NVH Analysis And Multi-objective Topology Optimization Of Engine Bedplate

The noise from engine affects comfort sense of customer, and bring out thecustomer’s complainer.so it need to be considered as a design factor. In a cherycompany’s NVH test, found a problem that there was a resonance noise about300-400Hz at1750r/min and the engine was full load. The noise need to be improved.Based on the CAE and NVH test analysis, confirmed the factors of noise. Theywere the speed response of the first bearing, the frequency of the second and thirdbearing. Then used the Hypermesh to do a multi—objective topology optimizationabout them.Tested the vibration response test about the side faces and bearing ofbedplate.after analyzed the data, got a conclusion that the key factors about noise werethe speed response of the first bearing, the frequency of the second and third bearing.The excitation was from the combustion press which was produced in the first cylinder.At the same time, analyzed the speed response of the first bearing, the frequency ofthe second and third bearing. Based on the analysis, the conclusion was the same as theconclusion of test, nearly.Finished these work, confirmed that the conclusion was reasonable. So decided tooptimize the objects which were the speed response of the first bearing, the frequency ofthe second and third bearing. It was a multi—objective topology optimization questionand the research in engine was scarce. In the paper, studied the multi—objectivetopology optimization method. For example, how to found the optimization function,how to ascertain the optimization coefficient which determined the different object’soptimization extent, etc. By Optistruct software, got the model which was optimized.Based on the design and techniques requirement, consummate the model. Use theHypermesh software to the analysis about the frequency and the speed response tocheck the optimization design of model. The conclusion was ok.the speed response wasdecreasing and the frequency of two bearings was increased distinctly.Through the research, got the multi—objective topology optimization method.The method can also be use for the other design development of part.