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UNSW Sydney

School of Mechanical and Manufacturing Engineering
MECH 9420
ASSIGNMENT #2: Composite Laminate Manufacturing and Mechanical Testing Report


Submission due 5 pm Friday, 25th April 2024 (Week 10)-T1 2025

The aim of this assignment is to expand your knowledge and understanding of the standard
manufacturing method of composite materials and their mechanical responses under mechanical
loads. The tensile tests will be conducted in accordance with standardized test methods of ASTM
International (American Society for Testing and Materials). In this assignment, you will be able
to conduct laboratory scale experiments on coupons made from Carbon/E-glass/Epoxy
composite panels using the vacuum infusion process. You will also be able to compare
estimated and experimental values predicted as per the ASTM Standards.


Problem Definition
Manufacturing and mechanical characterization of Carbon/E-glass/Epoxy hybrid composite
laminates


Proposal
Your tasks will be (1) to manufacture a large hybrid composite laminate comprising carbon and
E-glass fibre fabrics with an epoxy matrix; (2) to investigate the mechanical behaviour of the
Carbon/E-glass/Epoxy hybrid composite laminates under tensile load and determine the tensile
properties, including the tensile strength (), ultimate failure strain () and modulus (E).The
failure modes for tensile loading must be evaluated. (3) to study the three-pointing bending
flexural properties of the composite laminates.

Assignment Criteria

o Attendance and participation during the laboratory experiments.

o Presentation of a laboratory report covering the interpretation of experimental results.
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You will be required to use the corresponding ASTM standards described for the mechanical
testing methods to prepare your report for evaluation and assessment.
Report on Large Sample – Manufacturing and Testing
In Week 3, you are allocated to a group within which you have the opportunity to help prepare
a FRP composite panel which was processed by the vacuum resin infusion (VRI) closed-
molding process. After curing, mechanical test specimens are cut from the panel and tested for
tensile (Week 8) and flexural (Week 9) properties. In this assignment, you are asked to answer
some questions and perform some calculations regarding the sample panel, reflect on the
application of the VRI process and write a report on the manufacturing and mechanical (tensile,
flexural) tests that you performed.
Composite laminates for all students are the same.
Question 1 – 3 marks
(one page as a guide)
1.1 What is the architecture of your laminates? (Ply number, ply layup, fabric type etc.) and
what is the in-plane dimension (in length (mm)*width (mm)) of your manufactured laminate?
1.2 Given the following fibre and matrix data:
Fibre material g/m2 Weight fraction (%) (kg/mm3)
Plain weave carbon 198 30 1.81E-6
Plain weave E-glass 195 30 2.54E-6
Matrix material Parts and mix ratio Weight fraction
(%)
(kg/mm3)
RAKU-TOOL EL-
2203/EH-2970-1
Epoxy
10-parts part A: EL-2203
resin (1.16E-6 kg/mm3)
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What will the density
be?
3-parts part B: hardener:
EH-2970-1 curing agent
(0.96E-6 kg/mm3)
(a) Calculate the areal mass in kg/m2 of your cured laminate.
(b) Assuming the nominal ply thickness for carbon (C) and glass (G) ply is 0.22 mm, what is
the weight
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(in gram) of the epoxy matrix of your manufactured laminate?
(c) How much resin did you use for using VRI process, and why?
1.3. Compared with layup schemes of [C]8, [G]8 and [C/G/C/G]S, what are the advantages of
the layup scheme of your manufactured laminate, and why?
Question 2 – 3 marks
(2-3 pages as a guide, including pictures)
Vacuum resin infusion is a widely adopted composites processing method.
2.1 List four advantages and disadvantages of the method.
2.2 Describe the manufacturing process of your prepared composite panel in Week 3, in a
concise and coherent way. Please also clarify reasons/purposes for conducting each
operation/step to eventually manufacture a fibre composite laminate.
2.3 Suggest a novel application of the vacuum resin infusion processing method for a
composite component that you can think of, as opposed to an established method. Briefly
explain what advantages the use of the method would bring to the application in approx.150
words.
Question 3 – 12 marks
Write a report (4-5 pages as a guide) on the mechanical testing (3 specimens for tensile testing) in
Week
8. Your report must include the following elements:
(a) A brief introduction containing the experimental Aims in bullet-point form.
(b) A methodology section: Refer to the test standard—ASTM D3039 for tensile properties
whenever the standardization of the testing is required.
(c) The results section includes photos of the specimen you tested; before, during and after
failure. Clearly label each photo with a caption identifying the before/during/after failure.
(d) The results section should also refer to these photos in (c) and identify the failure modes
that you have observed.
(e) The results section, according to the test standard, should include:
• Date and location of test. Test machine name and model.
• The specimen length, width, and thickness in mm.
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• A Chart or Graph (Curve) for sets of test results as produced by the Instron machine
output.
• Calculation of the tensile stress, tensile strain and tensile chord modulus according to
ASTM standard.
(f) A discussion section summarizes the key observations you made.
(g) Write up the discussion of results.
(h) State your Conclusions
(i) Write a statement explaining what you have learned about the nature of typical failure
modes in composites compared with, for example, metals. [Hint: Consider the use of terms
such as brittle and ductile].
Question 4- 12 marks
(4-5 pages as a guide) to report the flexural testing results:
(a) A methodology section describing the experiment: Refer to the test standard—ASTM D790
for flexural properties whenever the standardization of the testing is required.
Describe how you conducted the experiment and what the key points are. You may like to
describe your composite panel, test setup, loading rate, and the required plots for load-
deflection, stress-strain etc. Is there anything you have noticed during the experimental program
that could lead to major deviation in analytical results? (2 marks)
(b) The results section includes photos of the specimens you tested before, during and after
failure. Clearly label each photo with a caption identifying the before/during/after failure. (2
marks)
(c) The results section should also refer to these photos in (c) and identify the failure modes that
you have observed. The results section, according to the test standard, must also include:
• Date and location of test. Test machine name and model.
• The specimen length, width, and thickness in mm.
• A Chart or Graph (Curve) for sets of test results as produced by the Instron machine
output.
• Calculation of the flexural stress, flexural strain and flexural modulus according to
ASTM standard.
Show the results of your analysis. The raw data for all test sets will be provided in lab classes.
You will be able to use the raw data for further analysis. You will need to show the graphs of
Stress vs Strain for all groups test results. You will need to calculate all the elastic properties
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and flexural strength. You will need to show the calculation methodology and results of the
material properties in detail, as shown in the following Table.
- Please try to take photos of your specimens to explain better the composite behaviour.
Most importantly: All material from the tests will be shared, try to make good photos for
your and for your classmates.
- Compilation of results will be required. You will need to show the results of all specimens
and explain the variation of results.
(8 marks)
[Instructions]
1) Tabulate group members’ names and student IDs on the cover page.
2) The references section at the end should include all the in-text references.
3) Write a contribution statement before the References section, for example, ‘Andrew
contributes to writing up of Section 1; Ben contributes to the data processing in
Section 3…’
4) It is suggested to use Times New Roman 12-point with 1.5 linespacing.
5) Page limits 18 including References and Appendix.
6) All figures and tables should be numbers in sequence in the text.
7) Each page should have a page number.
8) File format is to be either MS Word or Adobe Acrobat pdf.
Key parameters of flexural tests
1. Completed stress-strain curves
2. Modulus of elasticity in
bending
3. Flexural strength
4. Ultimate flexural strain
5. Failure mode

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