Improving Driver Experience by Eliminating Squeak & Rattle Noise

NEVS is highly knowledgeable regarding the use of simulation technologies to lead the automobile design process thanks to the team's experience of developing vehicles at Saab Automobile, but the team had not yet used simulation strategies to predict squeak and rattle issues.

Due to a long-standing relationship with Altair and its HyperWorks suite of simulation solutions, NEVS approached Altair ProductDesign to see if the interior quality issue could be tackled with simulation. To perform the project, Altair ProductDesign worked on site alongside NEVS Interior Simulation Team to implement Altair’s Squeak and Rattle Director (SnRD). SnRD is a comprehensive set of software automations that rapidly identify and analyze design alternatives to eliminate the root causes of squeak and rattle in assemblies.

Altair ProductDesign built a base model that could be used for squeak and rattle (S&R) risk analysis as a reference for the existing performance of the initial design. Geometric dimensioning and tolerancing (GD&T) data was then used to perform the initial evaluation stage along with worst case scenario and sine sweep loading conditions. The risk areas identified at this early stage were communicated back to the design team and a series of design recommendations could be proposed to the project team.

The model geometry was updated based on these suggestions, incorporating new materials that were identified as potentially improving S&R performance. After rounds of iteration, the Altair team performed root cause analysis to highlight critical interfaces and connections within the interior structure, and detailed investigations of the relative displacement profiles for dynamic behavior were documented to identify the optimum balance between global and local stiffnesses.

Lastly, component level optimization studies guided the design team in discovering efficient methods of improving the stiffness of key structures and the detailed reports produced guided the NEVS Interior Simulation Team in refining the different components and diminishing problematic gaps.

With the help of Altair ProductDesign and the SnRD, NEVS has been able to identify S&R risk zones without physical prototypes, and gained valuable inputs to eradicate those risk areas in order to arrive at a more robust design.

NEVS can now explore the effect of different deviations that could result from the manufactured parts through sensitivity studies such as the effect of different material properties, tolerance chains and different road loads. The required models are rapidly built and set up for analysis, with the results automatically post-processed, all while providing access to powerful and intelligent optimization technologies that identify improvements throughout the structure. The reduced requirement for prototype products has provided opportunities to save significant cost and time throughout the development program.