Ingelmann, M. and Bickelmann, H., "Lightweight and NVH Performance: New Solutions with High Performance Microcellular Polyrethanes.," SAE Technical Paper 2015-01-2341, 2015, doi:10.4271/2015-01-2341.
Microcellular Polyurethane is for many applications an alternative material to compact elastomers like rubber, with many beneficial and unique properties. Thus relates to the progressive load-deflection-characteristic, the amplitude-selective-damping, the good acoustic isolation and the high durability.The dynamic and static performance of the material, combined with the ability to work in limited packages, makes the usage beneficial for many automotive/transportation applications. The amplitude selective damping fits to the automotive requirements: small amplitudes are generating a low damping of the material; high amplitudes are increasing the damping. Translated in the characteristic for bushings and mounts, this results in a very good isolation for acoustic effects (e.g. rough road conditions) and a very good damping of vibrations (e.g. part- or system resonances).The requirement to deliver the best balance of safety & comfort, service life, weight, package and cost are requiring new NVH solutions for bushings and mounts. Here the micro-cellular structure of the material is enabling the realization of bushings and mounts with a higher Eigenfrequency, less resonance peaks and better high-frequency isolation in the same or even smaller packages. Those polyurethane elastomer parts a very good fit to the requirements of the new mobility with efficient, safe and comfortable vehicles, especially with hybrid or electrical powertrains. Motor mounts are limiting the transfer of high frequency noise, with a safe control of the deflections and a weight optimization of 30% over a conventional rubber mount. Other examples are gear box isolators or mounts for auxiliary units.