UFMFU6-15-3 Composite Engineering

Integrated Design Project:

Material Characterisation, Manufacturing and Design

Group Work Task

Deadlines:

Slide Submission 12/12/2024 14:00

Presentations weeks - 16/12/2024 and 06/01/2025

Outline

This assignment represents 75% of the total module marks. The assignment assumes you have engaged with the lecture notes and lab sessions. The assign-ment is assessed via a group presentation and subsequent questions. Groups are available on Blackboard and assigned by the module team. All members of your group are expected to work as a team and initially receive equal marks for this task. A peer assessment process distinguishes between members of your group identifying those that have made, significantly larger (or smaller) contri-butions to the submission. The peer assessment is available on Blackboard. As a reminder the project aims to integrate the various aspects of practical/design work you have completed throughout the module.

Learning Outcomes and Effort

The following learning outcomes are covered by this assignment:

• MO3 - Design optimum solutions with composite materials.

• MO4 - Critically analyse the inter-relationship between manufacturing process, mate-rial properties, quality and cost.

• MO5 - Appraise the performance and discuss the key conflicts of using composite materials with regard to sustainability and recyclability.

The total effort should reflect 40 hours of work - but this does not include time spent in classes.

Weightings

The group project contributes 75% of your overall module mark. The weighting of this assignment is 25% for the slides and their presentation and 75% for the following questions and your answers.

You will be asked to focus on two aspects of equal weighting for your presentation:

Main - 1 Design with Matlab.

Main - 2 Manufacturing and quality assurance.

However, you must include an appendix in your presentation slides. This must include the key results from the Composite and Structures lab activities:

Appendix - 1 Experimental analysis.

Appendix - 2 Initial Laminate calculations.

Each section has a deliverable associated with it, these key outcomes must be shown in your presentation.

We will review your appendix section before the presentation. We do not expect you to focus on this during your delivery however we may ask you to clarify some details as part of your response to questions.

As a team, you will be expected to answer technical questions about all aspects of the project. You should ALL be familiar with ALL parts of the project. Therefore you must commu-nicate effectively with each other. Your peer score will be affected by multiple factors such as your communication within the team, contributing to the analysis, and creating the final slides and presentation.

Blackboard Submission and presentation

A group submission point will be created for the slides in the assignments area.

This assignment is not eligible for extensions as it is group work.

Your presentation slot is treated like an examination. If you do not attend the presentation you will receive a mark of 0 even if the group completes the presentation without you. Please note that all assessments will be held in person by default.

Peer-Review

Each team member must submit their review form. on blackboard. Your group’s peer review scores is used to increase/decrease your personal mark relative to the group’s score. The maximum increase is capped at 10% of your group’s score. There is no lower limit, i.e. you will fail if you do not engage/contribute to the group assignment. The module team reserve the right to exercise their academic judgements with respect to peer scores.3

Formative Feedback

You should attend the scheduled laboratory sessions to discuss your work/progress with the lecturers. It is expected that you have completed the suggested laboratory exercises that are intended to support you in completing the assignment.

How to get started?

A review of the scheduled lab activities should be your starting point. Each week you will be provided with an activity that contributes to your final project. Please review these activities. Make sure you take a record of any data you obtain in the lab sessions.

How to get a good mark?

To get a good grade, as a team, you must show you have understood all aspects of the experimental work, what the implications of manufacturing choices mean for the quality of your product, and how to critically incorporate these into any design choices. You must be able to demonstrate your ability to research supporting information and critically appraise the performance of your design against a variety of metrics. You must also be able to articulate key findings and present these clearly.

FAQ

If in doubt, ask the module team. The module team will put answers to questions that will benefit all teams onto a FAQ/discussion area in blackboard. Keep checking this as it will be updated regularly.

Group Assignments and Group Working

Groups for this assignment will be allocated by staff at the start of the term. It is up to you to manage your group working demonstrating your skills - this is a professional competency expected of graduate engineers.

It is suggested that during your team meetings you:

• Review previous work and identify any work that is behind schedule.

• Identify and record actions for each team member.

• Agree on a work/meeting schedule including regular progress updates.

As part of being a professional engineer, you should agree to deliver your work promptly (well in advance of the deadline). This allows the whole team to review its content. If you believe a team member is struggling to deliver their work it is best to raise this courteously within the group first, and allow them an opportunity to explain. It may be that the task is more challenging than it first appeared and the team needs to adapt. Try to find an agreeable solution in advance. Conversely, if you know you can’t complete work assigned to you on-time don’t ignore this, try and let your team know, they may be able support you. A good use of your team is to have more than one person complete the calculations/analysis independently and then compare outputs. We expect you to show validation of your results to demonstrate critical evaluation skills.

SECTION Main - 1: Design with Matlab

A client is seeking to develop a lightweight vertical tower to support a wind-turbine that can be erected in remote locations, see Figure 1. The device must be easily transported and deployed in a variety of challenging environments - e.g. tropical, desert and coastal. Your priority is to minimise the mass of the structure and where possible its stowage volume.

The vertical tower shall be secured to a ground plate/foundation, via a bolted connection. This will provide sufficient restraint that a fully fixed boundary condition may be assumed. For the initial designs you may assume a structural requirement as shown in Figure 2a, i.e. a cantilevered column, subject to axial loading, transverse load at the tip, and a torque acting about the centroid of the beam. Each group has unique set of design requirements which can be found on blackboard.

As an initial design, a cylindrical hollow tube is proposed constructed from carbon fibre,. You may assume that the tube’s wall thickness H is small, relative to the tube’s diameter D, such that thin-walled analysis is appropriate, Figure 2b. However, you should also check this is true in your final design, and if not comment on what further analysis would be required (You are not expected to do it). You should use the Euler buckling formula to check the suitability of your design. However you must clearly state any effective length factors you have assumed and what simplifying assumptions you may have made regarding stiffness and second moment of area.

You do not need to design the bolted ground anchor, deployment mechanism, or any con-nections between sections. Analysis must be conducted in Matlab and supported with hand calculations.

Figure 1: Conceptual design of a wind-turbine anchored to the ground at the base

(a) Column like layout of beam, length L, with clamped support at the root, Vertical Force M, Horizontal Force, F and free-end torque, T.

(b) Cross section of the thin walled tube shown for illustrative purposes.

Figure 2: Assumed Structural Analysis

The following approach is suggested:

1. Using a quasi-isotropic laminate as the baseline and assuming the same carbon fibre pre-preg from the laboratory sessions. Propose initial design(s) for the tube that is/are sufficient to resist the applied loads. What is the mass/stowage volume of the structures?

2. Show, if possible, how the baseline quasi-isotropic layup could be improved to increase performance by tailoring the layup and exploiting a uniaxial (rather than biaxial pre-preg).

3. The client has observed that the expected deflection of the structure is excessive for their operational requirements. Modify your design to ensure that tip deflection is kept below the thresholds specified. Compare the deflection of your new design with the previous ones.

4. The client would like you to improve the stowage volume. How could your designs be modified to incorporate tapering of the beam and/or segmentation such that parts can be stowed concentrically within each other? What is the impact on the mass and deflections of the structure? Any simplifying assumptions must be conservative.

5. The company’s stakeholders have raised concerns about the sustainability of the chosen material. Propose a sustainable alternative and provide an estimate on the impact its inclusion would have on the final design requirements.

Advice

When proposing your design, think carefully about what design tolerance and loading factors may be appropriate. This should be reflective of any manufacturing method you intend to use and your observations from the expected performance of your material. When discussing your design you MUST provide quantitative evidence for your selected designs relative to other options and comments including the laminates strength reserve factor. The breadth of design comparisons shown should be consummate with the number of members in your group.

Deliverables

You must include the following information:

• Material and strength properties you have assumed. Including how you have obtained them. (See Appendix 2 requirements).

• Load conditions and any simplifying assumptions regarding structural behaviour or conservative use of formulae.

• Response characteristics, including deflection and maximum stress/reserve factors.

• Any layups and part geometry.

• Quantitative evidence for how you have selected your designs.

SECTION Main - 2: Manufacturing and Quality Assurance

Following the Design (with MATLAB) activity, the client has asked your team to recom-mend a manufacturing approach for the future build of 250 of these wind turbine towers. You should consult a range of sources (i.e. not just lecture notes) to provide them with a well-justified recommendation. Questions to be considered are:

1. What manufacturing process would you recommend for cost-effective production tar-gets?

2. What rate of production (or shipset per month) would this process be suited to?

3. A “right-first-time” approach is needed so how will you will minimise manufacturing defects?

4. What commercially available materials would you use for the manufacturing approach?

5. What would the indicative top down costings be for your approach?

6. What would the indicative top down costings be for your approach?

7. How will you demonstrate the performance of the component is adequate ahead of delivery. What quality assurance practices would you employ?

8. How could the operating environment impact long-term structural performance? What measures would be used to protect the structure?

9. In order to ensure continued optimum performance, what in-service inspection regimen would you propose to monitor the structure throughout its life cycle?

Advice

You should provide a recommended liquid infusion manufacturing approach that addresses the client’s questions, and this must be supported by suitably referenced sources. As part of your recommendation show how you will ensure the quality of the product in manufacture (particularly thinking of wrinkles in hoop direction and waviness along any tapering length) and during installed operation. Ideally, define the minimum acceptable defect size before corrective action would be required. Indicative costs will require some assumptions to be made, and so clearly state where those are or show links to reputable referenced sources. Consider the complexity of the manufacturing approach, especially in terms of tooling and how that impacts on defects, costs, and production rate. Provide details on how you will ensure the reliability/performance of your final product - you should consider the varied operational environment and intended use in any discussion. Be sure to highlight any addi tional considerations the client should be aware of when selecting the final design for their intended application (for example - what if the client then asks for any thoughts on how the structure would be lifted/assembled).

Deliverable

You must include the following:

• A recommended manufacturing approach with evidenced justification.

• How you will ensure the quality of your product.

• How you will ensure its ongoing functionality.

• Reflection on the lifecycle of the product and any sustainability challenges.

SECTION Appendix - 1: Experimental Analysis

The appendix information should be included in your slides but you do not need to deliver its content when you present.

Your group has manufactured and tested at least two different configurations of composite material. Review the data you have collected and decide which is most reliable. Use the data you obtained from standard tensile testing methods to determine:

• The tensile modulus of the materials.

• The tensile strength of the materials.

• The stress at initial fibre failure.

• Occurrence of matrix cracking, first ply failure or delamination - note that the failure mechanisms depend upon the type of material being tested.

Advice

You should consult Blackboard for the standard test methods and key material details etc. You should make sure you review the data to ensure you are selecting the correct ranges for your calculations.

Deliverable

You must show

• Which laminate’s data you have analysed.

• Graphically, your stress/strain response and any data points used to infer modulus or strength.

• A comparison to technicians’ benchmark data.

• Final modulus calculations, indicating any assumptions.

SECTION Appendix - 2: Initial Laminate Calculations

Using the information provided on blackboard (and where needed external sources) predict the theoretical performance of the composite panels you manufactured for Appendix A:

• Rule of Mixtures with Efficiency Factor.

• Simplified Classical Laminate Analysis formula.

• Classical Laminate Analysis (ElamX or Matlab).

Using these methods and knowledge of composite behaviour predict the samples’:

• Tensile modulus & strength.

• Tensile failure mechanism (first ply failure).

You should consider the advantages and limitations of each of these approaches and how well these compare with the experimental values you have observed.

Advice

You need to present a clear comparison of each of the methods for your specific samples and compare these results to those obtained experimentally. Review on any discrepancy between each method’s predictions and how well these compare to observed experimental results.

Based on the above analysis and other sources identify a full set of material and strength properties that you will use for your design analysis. State clearly why you have selected these values, and if appropriate, the source of any values that are taken from the literature.

Deliverable

You must show:

• Your measured values are the inputs for your calculations.

• Outputs from each of the methods and comparison to experimental values.

• Identify any discrepancies between methods and a justification for them.

SECTION Overall: Quality of presentation and its delivery

You are free to choose how you lay out and structure the information within your presenta-tion. The names of all contributing team members should be listed on the title page. You will have time to explain the content during the presentation so avoid large blocks of text. Your presentation should have a logical structure and highlight the key results. Where you have referenced external sources these should be cited as footnotes - with the references included at the bottom of the slide

You will get a maximum 10 minutes to present your work. This should comprise Sections 1 and 2 - not the appendices. You will be told to stop if you go over time. Your team members should all contribute to the presentation. You will then have 15 minutes of unseen technical questions. Questions will be posed to the team and all members should contribute to answering questions. There are no set questions, we will respond to your presentation and answers.

Deliverable

The presentation should submitted as a pdf - any other format means we cannot guarantee they will work.

You will be asked technical questions which cover all aspects of the brief. While it is accept-able for one person in the team to lead on different areas we still expect all group members to contribute to answering questions and to have familiarity with the details of all sections.

For the avoidance of any doubt. You MUST attend your presentation slot with your team, or you will get a zero score.