1. Hull, structure, outfitting, power pipeline and ship electricity

Technical design, submitted design, detailed design or construction design of gas engineering.

2. Finite element calculation and overall performance calculation of ship structure.

two

Hull lofting is the first process of hull construction. The so-called lofting, its direct meaning is to enlarge the design drawing drawn in a certain proportion on the drawing into a full-scale drawing (or scale drawing) as the basis for cutting and processing hull components. Because the hull surface is a smooth curved surface, it is required that the enlarged pattern must be smooth. Therefore, the purpose of hull lofting is not only to enlarge the design drawings, but also to eliminate the hidden shape errors and non-smooth factors of curves (surfaces) in the design drawings, that is, to smooth the contour lines; In addition, it is necessary to supplement the contents that are not fully expressed in the design drawings; According to the enlarged and smooth drawings, the real shape and geometric dimensions of the hull components are obtained, and the construction materials (sample rods, templates and sketches, etc.) are provided. ) for subsequent processes. Therefore, lofting is not only the embodiment and perfection of design intention, but also an important link to generate construction basis for subsequent processes.

The common methods of hull lofting are manual lofting and mathematical lofting. Manual lofting includes full-scale lofting according to the ratio of 1: 1 and lofting according to the ratio of 1: 10 (1: 5). The advantage of proportional lofting is that it can reduce the area of lofting platform and reduce the labor intensity of lofting. The lofting method is the same as full-scale lofting, but the drawing scale and lofting tools used are different.

Seeking to be different. Mathematical lofting is to define the hull line or hull surface with mathematical equations, establish a mathematical model, and complete the hull lofting with the help of electronic computer. Mathematical lofting will be introduced in chapter 3.

The contents of hull lofting mainly include theoretical profile lofting, rib profile lofting, hull structure profile lofting, hull component deployment and providing the required information for subsequent processes.

The marking of hull components is to mark (print) the cutting lines and processing lines of components on flat steel plates and profiles according to the component templates, sketches, sample rods and data provided by lofting. At the same time, it is also necessary to arrange the drawings of various components reasonably in materials in order to save materials and labor. This work is called nesting.

First, the hull line lofting

A, theoretical line lofting

The hull surface is a smooth spatial curved surface. Based on the principle of three-plane projection, three sets of perpendicular parallel sections (longitudinal section, transverse section and waterline) are adopted in the theoretical line diagram.

Draw three groups of section line (longitudinal section line, transverse section line and waterline) intersecting with that hull surface into three projection drawings (longitudinal section line, transverse section line and half-width waterline) to represent,

The hull curved surface mentioned here refers to the curved surface formed by the outer edge of the hull skeleton of a steel ship (excluding the thickness of the outer plate and deck).

In lofting, the drawing of theoretical circuit diagram is based on the theoretical value given on the designed theoretical circuit diagram, and the drawing principle and method are basically the same as those in the design, which has been learned in the process of hull drawing.

1. Drawing of lofting grid lines

The grid line on the section line is actually the projection line of each group of hull sections on the corresponding projection plane. In addition, the grid line is also the benchmark for measuring dimensions in line lofting. Therefore, ensuring the drawing accuracy of grid lines (straightness, verticality and spacing value) is the premise to ensure the accuracy of hull lofting.

In order to draw the grid line equivalent to the actual ship scale, there must be corresponding drawing methods to meet the accuracy requirements. There are many ways to draw grid lines in lofting, and now only the basic method of drawing grid lines with laser theodolite is introduced.

(1) laser theodolite

Laser theodolite is formed by adding a set of laser aiming device to the telescope of optical theodolite, so that a visible laser beam can be accurately emitted from the telescope along the collimation axis and projected to the measured target point. Therefore, the speed of capturing the measured object by optical theodolite is improved, and the measurement efficiency and adaptability of night use are improved. The optical theodolite is an optical measuring instrument, which can not only measure the horizontal angle between the measured object and the reference object (represented by a horizontal dial), but also measure the pitch angle between the measured object and the horizontal plane (represented by a vertical dial). The most qualified warp knitting machine is always perpendicular to the plane of the horizontal dial. The horizontal rotation center of the telescope is the center of the horizontal dial, and its vertical rotation center is the center of the vertical dial.

Before use, just adjust the plane of the horizontal dial to be horizontal (i.e. "leveling") and adjust the horizontal rotation axis of the telescope to pass through the reference point on the ground (or platform) (i.e. "centering").

(2) Draw a straight line (baseline) with a laser theodolite.

As shown in fig. 2.3, level the laser theodolite and place it in the center of reference point O. The rotating rod telescope is aimed at point A, that is, the linear orientation is carried out first, and the horizontal dial of the theodolite is locked, so that the telescope can only rotate in the vertical plane passing through point U and point A; Then, rotate the telescope to make the laser beam scan evenly between the two points 0 and A, and mark some points such as B, C'D, so that the points A, B, C, …, O must be on a straight line, and an ideal straight line can be obtained by connecting these points. This method is often used to draw the baseline and centerline in hull lofting. Generally, points A, B, C, ... O are 1 .5-2m.

What software can a ship design by looking at the drawings?

Computer aided design software of Autodesk company