05 July 2013

LMS Helps Transmission Manufacturer AISIN AW to Predict and Eliminate Clutch Judder

Leuven, Belgium, 5 July 2013 – LMS, the leading partner in test and mechatronic simulation, helped AISIN AW to evaluate transmissions in a whole vehicle context at an early stage in the development process to reduce the chances of self-excited judder occurring. LMS completed a project using a hybrid approach of combining simulation and test to correlate and validate a repeatable methodology for future use. This methodology allows AISIN AW to evaluate new vehicle applications for their transmission quicker, saving time and money.

In the Automotive Industry, the quest for greater efficiency, lower emissions and a greener brand image has put pressure on sub-system and component design, among which transmission design has some particular challenges to overcome. AISIN AW requested LMS to explore the possibilities of using simulation to improve the prediction of judder phenomenon. This was achieved using a 1-D model to simulate the transmission and vehicle influences combined with testing to correlate and validate the method for future use in their development processes.

To understand and diagnose problems using 1-D simulation a three step project was devised and executed to transfer the technology and knowledge.

  • Step 1 – Model the transmission units accurately using a 1-D model in LMS Imagine.Lab, including gearbox internals, torque converter, lock up clutch and lock up clutch controls.
  • Step 2 – Model whole vehicle driveline, bench testing carried out to understand correct parameters for driveline components (impedance & damping).
  • Step 3 – Carry out a sensitivity analysis to predict mode shapes and influencing components allowing design improvement activities to be targeted at specific components.

Steps 1 and 2 developed a 1-D transmission model using bench testing for validation and then added the whole vehicle parameters that affected judder (engine, driveline and tires). This whole vehicle model was correlated against a measured system to ensure its accuracy.

Step 3 used the validated model in the development process to analyze the judder phenomena and the component contributions to each judder mode found for a specific vehicle application. By ranking each components contribution recommendations and target damping values were worked out and simulated to test their effectiveness. These targets were then interpreted by AISIN AW into component design changes to improve their product.

The 1-D model developed allows AISIN to simulate several drive cycle scenarios and a wide range of vehicle parameters. Since calculation times are small, it is possible to evaluate many scenarios allowing it to also be used for troubleshooting. The project proved that 1-D simulation and analysis could bring benefits to the transmission engineering team, helping them to understand the NVH contribution of each component and allowing them to focus their efforts on areas that will give the best results. Importantly the process and knowledge on how to repeat this work was retained by AISIN AW for future transmission projects as part of LMS commitment to technology transfer.

About LMS, A Siemens Business

LMS is a leading provider of test and mechatronic simulation software and engineering services in the automotive, aerospace and other advanced manufacturing industries. As a business segment within Siemens PLM Software, LMS provides a unique portfolio of products and services for manufacturing companies to manage the complexities of tomorrow’s product development by incorporating model-based mechatronic simulation and advanced testing in the product development process. LMS tunes into mission-critical engineering attributes, ranging from system dynamics, structural integrity and sound quality to durability, safety and power consumption. With multi-domain and mechatronic simulation solutions, LMS addresses the complex engineering challenges associated with intelligent system design and model-based systems engineering. Thanks to its technology and more than 1250 dedicated people, LMS has become the partner of choice of more than 5000 manufacturing companies worldwide. LMS operates in more than 30 key locations around the world.

About Siemens PLM Software

Siemens PLM Software, a business unit of the Siemens Industry Automation Division, is a leading global provider of product lifecycle management (PLM) software and services with seven million licensed seats and more than 71,000 customers worldwide. Headquartered in Plano, Texas, Siemens PLM Software works collaboratively with companies, delivering open solutions to help them make smarter decisions that result in better products. For more information on Siemens PLM Software products and services, visit www.siemens.com/plm.

Note: LMS Virtual.Lab, LMS Imagine.Lab and SAMCEF are registered trademarks of LMS International or any of its affiliates. Siemens and the Siemens logo are registered trademarks of Siemens AG. All other trademarks, registered trademarks or service marks belong to their respective holders.

This press release was published by LMS International prior to Siemens PLM Software acquiring the company on January 3, 2013.