaluation standards and can provide safety protection for out-of-control vehicles. For more information about guardrails, please visit http://www.cqyuchang.com/, www.cq-ldzs.com, www.lindingjt.com.