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October 2015: The Journey from Solve to Innovate

Endurica: Pushing the Limits of Bushing Design with Optimization


Automotive suspension systems rely on elastomeric bushings to cushion interfaces between rigid members that otherwise could be damaged by impacts and vibrations. Bushing developers have to find geometry that can deform within the available spatial envelope and hit the compliance target for each axis of loading, as well as provide for durability that lives up to the automaker’s warrantee.

Given that an experimental program to evaluate bushing performance may cost between USD $20K to $200K, screening design options with Abaqus is widely practiced. But did you know that it is now possible to simulate and optimize the durability of a rubber bushing while simultaneously enforcing design constraints on stiffness and geometry?

A recent benchmark was able to hit target stiffnesses in 3 simultaneous directions while optimizing for durability. fe-safe/Rubber™ was used to calculate durability, the Isight parametric optimization solver was used to find an initial bushing geometry satisfying the stiffness targets, and then the nonparametric Tosca optimization solver was used to fine tune the shape of bushing voids.

The Isight solver was used to find the dimensions and placement of a pair of voids described by three independent variables. The durability of this design was then analyzed in fe-safe/Rubber, where it was found that the life was 9101 loading repeats. Next, the Tosca nonparametric optimization solver was applied with the goal of maximizing the fatigue life by evolving the shape of the voids. After eight iterations, an optimum life was obtained at 16088 loading repeats. For this problem, the iteration process executed in about two hours, and resulted in a life improvement of 76%.

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