FAQ #377
60 deg C Accumulator Container Composite and Adhesive Testing

Last Updated On 11/19/2024 08:07:03 AM by

sayovitz

Question
Accumulators are allowed to run at up to 59.9 deg C on track.
Steel and aluminum properties are not significantly affected at this temperature.
But most plastics and adhesives are softened.

F.10.1.4 requires material properties to be considered >= 60 deg C.
This is applied to both the container (which may be carbon fiber in a plastic matrix) and the segment structures (which are frequently plastic.)
F.10.1.5 requires adhesive properties to be considered >= 60 deg C 

If reference properties are not available >= 60 deg C for a regulated accumulator container material or adhesive, how are these properties established?
Answer
F.4.2.4 uses a three point test to derive composite material properties.

It is generally impractical to perform 3-point testing at elevated temperatures. Testing the sample at 60 deg C is NOT required
Perform tensile tests of skin coupons heated >=60 deg C for the duration of the test and compare to tensile tests of skin coupons at room temperature.
This establishes a reduction in equivalence to the three point test.

Shear tests are likely small enough to complete with the sample >=60 deg C.
Similarly, for regulated bonds, lap and T-peel tests are performed with the samples heated >= 60 deg C.
No room temperature comparison is needed for these tests
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