| As a special rescue equipment,airport fire truck is very important in fire rescue.On the one hand,in the event of a collision,the fire truck occupant room skeleton deformation,crisis occupant indoor safety;on the other hand,the impact of the liquid on the tank structure is instantaneously increased several times or even ten times as compared to the process of driving at a constant speed,deformation after the tanks will close and the distance between skeleton crew room dry involving failure become a problem to be solved at present stage.This paper make a analysis of mechanical properties of the crew room frame and structure of tank of fire trucks by finite element simulation,explores the safety of the whole fire truck and its structure in the process of emergency condition,making some optimization according to the analysis results.The main research contents of this paper are as follows:(1)Static analysis of skeleton in crew compartment.Establishing the finite element model of crew room frame is first work,a preliminary analysis of the crew room frame structure under the action of static structural changes,and then to explore the fire crew room frame structure in the engineering work will incentive form a resonance with the engine,the crew chamber on the natural frequencies of the frame structure,calculating the excitation frequency at the same time,by which we can get the influence of resonance and whether crew structure is reasonable.(2)Making a dynamic analysis of cabin frame.What to do firstly is buliding the finite element model of crew cabin by hybrid elements.The collision problems of the skeleton of the passenger compartment under frontal impact,A-pillar impact and rolled-over continuous impact were solved by using dynamics knowledge in reference to the collision standard of commercial vehicles.Virtual collision test shows that the structure of cabin met the requirement,and the deformation of the skeleton that might endanger the tank structure was obtained as 49.1mm.Then the mechanical analysis of the tank can be used to explore whether the two structures interfere with each other in the deformation.(3)The mechanical analysis of wave-proof plates of fire trucks tank.Perform static pressure,modal,and dynamic analysis on the tank.The structure of the tank body wave board meets the design requirements,the deformation of the front sealing plate of the tank body is 5.88 mm,and the total deformation of the two structures is 54.98 mm,which is less than the interval of 323 mm.However,under overload conditions,the stress at the weld between the wave breaker and the tank body is 178.62 MPa,which is greater than the allowable safety stress 166 MPa.Therefore,the tank body has potential safety hazards,so it is necessary to optimize the wave guard plate design.(4)The optimization of wave-proof plates of tank.To solve the problem in the previous chapter under overload condition,the response surface of the tank wave guard plate based on parameter sensitivity screening is optimized.Correlation analysis was carried out on the parameters related to the size of the wave-plate structure,and the main parameters were obtained through sensitivity screening.An approximate response surface model was established through the OSF experimental design method.Finally,the optimized size is finally obtained and tested and verified. |
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