CAE Analysis Of LNG Gas Tank Frame Structure

The LNG tank frame is an important load-bearing and fixed component of the LNG fuel device of heavy-duty trucks,playing an important role in the safe operation of heavy-duty trucks.When heavy-duty trucks are driving on the road,the tank frame is affected by various impact loads and vibrations from the road,and fatigue damage can be caused by cyclic stress during long-term driving.In response to these issues,this project conducts static strength analysis,modal analysis,frequency response analysis,and fatigue analysis of the tank frame based on finite element theory.This project used Soildwork to establish a solid model of the gas tank framework.Hypermesh handles meshes and preprocessing.Nastran solves for static strength analysis,modal analysis,and frequency response analysis.NCode established an analysis process for fatigue analysis.Through static strength analysis,the static strength safety coefficient of the gas tank frame is obtained under three working conditions:emergency turning,emergency braking,and extreme bumpy road surface.The results show that the overall static strength of the tank frame is qualified,but the static strength is relatively low under condition three.Subsequently,modal analysis was conducted on the tank frame,and the results showed that the first six natural frequencies of the tank frame were higher than the main frequency range of the road.Perform frequency response analysis on the tank frame based on modal results.The results show that under sinusoidal excitation in three directions,the resonance frequency of the gas tank frame is higher than the main frequency range of the road,and the stress response values within the main frequency range of the road are less than the material yield limit.There is no risk of vibration damage to the tank frame.Subsequently,fatigue strength analysis was conducted on the tank frame.The maximum damage value of the tank frame does not exceed 1 under both 8000 Km and 16000 Km operating conditions,but the damage value is 0.9 under 16000 Km operating conditions,which is close to fatigue failure.Based on the analysis results,structural improvements were made to the tank frame and verified through finite element analysis.The verification results indicate that the improved resonance frequency is higher than the excitation range of the road main frequency.The maximum increase in static strength safety factor was 113%.The maximum fatigue damage values at 8000 km and 16000 km have decreased by 53.5%and 27.9%,respectively,improving the safety of the tank frame in practical use.To explore the extent and variation pattern of the impact of the improved structure on the strength of the gas tank frame mentioned above,12 sets of orthogonal simulation experiments were designed for the improved structure.Explored the effects of reinforcing rib thickness,number of reinforcing ribs,side wall thickness,and weld leg height on the structure of gas tank frames.Through simulation experiments,the optimal levels of various factors were found,and it was found that the thickness of the side wall and the thickness of the reinforcing ribs need to be maintained at a certain thickness to ensure the overall strength of the gas tank frame.Additionally,the height of the welding leg has a significant impact on the fatigue strength of the gas tank frame.