Innovative Solutions
Dipping HyGe Sled
The Challenge
During a preliminary HyGe test programme it became apparent that the well proven standard HyGE Sled test significantly under-predicted the driver chest acceleration during a standard legislative crash event. Customer hypothesis suggested that "Steering Column Ride-Down" performance in particular, would be compromised by the vehicle cabin dipping forward during impact. Millbrook was requested to investigate the possibility of developing a solution using the sled to simulate the characteristic tilting of the cabin and a vertical movement of 120mm at the A-Pillars during the simulated crash event.
The Millbrook Approach
Due to the severe time constraints imposed by the customer, it was necessary for the Millbrook team to look at options based on a development of the existing sled. It was also clear that the solution would need to provide repeatable results and be tunable to reflect any future requirements to accommodate other SUV models. Investigations of the options available to the team also highlighted that whilst other designs of sled already exist, none were capable of replicating the dipping motion at the prescribed rates, and furthermore the cost and access to such systems was outside the scope of the project requirements.
The Solution
By considering the problem from first principles, the dipping movement was simulated through the introduction of a simple hinged sled carriage. The rate of dipping movement under impact was then controlled by a specific design and size of crushable medium. This method thus provides scope for easy calibration and subsequent simulation to ensure close correlation with the real-world vehicle impact.
The Result
Accurate simulation of the cabin pitch and chest acceleration was established within a very short timescale and cost. In response, the customer indicated that this small but significant innovation would result in product development savings in the region of 3million EUR.