A method for preventing and arresting cracking at right-angled corners of openings in enclosures of ship metal structures

Abstract

The invention discloses a method for preventing and stopping a crack of an open right angle corner of a ship metal structure trunk bulkhead. The method for preventing and stopping the crack of the open right angle corner of the ship metal structure trunk bulkhead is characterized in that the traditional crack-stopping hole design is replaced by using a crack-stopping crack design so that the stress originally concentrated on the right angle corner is transferred to an intersected deck (or an intersected trunk bulkhead) easy to reinforce or is dispersed to a specially designed anti-crack circular arc by using a specially designed crack-stopping crack; therefore, the convenience of the structure is convenient to reinforce or the concentrated stress is reduced to effectively stop and preventthe crack.

Description

technical field [0001] The invention belongs to the technical field of ship design and construction, and in particular relates to a method for preventing and arresting cracks at right-angled corners of openings of ship metal enclosure walls, especially ship metal structure enclosure walls of superstructures. Background technique [0002] The opening corner of the metal enclosure is a highly concentrated area of ​​stress in the metal structure. After being stressed, the highly concentrated stress value can easily exceed the design allowable stress value, resulting in corner cracks and further tearing of the entire metal enclosure. Therefore, the opening of the metal fence is usually designed as a circular arc to disperse the concentrated stress to the stress concentration area enlarged by the circular arc, effectively reducing the concentrated stress value and ensuring the working strength of the metal fence. [0003] Obviously, in terms of the dispersion of concentrated stre...

AI Technical Summary

Problems solved by technology

[0006] 1. Compared with the above-built cabin doors and other openings (generally ~700X1800), the Φ15 crack relief hole is still too small (radius 7.5, only 1% of the opening width, far less than 10% of the conventional requirement), although it has a certain effect, But it is still not enough to effectively prevent and stop cracking;

[0007] 2. Due to the inevitable error of the actual construction of the ship, and the inability to obtain the detailed structural diagram of the door frame of the channel equipment during design, etc., it is often difficult to realize the precise cutting of the door opening in the blanking stage: when blanking, it is necessary to leave a margin and only cut out for entry and exit For the process hole of the port, when the ship structure is basically assembled and welded in place, and when the cabin door is installed, the allowance shall be cut according to the actual situation.

At the same time, the small size of Φ15 often makes grinding difficult and the efficiency is extremely low;

[0008] 3. For the design of the crack relief hole, when the actual concentrated stress value is greater than the design allowable stress, there is no other effective strengthening method except for thickening the plate thickness at the corner of the opening

However, the increase of plate thickness has its certain limit (generally no more than 100% of the original plate thickness), and the small size of Φ15 often cannot greatly disperse and reduce the actual stress value

When increasing the thickness of the plate still cannot meet the strength requirements, the conventional crack arrest hole design has actually failed for crack prevention and crack arrest;

[0009] 4. The increase of plate thickness also increases the construction difficulty of the small-sized Φ15 crack arrest hole, which leads to the poor formation of the crack arrest hole, which further affects its crack prevention and crack arrest performance, etc.

[0010] All the phenomena described above can basically be attributed to the conventional crack arrest design of right-angled opening corners of ship metal structures. The actual process is poor in operability and the expected crack arrest effect is not good. It is difficult to guarantee the final quality of ship products during construction

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