Tailor-made Simulation Solution For Fatigue Testing

Center Testing International Corporation (CTI), the leading test laboratory in the Chinese test industry, is a wide-ranging, independent institution and specializes in testing, calibration, inspection, certification and technical services. As a provider of endurance testing of vehicle components, CTI needed a multi-axis road simulation solution for one of its key customers in China, GM Patac, a joint venture between General Motors and the Shanghai Auto Group.

Due to the complex test requirements, CTI turned to Moog, in particular because of Moog's reputation for excellent customer support on site with a global team of experts. Moog then developed a customized hydraulic simulation table (HST) in close partnership with CTI.

It consists of a compact and light platform and base plates on which tension-resistant hydrostatically mounted cylinders are attached. To meet the demanding requirements of the application, the Moog engineers have adapted the system in several ways. To complete the tests, CTI prepared a vehicle half and a drive train device as well as supports as a holding device for connecting the test specimens (engine, transmission, rear) to the HST. Moog has designed a rotary actuator with a connector that is used to apply input torque to the engine to simulate an engine output torque and to apply force to the test specimens during acceleration / deceleration maneuvers.

An additional electrical heating system is used to simulate the ambient temperature of all assembly areas. The temperature control is made possible by a PLC-controlled hot air blower and temperature sensors, the setpoint temperature is generated via the CAE heat analysis or by playing back measured values ​​(real run).

Another innovation of the hydraulic simulation table is the way the software is used to reduce the overall duration of the road simulation strength test while maintaining road fatigue damage to the test specimens. During the testing of the assembly strength, raw road data from the test site for journeys under extreme conditions is collected via a data acquisition device with sensors in critical vehicle positions in order to obtain sufficient iteration quality and correlation signal data.

After recording the raw data, deviating signals and signals with a lower amplitude are analyzed and removed by defining a raw signal amplitude in the time domain, an auto power spectrum in the frequency domain and rain flow / pseudo-damage in the fatigue range.

The solution with the tailor-made HST would not have been possible without the active application support and advice from Moog's China-based technical team and the seamless cooperation between CTI and Moog in the development of the test bench.

The flexible design of the simulation table product family also enables easy integration with a smaller footprint. (qui)

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