Reference no: EM132384862

301022 Advanced Computer Aided Engineering Assignment

School of Computing, Engineering and Mathematics - Western Sydney University, Australia

CAE Project - CAE of a Shredder

Learning goals -

To narrow down the gap between fundamental theories and practical applications of Finite Element Method (FEM) and Finite Element Analysis (FEA) on Computer Aided Engineering through synergistically and systematically applying what we learn in this unit 301022 Advanced Computer Aided Engineering to design a typical mechanical device - a shredder to perform a CAE practice and finish design loops in the assessment task - CAE Project.

Design of a mini shredder using gear drives -

A typical design of a hand-powered mini shredder using gear drives has been shown in Figure 1, which was especially designed for recycling thermoplastics, i.e., ABS (acrylonitrile butadiene styrene) and PLA (Polylactic acid).

Design Requirements -

Design Background - For the design project, we assume the SCEM 3-D Printing Lab - MakerSpace need a shredder, which is planned to develop a green 3-D printing closed-loop system for recycling polymer and metal materials, i.e., Waste Plastics Filament Extrusion, and reusing them in a filament extruder as depicted  in Figure 2.  In the proposed green 3-D printing closed-loop system, the shredder needs to be designed to shred, crush, and grind the thermoplastic wastes into small pieces that can fit into the extruder.  The size of the small pieces is usually 5 mm x 5 mm, which allow the auger or drill to transport them to the heat chamber of the extruder. Dimension consistency of the recycled and shredded plastic pieces helps avoid diameter variations on final product - the extruded filament.

The shredder sub-system is consisted of the following three main components: 1) shredder and gear drive-based speed reducer; 2) belt drive or chain drive; and 3) electric motor. Functions

The functions of the integrated shredder are as follows:

Speed Reducer

1. To receive power from an electric motor through a rotating shaft.

2. To transmit the power through machine elements that reduces the rotational speed to a desired value.

3. To deliver the power at the lower speed to an output shaft, this ultimately drives the shredder.

Shredder

4. To crush, shred and grind thermoplastic wastes fine enough with a size of 5 mm ? 5 mm.

Working conditions

• The whole shredder sub-system, which is required to run 6 hr/day, 5 days per week, with a design life of 10 years. This is approximately 15,000 hours of operation and its operation is generally smooth.
• The production speed of shredder sub-system is 2.0 kg/hour though the thermoplastic wastes might be shredded repeatedly several times for refinement.
• The shredder could run at a speed of 60 rpm and need a torque of 500 Nm at most to crush, shred and grind thermoplastic wastes. Both of them are permitted to vary ±5%.
• A stage of speed reducer is preferred but one stage is also acceptable. The speed reduction ratio of the speed reducer should be controlled in a range of 3.46 to 3.53 for each stage.
• A compact design is required to integrate the speed reducer with the shredder together with an overall size of 0.5 m x 0.3 m x 0.3 m.
• A mechanical efficiency of greater than 95% is desirable.

Selection Criteria

1. Safety: The shredder should operate safely and provide a safe environment for people near the machine.

2. Cost: Low cost is desirable so that the shredder appeals to a large set of customers.

3. Size: compact design with a small size is preferred.

4. High reliability.

5. Low maintenance.

6. Smooth operation: low noise and vibration.

Design Methodology - You will be allocated to a team of 2-4 students to achieve the design goals with creative ideas together and for equity, a peer-review report to evaluate each team member's contribution is employed with the group slides and design report for submission at the end of the semester as required in the learning guide. In your team you should have a unified and clear target to design the shredder and its accessories including belt/chain drive to transfer the power and torque from the electrical motor to the input shaft of the shredder. Electric motor could be chosen roughly. The team members should have a discussion to allocate the design tasks evenly. Your design may involve in the following commonly-used machine elements:

• Gear drives
• Belt and Chain Drives
• Keys, Couplings and Seals
• Machine Housing
• Shafts
• Bearings

The design will be mainly focused on gear, belt and chain drives and couplings, aligning with the unit contents of 301022 Advanced Computer Aided Engineering.

• Design identification and requirement analysis of the shredder machine system
• CAD modelling and motion analysis of the shredder machine system
• FE modelling and simulation of the shredder machine system by appropriately de-featuring the CAD model constructed, by choosing two or three or four studies (2 for a team of 2 Students, 3 for a team of 3 students, 4 for a team of 4 students, respectively) from the following finite element analyses highlighted, which are available in ANSYS Workbench

General criteria for assignments -

The highest grades will be given to submissions that:

• make clear statements about the CAE project in terms of needs and goals;
• show a high standard CAD model of the shredder machine system;
• show a high standard FE model of the shredder machine system;
• show a high standard understanding on FEA of the shredder machine system in appropriate loading scenarios;
• show clear evidence of literature research, and evaluation of products already on the market by paying considerable attention to their benefits and shortcomings;
• clearly document the CAE project's development and show consideration of alternative approaches, methods or material considerations; and
• provide a high standard evaluation that demonstrates an understanding of the strengths and weaknesses in the shredder machine system through detailed finite element analyses.

The qualities described above are critical features central to good CAE practice. Consider the methodologies you devise in order to communicate the extent of your personal achievements of the above criteria as your first CAE challenge.

CAE (FEA) report -

A CAE (FEA) report would most likely contain the following items (separated by headings and subheadings):

• Title page
• Executive Summary
• Table of Contents page
• Introduction & Background
• Aim and Objectives
• Main body - The contents of this section (divided into suitably headed subsections) is subject to change, and it depends upon what is being examined. Typical contents would be i ncl udi ng Detailed design information of the shredder machine system, Physical problem, CAD modelling of the machine, FE modelling of the machine, Finite Element Analyses of the machine (Preliminary analysis, de-featuring and assumptions made for FEA, decision making process and final analyses, Results and Discussion. The sub-sections in this main body can be suggested as follows:

1. Detailed design information of the shredder machine system

2. CAD modelling of the machine

3. FE modelling of the machine

4. Finite Element Analyses of the machine, de-featuring and assumptions made for FEA, decision making process

5. Results and Discussion

• Conclusions
• Acknowledgments
• References
• Appendices - Peripheral information, including catalogues, technical drawings and detailed calculations may be placed here or in the main body of the report depending upon its relevance (e.g. repetitive calculations should be left in the appendices, but you may wish to include a sample calculation within the body) 'standard' calculations would also be better in this section. Also there should be an appendix to indicate the technical contributions from each member.

Outcomes of CAE Project -

A group has to produce

• a PowerPoint-based presentation of the highlights of their CAE Project - particularly the aim and steps towards realising it, as well as how much in effect was accomplished in the time available for the exercise. The actual presentation should be made by each student involved in the project and summarise their project work in 10-min PowerPoint slides (at least 12 pages including cover page and references page) to show their design abilities built up during study; and
• a written CAE report: only one per group. The report should be prepared following up the format of a standard technical report (20-25 pages).

Attachment:- Advanced Computer Aided Engineering Assignment File.rar