7248

6754

كارشناسي ارشد

طراحي كاربردي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1391

[نه]، 87ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

مصطفي غيور

ضيايي راد

20/8/91

تيكني، موسوي

1396/09/21

كتابنامه

مكانيك

مهندسي مكانيك

ID6754

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

The Design of a Resonance Changer for a Particular Floating Vehicle Mohammad Behzadi m behzadi@me iut ac ir 5 28 2012 Department of mechanical engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Dr Mostafa Ghayour ghayour@cc iut ac irAbstractIn this research we want to eliminate the harmful longitudinal vibration using resonancechanger In fact resonance changer is a hydraulic vibration absorber which is modeled bymass spring and damper In ships this device is used because resonance of axial forcesdamage the components of propulsion system In submarines moreover there isprobability of detection by sonar which is sensible to waves propagated in water fromsubmarine body In the case of ships and submarines a major source of the radiated noiseis due to excitation of the hull modes resulting from vibration transmission through thepropeller shafting system Oscillations occur at the propeller due to small variations inthrust load when the propeller blades rotate through the non uniform wake resulting inaxial excitation of the propeller at the blade pass frequency This problem can be addressedby the use of a resonance changer For designing and optimizing of resonance changer first equations of system is written according to Newton laws and after that resonancechanger parameters including mass spring and damper will be dimensionless Foroptimisation of these parameters boundry of them are specified and continuous geneticalgorithm is used Since the genetic algorithm execution technique is not dependent on theerror surface we can solve multi dimensional non differential non continuous and evennon parametrical problems Cost function in ships is maximum amplitude of appliedforce to thrustmeter in operating range Applied force to thrustmeter is measured at the endof propulsion system Amplitude of this force in every frequency is obtained using impactfunction and fast fourier transformation and specified its maximum in operating range When the impact is applied to a mechanical system its frequencies is excited We canproduct amplitude of input force to output response because system is linear In submarinescost function is maximum time averaged power of radiated sound getting from productionof applied force to body and fluctuating velocity of submarine body Also other costfunction is considered as maximum amplitude of applied force to body Using resonancechanger causes more than ninety percent reduction in cost functions In order to investigatethe effect of resonance changer on other components of propulsion system graphs of theiroutput are drawen These output are applied force to thrust bearing displacement ofpropeller and displacement of thrust bearing Generally maximum of these parametersreduce by use of resonance changer Keyword Resonance changer genetic algorithm vibration absorber impact function

مصطفي غيور

ضيايي راد

تيكني، موسوي