Gantry kreynli konteyner gemilerinin boyuna mukavemeti

Abstract

Bu çalışmada, güvertesinde gantry kreyn olan tek ambarlı ve geniş güverte açıklıklı bir konteyner gemisinin, limanda yük alma/boşaltma işlemleri sırasında, kendi kreyni ile yapacağı yük elleçlemesinin, tekne yapısı üzerinde ortaya çıkaracağı gerilmeler ve sehimin, sakin suda, boyuna mukavemet açısından incelenmesi yapılmıştır. Elde edilen sonuçlara göre gerilmenin en yüksek değerleri, gemi üst binası ile ambar ağzı arasındaki bölge ve ambar ağzı ile baş kasara arasındaki bölgede oluşmaktadır.

Making calculations with computers brings the questions of model's media and recognizing is whether sufficient or not to answer. So the solution at the beginning startes with mathematically determined and countable model structures. Within this manner the question is here to solve a vessel's behavior against loading or unloading phase at sea. Scope of work covers, still water conditions satisfies given criteria by lloyds and section modulus of frames are sufficient for stresses in consider. Now the target for model is cleared. Second step has to be chosen of or creating of a method to achieve enough accuracy. At this point we know lots of study has been done and documented. Here instead of creating a method, existing one which proven itself chose and applied, where needed. The vessel as a model chosen one under construction, a container ship with single hold and large deck opening. Originally ship has not a gantry crane on board, so it means hatch coaming and frame structure calculated, assuming design of this area suitable for crane operation. For making further steps, it is better to see what type and sort of data we need: 1 - Vessel's geometry, 2- Hydrostatic data, 3- Structure of frames in consider, k- Structure of longitudinal members, 5- Loading conditions, 6- Weight distribution. 1- Vessel's geometry Geometry means here: offset plan, lines plan, span of frames, Outer contour description, specially fore and aft section of vessel in profile view. 2- Hydrostatic data Frame areas, Water plane areas, Volume, Displacement, Longitudinal center of buoyancy, Vertical center of buoyancy, Transversal center of buoyancy, Metacentric height of gravity. 3- Structure of frames in consider Structure element geometry, Statical moments, Section modulus of frames according to base line and deck, Moment of inertia. 4- Structure of longitudinal members Continuity of frame sections. 5- Loading conditions Chosen load type, Distribution of loads, Draughts at examined state, Consumables data, Vertical center of gravity. 6- Weight distribution Light weight distribution, Vertical center of gravity, Longitudinal center of gravity, Transversal center of gravity. VI To obtain listed data, it is easily seen first, a mathematically defined geometry is needed, second, drawings of structure has to be in hand an third, stability booklet of vessel has to be prepared. As a way of defining geometry, cubic spline is adopted. First, offset data used to evaluate reference points of curve fitting then total span method as a Lty DooK±et, taken consider Tor w--w--" ~~w..w -w " computation request of Germannisher Lloyd. Results of computer program developed "Lsmain", listed with comparison of lloyd's. Longitudinal strength calculations based on book written by Prof. Mesut SAVCI. The vessel described as a floating object and this object is a cantilever beam. This beam differs from the others by distribution and type of loads on it and carriage by water. All assumptions made on that this beam stays stable on water and forces are static. Sectional areas of frames, borders limited by base line at bottom and draught at side in [m2~\, at longitudinal direction of vessel on real coordinates multiply by water density creates buoyancy curve. Weight distribution curve can be obtained by calculating steel hull, engine plant, load, fuel, water etc. gravity and longitudinal center of them referencing aft perpendicular. Difference of two curves gives us effective load curve. Making numerical computation with this curve, shear forces and bending moments obtained at each station point. Bending moment results at ends has to be zero, it brings no integration constraint. Some mistakes ondrawings or in dimensions and center of gravities of weight and buoyancy are not in line, reflects to bending moment values not zero at ends. In this case either center of gravities made in line or displacement equalize with total weight or a linear corrections is made. Limits to linear correction are, vıı For shear farces: Qk-£= D.D3 Qmax Qmax = Maximum shear force, G.k = Residual shear farce at ends Far bending moments Mk-£ = 0.06 Mmax Mmax = Maximum bending moment, Mk = Residual bending moment at ends. The gantry crane on board moves from front bulkhead of superstructure at aft to beginning of for castle at fare. Full figure of crane in computations are: 50 tons of steel weight, k feet, 7 meters span of feet in transverse direction, 1 meter pressure area to each foot, From the loading case crane at deck holds 14 tons a container and completes its moving in eight steps. Results of values at this positions with graphics listed as well. After making calculations, maximum shear force values occurs at 12, 33 th meter from aft and 83.08 meter from aft. This section come across the where superstructure front bulkhead sits at 12,33 and forecastle starts at 83.08. Bending moment raise to maximum at aft of hatch coaming. Maximum shear forces and bending moments also calculated according to Turk Loydu's rules for steel hull construction. It has been observed that obtained values are not pass over the permissible shear stresses and permissible bending stresses. Results given at the end of this book. Vlll Prepared computer programme "LSMAIN" constructed on modules. Each module has piece of programmes. They are nat overlay files and all of them are stand alone enecultable files. Given names to this files call tbığive an.idea uihey they compute." Date structure is convertible between major database programmes like Dbase or lotus and numerical data entered or evaluated can be obtained in ASCII type also. After enterin offset date to programme first drains lines plan to screen to show if any point is missing or wrong typed, One another. While frames or water lines are drawing, area under curves with frame number appears bottom.