Coursework Assignment - 'Marine Drivelines and Transmission'
Assignment based on marine drivelines and transmission.
See table and figure below: Calculate the torsional vibratory response for the depicted driveline for the speed range from 500 to 720 rpm:
- Alternating torque amplitudes in the shaft sections and gear teeth connections
- Alternating stress amplitudes in the shaft sections
Evaluate your results based on:
- Likeliness of gear hammer occurring in the gear teeth connections
- Likeliness of fatigue failure in the shaft sections. Use allowable stress limits according to the international association of class societies document M68 with ck factor 0.8 and ultimate tensile strength 400 MPa (see section 6.1.6 in your extra lecture notes for details)
If you have identified a potential problem, show what natural frequency and corresponding mode shape is responsible for the problem.
Formulate two solutions. One solution based on changing the mass of the driveline, one solution changing the stiffness of the driveline.
Explain the risks of the new solution and possible extra calculations required to evaluate this risk.
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Nominal engine power
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675 W
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Nominal engine speed
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730
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Driving torque curve
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According to classic propeller curve: Torque1/Torque2 = (n1/n2)2
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Speed range
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500-720
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Number of blades propeller
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5
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Excitation blade passing frequency
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10% of driving torque
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E modulus shaft material
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2.1e11 Pa
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Damping shaft material ε
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1%
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Poisson ratio
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0.32
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Specific mass shaft material
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7835 kg/m3
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Archer value propeller damping
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25
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Ultimate tensile strength propeller shaft
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400 MPa
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Ck factor
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0.8
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Your report should contain the following:
An executive summary, containing a summary of aims and objectives of the calculations, evaluation criteria, conclusions from the results, and recommendations
Input value section, where you present the stiffness, mass and damping values you used in your discrete (FEM) model and the software you used for the calculation of the results.
Presentation of the results in a graph showing the calculated values set against the E motor speed (revolutions in rpm).
Presentation of the first two torsional mode shapes and corresponding natural frequencies.
Presentation of the evaluation of the results.
Presentation of the proposed solutions and how these solutions affect the torsional response of the driveline (explain the mechanisms).
Present a printout of your stiffness, mass and damping matrix at 730 rpm as an appendix to your report.
Attachment:- Assignment Files.rar