arrow_back_ios

Main Menu

See All Software See All Instruments See All Transducers See All Vibration Testing Equipment See All Electroacoustics See All Acoustic End-of-Line Test Systems See All Academy See All Resource Center See All Applications See All Industries See All Services See All Support See All Our Business See All Our History See All Global Presence
arrow_back_ios

Main Menu

See All Analysis & Simulation Software See All DAQ Software See All Drivers & API See All Utility See All Vibration Control See All High Precision and Calibration Systems See All DAQ Systems See All S&V Handheld Devices See All Industrial Electronics See All Power Analyzer See All S&V Signal Conditioner See All Acoustic Transducers See All Current and Voltage Sensors See All Displacement Sensors See All Force Sensors See All Load Cells See All Multi Component Sensors See All Pressure Sensors See All Strain Sensors See All Strain Gauges See All Temperature Sensors See All Tilt Sensors See All Torque Sensors See All Vibration Transducers See All Accessories for Vibration Testing Equipment See All Vibration Controllers See All Measurement Exciters See All Modal Exciters See All Power Amplifiers See All LDS Shaker Systems See All Test Solutions See All Actuators See All Combustion Engines See All Durability See All eDrive See All Production Testing Sensors See All Transmission & Gearboxes See All Turbo Charger See All Training Courses See All Upcoming Webinars See All Acoustics See All Asset & Process Monitoring See All Durability & Fatigue See All Electric Power Testing See All NVH See All OEM Custom Sensors See All Reliability See All Structural Dynamics See All Weighing See All Automotive & Ground Transportation See All Calibration See All Installation, Maintenance & Repair See All Support Brüel & Kjær See All Release Notes See All Compliance
arrow_back_ios

Main Menu

See All nCode - Durability and Fatigue Analysis See All ReliaSoft - Reliability Analysis and Management See All API See All Experimental Testing See All Electroacoustics See All Noise Source Identification See All Environmental Noise See All Sound Power and Sound Pressure See All Noise Certification See All Industrial Process Control See All Machine Analysis and Diagnostics See All Structural Health Monitoring See All Electrical Devices Testing See All Electrical Systems Testing See All Grid Testing See All High-Voltage Testing See All Dynamic Weighing See All Vehicle Electrification See All Calibration Services for Transducers See All Calibration Services for Handheld Instruments See All Calibration Services for Instruments & DAQ See All On-Site Calibration See All Resources See All Software License Management See All Business Ethics

With 5g in the precipice: HBK measurement technology in the Formula 1 of winter sports

TU München, Germany

Introduction

Forces acting on a racing bobsleigh in the ice channel at Berchtesgaden Königssee, Germany were systematically measured using a complete HBK measurement chain by the material triboloy group at the Zentralinstitut für Medizintechnik ZIMT of the TU München. Strain gages on the bob carriage and skids gave a first glimpse into force conditions during a bob race through the ice channel. The knowledge gained facilitates the route to systematic optimization of bob skids. Until now, skids for bob sport have been exclusively developed and produced on the basis of empirical information. Comprehensive experience of the bob pilot and trainer, together with long-term testing, are the main guarantee for top places in international competitions. Hard to reproduce training conditions, changing weather and track conditions make a direct comparison of different skid geometries and materials difficult. However, verified measurement results are the basis for specific influencing of skid characteristics and are essential as the input data for FEM calculations. In addition, they enable the determination of the forces acting on the bob and skid body, which enables an accurate description of the behavior between the skid and the ice. The knowledge of the location and level of penetration of the sliding body in the ice layer can help optimize the sliding process.

chevron_left
chevron_right

With MGCplus and catman® in the racing bob

High mechanical load, simultaneous measurement of 48 sensor signals with a sampling rate >2,000 Hz, accelerations up to 5g, low temperatures and battery operation, together with the smallest possible dimensions, all make the MGCplus the optimal partner in the ice channel. The strain on the skids, total load per skid and the accelerations on the skid and bob frame are measured. With regards to skid strain measurements, two skids could be measured simultaneously as the use of the MGCplus means that a total of 48 measurement channels are available. The use of capacitive sensors for additional accelerometer measurements was possible by simply exchanging the racks on site. Linear strain gages were used to determine the axle deflection. Rosette strain gages were attached to the skids for measuring the principle stresses and their directions.

The measurement runs

In total 21 measurement runs were carried out in the ice channel at Königssee with the Bavarian bob team members Karl Angerer, Christoph Gaisreiter and Katrin Dostthaler. In total, a data volume of 43MB per measurement run was recorded, calculated on a signal width of 32 bit, a measurement frequency of 2,400 Hz over 48 individual channels and a recording duration of 100 seconds.

The measurement data generated was stored in MGCplus on a compact flashmemory card and then read and processed on a notebook with the catman® software. The data acquisition system was positioned between the pilot and the brakeman when measurement runs were implemented in the twoperson bob.

Particular attention was paid to the installation to ensure that there was no danger of injury to the bob team. The MGCplus was grounded via the bob frame and skids.

Measurement results

As specific optimization of skid geometry is only possible when load, location, time and position of the bob are known, all measurement results generated must be linked with the geometric and construction properties of the ice channel.

This was implemented by assigning the measurement results using an event map developed for the bob track. Figure 5 (see PDF file) shows a schematic diagram of the bob track in combination with the recorded axle load of a two-person bob.

The various events in the ice channel can be clearly recognized as sensor signals in the diagram. Because of the centripetal forces acting on the bob, the axle deflection and the sensor signal acquired increases quadratically with increasing speed and linearly with decreasing track radius. 

At the last steep curve, the echo wall, the force acting on the pilot and team rises to five times their body weight. The bob is subject to the maximum force at this point.

Assigning the loads

The position of the bob was precisely determined using the signal for the precise assignment of loads to the corresponding location in the ice channel. This can be implemented by integrating the speed over time.

The speed can be determined by comparing the axle signals: The deflections of the front axle were repeated after a slight time delay at the rear axle.

The average speed could be determined because the axle distance of the bob was known.

Bob sport and measurement technology in the future

Greater competitive pressure and ever faster equipment requires systematic procedures in all further developments in this winter sport. Measurement technology holds a key position here as it can provide statements about arising loads and it can be used as the basis for verification of simulations.

Based on the measurement results recorded at the ice channel in Berchtesgaden, an FEM model was created at the Zentralinstitut für Medizintechnik of the TU München which permits the simulation of the measured processes.

At TUM, talents from all over the world come together to inspire each other, learn from one another and create innovations together. Our mission? As one of Europe’s most outstanding universities in research and innovation, we find solutions to the most important scientific and social challenges of our time.

 

"We value the diversity of talents, perspectives and experiences of each individual, we draw inspiration, motivation and creative energy from one another as members of a vivacious university community."

Prof. Thomas F. Hofmann, President Technical University of Munich

Technology used

Other case studies