Switchable crash absorber

Crash absorbers for cars are meant to limit the damage to the car and to protect pedestrians from injury. Typically, crash absorbers can only be optimized for one of the two functions. This newly developed absorber, however, can be adjusted to specific impact situations based on informations provided by the car's sensors.


The first element of the car's crash management system is typically an easily deformable element which offers very limited resistance, thus protecting pedestrians possibly involved in an accident. Unfortunately, this element increases the necessary installation space and offers very limited protection to the car if cashed into a solid obstacle. Thus, the damage inflicted in accidents where no pedestrians are involved is higher than necessary.

Our Solution

The newly developed switchable crash absorber can offer the best protection for both situations. It consists of 3-4 rods which are connected through joints, and can discreetly be placed behind the car's bumper (Fig.1).

Fig.1: Switchable crash absorber consisting of four rods connected through joints (1-4 upper right). The absorber can discreetly be placed behind the car's bumper (left) and can, in case of a hard collision, transmit the impact force into the car's support structure (left and bottom right). (Source: Prof. Dr.-Ing. Bachem)

In the default state the rods are flexible and can thus, in case of an accident involving pedestrians, fold up without offering much resistance. Thereby, the default state offers the necessary pedestrian protection. Only if the car's sensors detect with certainty that no pedestrians are involved in a crash, the absorber can be automatically switched into the second possible state, in which the joints are locked and the construction offers a significantly increased impact resistance. As a consequence, the damage to the car is reduced and thus the repair costs are lower (Fig.2).

Fig.2: The figure shows the average force along the deformation path in state 1 (pedestrian protection, thick black line) and in state 2 (solid obstacle, thin blue line). (Source: Patent application)


  • Pedestrian protection is ensured
  • Improved vehicle protection if no pedestrians are involved
  • Compact, discreet and simple design
  • Smaller installation space required


  • Pedestrian and vehicle protection for cars

Development Status

First tests and simulations have been successfully performed.

Patent Status

German patent application: DE102017125468A1
International patent application: WO2019086349A1

Applicant: Ostfalia University of Applied Sciences – Hochschule Braunschweig/Wolfenbüttel


Dr. Mirza Mackovic
Patent Manager Technology
E-Mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Tel.: +49 (0) 551 30 724 153
Reference: CPA-1945-FHBW

Tags: Automotive engineering


A subsidiary of

Georg-August-Universität Göttingen