MATS347 Experimental Materials and Methods
MATS347 Experimental Materials and Methods |
|
The following text should be used in your MATS347 coursework report.
This should (a) save you effort, and (b) make marking the assesment easier for me!
Do change references numbers to align with your list, or use the Harvard system.
Experimental materials and methods (section author: John Summerscales)
Sixteen groups from the AY2026-27 MATS347 student cohort each manufactured a composite plate, subjected their plate to mechanical testing and examined the fracture surfaces. Two replicates were produced from each combination of basalt, carbon, flax or glass reinforcement fabrics in either epoxy or polyester resin. The materials used are listed in Table 1:
Table 1: Materials used in the MATS347 coursework
Reinforcement Areal weight Weave Source Basalt fibre 220 gsm 2x2 twill fabric Basaltex BAS220T Carbon fibre 200 gsm 2x2 twill fabric Easy Composites BS-22-200-100 'Black Stuff 3k tow carbon Flax fibre 200 gsm 2x2 twill fabric Easy Composites FF-22-200-100 from Eco-Technilin Glass fibre 200 gsm 2x2 twill fabric Easy Composites GF-22-200-100 Matrix Curing agent Source IN2 epoxy infusion resin 30 phr AT30 slow hardener Easy Composites IP2 polyester infusion resin 1% Butanox M-50 standard MEKP catalyst Easy Composites Using an assumption of 50% fibre volume fraction for a woven biaxial reinforcement and a target plate thickness of 2 mm, the number of layers of reinforcement was calculated using fibre density (kg/m3) divided by fabric areal weight (gsm). The plates were produced by Resin Infusion under Flexible Tooling (RIFT) following the procedure described in MATS347 Appendix A [p]. Laboratory conditions and process parameters are recorded in the Results Section of this report.
The plates were cured for 24 hours at ambient temperature, then post-cured in an oven. Post-cure was 60 °C for six hours for the epoxy, or 80 °C for three hours for the polyester. Test samples were cut from the plate usng the Sharp & Tappin Compcut® ACS300 advanced composite plate saw (model CPS200, serial number 201-22-02-22).
The plates were tested according to BS EN ISO14125:1998 [q] for flexural modulus and strength, using the Instron universal testing machine 3345K1669 (displacement calibration E32601152443553, speed calibration E326011524145834) with the Instron 10 kN load cell 2519-107/51499 (force calibration E326011524132835). All calibrations 15 January 2024 and had expired by the test date. Crosshead speed was 5 mm/min with 10 mm maximum deflection. Test samples were Class III 60 mm long, 40 mm span for glass, basalt and flax, or Class IV 100 mm long, 80 mm span for the carbon samples. Groups C and F samples were tested at 1.4x standard span to retain a sensible span/depth ratio for the thicker samples.
Samples from the plates were tested according to BS EN ISO14130: 1998 [r] for apparent interlaminar shear strength, using the Instron universal testing machine 5582J7466 (displacement calibration E326011524163213, speed calibration E326011524164625) with the Instron 10 kN load cell 2525-801 serial number 833 (force calibration E326011524154847). All calibrations 15 January 2024 and had expired by the test date. Crosshead speed was 1 mm/min with 1.2 mm maximum deflection. Test span was 10 mm for all samples, except that Groups C and F samples were tested at 14 mm span (The EasyComposites specification suggests a consolidated thickness of 0.59 mm/ply).
The failure modes of selected samples were observed using loupes, optical microscopy and/or the Carl Zeiss EVO15 electron microscope (model 354900-9041-100, serial number 8003014386). Failure modes were confirmed to be valid (or not) for the test samples using the reference images in MATS347 Appendix B [s] taken from the respective standards and the CRAG test methods document [t].
Table 2: Failure mode codes for flexural and interlaminar shear tests
Flexural Failure modes Code ILSS failure modes Code Compression C Compression (test not valid) C Microbuckling MB Interlaminar shear ILS Multiple shear MS Microbuckling MB Off centre hinge OCH Multiple shear MS Plastic/fell between supports P Off centre hinge OCH Pull-out PO Plastic/fell between supports P Single shear SS Pull-out PO Stress whitening SW Single shear SS Tension T Stress whitening SW Shear across a single ply x-ply Tension (test not valid) T Shear across a single ply x-ply No obvious failure * No obvious failure * References:
- J Summerscales, R Cullen and L Branca, Composite plate manufacture by resin infusion, University of Plymouth module MATS347 Appendix A, 22 September 2026.
- BS EN ISO 14125:1998. Fibre-reinforced plastic composites - determination of flexural properties, March 1998, confirmed in 2024.
- BS EN ISO 14130:1997. Fibre-reinforced plastic composites - determination of the apparent interlaminar shear strength by short beam method, December 1997, confirmed 2023.
- J Summerscales, Composite mechanical testing, University of Plymouth module MATS347 Appendix B, no date, accessed 08 October 2026
- PT Curtis, CRAG Test Methods for the Measurement of the Engineering Properties of Fibre Reinforced Plastics, Royal Aerospace Establishment Technical Report RAE-TR-88-012, February 1988.