Once the face and profile of a propeller blade have been designed from the sole consideration of hydrodynamics, thickness at every point is chosen based on strength requirements. To this end, prediction of loading distribution is the first step in a rational design, and again involves hydrodynamics. A structural model of the blade is then used to perform the strength analysis.
{"title":"Strength of Propeller Blades - A Numerical Approach","authors":"M. Jourdain, M. Aucher","doi":"10.5957/pss-1978-016","DOIUrl":"https://doi.org/10.5957/pss-1978-016","url":null,"abstract":"Once the face and profile of a propeller blade have been designed from the sole consideration of hydrodynamics, thickness at every point is chosen based on strength requirements.\u0000 To this end, prediction of loading distribution is the first step in a rational design, and again involves hydrodynamics. A structural model of the blade is then used to perform the strength analysis.","PeriodicalId":330921,"journal":{"name":"Day 2 Thu, May 25, 1978","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121161939","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}
The unsteady lifting surface theory has been utilized in the study of the hydrodynamic interaction of a propeller and enshrouding nozzle when both lifting surfaces are immersed in a non-uniform inf low field (hull wake). The actual geometry of propeller and enshrouding duct, including their thicknesses, camber distributions and the conicity angle of the duct are taken into account. A numerical ana lysis and corresponding computer program have also been developed, adaptable to a high-speed digital computer furnishing information about the steady and time-dependent pressure (loading) distributions on both lifting surfaces and the resulting hydrodynamic forces and moments generated by this propulsive device.
{"title":"Propeller-Duct Interaction Due to Loading and Thickness Effects","authors":"S. Tsakonas, W. R. Jacobs","doi":"10.5957/pss-1978-011","DOIUrl":"https://doi.org/10.5957/pss-1978-011","url":null,"abstract":"The unsteady lifting surface theory has been utilized in the study of the hydrodynamic interaction of a propeller and enshrouding nozzle when both lifting surfaces are immersed in a non-uniform inf low field (hull wake). The actual geometry of propeller and enshrouding duct, including their thicknesses, camber distributions and the conicity angle of the duct are taken into account. A numerical ana lysis and corresponding computer program have also been developed, adaptable to a high-speed digital computer furnishing information about the steady and time-dependent pressure (loading) distributions on both lifting surfaces and the resulting hydrodynamic forces and moments generated by this propulsive device.","PeriodicalId":330921,"journal":{"name":"Day 2 Thu, May 25, 1978","volume":"29 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113976045","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}
This paper describes first a design method for contra-rotating propellers using the momentum theory to determine the mutually induced velocities. Approximate formulae for these velocities have been worked out allowing both the design and the performance analysis of contra-rotating propellers. This is achieved by separating the treatment of a set of propellers into two independent ones with corrections on the intake velocities and on the speed of rotation of the aft propeller. A practical application of a contra-rotating propeller in a highspeed power boat is then discussed. It turned out that this propulsion device is economically beneficial if used together with a stern-drive unit. Smaller propeller, diameter, better cavitation characteristics, smaller vibration level and absence of a heeling moment also contribute to the benefits of a contrarotating propeller as a propulsion system for high-speed craft.
{"title":"On the Design and Use of Contra-Rotating Propellers in High-Speed Craft","authors":"M. Honkanen","doi":"10.5957/pss-1978-012","DOIUrl":"https://doi.org/10.5957/pss-1978-012","url":null,"abstract":"This paper describes first a design method for contra-rotating propellers using the momentum theory to determine the mutually induced velocities. Approximate formulae for these velocities have been worked out allowing both the design and the performance analysis of contra-rotating propellers. This is achieved by separating the treatment of a set of propellers into two independent ones with corrections on the intake velocities and on the speed of rotation of the aft propeller.\u0000 A practical application of a contra-rotating propeller in a highspeed power boat is then discussed. It turned out that this propulsion device is economically beneficial if used together with a stern-drive unit. Smaller propeller, diameter, better cavitation characteristics, smaller vibration level and absence of a heeling moment also contribute to the benefits of a contrarotating propeller as a propulsion system for high-speed craft.","PeriodicalId":330921,"journal":{"name":"Day 2 Thu, May 25, 1978","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129388520","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}
Stresses in monobloc propeller blade and hub normally are calculated separately. In the blade stress calculation, for which nowadays the finite element method is generally prefer red, the hub is assumed to be rigid. On the other hand the blade is completely ignored if hub strength is considered. The finite element program, the author used for the blade, also allows the examination of the interference between the stress conditions in both parts since it enables three-dimensional elastic analyses. Moreover, detailed experimental data, obtained in strain gauge measurements on a full scale blade, proved the validity of the chosen element type and mesh for application on propeller blades. Therefore strong tools are available to shift the disturbing boundary conditions from the blade root to the hub-shaft interface and obtain reliable information about the blade root loading and its resolution in the hub. Results of comparative calculations show the strong influence of the hub elasticity on the stress distribution in the blade root section.
{"title":"Hub-Blade Interaction in Propeller Strength","authors":"G. Beek","doi":"10.5957/pss-1978-015","DOIUrl":"https://doi.org/10.5957/pss-1978-015","url":null,"abstract":"Stresses in monobloc propeller blade and hub normally are calculated separately. In the blade stress calculation, for which nowadays the finite element method is generally prefer red, the hub is assumed to be rigid. On the other hand the blade is completely ignored if hub strength is considered.\u0000 The finite element program, the author used for the blade, also allows the examination of the interference between the stress conditions in both parts since it enables three-dimensional elastic analyses. Moreover, detailed experimental data, obtained in strain gauge measurements on a full scale blade, proved the validity of the chosen element type and mesh for application on propeller blades. Therefore strong tools are available to shift the disturbing boundary conditions from the blade root to the hub-shaft interface and obtain reliable information about the blade root loading and its resolution in the hub.\u0000 Results of comparative calculations show the strong influence of the hub elasticity on the stress distribution in the blade root section.","PeriodicalId":330921,"journal":{"name":"Day 2 Thu, May 25, 1978","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129941521","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}
By means of a specially designed propeller drive, steady vibrations of the propeller hub were generated, at constant advance speed and shaft rotation. By changing the frequency, resonance with blade vibrations could be realized. These tests have been performed for a non- rotating propeller in air and in water. Also, for the propeller operating in a homogeneous flow such a test has been performed. By measuring the blade response, information of the resonance frequency and information about added mass of water and hydrodynamic damping is obtained. It is shown, that, although the damping is clearly present , still an appreciable magnification of the blade vibrations at resonance will occur. Whereas close to or at resonance operation for large diameter, wide blade or highly skewed propellers is possible, these results have to be seriously accounted for when designing such propellers.
{"title":"Model Tests on Hydrodynamics of Propeller Blade Vibrations","authors":"S. Hylarides","doi":"10.5957/pss-1978-010","DOIUrl":"https://doi.org/10.5957/pss-1978-010","url":null,"abstract":"By means of a specially designed propeller drive, steady vibrations of the propeller hub were generated, at constant advance speed and shaft rotation. By changing the frequency, resonance with blade vibrations could be realized. These tests have been performed for a non- rotating propeller in air and in water. Also, for the propeller operating in a homogeneous flow such a test has been performed.\u0000 By measuring the blade response, information of the resonance frequency and information about added mass of water and hydrodynamic damping is obtained. It is shown, that, although the damping is clearly present , still an appreciable magnification of the blade vibrations at resonance will occur.\u0000 Whereas close to or at resonance operation for large diameter, wide blade or highly skewed propellers is possible, these results have to be seriously accounted for when designing such propellers.","PeriodicalId":330921,"journal":{"name":"Day 2 Thu, May 25, 1978","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123994922","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}
An ultrasonic inspection apparatus is newly developed to detect internal flaws behind the surface of the actual marine propeller blade. An ultrasonic transducer scans automatically on required area of a blade. If ultrasonic sound waves are bounced from internal flaws, echo signals are plotted on a X-Y recorder obtaining C-scope patterns. The system also has B-scope display to indicate the depth to the flaws. Voids tears-cracks or clusters of these flaws having cross sections larger than 2mm2 are detectable. This nondestructive testing method is applicable to marine propellers made of Ni-Al bronze, but not to propellers made of Mn bronze because of extremely high attenuation of sound waves. The report includes some detection examples of actual flaws showing fairly good agreement between actual size of flaw and that of detected results.
{"title":"Development of Ultrasonic Flaw Detection Technique on Marine Bronze Propeller","authors":"M. Iwasaki, N. Suzuki","doi":"10.5957/pss-1978-017","DOIUrl":"https://doi.org/10.5957/pss-1978-017","url":null,"abstract":"An ultrasonic inspection apparatus is newly developed to detect internal flaws behind the surface of the actual marine propeller blade.\u0000 An ultrasonic transducer scans automatically on required area of a blade. If ultrasonic sound waves are bounced from internal flaws, echo signals are plotted on a X-Y recorder obtaining C-scope patterns. The system also has B-scope display to indicate the depth to the flaws.\u0000 Voids tears-cracks or clusters of these flaws having cross sections larger than 2mm2 are detectable. This nondestructive testing method is applicable to marine propellers made of Ni-Al bronze, but not to propellers made of Mn bronze because of extremely high attenuation of sound waves.\u0000 The report includes some detection examples of actual flaws showing fairly good agreement between actual size of flaw and that of detected results.","PeriodicalId":330921,"journal":{"name":"Day 2 Thu, May 25, 1978","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123411620","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}
Shafting alignment in the vertical and horizontal planes is known to be affected by the steady forces and moments generated by the propeller when it rotates. A review is first given of the scant literature on the problem. The origin of the propeller loads is then discussed and it is shown how they can be predicted on the basis of unsteady lifting surface theory. Calculations and some model measurements of steady lateral loads for eight shaft systems are then presented. The effect of each of the six load components on shaft alignment is discussed in some detail. Results are presented from a study based on mathematical optimization techniques in which propeller loads were included systematically in the shaft alignment selection phase. Recommendations are given for needed research that should aid in avoiding alignment-related failures.
{"title":"The Influence of Propeller Mean Loads on Propulsion Shaft Alignment","authors":"L. Vassilopoulos","doi":"10.5957/pss-1978-013","DOIUrl":"https://doi.org/10.5957/pss-1978-013","url":null,"abstract":"Shafting alignment in the vertical and horizontal planes is known to be affected by the steady forces and moments generated by the propeller when it rotates. A review is first given of the scant literature on the problem. The origin of the propeller loads is then discussed and it is shown how they can be predicted on the basis of unsteady lifting surface theory. Calculations and some model measurements of steady lateral loads for eight shaft systems are then presented. The effect of each of the six load components on shaft alignment is discussed in some detail. Results are presented from a study based on mathematical optimization techniques in which propeller loads were included systematically in the shaft alignment selection phase. Recommendations are given for needed research that should aid in avoiding alignment-related failures.","PeriodicalId":330921,"journal":{"name":"Day 2 Thu, May 25, 1978","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129300712","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}
Considerations for the design, installation, survey and repair of propellers and tailshafts are discussed. Particular emphasis is placed on stress concentrations and other factors which cause in service problems. The recognition of the more common problems, and methods of repair are discussed. A method for calculating the stress in a typical tailshaft is included as an appendix. This calculation is based on the fatigue analysis method.
{"title":"Summary of Propeller and Tailshaft Interface Considerations","authors":"R. Rothamel","doi":"10.5957/pss-1978-014","DOIUrl":"https://doi.org/10.5957/pss-1978-014","url":null,"abstract":"Considerations for the design, installation, survey and repair of propellers and tailshafts are discussed. Particular emphasis is placed on stress concentrations and other factors which cause in service problems. The recognition of the more common problems, and methods of repair are discussed.\u0000 A method for calculating the stress in a typical tailshaft is included as an appendix. This calculation is based on the fatigue analysis method.","PeriodicalId":330921,"journal":{"name":"Day 2 Thu, May 25, 1978","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120951978","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：