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A study of vibro-acoustic behaviour variation of thin sheet metalcomponents manufactured through deep drawing process

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Deep drawing is one of the most widely used manufacturing methods in the automobile industry.Therefore, a thorough understanding of this method is very important. Only for certain kinds of materialsthe forming process knowledge to achieve the desired dimensional accuracy is currently available. With theadvent of different kinds of steels—corrosion resistant, dent resistant and cost-effective alloys—in the market,the deep drawing manufacturing method gained a significant momentum in the recent past. Achievingthe desired dimensional accuracy of a designed part still remains a challenge as complex phenomenaincluding spring-back are associated with the manufacturing process. It is often seen that the deep drawingprocess results in both geometric profile and thickness variations as compared to the nominal part design.These deviations are important with respect to the geometrical dimensional accuracy, but in addition theycan also have a significant effect on the vibro-acoustic behaviour of the manufactured components. Hence,most often the simulation results of a nominal CAD part design using Finite Element Analysis (FEA) do notrepresent the actual behaviour of the component. In this research paper, a variation analysis—using bothsimulation and experimental methods—of a component manufactured through deep drawing, startingfrom a blank sheet made of mild steel material, is presented in a systematic manner. After a thorough analysisof the dynamic behaviour of the blank, an industrial component—an oil pan look-a-like—with a highdraw ratio is designed, manufactured and analysed for understanding the impact of geometrical deviationson it’s vibro-acoustic behaviour. The geometry of the actual component is obtained through a white-lightscanning process. It is observed that a geometry profile deviation up to 5 mm and a thickness variation of40% occurred in the actual manufactured part as compared to the nominally designed part. The eigenfrequenciesof the actual part have deviations up to 14% as compared to that of the nominal part. The modeshape comparison—using the Modal Assurance Criterion (MAC)—between the experimental and the simulationresults proves the necessity of incorporating geometric deviations. The acoustic simulation resultsobtained from the geometries of the nominal CAD design and the actual part are compared and it is foundthat the actual part design results are in good agreement with the experimental results. Hence, this paperfocuses on establishing the importance of considering geometry and thickness deviations, that occur in thedeep drawing process, when predicting vibro-acoustic properties. It is demonstrated that there is a significantincrease in the accuracy of the simulation predictions by incorporating the manufacturing effects.
Tijdschrift: Applied Acoustics
ISSN: 0003-682X
Issue: 2018
Volume: 153
Pagina's: 110 - 126
Jaar van publicatie:2019