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F.10.3.1 Accumulator Containers must be attached to the Major Structure of the chassis
F.10.3.2 Attachment of the Accumulator Container must be documented in the SES
F.10.3.3 Any fasteners used to attach Accumulator Container(s) are Critical Fasteners, see T.8.2
F.10.3.4 Each attachment point to a composite Accumulator Container requires steel backing plates with a thickness of 2 mm minimum.
Alternate materials may be used for backing plates when proven Equivalent
F.10.3.5 Teams may justify the Accumulator Container attachment using one of:
Corner Attachments and Analysis per F.10.3.6
Load Based Analysis per F.10.3.7
F.10.3.6 Accumulator Attachment – Corner Attachments
a. Eight or more attachments are required for any configuration.
One attachment for each corner of a rectangular arrangement of multiple Accumulator Segments
More than the minimum number of fasteners may be required for non rectangular arrangements
Examples: an extruded L shape would require attachments at 10 convex corners (the corners at the inside of the L are not convex); an extruded hexagon would require 12 attachments
b. The mechanical connections at each corner must be:
50 mm or less from the corner of the Segment
Spaced minimum 50 mm from the mechanical connection of any other corner
The same fastener diameter and grade
c. Each attachment point must be able to withstand a Test Load.
The Test Load is equal to 1/4 of total mass of the container accelerating at 40 g
Every fastener must withstand the Test Load in pure shear, using the minor diameter if any threads are in shear.
Every Accumulator bracket, chassis bracket, or monocoque attachment point must withstand the Test Load in bending, in pure tearout, pure pullout, pure weld shear if welded, and pure bond shear and pure bond tensile if bonded.
F.10.3.7 Accumulator Attachment – Load Based
a. The number of attachment points that must be used depends on the total mass of the container:
Accumulator Weight Minimum Attachment Points
< 20 kg 4
20 – 30 kg 6
30 – 40 kg 8
> 40 kg 10
b. Any brackets which attach the Accumulator Container to the chassis must:
Be made of steel 1.6 mm minimum thickness or aluminum 4 mm minimum thickness
Have gussets to carry bending loads.
c. Each attachment point, including any brackets, backing plates and inserts, must be able to withstand 15 kN in any direction
d. Fasteners must spaced minimum 50 mm apart to be counted as separate attachment points.