nshryh mhndsy dryPub Date : 2020-11-01DOI: 10.29252/MARINEENG.16.32.131
Saeed Soheili, Poorya Ghasemizadeh, E. Hosseini
{"title":"Design of vibration reducer for thrust bearing of marine shaft","authors":"Saeed Soheili, Poorya Ghasemizadeh, E. Hosseini","doi":"10.29252/MARINEENG.16.32.131","DOIUrl":"https://doi.org/10.29252/MARINEENG.16.32.131","url":null,"abstract":"of marine propulsion shafting system may bring serious problems and many efforts have been performed to mitigate theses vibrations. Propeller oscillations due to the small variations of thrust, when the propeller blades rotate through the non-uniform wake, result in the longitudinal vibrations in the propulsion shafting system. These oscillations can be transmitted to the hull through the thrust bearing of the vessel. In this study, the propulsion shafting system is modeled with the decomposition of FRF method. The comparison between the numerical solution of system in MATLAB Simulink software, and the decomposition of FRF method; shows that the numerical solution has less 4 percent error. In order to decrease the transmitted vibrations to the hull, Goodwin Resonance Changer (RC) is utilized. An optimization method is used to optimize the RC’s stiffness, damping and mass coefficients . The results show that if the appropriate coefficients are selected, the transmitted vibrations can be reduced up to 99 percent in the hull.","PeriodicalId":33555,"journal":{"name":"nshryh mhndsy dry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48022761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
nshryh mhndsy dryPub Date : 2020-04-10DOI: 10.29252/MARINEENG.16.31.109
صادق فاضل, ناصر پریز
{"title":"شبیه سازی ریسک-پایه و پویای صحنه عملیات دریایی با هدف مسیریابی ایمن شناورهای سطحی","authors":"صادق فاضل, ناصر پریز","doi":"10.29252/MARINEENG.16.31.109","DOIUrl":"https://doi.org/10.29252/MARINEENG.16.31.109","url":null,"abstract":"","PeriodicalId":33555,"journal":{"name":"nshryh mhndsy dry","volume":"247 1","pages":"109-121"},"PeriodicalIF":0.0,"publicationDate":"2020-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69862566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
nshryh mhndsy dryPub Date : 2020-04-01DOI: 10.29252/marineeng.16.31.123
Majid Askary Sayar, Abolfath Askarian khob, Karim Akbari Vakil Abadi, H. Ghassemi
{"title":"The Seakeeping Investigation of an Inverted Bow Hull by Experimental Method","authors":"Majid Askary Sayar, Abolfath Askarian khob, Karim Akbari Vakil Abadi, H. Ghassemi","doi":"10.29252/marineeng.16.31.123","DOIUrl":"https://doi.org/10.29252/marineeng.16.31.123","url":null,"abstract":"This paper investigates the heave and pitch motion responses of an inverted bow hull. The experimental data were obtained from seakeeping tests with two scaled models of reference fishing vessel NA8-14 BSRA. The bow shape of the models is redesigned by inverted shape in two angles of 45 and 60 degrees. Several tests were conducted on the models at different speeds of 0.6, 0.9, and 1.2.m/s. Generated waves in the towing tank are of the regular type with the wavelength changing from 0.6L to 1.6L by an increment of 0.2L m. The amplitude of the waves was equal to either 35 mm. The heave and pitch response amplitude operator (RAO) versus no dimensional frequencies are presented. The investigations demonstrated that by decreasing inversion angle of bow to 45 degrees motions of the model improved. The results also showed that the interactions between the motions responses leads to the frequent appearance of “Kinks” in a coupled form with the responses of other motions .","PeriodicalId":33555,"journal":{"name":"nshryh mhndsy dry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47764404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}