3542

3348

كارشناسي ارشد

طراحي كاربردي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1385

پانزده، 92،[II] ص: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

مصطفي غيور

احمد صداقت

27/3/86

حسن نحوي، عباس فتاح

مهندسي مكانيك

ID3348

به فارسي و انگليسي: قابل رويت در نسخه ديجيتال

abstract Shells and specially cylindrical shells are the main part of many engineering structuresin industrial fields such as marine petroleum nuclear and aerospace Shell s vibration isan important subject which attract many researchers in this fields Different stiffeners and composite shells with different orientations have generally usedto achieve special mechanical properties as well as an appropriate weight to stiffness ratio Fluids such as air or water around shells can interact with shells and complicate theproblem The radiated pressure in fluid and the response of elastic shells should be foundsimontanusely because of feedback coupling between them After years there are no specific relations to model end effects of finite submergedcylindrical shells instead approximate methods have been used Among analyticalmethods the wave propagation approach appear to produce good results by means ofsimilarity between the propagated waves in flextural vibration of a beams and a cylindricalshells In this research the wave propagation approach by means of thin shell theorem is usedto find natural frequencies of an isotropic finite cylindrical shell invacu and in a submergedfluid Frequenies of a fluid filled cylindrical shell and one in contact with internal andexternal fluid are found too by the same approach and are compared with frequencies invacu to investigate the effect of virtual added mass decreasing of natural frequencies theeffect of medium ideal fluid on natural frequencies and mode shapes of a finitecylindrical shell Effects of different parameters such as circumferential modal number n longitudinal modal number n thickness to radius ratio h R and boundary conditions onnatural frequencies of a submerged cylindrical shell are investigated Natural frequenciesof a composite cylindrical shell with orthotropic layers by the wave propagation approach natural frequencies of stiffened cylindrical shell are obtained in this work After validation of ABAQUS results in modeling of fluid and shell interaction acombinated shell include of a cylindrical shell and some spheroidial and conical which canbe a submarine shell are modeled and the corresponding natural frequencies are computed

مصطفي غيور

احمد صداقت

حسن نحوي، عباس فتاح