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Recently introduced “Stow-'n-Go” feature in minivans provides the option of folding the 2nd and 3rd row seats flat into a special compartment. These special storage compartments, or “tubs”, are designed under many challenging and competing design requirements, one of which is noise and vibration. In this study, both experimental and analytical tools are used to study the NVH performance of seat tubs considering different materials, constructions and damping treatments. The challenge of balancing stiffness and damping in a tight packaging space is augmented by the minimum weight and cost requirements. The details of material selection process for the minivan tubs are presented considering different materials and damping treatments. Various design alternatives considered during the optimization of weight, packaging space, and NVH performance are discussed. Results of the component and the vehicle testing are complemented with SEA modeling.

In industrial applications, both constrained and unconstrained damping treatments are used frequently for noise and vibration control. The additional Damping Loss Factor (DLF) and stiffness gained from these damping treatments are quantified by a standard test procedure, as detailed in ASTM and SAE standards. In this test procedure, which is commonly referred to as Oberst beam testing, the uniform isotropic behavior of traditional damping material is evaluated by measuring one-dimensional flexural vibration response of a simple beam. The recent advances in damping technology have led to emergence of robotic Liquid Applied Spray-on Damping (LASD) treatments. The application of LASD can result in non-uniform thickness, uneven distribution, and orthotropic behaviors.

Finite Element analyses and tests are performed in order to verify appropriate use of material models to represent epoxy foam in FEA. Two types of material models are studied that utilize different approaches to model behavior of materials. One uses nominal stress/strain data to depict yield condition. The other uses plastic stress/strain data and von Mises type yield condition. Due to the particular and different behaviors of epoxy foam in compressive and tensile testing, material curves in both compression and tension areas are utilized. After validation of the material model in both compressive and tensile testing, three point bending tests and simulation of foam and composite beams are carried out. Simulations of material failure and interface effects are also discussed.

Statistical Energy Analysis (SEA) method is used to predict Sound Transmission Loss (STL) of sound barrier assemblies (SBA) commonly used in automotive dashmat design. Tests are performed for dashmat plaques with and without design features, and SEA equations have been used for predicting transmission loss with acceptable accuracy below the interception (cavity resonance) frequency. For frequency range higher than interception point, the SEA software used overestimates STL. For dashmat tests with design features, test results and SEA predictions are generally agreeable.