Reference no: EM132373509 , Length: word count : 8000
CAE Project
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.
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.
4. To crush, shred and grind thermoplastic wastes fine enough with a size of 5 mm x 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 N.m 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
Peer-review report is also employed to clearly indicate each member’s contribution to the CAE project and the marks from peer review will be used to modulate the marks for individuals.
Attachment:- CAE Project-Information.rar