| As one of the representatives of the power transport, motorcycle is welcomed by the majority of consumers, because of its good performance at economic, convenience and so on. At the same time, there are many factories producing motorcycle in our country. So how to develop high competitive products has become the urgent problem that every motorcycle enterprise need to solve.The frame and its components are the important parts of the motorcycle. So they affect the whole performance of the motorcycle directly. Thus, it’s necessary to develop the structure that satisfies intensity and vibration requirement. The CAE analysis technology based on finite element is very effective to solve the above problems. But the traditional motorcycle CAE analysis usually does not consider the nonlinearity of the components. So the accuracy is limited. Pavement simulation requires large number of mesh. So it takes a long time for analysis. In the paper, it provides a method for improving the accuracy and speed of the motorcycle model, based on the traditional CAE analysis. The main contents and conclusions are as follows:① Dynamic strength analysis of entity road excitationThrough the time domain conversion, get the source data for the road modeling, using the harmonic superposition method and MATLAB software; According to the source data, establish the road model by using ANSA and MATLAB; Establish motorcycle model with nonlinear components, such as the suspension and the tires; Through the calculation of the finite element model, the maximum stress of the target frame is 226.56 Mpa, meet intensity requirements.② Dynamic strength analysis of displacement road excitationStudy the quantification method for road excitation when the motorcycle is traveling on rough road surface.Find the Suitable method called displacement road excitation, which can replace road excitation; Through the calculation of the finite element model, the maximum stress of the target frame is 223.18 Mpa, meet intensity requirements; Comparing the results of the two methods, find the results are very similar to the stress cloud, the mean stress, the maximum stress, and the maximum stress. The average error is within 5%. So it is an effective and accurate method to use displacement road excitation.③ vibration analysis of motorcycle under the road and engine excitationAccording to the national standard, three simulation condition is selected;Get the engine excitation through Kinematics and dynamics analysis of the crank linkage mechanism; Get the engine excitation and road excitation by MATLAB programming; Analyze vibration performance at different positions, find auxiliary pedal is the worst in every direction. So it’s needs to be improved. Analyze vibration performance at different condition, find the best performance is condition 1, not condition 2. So the vibration performance of common speed is also need to be improved.④Structure improvement and vibration reanalysisAccording to the results of previous analysis, the structure modification scheme is proposed by combining modal analysis and topological optimization results: Increase V structure in the auxiliary pedal bracket; while increase the thickness of the engine support; Through reanalysis of improved structure, find vibration performance improved at every condition, especially for auxiliary pedal; Comparing the results of different condition, find the improve effect is no the same. The changes for commonly used speed is most obvious. The cause of this difference is the factors interaction.In summary, this paper studies the simplified simulation method for road excitation. Through comparative analysis, it is considered that displacement excitation is an effective method for road excitation. After that, use the method for strength and vibration analysis. Make the objective evaluation and suggestions for improvement. This method can provide ideas for similar studies. |
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