The paper concerns the development of techniques which take full advantage of the capabilities of curved finite elements as applied to the problem of stress analysis of marine propellers. The advantages of the proposed techniques are discussed in regard to data generation, analysis and presentation, analysis and presentation results. Hypothetical and conventional propeller forms are analyzed in order to verify and show capabilities of the proposed techniques.
{"title":"A Practical Stress Analysis Procedure for Marine Propellers Using Curved Finite Elements","authors":"P. Atkinson","doi":"10.5957/pss-1975-006","DOIUrl":"https://doi.org/10.5957/pss-1975-006","url":null,"abstract":"The paper concerns the development of techniques which take full advantage of the capabilities of curved finite elements as applied to the problem of stress analysis of marine propellers. The advantages of the proposed techniques are discussed in regard to data generation, analysis and presentation, analysis and presentation results. Hypothetical and conventional propeller forms are analyzed in order to verify and show capabilities of the proposed techniques.","PeriodicalId":205788,"journal":{"name":"Day 1 Tue, July 22, 1975","volume":"32 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1975-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125911101","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}
A finite element displacement model was utilized to predict the elastic behavior of a propeller blade having an arbitrary shape and subjected to prescribed loading. Solid elements in their general form were adapted. The use of curvilinear coordinates in element space provides a practical means for defining complex design surfaces and also provides an expedient method for stress calculations . The curved three-dimensional elements fit readily to a skewed geometry of curved boundary and their application to propeller problems is simple and straight-forward. The performance of the curved solid finite elements has been found to be excellent and the computed results, because of the general nature of the solid elements are assured to converge to the true solution . The high degree of accuracy obtained from a recent analysis of a full size propeller strongly suggests that the current development represents a realistic and reliable approach to the general solution of the propeller stress problem.
{"title":"Propeller Stress Calculation Using Curved Finite Element","authors":"J. H. Ma, W. C. Schnobrich, C. Stuber","doi":"10.5957/pss-1975-001","DOIUrl":"https://doi.org/10.5957/pss-1975-001","url":null,"abstract":"A finite element displacement model was utilized to predict the elastic behavior of a propeller blade having an arbitrary shape and subjected to prescribed loading. Solid elements in their general form were adapted. The use of curvilinear coordinates in element space provides a practical means for defining complex design surfaces and also provides an expedient method for stress calculations . The curved three-dimensional elements fit readily to a skewed geometry of curved boundary and their application to propeller problems is simple and straight-forward. The performance of the curved solid finite elements has been found to be excellent and the computed results, because of the general nature of the solid elements are assured to converge to the true solution . The high degree of accuracy obtained from a recent analysis of a full size propeller strongly suggests that the current development represents a realistic and reliable approach to the general solution of the propeller stress problem.","PeriodicalId":205788,"journal":{"name":"Day 1 Tue, July 22, 1975","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1975-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125833677","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 state of the art is reviewed for predicting analytically and measuring, in the model or full scale, loads on propeller blades and the resulting stresses and deformations. Examples are next given of the utility of beam theory and the finite element method during the lifting- line and post lifting-surface stages of design, respectively. An economic assessment is finally offered of the various methods that can be used prior to construction to minimize blade failures.
{"title":"Structural Considerations in the Design of Propeller Blades","authors":"L. Vassilopoulos","doi":"10.5957/pss-1975-005","DOIUrl":"https://doi.org/10.5957/pss-1975-005","url":null,"abstract":"The state of the art is reviewed for predicting analytically and measuring, in the model or full scale, loads on propeller blades and the resulting stresses and deformations. Examples are next given of the utility of beam theory and the finite element method during the lifting- line and post lifting-surface stages of design, respectively. An economic assessment is finally offered of the various methods that can be used prior to construction to minimize blade failures.","PeriodicalId":205788,"journal":{"name":"Day 1 Tue, July 22, 1975","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1975-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129977147","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 ability to predict the blade natural frequencies and the stresses under operating conditions is a necessary requirement of the blade design process. This requires an accurate definition of the steady and cyclic pressure loads over the blade surface. It also requires an appropriate structural model and analytic procedure for solving the structural response of the blade. This paper presents the results achieved by application of a finite difference helicoidal shell analysis computer program to a supercavitating marine propeller blade. The natural frequencies, mode shapes, steady stress and cyclic stress are evaluated, and the results are compared to measured values. Comparison with test results is made using both analytically derived and measured pressure distributions. Correlation of measured and calculated "in air" natural frequencies and mode shapes is quite good particularly for the higher modes. The calculated stresses agree well when compared to calculations based upon measured pressures.
{"title":"Evaluation of a Finite Difference Helicoidal Shell Analysis by Comparison with Test Results for a Marine Propeller","authors":"W. Westervelt","doi":"10.5957/pss-1975-003","DOIUrl":"https://doi.org/10.5957/pss-1975-003","url":null,"abstract":"The ability to predict the blade natural frequencies and the stresses under operating conditions is a necessary requirement of the blade design process. This requires an accurate definition of the steady and cyclic pressure loads over the blade surface. It also requires an appropriate structural model and analytic procedure for solving the structural response of the blade.\u0000 This paper presents the results achieved by application of a finite difference helicoidal shell analysis computer program to a supercavitating marine propeller blade. The natural frequencies, mode shapes, steady stress and cyclic stress are evaluated, and the results are compared to measured values. Comparison with test results is made using both analytically derived and measured pressure distributions.\u0000 Correlation of measured and calculated \"in air\" natural frequencies and mode shapes is quite good particularly for the higher modes. The calculated stresses agree well when compared to calculations based upon measured pressures.","PeriodicalId":205788,"journal":{"name":"Day 1 Tue, July 22, 1975","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1975-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124140204","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}
Propeller strength analysis and prediction methods were investigated. The primary tool was the finite element technique. More specifically, the thins hell approximation was adopted and modeled by a commercially available (MARCCDC) program. To verify that the program was performing correctly, holographic, strain gage, and stress coat experiments were performed on model and full-size propellers. Static loads were applied and measured together with displacements, strains and stresses. Comparison of the results of the numerical (FEM) solutions to the experimental results shows that this method is highly reliable. The experimental results also show patterns in the behavior of the blade which can guide the formulation of a design tool for the strength analysis of a propeller without r e course to the finite element analysis (except at the end of the design, as a final check ). Instead, a modified beam theory, based on observed patterns, can guide the designer to optimum design shape for hydrodynamics and strength.
{"title":"Experimental Verification of Finite Element Analyses of Propeller Strength","authors":"P. Genalis","doi":"10.5957/pss-1975-002","DOIUrl":"https://doi.org/10.5957/pss-1975-002","url":null,"abstract":"Propeller strength analysis and prediction methods were investigated. The primary tool was the finite element technique. More specifically, the thins hell approximation was adopted and modeled by a commercially available (MARCCDC) program.\u0000 To verify that the program was performing correctly, holographic, strain gage, and stress coat experiments were performed on model and full-size propellers. Static loads were applied and measured together with displacements, strains and stresses.\u0000 Comparison of the results of the numerical (FEM) solutions to the experimental results shows that this method is highly reliable.\u0000 The experimental results also show patterns in the behavior of the blade which can guide the formulation of a design tool for the strength analysis of a propeller without r e course to the finite element analysis (except at the end of the design, as a final check ). Instead, a modified beam theory, based on observed patterns, can guide the designer to optimum design shape for hydrodynamics and strength.","PeriodicalId":205788,"journal":{"name":"Day 1 Tue, July 22, 1975","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1975-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132927296","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 results are presented of model measurements of the unsteady forces on one blade of a Propeller behind a single screw merchant ship· During the tests the propeller loading, the number of blades and the drift angle were varied as parameters. Moreover the installation required for the measurements and the method are described.
{"title":"Propeller Blade Loading in Non-Uniform Flow","authors":"J. Blaurock","doi":"10.5957/pss-1975-004","DOIUrl":"https://doi.org/10.5957/pss-1975-004","url":null,"abstract":"The results are presented of model measurements of the unsteady forces on one blade of a Propeller behind a single screw merchant ship· During the tests the propeller loading, the number of blades and the drift angle were varied as parameters. Moreover the installation required for the measurements and the method are described.","PeriodicalId":205788,"journal":{"name":"Day 1 Tue, July 22, 1975","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1975-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123016559","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}
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