- Email: [email protected]
Railroad traffic analysis using interactive computer graphics
i
II
I I III
II
IIII
II
Civil and structural engineering Blandford, G E, Ingraffea, A R and Liggett, J A 'Two-dimensional stress intensity factor computations using the boundary element method' Int. J. Numer. Methods Eng. Vol 17 No 3 (March 1981 ) pp 387--404 A multidomain boundary element formulation for the analysis of general 2D plane strain/stress crack problems is presented. The numerical results were accurate and efficient. The analyses were performed using traction singular quarter-point boundary elements on each side of the crack tip(s) with and without transition elements. Current research studies for the crack propagation analysis of quasi-static and fatigue fracture problems are discussed. Imai, K and Shoji, M 'Minimum cost design of framed structures by the mini-max dual method' Int. J. Numer. Methods Eng. Vol 17 No 2 (February 1981) pp 213-229 Minimum cost design of a framed structure is considered by using the mini-max dual method. Stress and/or displacement constraints are imposed as behavioural constraints. The minimum cost design problem has a discrete objective function and discrete design variables. A sequence of approximate optimization problems is created by using the first-order Taylor series expansion for displacements with respect to the reciprocals of cross-sectional areas and moments of inertia. Each approximate problem is solved in the dual space. Two simple structural examples are given to show the appropriateness and efficiency of the proposed procedure. Bathe, K --I and Ha, L - W 'A simple and effective element for analysis of general shell structures' Comput. Struct. Vol 13 Nos 5 - 6 (1981) pp 673-681 A simple flat three-node triangular shell element for linear and nonlinear analysis is presented. The element stiffness matrix with 6 degrees-of-freedom per node is obtained by superimposing its bending and membrane stiffness matrices. An updated Lagrangian formulation is used for large displacement analysis. The application of the element to the analysis of various linear and nonlinear problems is demonstrated. Will, K M, Virk, S P, Schelling, D R and Emkin, L Z 'An integrated bridge design system' in Proceedings of the first international conference on computing in civil engineering ASCE, New York, NY, USA (1981) A research program was initiated to develop a prototype integrated bridge design system which would provide a framework for future development. The first phase of the research
v o l u m e 14 n u m b e r 2 march 1982
II
I
progarm was concerned with defining the needs of the bridge engineering community and evaluating existing computer programs. The second phase was then devoted to developing a system which supported a global database and a problem oriented language. Application modules for bridge geometrics and the analysis and design of continuous steel girders were incorporated into the system. Kornhauser, A L and Hazony, Y 'Railroad traffic analysis using interactive computer graphics' in Proceedings of the first international conference on computing in civil engineering ASCE, New York, NY, USA (1981) For the past six years researchers at Princeton University have been developing an interactive computer graphic methodology for the analysis of planning, marketing and operating issues confronting the US railroad system. The analytical techniques developed have been uniquely coupled with the assambling of interactive computer graphic hardware and software at Princeton. The paper only summarizes the network analysis techniques, data sources and hardware configurations. It focuses on the various unique applications in which the interactive computer graphic capabilities have been indispensable. Matthies, H and Payer, H G 'Elastic--plastic post-buckling behaviour of ship plating' Comput. Struct. Vol 13 Nos 5 - 6 (1981) pp 745-750 This paper presents an investigation by the finite element method of highly loaded stiffened and unstiffened plates as they occur in marine structures. Additionally, the performance of the computational methods in the solution of larger systems is evaluated. Flat plates and plates with initial pre-deformation (shallow shells) are studied under various Ioadings, such as lateral pressure, edge shear, compression and tension as well as differing boundary conditions. McConnel, R E and Klimke, H 'Geometrically nonlinear pin-jointed space frames' in Numerical methods for nonlinear problems: proceedings of the international conference, University College, Swansea, UK Vol 1 (1980) The analyses of some pin-jointed space frames in which geometrically nonlinear large deflection behaviour is significant, are presented. A constant stiffness, large deflection, iterative analysis method is briefly discussed. This simple approach has given satisfactory results for various real, and numerous proposed structures. Calculations for a number of domes, and a hyperbolic paraboloid, are presented.
Kao, R 'A comparative study on the elasticplastic collapse strength of initially imperfect deep spherical shells' Int. J. Numer. Methods Eng. Vol 17 No 3 (March 1981) pp 427-444 A finite difference method for the large deformation elastic-plastic analysis of spherical caps is applied to predict the collapse strength of initially imperfect deep spherical shells. Twelve uniformly loaded hemispherical shell models with flat spots at their apex are analysed. Present solutions are in good agreement with existing experimental and empirical results. The good comparison suggests that initially imperfect deep spherical shells may be analysed by using a much simpler mathematical model - the spherical cap - and thus the analytical cost may be greatly reduced. This also demonstrates that the collapse of imperfect spherical shells is primarily a local phenomenon and therefore dependent on local geometry.
Wu, B C and Altiero, N J 'A new numerical method for the analysis of anisotropic thinplate bending problems' Comput. Methods Appl. Mech. Eng. Vol 25 No 3 (March 1981) pp 343--353 A new method is presented for the analysis of anisotropic thin-plate bending problems. This method appears to enjoy several advantages over other numerical methods for linear problems. Several example problems are presented, demonstrating the ability of the method to deal with difficult geometries and boundary conditions and with material anisotropy.
Muller, G, Jovanovic, D and Haas, P 'Tracks-gravel-bridge interaction' Comput. Struct. Vol 13 (1981) pp 607-611 For various long valley bridges the interaction between tracks, gravel and bridge girders is investigated. Two load cases were assumed: horizontal forces due to braking and horizontal loading due to temperature difference between tracks and girders. The behaviour of gravel is approximated by a nonlinear load-dependent elastic-plastic material law. The aim of the study is to find out a system which is capable of carrying the horizontal loads without exceeding a given stress limit in the rails. Saleeb, A F and Chen, W F 'Elastic-plastic large displacement analysis of pipes' ASCE J. Struct. Div. Vol 107 No ST4 (April 1981) pp 605-626 A numerical procedure based on the finite segment method is presented and applied to large displacement analysis of pipe bending problems frequently encountered in offshore structural engineering applications.
123
II
I I III
II
IIII
II
Civil and structural engineering Blandford, G E, Ingraffea, A R and Liggett, J A 'Two-dimensional stress intensity factor computations using the boundary element method' Int. J. Numer. Methods Eng. Vol 17 No 3 (March 1981 ) pp 387--404 A multidomain boundary element formulation for the analysis of general 2D plane strain/stress crack problems is presented. The numerical results were accurate and efficient. The analyses were performed using traction singular quarter-point boundary elements on each side of the crack tip(s) with and without transition elements. Current research studies for the crack propagation analysis of quasi-static and fatigue fracture problems are discussed. Imai, K and Shoji, M 'Minimum cost design of framed structures by the mini-max dual method' Int. J. Numer. Methods Eng. Vol 17 No 2 (February 1981) pp 213-229 Minimum cost design of a framed structure is considered by using the mini-max dual method. Stress and/or displacement constraints are imposed as behavioural constraints. The minimum cost design problem has a discrete objective function and discrete design variables. A sequence of approximate optimization problems is created by using the first-order Taylor series expansion for displacements with respect to the reciprocals of cross-sectional areas and moments of inertia. Each approximate problem is solved in the dual space. Two simple structural examples are given to show the appropriateness and efficiency of the proposed procedure. Bathe, K --I and Ha, L - W 'A simple and effective element for analysis of general shell structures' Comput. Struct. Vol 13 Nos 5 - 6 (1981) pp 673-681 A simple flat three-node triangular shell element for linear and nonlinear analysis is presented. The element stiffness matrix with 6 degrees-of-freedom per node is obtained by superimposing its bending and membrane stiffness matrices. An updated Lagrangian formulation is used for large displacement analysis. The application of the element to the analysis of various linear and nonlinear problems is demonstrated. Will, K M, Virk, S P, Schelling, D R and Emkin, L Z 'An integrated bridge design system' in Proceedings of the first international conference on computing in civil engineering ASCE, New York, NY, USA (1981) A research program was initiated to develop a prototype integrated bridge design system which would provide a framework for future development. The first phase of the research
v o l u m e 14 n u m b e r 2 march 1982
II
I
progarm was concerned with defining the needs of the bridge engineering community and evaluating existing computer programs. The second phase was then devoted to developing a system which supported a global database and a problem oriented language. Application modules for bridge geometrics and the analysis and design of continuous steel girders were incorporated into the system. Kornhauser, A L and Hazony, Y 'Railroad traffic analysis using interactive computer graphics' in Proceedings of the first international conference on computing in civil engineering ASCE, New York, NY, USA (1981) For the past six years researchers at Princeton University have been developing an interactive computer graphic methodology for the analysis of planning, marketing and operating issues confronting the US railroad system. The analytical techniques developed have been uniquely coupled with the assambling of interactive computer graphic hardware and software at Princeton. The paper only summarizes the network analysis techniques, data sources and hardware configurations. It focuses on the various unique applications in which the interactive computer graphic capabilities have been indispensable. Matthies, H and Payer, H G 'Elastic--plastic post-buckling behaviour of ship plating' Comput. Struct. Vol 13 Nos 5 - 6 (1981) pp 745-750 This paper presents an investigation by the finite element method of highly loaded stiffened and unstiffened plates as they occur in marine structures. Additionally, the performance of the computational methods in the solution of larger systems is evaluated. Flat plates and plates with initial pre-deformation (shallow shells) are studied under various Ioadings, such as lateral pressure, edge shear, compression and tension as well as differing boundary conditions. McConnel, R E and Klimke, H 'Geometrically nonlinear pin-jointed space frames' in Numerical methods for nonlinear problems: proceedings of the international conference, University College, Swansea, UK Vol 1 (1980) The analyses of some pin-jointed space frames in which geometrically nonlinear large deflection behaviour is significant, are presented. A constant stiffness, large deflection, iterative analysis method is briefly discussed. This simple approach has given satisfactory results for various real, and numerous proposed structures. Calculations for a number of domes, and a hyperbolic paraboloid, are presented.
Kao, R 'A comparative study on the elasticplastic collapse strength of initially imperfect deep spherical shells' Int. J. Numer. Methods Eng. Vol 17 No 3 (March 1981) pp 427-444 A finite difference method for the large deformation elastic-plastic analysis of spherical caps is applied to predict the collapse strength of initially imperfect deep spherical shells. Twelve uniformly loaded hemispherical shell models with flat spots at their apex are analysed. Present solutions are in good agreement with existing experimental and empirical results. The good comparison suggests that initially imperfect deep spherical shells may be analysed by using a much simpler mathematical model - the spherical cap - and thus the analytical cost may be greatly reduced. This also demonstrates that the collapse of imperfect spherical shells is primarily a local phenomenon and therefore dependent on local geometry.
Wu, B C and Altiero, N J 'A new numerical method for the analysis of anisotropic thinplate bending problems' Comput. Methods Appl. Mech. Eng. Vol 25 No 3 (March 1981) pp 343--353 A new method is presented for the analysis of anisotropic thin-plate bending problems. This method appears to enjoy several advantages over other numerical methods for linear problems. Several example problems are presented, demonstrating the ability of the method to deal with difficult geometries and boundary conditions and with material anisotropy.
Muller, G, Jovanovic, D and Haas, P 'Tracks-gravel-bridge interaction' Comput. Struct. Vol 13 (1981) pp 607-611 For various long valley bridges the interaction between tracks, gravel and bridge girders is investigated. Two load cases were assumed: horizontal forces due to braking and horizontal loading due to temperature difference between tracks and girders. The behaviour of gravel is approximated by a nonlinear load-dependent elastic-plastic material law. The aim of the study is to find out a system which is capable of carrying the horizontal loads without exceeding a given stress limit in the rails. Saleeb, A F and Chen, W F 'Elastic-plastic large displacement analysis of pipes' ASCE J. Struct. Div. Vol 107 No ST4 (April 1981) pp 605-626 A numerical procedure based on the finite segment method is presented and applied to large displacement analysis of pipe bending problems frequently encountered in offshore structural engineering applications.
123