Test panels must: • Measure one of the two options: 138 mm x 500 mm OR 275 mm x 500 mm • Be supported by a span distance of 400 mm • Have equal surface area for the top and bottom skin • Have bare edges, without skin material
The SES must include:
• Data from the 3 point bending tests • Pictures of the test samples • A picture of the test sample and test setup showing a measurement documenting the supported span distance used in the SES
Test panel results must be used to derive stiffness, yield strength, ultimate strength and absorbed energy properties by the SES formula and limits for the purpose of calculating laminate panels equivalency corresponding to Primary Structure regions of the chassis.
Test panels must use the thickest core associated with each skin layup. Designs may use core thickness that is 50% - 100% of the test panel core thickness associated with each skin layup.
Calculation of derived properties must use the part of test data where deflection is 50 mm or less.
Calculation of absorbed energy must use the integral of force times displacement
Teams must make an equivalent test that will determine any compliance in the test rig and establish an absorbed energy value of the baseline tubes. • The comparison test must use two Side Impact steel tubes (F.3.2.1.e) • The steel tubes must be tested to a minimum displacement of 19.0 mm • The calculation of absorbed energy must use the integral of force times displacement from the initiation of load to a displacement of 19.0 mm
a. The Perimeter Shear Test must be completed by measuring the force required to push or pull a 25 mm diameter flat punch through a flat laminate sample. b. The sample must: • Measure 100 mm x 100 mm minimum • Have core and skin thicknesses identical to those used in the actual application • Be manufactured using the same materials and processes c. The fixture must support the entire sample, except for a 32 mm hole aligned coaxially with the punch. d. The sample must not be clamped to the fixture e. The edge of the punch and hole in the fixture may include an optional fillet up to a maximum radius of 1 mm. f. The SES must include force and displacement data and photos of the test setup. g. The first peak in the load-deflection curve must be used to determine the skin shear strength; this may be less than the minimum force required by F.7.3.3 / F.7.5.5 h. The maximum force recorded must meet the requirements of F.7.3.3 / F.7.5.5
When a laminate schedule(s) are NOT a Quasi-Isotropic Layup (F.4.2): a. Results from the 3 point bending test will be assigned to the 0 layup direction. b. The monocoque must have the tested layup direction normal to the cross sections used for Equivalence in the SES, with allowance for taper of the monocoque normal to the cross section. c. All material properties in the weakest direction must be 50% or more of those in the strongest direction as calculated by the SES.
The Lap Joint Test measures the force required to pull apart a joint comprised of two laminate samples that are bonded together. a. Do two separate pull tests with different orientations of the adhesive joint: • Parallel to the pull direction, with the adhesive joint in pure shear • T peel normal to the pull direction, with the adhesive joint in peel b. The samples used must: • Have skin thicknesses identical to those used in the actual monocoque • Be manufactured using the same materials and processes • Have the same overlap as used in the regulated structure. No scaling is permitted. c. The force and displacement data and photos of the test setup must be included in the SES. d. The shear strength of the bond must be more than the UTS of the skin
F.4.4 Equivalent Flat Panel Calculation F.4.4.1 When specified, the Equivalence of the chassis must be calculated as a flat panel with the same composition as the chassis about the neutral axis of the laminate. F.4.4.2 The curvature of the panel and geometric cross section of the chassis must be ignored for these calculations. F.4.4.3 Calculations of Equivalence that do not reference this section F.4.4 may use the actual geometry of the chassis