UDU Crush Testing
The graph below shows data from an actual crush test, in which the UDU skin was designed to reach but not exceed a maximum of 75,000 lbs. The goal is have the test sample approach maximum and hold a constant force over time. The area under the red line represents the maximum amount of energy that can be absorbed over a one-inch crush distance in that particular design space. The green test curve shows that the force has been limited to just less than the maximum allowable. In other words, the skin structure has done its job. By adjusting the stiffness and density of the internal foam material, the middle portion of the green crush curve can be lifted up to approach the ideal energy absorber.
Since the UDU technology is modular, this constant force crush behavior can be maintained over relatively long distances. The segments can be stacked and clustered to create virtually an infinite number of shapes and sizes. In the case of a vehicle front crash, it can be designed to crush as much as a meter of length, if required, to limit forces. In the case of a side crash in an EV, the structure can be designed to limit intrusion into the battery compartment while absorbing the crash energy and directing forces to existing load path members.