Accelerating Test-based Durability Engineering

Executing extensive field tests to validate the durability performance of mechanical designs is very expensive and time-consuming. This pressures automotive OEMs and suppliers to efficiently reproduce equivalent laboratory tests. LMS TecWare and LMS TWR offer a robust solution that integrates and automates the physical durability testing workflow, from load data processing over test schedule optimization up to drive file generation for test rig campaigns. This complements the IST solution for test rig setup, control and data management, and durability test execution, to form the complete integrated Durability Alliance software suite for environmental durability simulation.

After a day of collecting field test data, engineers want to efficiently analyze the vast amounts of accumulated data. LMS TecWare 2.12 allows data from a wide range of (durability) data formats to be automatically imported. Its optimized displays and easy-to-use data analysis and synthesis tools serve multiple purposes. Besides effective load data cleaning and validation, they facilitate the monitoring and comparison of essential loading portions from a durability perspective. The streamlined process allows users to choose between interactive and automatic operation modes and to automatically distribute reports that consist of a customizable mix of time histories, rainflow matrices and statistical results. In addition, Rev 2.12 of LMS TecWare offers dedicated batch files that enable the execution of LMS FALANCS based fatigue-life predictions, starting from acquired rosette strain gauge measurements.

Optimized test schedules yield substantial time savings
 

Firmly decreasing the duration of validated load data signals is essential in drastically reducing the time required to execute durability tests. LMS TecWare succeeds in this by efficiently determining sets of compressed load time histories that preserve the same damage potential as originally present – enabling both the generation of new and the optimization of existing test schedules. It significantly facilitates this process by offering dedicated batch files that encapsulate the process of rainflow projection filtering, test pre-processing and the creation of summary reports. In addition, this new release introduces new tools for efficiently converting these essential load data signals into test schedules that are specifically adapted to the available test infrastructure, such as constant-amplitude test benches. Rev 2.12 of LMS TecWare is very easy-to-use and highly efficient because it delivers test schedules that are much more time-efficient than the validated load data signals they are based on. It even allows test schedule optimization algorithms to be adapted quickly according to the properties of specific materials, such as steel and rubber.

Reproducing field test conditions on durability test rigs is very challenging, due to the high-amplitude related non-linear behavior of test rig controllers and tested components and assemblies. LMS/IST TWR (Time Waveform Replication) 3.5E accurately defines a system model, which is used to experimentally define the rig-specific control signals through an iterative and flexible process. Through the tight integration of LMS/IST TWR with the IST RS LabSite durability software, the comparison of target and measured road profiles and the updating of rig control signals can be executed fully automatically. Once the prescribed correlation levels are reached, this iterative process is automatically stopped. Template-based interactions between LMS/IST TWR and IST’s digital Labtronic 8800 controller help engineers to set up test rigs quickly, enabling operators to efficiently generate test rig drive files and execute durability test campaigns.

The integrated process, optimized workflow and dedicated tools provided by LMS TecWare and LMS TWR empower automotive OEMs to efficiently reproduce durability-specific field test conditions on time-efficient laboratory rig tests. Among their key environmental durability simulation customers, LMS and IST count BMW, DaimlerChrysler, Ford, Honda, Opel, Renault and Volkswagen. This solution is also very important for automotive suppliers, as it enables them to thoroughly and efficiently test the durability performance of their specific assemblies “as if” they are built into the full vehicle. Automotive suppliers include Denso, Faurecia, Johnson Controls, Tenneco, TRW and ZF. The extensive customer list also includes truck and bus manufacturers DaimlerChrysler, MAN, Mitsubishi Motor Corporation and ZF.