TechArchive

Original article date: February 2000

Audi is now well placed to record real-time corrosion effects, thanks to Weiss Technik’s all-plastic environmental testing chamber

Asked by Audi to build an all-plastic corrosion test chamber, Weiss Technik’s construction is a two-chamber facility which can record corrosion patterns of car suspensions under mechanical stress (with temperature, torsion, vibration and spray). The chamber was also required to include a dynamic road simulation system with active, moveable actuators.

The objective was to test complete vehicle suspensions under real conditions. The call for an entirely plastic chamber was been dictated by the need for a neutral system in which there is no possibility of false readings resulting from the corrosion of, or other chemical reactions with, the chamber itself.

With the completion and installation of the chamber, Audi is now well placed to record real-time corrosion effects that occur while a mechanical stress is applied. These corrosive effects were previously unknown. New designs can now be undertaken with full data detailing the results of higher corrosion levels of cars and components under test, which ultimately results in a better product for the consumer.

All chamber inner test space is constructed from a special plastic able to withstand temperatures from -30 to +130degC. All internal components, such as fans and spray devices, are made of plastics, while the conventional internal units, such as the air handling unit, are now all external.

Metal heat exchanger

One of the largest problems to be overcome was the construction of the metal heat exchanger. Of course, metal has superior thermal properties, but traditional construction elements, such as aluminium, copper and stainless steel, are the highest contributors to secondary corrosion effects. And so a pumped, indirect conditioning system was developed to remove the need for an evaporator and refrigeration system. Another departure from current practice in the new chamber is the use of real-time testing incorporating high and low temperature tests with humidity. Historically, tests have been accelerated at high temperatures, but real-time testing is required to combine correctly all effects for all parameters.

A lightning conductor is required inside the facility to cope with the high voltage discharge caused by static.

The facility comprises two chambers of 10 and 14m?, for which Weiss Technik developed special seals to allow positioning of the moveable actuators of the dynamic road simulation system.

• Weiss Technik

February 2000