Daimler Trucks uses LMS Tecware measurement instrumentation to collect data yields on customer usage profiles and develop its durability test cycles
Durability testing is of utmost importance in the truck market standards are more demanding than for passenger cars, and differ from region to region.
“Mercedes-Benz cars are designed to withstand 300,000km without major repairs. Long-haul standard trucks are designed to last 1,200,000km. Harsher environmental conditions, overload and more dynamic driving will shorten the service life of the truck,” says Dr Christof Weber, manager of the Daimler Durability and Bench Testing Competence Center in Wörth am Rhein, Germany.
“For example, in Brazil, the same standard non-reinforced trucks will only last 900,000km. At the same time, we know of 30-year-old and even 40-year-old trucks that are still in daily use. You might have to change the engine or the axles, but as a backbone, the chassis should never break,” Dr Weber adds.
Daimler Truck’s durability testing and validation procedures focus on the specific demands of customer usage cycles. “Application-specific testing is based?on customer usage profiles, market intelligence and expectations, and field measurements from all over the world. Siemens PLM Software is our partner in retrieving all this information. We also do measurements together with customers in their applications. That way we learn how a truck is used on a day-to-day basis.”
The usage intelligence gained from these customer trials is linked to each cell of the application matrix, and varied by putting a scatter of distribution over the parameters.
“By adopting these statistical methods, we are able to simulate more or less 100,000 different customers for each application cell. With this enriched application matrix, we can create design targets for trucks worldwide.”
Weber continues, “It starts with simulation we try to get as much work done in the low-cost areas early in the development process using simulation, limiting the amount of field tests as much as possible. Simulation accuracy is assured by conducting specific tests and constant feedback loops between test and simulation. Of course, this approach necessitates the full integration of simulation and test procedures.”
Testing all variants would be far too costly and time consuming; therefore, a specific vehicle combination is selected to represent an entire platform range. Only this one vehicle will undergo a rig test or a complete road test.
“If you are able to map the mutual influences for different systems in a truck, you automatically know how many variants you need to test,” explains Weber. “The truck selection is based on targeted simulation and long-term engineering experience. DOE is a very helpful tool. It enables us to estimate how different components will interact and how this will affect the truck’s overall durability.”
Understanding market requirements?
Daimler also conducts physical tests at its proving ground in Wörth am Rhein, which is part of the Development and Test Center at the Mercedes-Benz Wörth plant.
The 550,000m² facility has test lanes with gradients of up to 26°, which are used for functional testing, such as brake tests. The inside area features a range of rough-terrain tracks, with 14 different types of road surfaces.
All test vehicles are equipped with GPS. A cockpit display informs the driver of their actual and target speed, and possible tolerances. The driver can also be warned via sound alerts.
“By cleverly combining customer profiles with specific track characteristics, we’re able to design a durability test track program that accurately represents a specific market requirement,” notes Weber.
Daimler recently inaugurated its new state-of-the-art production facility in Oragadam, India. This site also houses an integrated R&D center and test track, which spans approximately 19ha and has two different tracks.
The three-lane outer track has a total length of 1.55km and is specially designed for testing the powertrain and vehicle noise. The two-lane inner track is 1.16km long and offers features including a water trough, a dusty road and poor road surfaces. Facilities for testing on gradients and steering will be added in the near future.
Forging a strong collaboration
Daimler Trucks and Siemens PLM Software also work closely together in rig testing. “Initially we called them to support us but this has developed into a strategic partnership. Siemens PLM Software equips our test vehicles with state-of the art sensors and measurement equipment including strain gauges,” explains Weber.
“Measurement regimes on the proving ground and in the field are also performed together with the LMS engineering teams and a Daimler test engineer. The LMS TecWare software tool has become an integral part of our everyday operation. We very much appreciate the collaboration with Siemens PLM Software, especially the fully integrated service offered. It is not only about evaluating data; when needed, Siemens PLM Software can provide us with a complete range of services.”
June 16, 2017
