Anti-collision Performance Research Articles

Structural design and safety performance of a novel high-strength steel lightweight guardrail.

Highway guardrails are critical safety infrastructure along roadways, designed to redirect vehicles back into their lanes and facilitate a gradual deceleration to a complete stop. Traditional highway steel guardrails exhibit significant limitations, including inadequate energy absorption, susceptibility to corrosion, and an increased risk of vehicles leaving the roadway during severe collisions. Furthermore, the production and transportation of these guardrails contribute to substantial carbon emissions and environmental pollution. This study presents an optimization of the cross-sectional shape of the conventional corrugated beam guardrail, proposing a lightweight structure that incorporates high yield strength steel plate HR700F to enhance energy absorption capacity. The safety performance of the proposed guardrail is rigorously assessed through finite element numerical simulations and full-scale collision tests with real vehicles. Key performance indicators-such as the maximum dynamic lateral deflection of the guardrail, occupant impact velocity, and acceleration-are utilized to evaluate the energy absorption and protective efficacy of the structure. Results indicate that the optimized guardrail not only meets SB-level safety standards but also demonstrates superior anti-collision performance and effective energy absorption and buffering characteristics. The proposed design achieves a reduction in beam plate thickness by 1.3 mm, resulting in a lightweight structure with a weight reduction of up to 44%, thereby supporting the advancement of low-carbon, environmentally sustainable transportation solutions.

Numerical study on the anti-collision performance of recycled foam concrete beam guardrail under vehicle collision

Recycled foam concrete (RFC) possessed excellent energy absorption capabilities and could be used in the anti-collision field. To address the insufficient anti-collision performance of existing guardrails, this paper presented a novel RFC beam guardrail by combining RFC with box-shaped steel shells. The quasi-static compressive tests and drop hammer impact tests were applied to analyze the static and dynamic mechanical characteristics of RFC with different densities and sand-cement ratios. Then, the vehicle collision performance of the RFC beam guardrail (RBG) and standard beam guardrail (SBG) was tested by LS-DYNA. The results showed that, compared with SBG, RBG had better guiding and energy absorption effects, reduced the peak vehicular acceleration by 44.15 % and the maximum guardrail displacement by 73.22 % during vehicle collisions, and mitigated the damage to the vehicle. Therefore, it is a viable way to utilize RFC to fabricate RBG, which could not only repurpose the construction and demolition wastes (CDW) but also acquire guardrails with enhanced anti-collision performance.

Improving Traffic Safety in Existing and New Road Tunnels with the Novel NDBA Concrete Safety Barrier

Abstract Two main elements are essential in terms of road traffic safety. The first element is accident prevention and the second is the minimization of accident severity once a crash has occurred. Concrete safety barriers have very good anti-collision performance against roadside obstacles, relatively modest construction and maintenance costs, and low dynamic deflection and therefore are widely used in tunnels. Thanks to their characteristic redirective profile these barriers can redirect errant vehicles into their original lane after collisions. However insufficient research has been done for increasing the performance of concrete barriers purposely designed for tunnel installations. This research presents the new “NDBA Tunnel” concrete safety barrier designed and constructed by the Italian Road Operator ANAS indicated to be installed in road tunnel sections for safety improvements. In Europe, road safety barriers must be designed in compliance with the European Standard EN 1317. Therefore, the barrier “NDBA Tunnel” was subject to the TB11 and TB81 full-scale crash tests according to the European EN 1317 regulation. The results prove the barrier's ability to absorb impact loads of light and heavy vehicles with a working width W2. Therefore, the NDBA concrete barrier can be installed on existing or new tunnels at a distance less than or equal to 70 cm from the facing of the tunnel wall.

Impact resistance of bridge columns with energy-absorbing crash dampers under vehicle collisions

Bridge structures are often vulnerable to vehicle collisions, necessitating innovative solutions to enhance safety. This paper introduces a concept employing energy-absorbing crash dampers to safeguard bridge structures. The primary objective is to optimize energy dissipation while ensuring uninterrupted bridge functionality. Utilizing the finite element modeling approach, and incorporating realistic constitutive relationships and boundary conditions, simulations were performed to encompass X-shaped damper impact tests and collisions involving trucks with steel-reinforced concrete columns. The study affirms the effectiveness of the numerical model in simulating the dynamic response of steel dampers and column structures under vehicle impacts. Leveraging this modeling approach, this research compares the anti-collision performance of urban bridge structures, both with and without the proposed bridge pier. The methodology involves two key steps: first, a response surface optimization analysis is conducted for the primary energy-absorbing component, the anti-collision hollow diamond-shaped damper, determining optimal dimensions for the device at varying vehicle collision speeds. Second, a comparative study explores failure modes, collision capabilities, deflection changes, and energy absorption of bridge structures with and without the energy-absorbing crash dampers under vehicle impacts. Subsequently, this study performs an optimization design and calculation for the bridge structures. The outcomes reveal that the bridge with the pier experiences a substantial reduction in impact peak force. The damper effectively absorbs part of impact energy, with the optimized damper demonstrating superior energy absorption.

Dynamic responses and interactive failure mechanisms of carbon fiber composite face sheets/double-layer corrugated core sandwich structures under low-velocity impacts loading

A single-layer and double-layer corrugated core sandwich structure consisting of carbon fibre–reinforced polymer (CFRP) panels and aluminium alloy core layers was designed. Numerical simulations were carried out in HyperMesh/LsDyna, and the simulation results of single-layer and double-layer corrugated sandwich structure were compared with the experimental results to verify the reliability of the proposed numerical model. Compared with the results of single-layer and double-layer corrugated sandwich structure, the superiority of a double-layer corrugated sandwich structure in anti-collision performance is verified. Considering the effects of impact energy and impact position on impact force, energy absorption capacity, and failure mode, a series of low-velocity impact finite element simulations was carried out. It was found that the main failure mode of composite laminates included fibre damage, matrix damage and delamination, and core buckling. At the same impact position, the higher the impact energy, the greater the initial slopes of the contact force-time and absorbed energy-time curves, the higher the peak force, and the larger the energy absorption capacity. Under the same impact energy, when the impactor hit the wave crest of the sandwich structure, the damage to the structure was small; however, the maximum impact force on the structure was large (∼8 kN).

Performance analysis of indirect contact heat pipe radiator for space nuclear power system

The heat pipe radiator, with excellent thermal conductivity and anti-collision performance, is expected very suitable for heat emission in nuclear-power spacecraft. Indirect contact heat pipe radiator could operate longer life with lower capital cost. In this paper, the fluid-solid coupling heat transfer method is integrated to solve the energy model and S–S radiation model based on the k-epsilon model. Optimization objectives, heat dissipation performance and temperature uniformity are adopted to optimize the radiator structure. A comparison analysis between the ordinary and optimized radiator is conducted based on energy and entropy variation. The results show that the temperature uniformity and heat dissipation characteristic of the radiator after the optimization of connection mode of heat pipe and coolant pipe, fin shape, and fins welding direction have been improved without changing the area of fins and the weight of radiator. Through the comparative of radiators after changing the working conditions, some useful conclusions are drawn, which provide the theoretical foundation for the experimental research and engineering practice.

Simulation and performance analysis of passenger bus collision with rigid guardrail of expressway bridge

Aiming at the anti-collision performance of SS-grade concrete guardrail of Chinese highway bridges, the nonlinear dynamic simulation of collision is carried out. On this basis, aiming at the defects of rigid guardrail, a rigid and flexible composite double-layer guardrail is proposed, and its anti-collision performance is evaluated. The vehicle factor analysis shows that the energy absorbed by the guardrail system, crash force, guardrail damage and reinforcement stress range increase with the increase of vehicle speed and impact angle. The effect of concrete grade on improving the anti-collision performance of guardrails is limited. It is not that the higher the strength grade, the better the effect. Compared with concrete guardrail, the vehicle deformation energy of double-layer guardrail system is only 59.1% of that of concrete guardrail system. This shows that the deformation of the vehicle is more serious when the vehicle hits the concrete guardrail, and the damage to the driver and passenger is greater, while the double-layer guardrail can improve the safety of the driver and passenger. The crash force of double-layer guardrail is reduced, so the impact suffered by passengers is reduced and the double-layer guardrail has good buffering effect.

Evaluation of a novel steel box-soft body combination for bridge protection against ship collision

Abstract Ship–bridge collision is a common type of accident in bridge engineering which could cause heavy casualties and economic losses. To ensure the safety of both the ships and bridges during collision, a novel steel box-soft body combination was proposed in this work. The time history curves of the impact force of three downscaled facility specimens were obtained through the horizontal impact test. The influence of the steel box web spacing and the existence of the anti-collision facilities on the ship collision force reduction rate was investigated. The collision failure modes of ship bow and the anti-collision facilities, as well as the energy absorption behavior of the facility were analyzed. Based on ANSYS/LS-DYNA finite element (FE) analysis software, the nonlinear numerical models of the anti-collision facilities were generated. The analysis results show that the proposed anti-collision facility can not only greatly reduce the ship impact force, but the bow damage as well. The densified steel box web can improve the anti-collision performance of the whole anti-collision facilities to a certain extent. Compared with the direct impact on the steel plate, the maximum reduction rate of peak force of the proposed facility can be achieved to be 31.07%. The anti-collision facilities deformation energy absorption accounts for more than 70% of the total energy, which shows that the facility is able to absorb most of the energy and protect the bow. The FE simulation results coincide with the experimental outcomes, indicating the acceptable accuracy of the FE models.

Analysis of anti-collision performance of a new assembled rolling guardrail

Bridge guardrails play an important role in vehicle safety. Bridge guardrails frequently use concrete guardrails and beam-column guardrails. However, they have the disadvantages of poor buffering effect, being difficult to replace after damage, and being easy to cause damage to the bridge. A novel style of assembled rolling guardrail is presented in light of these drawbacks. In this research, a vehicle-guardrail collision numerical model is built in LS-DYNA. Subsequently, the performance of Beam-column guardrail (B-C.G), Assembled Guardrail (A.G), and Assembled rolling guardrail (A-R.G) is evaluated. The findings demonstrate that the A-R.G satisfies the specification’s requirements, can increase the construction efficiency, and, in contrast to the conventional beam-column guardrail, essentially does not cause damage to the bridge. Additionally, it performs better than the other two types of guardrails. Compared with the A.G and the B-C.G, the A-R.G has better energy absorption effect, steering effect. Moreover, the A-R.G significantly reduces the acceleration of the vehicle. The A-R.G dramatically lessens guardrail and vehicle damage, enhances the guardrail’s structural integrity, and increases passenger safety.

Study on anti-collision behavior of new precast concrete curb components in a highway tunnel

In order to improve the prefabrication level of highway mountain tunnels, improve the quality of the project, and shorten the construction period, a new type of prefabricated concrete curb member was developed based on an actual project. The production process, construction technical points, and on-site assembly technology are discussed. In addition, a method to calculate the anti-collision performance of the curb components is proposed, that is, the collision force of 850 kN was calculated by the pseudo-static method, and then finite element simulation analysis was used to obtain the stress of the concrete structure and reinforcement. The results show that the reinforcement will not fail, which will ensure the curb component will not undergo brittle fracture. This study provides a reference to improve the prefabrication level of highway tunnels.

Anti-collision performance of RC columns strengthened with a composite of FRP grid and UHPC

To improve the anti-collision performance of existing reinforced concrete (RC) columns subjected to vehicle impact loading, this paper proposes a composite strengthening method involving the use of fiber-reinforced plastic (FRP) grid and reinforced ultra-high performance concrete (UHPC). An RC column strengthened with the composite of FRP grid and UHPC and an ordinary RC column were prepared to investigate their anti-collision performance under impact loading. Using the methods of numerical analysis and tests, the effects of the vehicle impact velocity, reinforcement layer thickness, and material strength on the anti-collision performance were discussed. The test results showed that the lateral displacement of the RC column significantly decreased after strengthening with the composite. This indicated that the anti-collision performance of RC columns strengthened with the composite of FRP grid and UHPC can be effectively improved. The numerical results showed that the lateral displacement of the strengthened columns was increased by 37.8 % with an increase in the impact velocity from 3.69 m/s to 4.3 m/s; however, the impact velocity had no evident effect on the impact force acting on the surface of the RC columns. In addition, the anti-collision properties of the strengthened RC columns were significantly enhanced with the increase in the FRP grid–UHPC composite thickness and material strength. The lateral displacement of the strengthened RC columns reduced by 7.5 %–13.5 %, and its peak impact force increased by 14.9 %–33.2 % with an increase in the composite thickness from 20 mm to 40 mm. Moreover, the lateral displacement of the strengthened RC columns reduced by 14.5 %–36.1 %, and its peak impact force increased by 10.9 %–46.4 % with the increase in the compressive strength of concrete from 45 MPa to 210 MPa.

Study on the forming limit of rectangular-ribbed profile (日-shaped section) in rotary bending with flexible core die

The profile with rectangular ribbed (日-shaped) section is applied to the anti-collision beam of commercial vehicles, which not only improves the anti-collision performance but also improves the lightweight of the car. With the gradual decrease of the bending radius of the profile, the profile is prone to defects such as wrinkling of the inner wall or fracture of the outer wall. In this paper, the ABAQUS, a finite element simulation software, is used to establish the simulation model of the profile with rectangular ribbed section during the process of rotary draw bending, and the stress and strain laws are analyzed. The bending forming limit of the profile with rectangular ribbed section is studied by choosing the fracture of the outer wall as the evaluation standard. And the influences of bending speed, friction coefficient, and thickness on the forming limit are obtained. The minimum bending radius decreases as the bending speed increases and increases with increasing of friction coefficient and thickness.

Experimental study on the behavior of precast segmental piers under ship impact loading

This paper is to study the difference of anti-collision performance between precast segmental piers and conventional monolithic reinforced concrete (RC) piers. A reduced scale model was used, and the dynamic responses of piers with different structures under impact were compared and analyzed. The nonlinear finite element (FE) model of pier impact was established and numerical simulation of the impact responses and the failure mode of piers was carried out. The research results indicated that under impact, the failure mode of monolithic pier is tension bending failure, and for the segmental piers, the shear slip and concrete crushing in the impact segment occur mainly. The test results also indicated that the segmental piers are more flexible than monolithic piers, which leads to the peak impact force of the segmental pier reduced by 21.25% and 6.55%, respectively, under the impact of rigid head and ship bow compared to that on the monolithic pier. The study also found that segmented piers have better deformation capability and less residual displacement, but fail to show good self-reset capability. The results of FE calculation match well with the test results, which verifies the applicability and reliability of the FE model used in this paper.

Dynamic Behavior of RC Columns Confined with Micro-Expansive Concrete-Filled Steel Tubes Subjected to Lateral Low-Velocity Impact: Experimental and Numerical Study

In order to improve the anti-collision capacity of existing reinforced concrete (RC) columns under vehicle impact load, an experimental study on the anti-collision performance of RC columns strengthened with micro-expansive concrete filled steel tube was carried out. By combining an experiment and finite element calculation, the influence of steel tube strength, micro-expansive concrete strength and steel tube wall thickness on the anti-collision performance of strengthened RC columns were studied. The results showed that the peak displacement of an SM-RC column is 25.9% lower than that of an RC column, due to the increased stiffness, the peak impact force increased by 138.2%. The micro-expansive concrete filled steel tube reinforcement method can significantly improve the anti-collision performance of RC columns and reduce the lateral deformation. Increasing the strength grade of steel tube and thickness of steel tube can greatly improve the impact resistance of strengthened RC columns and reduce the lateral deflection deformation of short columns, compared with steel tube strength Q235, the displacement of Q690 is reduced 47.4%. the displacement of the 8-mm thick steel tube is reduced by 48.1% compared with the 4-mm one. while the strength grade of micro-expansive concrete has little effect on the impact resistance and lateral deflection deformation of strengthened RC columns.

Study on the Anticollision Performance of a New Corrugated Steel Protection System for Bridge Pier

A new type of corrugated steel protection system (CSP) for the bridge pier is proposed to improve the impact resistance of the bridge pier and reduce the loss caused by the collision of the ship against the pier. A new bolt numerical simulation method and finite element model establishment method are proposed and verified by the impact test. The results show that the new method can effectively simulate the mechanical behavior of bolts and CSP. Parameters analysis was carried out subsequently by the verified finite element model which showed that the energy absorbing ability of CSP increases with corrugated steel pipe wall thickness and its weight decreases. It is concluded that CSP (2.0 mm) is the optimal structural type, and compared with the existing FRP Fender System. The results show that the energy absorbing ability of CSP (2.0 mm) is strong, and its final absorbed energy can reach 86.13% of the total energy of the model structural system (7.22 MJ).

Energy absorption characteristics and optimization of three-beam star honeycomb

With the increase of demands for anti-collision performance in many fields, the negative Poisson’s ratio structure has attracted the attention of researchers due to its light weight and high shear stiffness. Therefore, a new negative Poisson's ratio (NPR) structure named three-beam star honeycomb (TBSH) is proposed based on the classical star honeycomb (CSH). The stress equation of TBSH is derived by energy method, and its deformation characteristics and mechanical properties are studied. The results show that the structural deformation modes are different under different impact velocities, and TBSH has more obvious NPR effect. In addition, the influence of geometrical parameters on energy absorption of structures is also investigated. Finally, the thickness gradient is introduced into this structure, and the thickness gradient is optimized by multi-island genetic algorithm (MIGA). After optimization, the specific energy absorption (SEA) of the structure is significantly improved, while the initial peak stress (IPS) is decreased. The new structure proposed in this paper is expected to provide a novel design thinking and optimization idea for superstructure design.

Mini Electric Vehicle Based on LMD Algorithm and Green Travel Concept

With the progress of society, people's awareness of environmental protection is gradually increasing. The sustainable development of society is threatened by many problems, such as resource shortage, global warming and other issues, and miniature electric vehicles play an invaluable role in solving environmental pollution and traffic congestion. The design and development of electric vehicles is even more important. Combined with the social development trend and the concept of green travel, this paper takes the design of micro electric vehicles as the research object. Through market research, it analyzes users' needs for micro electric vehicles from three perspectives, such as styling style design, color design, and performance demand design, and determines the design plan. After designing the preliminary model of the electric vehicle, the satisfaction of 50 users in experiencing the mini electric vehicle was tested, and the results showed that the majority of users had a high degree of satisfaction and could be put into mass production. Later, the LMD algorithm is used to detect the damage degree of the miniature electric vehicle under the condition of door deformation. The experimental results prove that the miniature electric vehicle designed in this paper has good anti-collision performance.

Test for Influence of Socket Connection Structure on Dynamic Response of Prefabricated Pier under Vehicle Collision

In order to obtain the difference of anti-collision performance between the socket assembled bridge pier and integral bridge pier, this research conducted the model test of the bridge piers subjected to vehicle impact. The influence of the socket connection form and structure parameters such as embedment depth, interface roughness, and reserved hole opening size on the response of bridge piers to vehicle collision was analyzed by comparing them with those of the cast-in-place bridge pier. Results show that vehicle speed and socket depth are important factors affecting the dynamic response of socket bridge piers to vehicle crash. The maximum impact force on a bridge pier is obviously affected by the embedment depth of the pier column, but no clear change rule exists between them. The opening size of the reserved cavity affects the impact force slightly when the vehicle speed is low, but gradually increases with the increase in vehicle speed. The damage degree of the bridge pier gradually decreases with the increase in the embedment depth of the pier column and increases with the increase in vehicle speed. The acceleration of the bridge pier tends to increase with the vehicle speed, but no clear law of change with the socket depth exists. The maximum strain of the steel bar at the root of the socket pier is greater than that of the impact position, and the maximum strain distribution of the steel bars of the pier column with the socket embedment depth greater than or equal to 1.0 times diameter of the column is similar to that of the cast-in-place one. The maximum strain of steel bars of the both are at the root of the pier column. The study results provide a data reference for further studying the actual vehicle bumping on socket bridge pier and prefabricated bridge anti-collision design.

A novel flexible phase change material with well thermal and mechanical properties for lithium batteries application

Battery thermal management and battery collision prevention are very important for the safe operation of batteries of electric vehicles. This study proposes a novel flexible phase change material (PCM) with both battery thermal management and anti-collision performance. Experiments were conducted to test the thermophysical properties and battery thermal management performance of PCM. Under 3C discharge, the battery thermal management system (BTMS) of the material can control battery temperature and the temperature difference of 45.7 °C and 1.7 °C, respectively. Moreover, the battery drop experiment and simulation were also performed to evaluate the anti-collision performance of flexible PCM. The results show that the PCM has a good impact buffering effect. The battery can reduce the stress of the battery shell and core by 96.3% and 41.9%, respectively, than the system without the flexible PCM when dropped from a height of 1 m.

Dynamic Research Based on the Width and Height of Prefabricated Concrete Anti-collision Wall

Aiming at the problem that there is no uniform requirement for the section height of the prefabricated concrete anti-collision wall, the critical height of the prefabricated concrete anti-collision wall during design and installation cannot be confirmed. The co-simulation method of LS-DYNA and Hypermesh is used based on the common anti-collision on the market. Five finite element models of concrete anti-collision walls with different heights and widths were established for the wall, and common cars were used to simulate their collisions. The three indicators of vehicle turning, seat position acceleration, and vehicle exit angle are selected to evaluate the anti-collision performance of the anti-collision wall. The research results show that increasing the height of the anti-collision wall can significantly increase the anti-collision performance of the anti-collision wall when the width of the anti-collision wall is constant and the position is fixed.