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Ship Hull Design

Ship Hull Design. 赵宏艳 Email: hongyanzhao_cn@yahoo.com.cn Nov. 21, 2007. 1. 2. 3. References. F. Pérez, J.A. Suárez. Quasi-developable B-spline Surfaces in Ship Hull Design, Computer-Aided Design, 2007, 39(10):853-862. F. Pérez, J.A. Suárez, L. Fernández. Automatic Surface

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Ship Hull Design

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  1. Ship Hull Design 赵宏艳 Email: hongyanzhao_cn@yahoo.com.cn Nov. 21, 2007

  2. 1 2 3 References F. Pérez, J.A. Suárez. Quasi-developable B-spline Surfaces in Ship Hull Design, Computer-Aided Design, 2007, 39(10):853-862. F. Pérez, J.A. Suárez, L. Fernández. Automatic Surface Modeling of a Ship Hull, Computer-Aided Design, 2006, 38(6):584-594. 张明霞，林焰，纪卓尚. 船体曲面造型研究进展. 大连理工 大学学报, 2003, 43(2): 207-212.

  3. 1 2 3 References F. Pérez, J.A. Suárez. Quasi-developable B-spline Surfaces in Ship Hull Design, Computer-Aided Design, 2007, 39(10):853-862. F. Pérez, J.A. Suárez, L. Fernández. Automatic Surface Modeling of a Ship Hull, Computer-Aided Design, 2006, 38(6):584-594. 张明霞，林焰，纪卓尚. 船体曲面造型研究进展. 大连理工 大学学报, 2003, 43(2): 207-212.

  4. Concepts Stations Waterlines

  5. 1 2 3 References F. Pérez, J.A. Suárez. Quasi-developable B-spline Surfaces in Ship Hull Design, Computer-Aided Design, 2007, 39(10):853-862. F. Pérez, J.A. Suárez, L. Fernández. Automatic Surface Modeling of a Ship Hull, Computer-Aided Design, 2006, 38(6):584-594. 张明霞，林焰，纪卓尚. 船体曲面造型研究进展. 大连理工 大学学报, 2003, 43(2): 207-212.

  6. 船体曲面造型研究进展 张明霞，林焰，纪卓尚 大连理工大学学报, 43(2): 207-212

  7. 船舶总性能的计算 etc. 船舶适航性、 受力分析等研究 船舶生产设计 计算机辅助 船舶设计 船体结构设计 船舶总布置设计 计算机辅助船舶设计的实际应用

  8. 3D网格的生成 曲面的参数化 控制顶点确定 确定合适的边界条件 船体曲面NURBS造型的关键技术

  9. Automatic Surface Modelling of a Ship Hull F. Pérez-Arribas, J.A. Suárez-Suárez, L. Fernández-Jambrina Computer-Aided Design, 38(6): 584-594

  10. Author introduction • Francisco L. Pérez Arribas • Associate Professor in the Naval Architecture and Marine Engineering School of Madrid (ETSIN), UPM. • Research interests: ship hull modeling, parametric ship design and geometric modeling • José Antonio Suárez • PhD student at the ETSIN • Research interests: parametric ship design • Leonardo Fernández-Jambrina • Professor of Applied Maths at the Universidad Politécnica de Madrid • Research interests: computer-aided design and geometric modeling with applications to naval architecture

  11. Output Input Automatic Surface Modelling of a Ship Hull • Thorough procedure for automatic modeling with a fair NURBS surface • Lists of • Points • On • stations

  12. Mean square approximation of stations with a cubic spline • Choosing the list of knots • Choosing a parameterization • Solving the approximation problem • Searching for the optimal parameterization • Stations with straight pieces Generation of a spline surface through the stations Fairing process • Fairing criterion • Local fairness criterion • Local fairing iteration • Final comments to the fairing process Automatic Surface Modelling of a Ship Hull • OUTLINE

  13. Curve approxi- mation Surface generation Surface fairing Automatic Surface Modelling of a Ship Hull First step Second step Final step

  14. Mean square approximation of stations with a cubic spline • Choosing the list of knots • Choosing a parameterization • Solving the approximation problem • Searching for the optimal parameterization • Stations with straight pieces Generation of a spline surface through the stations Fairing process • Fairing criterion • Local fairness criterion • Local fairing iteration • Final comments to the fairing process Automatic Surface Modelling of a Ship Hull • OUTLINE

  15. Quasi-developable B-spline Surfaces in Ship Hull Design F. Pérez-Arribas, J.A. Suárez-Suárez Computer-Aided Design, 39(10): 853-862

  16. Quasi-developable B-spline Surfaces in Ship Hull Design

  17. Output Input Quasi-developable B-spline Surfaces in Ship Hull Design • Generate • quasi-developable • surfaces • with B-spline surfaces • Two • directrices

  18. Finding a developable surface Working with B-spline curves and nomenclature 7 1 2 3 4 5 6 The area of regression Generation of a B-spline surface through the rulings Gaussian curvature of the created surfaces Examples Quasi-developable B-spline Surfaces in Ship Hull Design • OUTLINE Searching for the rulings

  19. Finding a developable surface Working with B-spline curves and nomenclature 7 1 2 3 4 5 6 Searching for the rulings The area of regression Gaussian curvature of the created surfaces Examples Quasi-developable B-spline Surfaces in Ship Hull Design • OUTLINE Generation of a B-spline surface through the rulings

  20. Finding a developable surface

  21. Finding a developable surface • The tangent planes to the surface are also tangent to the two directrix lines. • The normal vectors at the endpoints of a ruling are parallel. • Warp angle

  22. Finding a developable surface Working with B-spline curves and nomenclature 1 2 3 4 5 6 7 Searching for the rulings The area of regression Gaussian curvature of the created surfaces Examples Quasi-developable B-spline Surfaces in Ship Hull Design • OUTLINE Generation of a B-spline surface through the rulings

  23. Working with B-spline curves and nomenclature • Model the chines, centre line and sheer lines as B-splines.

  24. Finding a developable surface Working with B-spline curves and nomenclature 7 1 2 3 4 5 6 Searching for the rulings The area of regression Gaussian curvature of the created surfaces Examples Quasi-developable B-spline Surfaces in Ship Hull Design • OUTLINE Generation of a B-spline surface through the rulings

  25. Searching for the rulings

  26. Searching for the rulings • For every fixed value of parameter on • Step 1: compute the tangent ; • Step 2: obtain different values of parameter with step ; • 2.1: compute the tangent for each ; • 2.2: compute and ; • 2.3: compute the warp angle ; • Step 3: detect the minimum value of the warp angle ; • 2.1: turn to local search until the warp angle is below a tolerance or low enough; • Next • Lofting surface with rulings

  27. Searching for the rulings

  28. Finding a developable surface Working with B-spline curves and nomenclature 7 1 2 3 4 5 6 Searching for the rulings The area of regression Gaussian curvature of the created surfaces Examples Quasi-developable B-spline Surfaces in Ship Hull Design • OUTLINE Generation of a B-spline surface through the rulings

  29. The area of regression • Rulings overlap

  30. The area of regression • Problem: rulings overlap • Solution: multiconic algorithm

  31. Finding a developable surface Working with B-spline curves and nomenclature 7 1 2 3 4 5 6 Searching for the rulings The area of regression Gaussian curvature of the created surfaces Examples Quasi-developable B-spline Surfaces in Ship Hull Design • OUTLINE Generation of a B-spline surface through the rulings

  32. Finding a developable surface Working with B-spline curves and nomenclature 7 1 2 3 4 5 6 Searching for the rulings The area of regression Gaussian curvature of the created surfaces Examples Quasi-developable B-spline Surfaces in Ship Hull Design • OUTLINE Generation of a B-spline surface through the rulings

  33. Finding a developable surface Working with B-spline curves and nomenclature 7 1 2 3 4 5 6 The area of regression Generation of a B-spline surface through the rulings Gaussian curvature of the created surfaces Examples Quasi-developable B-spline Surfaces in Ship Hull Design • OUTLINE Searching for the rulings

  34. Examples • Hard chine • One chine, sheer and centre line

  35. Examples • UBC fishing vessel • Two chines, one sheer and centre line

  36. Thank You !

  37. Choosing the list of knots • Knots • Knots number

  38. Choosing a parameterization • Centripental parametrization

  39. Solving the approximation problem • Equation • Matrix system

  40. Iterative process Searching for the optimal parameterization

  41. Stations with straight pieces

  42. Fairing criterion • A spline surface is fairer in a neighbour- hood of the inner knot if is locally at . (Hahmann S. Shape improvement of surfaces. Comput Suppl 1998;13:135-52.) • Reducing the differences between third-order partial derivatives at .

  43. Local fairness criterion • Smallest deformation of the original surface • Local smoothness measure is zero

  44. Final comments to the fairing process • Longitudinal distribution of curvature • Bumps • Shape preservation

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