BS EN 6038:2015 download free.Aerospace reinforced method the com impact series Fibre plastics Test Determination pression strength of after.
1 Scope
BS EN 6038 defines a method to be used to measure the low speed impact resistance characteristics of fibre reinforced plastics.
It is applicable to composite laminates with unidirectional plies or woven fabric reinforcement.
This standard does not give any direction necessary to meet health and safety requirements. It is the responsibility of the user of BS EN 6038 to consult and establish appropriate health and safety precautions.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated relerences, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN 2374, Aerospace series — Glass fibre reinforced mouldings and sandwich composites — Production of test panels
EN 2565, Aerospace series — Preparation of carbon fibre reinforced resin panels for test purposes 1)
EN 2743, Aerospace series — Fibre reinforced plastics — Standard procedures for conditioning prior to testing unaged materials
EN 2760, Aerospace series — Steel FE-PL78 — 1 760 ≤ Rm ≤ 2 000 MPa — Bar — D ≤ 75 mm 1)
3 Terms and definitions
For the purposes of BS EN 6038, the following terms and detThitions apply.
6.1 Impact machine: drop weight impact tester, capable of capturing the drop weight after the first impact so that a restrike shall not occur (see Figure 3).
6.2 Impactor with the following characteristics (see Figure 1).
6.3 flat-faced micrometer with 6 mm diameter anvils, calibrated to within 0,01 mm.
6.4 Depth gauge with hemispheric adapter, diameter 3 mm and calibrated to within 0,01 mm accuracy.
6.5 Test machine accurate to within 1 % in the relevant load range.
6.6 Compression tools (drawings in Figure 4 for information).
6.7 Vernier slide callipers calibrated to within 0,1 mm.
7 Test specimen
7.1 Specimen description
For the description, dimensions, tolerances see Figure 5.
7.2 Specimen preparation
The specimens are cut out from laminates. The coefficient of variation in the thickness measurements shall be smaller than 2 % per laminate. The laminates shall be produced according to EN 2565 for carbon, or according to EN 2374 for glass.
The laminate should be inspected for example by C-Scan to establish that the laminate is worth testing. If the NDT reveals unacceptable defects, limits defined by the specification invoking the test, the laminate should not be tested.
The process parameters shall be in line with the specification invoking the test.
8.2 Determination of dimensions
Measure and record the thickness and width at three points of the specimen. Use the micrometer for the
thickness and the vernier slide calipers for the width.
8.3 Impact tests
As shown in Figure 3, secure the specimen to a flat mounting plate using four snap fasteners. This leaves a clear window of [75 (± 0,1) x 125 (± 0,2)] mm.
Set the drop height according to the selected impact energy (see formula in 9.1).
Subject the specimens to impact with energy: 9, 12, 16, 20 and 25 joules (impactor 1 kg to 3 kg), 30 and 40 joules (impactor 4 kg to 6 kg).
The specimens must only receive one impact. Therefore bouncing must be prevented using a suitable device.
8.4 Indentation inspection
Inspect each specimen and assess, on the impact face and the opposite face:
— the visibility of the Indentation,
— any breaks in the fibres.
lust prior to perform the compression test, set the specimen between two appropriate tabs. Using a depth gauge, measure the indentation depth on the impacted face to within 0,05 mm with the following procedure:
— measure the depth gauge value in the deapest part of the indented area.
— then measure the depth gauge value on 4 points as shown in Figure 2 and substract from the value in the indented area,
8.5 Study of the barely visible impact damage (BVID)
Draw up the curve of the evolution of the indentation depth as a function of the impact energy.
By linear interpolation, determine the energy EKvw (energy for the barely visible impact damage) corresponding to an indentation of 0,3 mm.
Subject three specimens to impact with energy EHVID.
After having been impacted inspect on those three specimens the depth of the indentation (same as
defined 8.4) and perform the compression test (same as defined In 8.6).
8.6 Compression tests on impacted specimens
Compression strength after impact has to be determined for all the specimens subjected to impact testing.
If required in the relevant specification, two strain gauges should be on the front face of the lowest impact energy specimen.
Carefully align the impacted specimen in the test rig (if any, the strain gauges should be at the top of the specimen during testing).
Select the range of loads so that break failure occurs between 20 % and 80 % of the scale.
Select a cross head speed of 0,5 mm/mm.
Note the load Pr of the break failure.
Record the curve load versus time.
9 Presentation of the results
9.1 Impact energy
Pr is the break failure load, in N; w is the specimen width, in mm;
t, is the nominal thickness of the specimen, in mm.
10 Test report
The test report shall refer to this standard and shall include the following:
10.1 Complete Identification of the material tested, including at least type, source, manufacturer’s code number, fibre areal weight, filament count, processing details.
10.2 All details regarding specimen preparation.
10.3 The measured test specimen.
10.4 Date of test, facility and identification of individuals performing the test.
10.5 Equipment, method and test parameters used.
10.6 For each Impacted specimen record of:
— impact energy,
— visibility and depth of indentation,
any breaks In the fibres (on both faces of the specimen),
— compression strength after impact.
10.7 Curve of compression strength after impact versus energy.
10.8 Curve of indentation depth versus energy.