Study On Collision Performance Of Airbag Crashworthy Device

With the rapid development of infrastructure and transportation industry,there are more and more ships and bridges in China,and the probability of collision between bridges and ships increases.At present,most of the bridge anti-ship collision crashworthy device are steel casing boxes.As a mature buffer device applied in the field of automobile,aerospace and aviation,the airbag is foldable and has large deformation during collision,which can change the direction of ships,but it is rarely used in ship bridge collision at present.Therefore,the research on the collision performance of airbag crashworthy device is of great significance for ship bridge collision.In order to study the collision performance of airbag crashworthy device,a single airbag is taken as the research object in this thesis.Through the material performance test and single airbag anti-collision model test,combined with the finite element simulation method,the anti-collision performance of airbag at different ship speeds and collision angles is studied.And the influence of some airbag parameters on the collision performance is studied.The main research contents and conclusions of this thesis are as follows:Firstly,the uniaxial tensile test is carried out on the constituent materials of the airbag(including single-layer polyurethane material specimen,single-layer ultra-high molecular polyethylene silk material specimen and three-layer material specimen).The material parameters of the three specimens are obtained,and the orthotropic characteristics of polyurethane material and ultra-high molecular polyethylene silk material are determined,which provides material parameters for the collision simulation analysis of airbag crashworthy device.Secondly,the model test of single airbag crashworthy device and ship collision is carried out.Taking a single airbag as the test object,under the condition of maintaining frontal collision,the design collision speeds are 0.4 m/s,0.5 m/s,0.6 m/s and 0.7 m/s respectively.Under the condition of maintaining the collision speed of 0.5 m/s,the test is carried out under three different working conditions with the designed collision angles of 5°,10° and 15°.The test results show that the airbag can protect the pier in varying degrees under all seven working conditions.The peak value of collision force on pier increases linearly with the increase of collision speed and decreases with the increase of collision angle.The peak pressure in the airbag increases linearly with the increase of collision speed and decreases slightly with the increase of collision angle.Under the condition of maintaining frontal collision,the ship peak acceleration increases with the increase of collision speed.Under the condition of maintaining the collision speed of 0.5 m/s,with the increase of collision angle,the acceleration of the ship decreases in the direction of travel and increases in the direction of ship width.Finally,taking the model test of single airbag crashworthy device and ship collision as the prototype,a simplified finite element analysis model is established,and the influence of different modeling methods of airbag materials on the calculation results is discussed and compared with the test results.The results show that the method of defining airbag material by equivalent single layer is more accurate.Compared with the test results,the half-way collision time is 3.57% less,the peak value of airbag internal pressure is 9.02% more,the extreme value of collision force is 7.08% more,and the ship acceleration is 18.78% less.The reliability of the finite element method is verified.According to this method,the collision performance under the influence of single variable is studied,and the influence laws of airbag size,airbag thickness,airbag initial internal pressure,airbag deflating pressure and airbag deflating area on the peak value of collision force and ship acceleration of pier are obtained.Through the combination of test and simulation,this thesis studies the anticollision performance of a single airbag and the influence of multiple factors on the collision performance of airbag.The research results can provide the design basis for the airbag crashworthy device in the future.