MTS Roehrig Testing Systems
Electrically actuated MTS damper systems require far less capital investment and infrastructure than hydraulic solutions, are cleaner and quieter, faster to setup, and easier to maintain and repair (left to right: SYD System, EMA System, LEMA System)

MTS Roehrig Testing Systems
The new Model 853 NVH Damper System is engineered specifically to address the entire range of damper noise phenomena, including air-born Swish, Squeak and structure-born Chuckle.

MTS Roehrig Testing Systems
The Model 852 Mud/Slurry add-on provides a precise, clean and efficient means for conducting damper seal tests in the presence of dry powders, particulate/liquid volumes or particulate/liquid sprays.

The Evolving MTS Damper Portfolio

The MTS damper testing portfolio has evolved dramatically in recent years, adapting to meet growing demands for improved test system efficiency as well as increasingly more complex and challenging damper test requirements. Once exclusively servohydraulic, this newly expanded solution set now incorporates both high-performance electric and servohydraulic systems to fulfill a comprehensive range of test application requirements, spanning quality, characterization, friction force, noise and durability.

The most significant milestone of this evolution is MTS’ 2014 acquisition of a portfolio of electrically actuated damper characterization products, renowned among race teams and damper manufacturers worldwide for their precision and ease-of-use. Featuring compact, low-maintenance designs and clean, energy efficient operation, these electric systems represent the ideal response to growing industry demands for greener and more efficient damper test solutions. The MTS electrically actuated offering currently includes:
  • MTS SYD (Scotch Yoke Dynamometer) Damper Test Systems - a family of highly portable electro-mechanical crank (rotary) dynos for performing simple, single-specimen sinusoidal damper testing. These dynos are very easy to use and capable of delivering the fast, accurate test results race teams need to re-valve and tune shock absorbers based on input gathered from drivers during practice sessions.
  • EMA (Electro-Magnetic Actuation) Damper Test Systems – a family of programmable linear electric load frames for performing a broader range of single-specimen damper testing applications. These compact, high-performance systems are deployed worldwide for damper characterization and custom applications such as NVH, high-velocity testing and road profile playback.
  • LEMA (Line Electromagnetic Actuator) Systems - these adapted, production line EMA systems feature an open architecture that can be integrated into a line to or enabled for automation through a facility’s existing robotics. Their programmability, ease-of-use and range of force capacities make them ideal for maintaining damper production quality at high rates of throughput.
A more recent milestone for the MTS portfolio is the development of the Model 853 NVH Damper System, engineered specifically to push the boundaries of damper noise testing. The need for this solution was prompted by advent of more fuel-efficient electric and hybrid vehicles; the lighter, thinner materials making up the chassis of these vehicles create an environment where not only air-born “swish” and “squeak,” but also, structure-born “chuckle” noises threaten to compromise ride comfort and quality.

Truly meaningful chuckle analysis requires a test system capable of providing very pure sinusoidal excitation with very little total harmonic distortion. To meet this challenge the innovative Model 853 NVH Damper system draws from a variety of MTS technologies, including MTS servohydraulic damper, servohydraulic elastomer and the recently-acquired, electrically actuated EMA damper test systems.

To perform damper NVH measurements with fidelity and accuracy up to the required 700Hz, the Model 853 employs high-bandwidth transducers that are typically used to measure displacement, force and vibration in high-frequency elastomer test systems. It also features an elastomer test system’s high-stiffness load frame, along with larger diameter columns, a thicker crosshead and a more robust base to avoid the resonant modes that can corrupt measurements.

Linear EMA technology is an ideal source for the clean sinusoidal input and low harmonic distortion the system requires for effective chuckle testing. MTS’ EMA technology combines fixed, powerful neodymium magnets and moving air-core (ironless) electric motors. The lack of ferrous metal makes the motor extremely lightweight, which is what enables the actuator’s high-frequency response and high acceleration. The ironless motor also means there is no attractive force between the motor and the magnet and therefore no risk of cogging effects that can compromise the velocity waveform.

As with MTS servohydraulic test systems, the Model 853 is driven by versatile FlexTest® controller technology and capable of reproducing virtually any type of signal - i.e., sine block, sweeps, road signals; and high bandwidth PID control will enable it to follow a specified wave shape precisely, without iterations.

Not all recent MTS damper system evolution includes electric actuation; MTS servohydraulic systems, too, are subject to adaptation to meet changing industry demands. An example of this is the recently introduced Mud/Slurry add-on, specifically engineered to expand the utility of the MTS Model 852 Damper Test System to include the durability testing of damper seals when cycled in the presence of contaminants such as dust, mud and slurry.

The Model 852 Mud/Slurry add-on features an innovative overhead actuation design in which the slurry containment cups are fixed to the bodies of inverted damper test specimens. This configuration allows the containment cups to remain stationary relative to the cycling damper rods, providing a precise, clean and efficient means for conducting damper seal tests in the presence of dry powders, fixed volumes or heights of particulate/liquid mixtures, or constant particulate/liquid sprays.

Available as a Model 852 system field upgrade, the new mud/slurry option includes a crosshead-integrated 25kN actuator with 100mm stroke, slurry containment cups and a slurry distribution system. The distribution system comprises a mixer tank with removal drain, contamination-resistant pumps with a flow rates up to 9.5lpm (2.5gpm), and contamination-resistant electromagnetic flow sensors. The mud/slurry add-on is compatible with Model 852 standard fixturing, and can be easily configured to test a single specimen or up to eight dampers simultaneously.

Contact MTS today and explore how these new additions to the evolving MTS damper testing portfolio can help you meet changing damper testing requirements with accuracy, efficiency and confidence.



MTS Systems

14000 Technology Drive
Eden Prairie, MN USA

Tel: 952.937.4000
Tel: 800.328.2255
Fax: 952.937.4515