This paper was produced for the 2019 NAFEMS World Congress in Quebec Canada
Weight is a major factor during the development of Automotive Powertrains due to the rising prices of raw materials and the stringent fuel economy standards. In particular, the NVH (Noise, Vibration and Harshness) CAE engineers are challenged by the weight requirements during the upfront design of the under hood components aimed at reducing noise and vibrations.
This paper presents a comprehensive process established to optimize automotive under-hood components for weight and NVH attributes. This optimization is performed at three different phases of the design cycle: 1) Architecture Phase, (2) Concept Phase, and (3) Final Design Phase. During the Architecture Phase, a generative design optimization of the CAD geometry is performed to determine the material density distribution for best NVH and lowest weight; in this phase, the modal frequency of the component is set as the NVH metric. The results of the CAD based generative design optimization are used to secure the design space required to deliver the desired NVH performance. The Concept Phase involves FEA-based topology optimization to determine the material density distribution for best NVH and lowest weight. The results of the FEA-based topology optimization and the generative design optimization are used to create a structural ribbing of the component that accounts for manufacturing feasibility. During the Final Design Phase, a DOE optimization with the multi-strategy self-adapting algorithm is used, in combination with adaptive FEA meshing, to fine tune the geometry of each of the structural rib. During the Concept and Final Design Phases, the structure borne and the airborne parts of the component’s dynamic response are set as the NVH metrics.
This paper illustrates the application of the 3-phases optimization process in the design of an inline 3-cylinders engine front cover. This component is a high source of airborne and structure borne noises since it it is made of thin walled large panels and it incorporates a footprint to support the engine mount. The design achieved through this process is compared to that obtained using a more traditional design approach. Besides improvement in NVH and weight reduction, the proposed process also contributes to a significant increase in engineering efficiency through a reduction in the number of design iterations. This process is highly recommended, as a key enabler of a First Time Right Design methodology for the development of automotive powertrains.
|Date||18th June 2019|
|Organisation||Ford Motor Company|