Study On Structural Strength And Crashworthiness Structure Of Large Opening Anti-collision

In recent years,with the rapid development of national highways and railways and inland waterways,more and more bridges have been built on major rivers.Along with this,the number of bridge collision accidents has increased significantly in recent years,and the design and research work on bridge anti-ship collision facilities is more urgent.This paper mainly studies 1)the key parameters of bridge ship collision based on statistical analysis of AIS data,and evaluates the crashworthiness of honeycomb structure anti-collision facilities from impact location,impact velocity and structural scale.2)The wave load of the ship’s anti-ship collision tank under the regular wave and the strength analysis of the wave load corresponding to the dangerous wave load condition.The specific work is as follows:(1)Based on the AIS data analysis,the information obtained by the bridge area navigation vessel includes: ship type distribution,ship tonnage distribution,average ship speed,and 95% over-probability speed.This provides more accurate calculation parameters for the bridge ship collision simulation process.After comparing the impact force and finite element numerical simulations of the three large tonnage representative ship models to obtain the maximum collision force,it is found that most of the empirical formulas are based on the energy impulse theory or the energy conservation theory,they give the bridge The collision force is too small.(2)Selecting a 100,000-ton anti-collision representative ship is hitting the antiship collision facility for finite element simulation calculation,and controlling variables such as impact position,impact speed,and anti-ship collision facility structure itself.Extracting the impact time history curve between the ship and the collision avoidance facility and the pier and antiship collision facilities,as well as the collision depth-impact force curve of the collision avoidance facility and the equivalent stress cloud diagram at the peak of the impact force to the collision avoidance facility The crashworthiness performance was evaluated.It was found that the energy absorption effect of the anti-collision facilities was significant at the three impact positions,and the anti-collision effect was excellent.The three-layer X-shaped structural sandwich is used in the front and rear of the steel box of the floating anti-ship collision facility.This multi-layered sandwich can spread the collision-proof facilities from the impact to the surrounding when it is hit by the bow.The force is more uniform,which expands the range of the ship’s impact force,and suppresses the “perforation phenomenon”,which greatly improves the energy absorption effect of the collision avoidance facility and reduces the peak impact force.The study of the impact velocity is to verify the impact of the impact kinetic energy on the structural failure,and it is concluded that the anti-collision facilities are still sufficient under the dangerous conditions.The study of structural dimensions found that the structure of the anti-collision facility was subjected to the failure deformation sequence when the collision occurred.When the collision occurred,the two inner and outer layers were respectively deformed by the compression of the ship and the reaction force of the pier,and the intermediate layer played.It is the role of transmitting and dispersing the impact force.(3)After calculating the frequency domain of the regular wave,the natural period of the structure is found.When the wave period is near the three periods,the amplitude of the motion in these three directions will have an amplification effect.Due to the very large size of the anti-ship collision structure,the wave is diffracted,and the wave phase and wave height of the regular wave wave are deformed during the transmission process,resulting in a “superposition effect”.The frequency and wave angle of the dangerous load conditions under these "stacking effects" do not correspond to the frequency and wave angle at which the maximum motion amplitude occurs.These dangerous conditions are not taken into account by existing ship codes and offshore platform specifications.Through AQWA post-processing,the search produces the maximum bending moment,shearing condition,finds five dangerous working conditions,and transmits the wave load of these working conditions to the structural model.The stress safety tool should analyze its structural strength and search for the structure.Weakness.It was found that the entire side box of the anti-ship collision facility,the inner peripheral panel of the box head,and the corner bottom plate were weak in structure,and the failure deformation was severe when subjected to wave load.