Helped by advanced simulation tools, European and U.S. automakers have been aggressive in adopting engineering plastics in their vehicles according to one of the proponents of such software.
|Wheel weight minimized through extensive utilization of Ultrasim software. Top photo shows geometry measurement. Bottom photo shows the tool used.
BASF (Ludwigshafen, Germany) says that its Ultrasim simulation and optimization software is playing a key role in vehicle lightweighting through its ability to assist in designing structural load bearing, and crash-relevant parts.
Ultrasim, for example, played a major role in the development of the polyamide wheels developed for the recently announced smart forvision concept car. The 6-kg wheel rims represent a significant saving over traditional 9-kg aluminum rims and the real weight savings are even more impressive given the rotational nature of wheels. This means any saving in kilograms is multiplied by a factor of 1.5. Technically, the wheel is not entirely plastic, however; a metal insert forms the interface with the axle.
Andy Postlethwaite, Senior Vice President, Engineering Plastics, Asia Pacific for BASF notes that "Nowadays, a European luxury vehicle may use up to 35 kg of engineering plastics whereas in Japan, the typical car would employ about 10 kg and in China only 5 kg of engineering plastics would be used, mainly in the manifold." He does note that South Korean automakers have made more progress, at around 15 kg per vehicle. European vehicles often employ front end carriers, lower bumper stiffeners, structural inserts, and engine mounts, for example, that are made from engineering plastics but these components are still mainly made from steel in Asia.
In another recent innovation, BASF employed Ultrasim simulation software extensively in development of a weight- and space-saving seat that extensively employs plastics. Used commercially in the Opel Insignia OPC, the seat is not only 20% lighter but several centimeters have also been shaved from its thickness profile.
The Opel seat uses a 50% glass fiber-reinforced, surface improved grade of Ultramid polyamide (B3G10Si) for the back, a 40% glass fiber-reinforced Ultramid grade for the base (B3ZG8) and Neopolen P expanded polypropylene foam. "The seat endures all of the standards that auto seats are required to fulfill [such as rear crash and cargo retention], plus additional ones stipulated by the automaker," says Postlethwaite. He goes on to state that because the Ultrasim software package is standardized for use with BASF Ultramid PA and Ultradur PBT materials, maximum simulation accuracy can be realized, which translates to the minimum possible part weight.
Accurately reflecting fiber orientation, including for long fiber grades, is one of the key factors when simulating glass fiber filled grades according to BASF,. "Fiber orientation is highly dependent on gate position and it has a major effect on localized part strength," notes Raichib Zeidam, Senior Regional Manager, Engineering Plastics, Asia Pacific. Furthermore, says Zeidam, "Ultrasim enables comprehensive part design from topological optimization of a design space, through actual part design, filling simulation and fiber orientation, to stress simulation and performance evaluation by failure criteria."-[email protected]