The Experts below are selected from a list of 225 Experts worldwide ranked by ideXlab platform

John R Mackay - One of the best experts on this subject based on the ideXlab platform.

  • Partial Safety Factor approach to the design of submarine pressure hulls using nonlinear finite element analysis
    Finite Elements in Analysis and Design, 2013
    Co-Authors: John R Mackay, Fred Van Keulen
    Abstract:

    A framework for the design of submarine pressure hulls using nonlinear finite element (FE) analysis is presented in order to improve upon the conventional analytical-empirical design procedure. A numerical methodology is established that allows the collapse pressure of a hull to be predicted with controlled accuracy. The methodology is characterized by quasi-static incremental analysis, including material and geometric nonlinearities, of FE models constructed from shell elements. The numerical methodology is used with ANSYS to predict the results of 47 collapse experiments on small-scale ring-stiffened cylinders representative of submarine hulls. A probabilistic analysis is applied to the experimental-numerical comparisons in order to estimate the accuracy of the FE methodology and derive a Partial Safety Factor (PSF) for design. It is demonstrated that a high level of accuracy, within 10% with 95% confidence, can be achieved if the prescribed FE methodology is followed. Furthermore, it is shown that the PSF for design does not need to be very large, even if a high degree of statistical confidence is built in. The designer can be 99.5% confident that the FE error has been accounted for by dividing the predicted collapse pressure by a PSF=1.134.

  • quantifying the accuracy of numerical collapse predictions for the design of submarine pressure hulls
    Thin-walled Structures, 2011
    Co-Authors: John R Mackay, Fred Van Keulen, Malcolm J Smith
    Abstract:

    An overview of current design practices for submarine pressure hulls is presented, along with the results of a survey of the literature that was conducted to determine standard nonlinear numerical modelling practices for those structures. The accuracies of the conventional submarine design formulae (SDF) and nonlinear numerical analyses for predicting pressure hull collapse are estimated by comparing predicted and experimental collapse loads from the literature. The conventional SDF are found to be accurate within approximately 20%, with 95% confidence, for intact pressure hulls. The accuracy of a wide range of nonlinear numerical methods, including axisymmetric finite difference and general shell finite element (FE) models, is found to be within approximately 16% with 95% confidence. The accuracy is found to be within 9% when only higher fidelity general shell FE models are considered. It is shown how the observations taken from the survey could serve as a starting point for establishing modelling guidelines, quantifying the accuracy of nonlinear FE analysis in pressure hull collapse calculations, and introducing this method into a design procedure by way of a Partial Safety Factor.

  • Design of Pressure Hulls Using Nonlinear Finite Element Analysis
    Volume 3: Safety and Reliability; Materials Technology; Douglas Faulkner Symposium on Reliability and Ultimate Strength of Marine Structures, 2006
    Co-Authors: John R Mackay, Malcolm J Smith, Neil Pegg
    Abstract:

    Through the use of nonlinear finite element analysis (NLFEA), submarine pressure hull designs could potentially be based on calculated limit states that include the full geometric complexity of the structure, and real-world effects such as build imperfections. In addition, NLFEA could provide a rational means of assessing the effects of in-service damage on structural performance. Analysis of pressure hulls using 3D NLFEA is not currently supported in design codes, primarily because the uncertainty regarding the accuracy of the method has not been quantified. Defence Research and Development Canada (DRDC), the R&D branch of the Canadian Navy, is undertaking work to develop a Partial Safety Factor for 3D NLFEA of pressure hulls, by comparison of numerically calculated collapse pressures to experimental results. Data from experiments previously conducted at various institutions will be augmented by a pressure hull testing program currently being undertaken by a joint project of DRDC and the Ministry of Defence of the Netherlands. The development of NLFEA modeling and analysis guidelines, as well as a revised design/analysis procedure, will be discussed, as well as a history of the DRDC submarine structures research program.Copyright © 2006 by Defence Research and Development Canada

Fred Van Keulen - One of the best experts on this subject based on the ideXlab platform.

  • Partial Safety Factor approach to the design of submarine pressure hulls using nonlinear finite element analysis
    Finite Elements in Analysis and Design, 2013
    Co-Authors: John R Mackay, Fred Van Keulen
    Abstract:

    A framework for the design of submarine pressure hulls using nonlinear finite element (FE) analysis is presented in order to improve upon the conventional analytical-empirical design procedure. A numerical methodology is established that allows the collapse pressure of a hull to be predicted with controlled accuracy. The methodology is characterized by quasi-static incremental analysis, including material and geometric nonlinearities, of FE models constructed from shell elements. The numerical methodology is used with ANSYS to predict the results of 47 collapse experiments on small-scale ring-stiffened cylinders representative of submarine hulls. A probabilistic analysis is applied to the experimental-numerical comparisons in order to estimate the accuracy of the FE methodology and derive a Partial Safety Factor (PSF) for design. It is demonstrated that a high level of accuracy, within 10% with 95% confidence, can be achieved if the prescribed FE methodology is followed. Furthermore, it is shown that the PSF for design does not need to be very large, even if a high degree of statistical confidence is built in. The designer can be 99.5% confident that the FE error has been accounted for by dividing the predicted collapse pressure by a PSF=1.134.

  • quantifying the accuracy of numerical collapse predictions for the design of submarine pressure hulls
    Thin-walled Structures, 2011
    Co-Authors: John R Mackay, Fred Van Keulen, Malcolm J Smith
    Abstract:

    An overview of current design practices for submarine pressure hulls is presented, along with the results of a survey of the literature that was conducted to determine standard nonlinear numerical modelling practices for those structures. The accuracies of the conventional submarine design formulae (SDF) and nonlinear numerical analyses for predicting pressure hull collapse are estimated by comparing predicted and experimental collapse loads from the literature. The conventional SDF are found to be accurate within approximately 20%, with 95% confidence, for intact pressure hulls. The accuracy of a wide range of nonlinear numerical methods, including axisymmetric finite difference and general shell finite element (FE) models, is found to be within approximately 16% with 95% confidence. The accuracy is found to be within 9% when only higher fidelity general shell FE models are considered. It is shown how the observations taken from the survey could serve as a starting point for establishing modelling guidelines, quantifying the accuracy of nonlinear FE analysis in pressure hull collapse calculations, and introducing this method into a design procedure by way of a Partial Safety Factor.

Marija Docevska - One of the best experts on this subject based on the ideXlab platform.

  • assessment of damaged timber structures using proof load test experience from case studies
    Construction and Building Materials, 2015
    Co-Authors: Toni Arangjelovski, Kiril Gramatikov, Marija Docevska
    Abstract:

    Abstract In this paper assessment of damaged timber structures using proof load test is given, which is mandatory according to Macedonian standards. Two types of structures were analyzed in the paper: Glued laminated timber structure, Cambered beam span of L  = 24.00 m and Glued Laminated pedestrian timber bridge, two-hinged arch, span of L  = 26.00 m plus two simple supported beams span of L  = 12.5 m each. The results were also used for reliability verification to define Partial Safety Factor for material for ultimate limit state and serviceability limit state, according to Eurocodes EN1990 and EN1995.

  • Assessment of damaged timber structures using proof load test – Experience from case studies
    Construction and Building Materials, 2015
    Co-Authors: Toni Arangjelovski, Kiril Gramatikov, Marija Docevska
    Abstract:

    Abstract In this paper assessment of damaged timber structures using proof load test is given, which is mandatory according to Macedonian standards. Two types of structures were analyzed in the paper: Glued laminated timber structure, Cambered beam span of L  = 24.00 m and Glued Laminated pedestrian timber bridge, two-hinged arch, span of L  = 26.00 m plus two simple supported beams span of L  = 12.5 m each. The results were also used for reliability verification to define Partial Safety Factor for material for ultimate limit state and serviceability limit state, according to Eurocodes EN1990 and EN1995.

Van Keulenfred - One of the best experts on this subject based on the ideXlab platform.

Toni Arangjelovski - One of the best experts on this subject based on the ideXlab platform.

  • assessment of damaged timber structures using proof load test experience from case studies
    Construction and Building Materials, 2015
    Co-Authors: Toni Arangjelovski, Kiril Gramatikov, Marija Docevska
    Abstract:

    Abstract In this paper assessment of damaged timber structures using proof load test is given, which is mandatory according to Macedonian standards. Two types of structures were analyzed in the paper: Glued laminated timber structure, Cambered beam span of L  = 24.00 m and Glued Laminated pedestrian timber bridge, two-hinged arch, span of L  = 26.00 m plus two simple supported beams span of L  = 12.5 m each. The results were also used for reliability verification to define Partial Safety Factor for material for ultimate limit state and serviceability limit state, according to Eurocodes EN1990 and EN1995.

  • Assessment of damaged timber structures using proof load test – Experience from case studies
    Construction and Building Materials, 2015
    Co-Authors: Toni Arangjelovski, Kiril Gramatikov, Marija Docevska
    Abstract:

    Abstract In this paper assessment of damaged timber structures using proof load test is given, which is mandatory according to Macedonian standards. Two types of structures were analyzed in the paper: Glued laminated timber structure, Cambered beam span of L  = 24.00 m and Glued Laminated pedestrian timber bridge, two-hinged arch, span of L  = 26.00 m plus two simple supported beams span of L  = 12.5 m each. The results were also used for reliability verification to define Partial Safety Factor for material for ultimate limit state and serviceability limit state, according to Eurocodes EN1990 and EN1995.