CAE Model Correlation & Design Optimization of a Laminated Steel Oil Pan by means of Acceleration and Strain Measurement on a Fired Engine

Abstract

In this paper, a simultaneous design and development work for a diesel engine oil pan is presented. The interesting point making the design of the oil pan so special is its laminated steel material. Beside its material, due to the deep-drawing production method, to determine the natural frequencies of the structure with Computer Aided Engineering (CAE) methodology is a problem for the design engineer. Especially when the highly nonlinear character of the oil pan and regions at different thicknesses sum up with the hardness of liquid modelling, free vibration modal analysis of the design at virtual environment becomes extremely challenging. Therefore, instead of refining the material characteristics in virtual design, first a primary 3D dummy design is generated. Afterwards, a production method and material intent sample is produced with soft tool. Hammer test is applied on this sample filled with oil, therefore modal shapes and frequencies are gained. As a result, CAE modal analysis is generated and correlated by hammer test results; hence the first challenge of modelling the liquid is overcome. Then, critical stress locations are determined with the CAE durability analysis. After instrumenting the pan with optimum number of accelerometers and strain-gages from these critical locations, a durability test on a fired engine is run. With the measurements here, the CAE durability analysis is refined so the second challenge of material nonlinearity and thinning due to the deep-drawing method is also overcome. Lastly, with the CAE durability simulation, a secondary 3D design proposal is established. Normally the method reach to success here, but to validate it, a secondary sample is produced, instrumented again with accelerometers & gages and tested resulting in significant improvement in terms of durability. With this approach, a method to perform a fail-safe oil pan design in single loop is verified.