Customised hydraulic simulation table

CTI is a comprehensive third-party agency that specialises in testing, calibration, inspection, certification and technical services. As a vehicle components durability test service supplier, CTI required multi-axle road simulation testing capabilities for one of its most important customers in China, GM PATAC – a joint venture between General Motors and Shanghai Auto Group which has become one of the most renowned vehicle R&D institutes in China.

The Hydraulic Simulation Table (HST) consists of a compact and light platform and base plates on which stress resistant hydrostatic jacks are assembled with rods jutting from the jacks connected to the platform structure. In order to meet the needs of the application Moog engineers customised the system in several ways. To complete the test CTI prepared a vehicle half body, and powertrain assembly and pillars as fixtures for connecting test mounts (engine, transmission, rear end) with the HST. Moog designed one rotary actuator with a connection fixture that was used to add torque input to the engine to simulate engine torque output and add force on the test mounts at acceleration/deceleration events. An accessary electric heating system was also used to simulate the circumstance temperature of each mount area. Closed loop control of temperature was achieved by a heating gun PLC and temperature sensors, and the temperature set point was determined from thermal CAE analysis or Vehicle Real Road RLDA.

Another key innovation of the Hydraulic Simulation Table was the way the software is used to decrease the total road simulation durability test period while retaining road fatigue damage on the test mounts. During the mount durability test process, road raw data is collected from the proving ground for various rough road events through a data acquisition device with transducers put on key vehicle positions to obtain sufficient iteration response and correlation signal data. After obtaining the raw data, abnormal and smaller amplitude signals are analysed and deleted by assessing raw signal amplitude on the time history domain, PSD on the frequency domain, and rain flow/pseudo damage on the fatigue domain.

The solution, using a customised Moog HST, would not have been possible without strong application technical support and consultation from the Moog technical team based in China, and the close collaboration between CTI and Moog throughout the rig’s development. For this complex testing need, CTI turned to Moog, due in large part, to Moog’s reputation for outstanding local client support backed by a global team of experts. The flexible design of the Moog family of HST systems also allowed for easy integration and a smaller footprint. The HST system was designed on a proven platform of advanced building blocks which deliver leading levels of performance and reliability in an efficient package that can be easily customised to meet the needs of CTI.

“We were looking for a solution to a particularly complex durability test which we needed to perform for one of our key customers,” said Lilac Lai, Key account manager, CTI Suzhou. “Moog’s approach of providing collaborative support through their expert team in China allowed us to comprehensively communicate our goals for the project, and also allowed Moog to translate this vision into customised solutions that met our needs, so that we were able to deliver on our commitments to our customer.”

Moog worked closely in partnership with CTI Suzhou, collaborating through all stages of the project – consulting on the solution design, providing expert installation, and commissioning services to ensure the solution was a match for client needs and goals. The end result was a hydraulic simulation table that was able to successfully provide powertrain mount durability testing and cooling fan and radiator assembly durability testing.

Will Opie, general manager of Moog’s global testing business commented, “Moog is a large global company. We have experts and facilities around the world that are dedicated to supporting our customers. Meanwhile we provide rapid local support from the teams located close to our customers who can call on resources and experts from our wider global organisation. For CTI and our other Chinese customers, this means rapid local support backed up by our global team of experts.”