Standard Impact Attenuator Design
2015 - 2016 Formula SAE Standard Impact Attenauator, Type 14
There is no change from the 2013 (Type 13) Impact attenuator. The 2012 drawing applies for the 2015 - 2016 competition year. (See Below)
There is one clarification, however. If the attenuator is made of more than one piece of foam those pieces must be glued together using a structural adhesive that is compatible with the Impax foam. Segments may not be stacked without glue.
2013 Formula SAE Standard Impact Attenauator, Type 13
There is no change from the 2012 (Type 12) Impact attenuator. The 2012 drawing applies for the 2013 competition year.
Formula SAE Standard Impact Attenuator, Type 11
Posted 24-Jan-2011 to http://students.sae.org/competitions/formulaseries/
For the purpose of this notice and subsequent discussions an impact attenuator that has been (1) properly fabricated (2) from the required material and (3) to the dimensions of the standard impact attenuator design posted to THIS PAGE is referred to as the “Type 11 Impact Attenuator”.
The Formula SAE Rules Committee has tested a Type 11 impact attenuator specimen built from Dow Impaxx® 700 energy absorbing foam. Our test results indicated that the specimen satisfied the requirements of B3.21.1. Properly fabricated and mounted impact attenuators made from Dow Impaxx® 700 and which meet the Type 11 dimensions will be accepted as complying with Rule B3.21.11 and as such are exempt from physical testing.
Teams building a Type 11 impact attenuator must support their use of Dow Impaxx® 700 by bringing a receipt for the material to technical inspection. The technical inspectors may choose to verify the dimensions and the material and have the authority to conduct any measurements, inspections or tests they feel are necessary. However, teams have the burden of proof to show their foam is the required material. Examples of good documentation include a receipt from that competition year, a packing slip or letter of donation.
There is no required supplier of the Dow Impaxx® 700 foam. However, Dow Impaxx® 700 pre-cut to the Type 11 shape is available for US$150 each plus shipping from BSCI Energy Impact Systems (contact information below). Pricing and availability are subject to change and are at the sole discretion of BSCI Energy Impact Systems. BSCI Energy Impact Systems is not affiliated with SAE International or the Formula SAE Rules Committee.
The Type 11 Impact Attenuator is approved for the 2011 FSAE competition season only and the minimum required design may change in future years.
More information about the Dow Impaxx foam can be obtained from the Dow website at: http://www.dowautomotive.com/products/impaxx/700.htm
BSCI Energy Impact Systems
Special thanks to BSCI who donated the test specimens used in the verification testing.
Frequently Asked Questions:
Question 1: Is the mounting scheme shown on the part drawing the only allowable configuration?
Answer: The team should determine the best method of attaching the standard design to their vehicle. The mounting shown on the part print is a suggested method that could be used. Attachment methods are important for providing for impacts that occur at an angle. Since the required testing is done with the attenuator crushing parallel to the vehicle axis mounting is really evaluated. Teams should use good engineering practice and calculations to determine the best mounting method for their vehicle.
Question 2: Rule B3.21.9 requires the attenuator to be mounted to the anti-intrusion plate and sets a maximum deflection for the plate. How should this be handled with the standard design?
Answer: To address this, teams should determine, either by testing or analysis, that their configuration for front bulkhead and anti-intrusion plate can support the required 117,720 N (26,755 lbf) of load from the anti-intrusion plate assuming a uniform pressure applied load across the area where the anti-intrusion plate mounts. These calculations or test data should be included in the impact attenuator data submission and should include predicted strength and deflections. Deflections must be less than the 25.4mm (1 inch) maximum called out in rule B3.21.9.
Question 3: Are we required to submit an impact attenuator data submission by the action deadline on the website? What should be included in this submission? Should we include pictures, dimensions or other information?
Answer: Yes, please see B3.21.11 for the specific details of what must be included in the submission and be sure to include the necessary anti-intrusion plate information (Question #2 above).