Static And Dynamic Strength Analysis Of Fully Integral Bus With Airsuspension

Bus body dynamic and static strength impact on the use performance,safety and life of the vehicle and parts directly.The most important reason of bus body structure cracking and failure is the high dynamic stress caused by road random excitation.Big bus matching installation air suspension can mitigate the impact of the road more effectively than leaf spring suspension,and air suspension can improve the vehicle rid and passengers comfort.Select a fully integral hybrid power urban bus with air suspension as the research object in the paper.To carry out bus body dynamic strength research based on body static conditions and vibration analysis,and it has significance reference to the vehicle parts matching,bus body design and dynamic strength performance improvement.And then,the finite element modeling method analysis of air suspension could improve the accuracy of bus body finite element analysis.Body frame and air suspension finite element models are built up in HYPERMESH software.With reference to GB/T 6792-2009 of the bus body frame stress and strain measurement method,analyze and evaluate the body static performance of strength and stiffness when the bus in pure bending,emergency braking,ultimate torsion and emergency turning conditions.Then,find out the weak structure and put forward improvement ideas.Set up vehicle multi-body dynamics model in MOTIONVIEW software.Choose steady turning experiment to verify the accuracy of bus model,carry out emergency braking condition simulation to analyze the forces of air suspension hard points.Choose emergency braking condition as example,to analyze the accuracy and characteristics of two kinds air suspension finite element modeling methods comparatively.Carry out bus body free modal and constraint modal research comparatively,to analyze the body modal characteristic,and the effect of boundary constraints on body frame modal,and the vehicle local vibration mode.To analyze bus body frequency response characteristics based on the modal superposition method,research and evaluate key points displacement harmonic response on body seat bottom,and the vehicle resonance performance under the incentive of engine.Analyze body dynamic strength when bus running at 50 km/h.Carry out grade B and C roads random vibration analysis of bus body,use 3 sigma statistical theorem to evaluate the structure dynamic strength,and find out high stress concentration areas of body frame.And then,carry out bus body structure fatigue life calculation based on Gaussian distribution and the law of Miner linear damage cumulative.