KR100234470B1 - A strain gauge for stress monitoring apparatus of hull - Google Patents

Abstract

The present invention relates to a long-based strain rate gauge in a hull stress monitoring apparatus used to monitor a stress change of a hull, wherein a long-base strain is measured to measure a strain of a section of the hull. A rod member 3 of a predetermined length, fixed to (5) and supported at the other end so as to be free to move from side to side; It is connected to the extension line of the other movable end of the rod member 3 is fixed to the hull (5), the linear to receive the linear displacement amount of the rod member 3 in accordance with the deformation of the hull 5 to convert it into an electrical amount Variable differential transducer 23; A zero adjustment bar 49 provided at the other end of the rod member 3 that is movable; And an amplifier 51 electrically connected to the linear variable differential transducer 49 to amplify the amount of electricity converted by the linear variable differential transducer 49, thereby providing for the entire life of the ship. A mechanical mechanism that can subsequently measure and monitor the stress of the hull and obtain stress data over a long baseline corresponding to at least the entire length of the rod member of the strain gauge, rather than local stress data about one point of the hull. It is effective to provide a long-base strain gauge that operates with

Description

Strain Gauge for Hull Stress Monitoring Devices

(Technology field)

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a strain rate gauge for forming a sensor part for measuring a strain of a hull in a hull stress monitoring apparatus used for monitoring a stress change of a hull. It relates to a long-based strain gauge.

(Prior art)

Vessels manufactured to sail on water with a balance of buoyancy and gravity, unlike onshore vehicles, are a variety of materials, such as hogging, sagging, racking, or slamming during sailing. The external force in the longitudinal direction and the transverse direction or the local strength is received, and the ship basically has sufficient strength to cope with the external force in consideration of the purpose of the ship, the loading capacity, the operating speed, and the characteristics of the route. Are manufactured.

However, the ship is aging as it is continuously subjected to external force during its life, and eventually the strength of the members constituting the hull is gradually reduced, the strength of the hull that resists the external force, that is, the stress is lowered. Such hull stress reduction has a significant effect on the safety of ships, and a hull stress measuring apparatus for measuring the stress of the hull has been developed.

Recently, in the context of increasing interest in the safety of ships, a system has been developed to continuously measure and monitor the stress change of the hull by fixedly installing a hull stress monitoring device on the ship, and in particular, the International Maritime Organization (IMO) The International Maritime Organization recommends fixed installation of hull stress monitoring devices for cargo ships that load and unload heavy cargoes from time to time for the safety of the ship.

When an external force is applied to an object, the object deforms and at the same time generates a resistance to the external force, and the stress represented by the magnitude of the internal force per unit area and the amount of deformation of the object are proportional within a certain range. The hull stress monitoring device is a device that converts the amount of deformation of a hull measured by a strain gauge provided on a hull into the stress of a hull by using the principle that a stress and a strain are proportional.

The strain gauge that forms the sensor part for measuring the strain in the hull stress monitoring device utilizes the pressure resistance effect of changing the resistance value when deformation is applied to the steel component. In the strain gauge of the conventional hull stress monitoring device, the strain gauge generally is a point strain gauge. (point strain gauge) has been used.

4 schematically illustrates a conventional point strain gauge. As shown, the point strain gauge is a foil which is attached to the hull of which the strain is to be measured and formed by forming a foil pattern grid 103 having a predetermined width and length in a matrix 101 made of a conductor. Strain gauge. This foil strain gauge is very small in size and measures the strain of the hull by measuring the resistance that changes with the tension of very thin grid lines. However, these foil strain gauges usually have a short lifespan, ranging from one to three months, which means that the strain gauges need to be replaced frequently, since the stresses of the hull can't be measured for the entire life of the ship, which lasts over 20 years. There is a problem that a local stress that cannot be represented may be measured.

It is therefore an object of the present invention to provide a long-baseline strain gauge that can be used for the entire life of a ship and operates with a mechanical mechanism that can exclude the local stresses of the hull from being measured.

An object of the present invention described above is a rod member having a predetermined length, one end of which is fixed to the hull and the other end of which is supported to be free to move from side to side; A linear variable differential transformer (LVDT) connected to an extension line of the other movable end of the rod member and fixed to the hull, and receiving a linear displacement amount of the rod member according to the deformation of the hull and converting the linear member into an electrical quantity; A zero adjustment bar installed at the other movable end of the rod member; And an amplifier electrically connected to the sinusoidal variable differential transducer to amplify the amount of electricity converted by the linearly variable differential transducer.

1 shows a strain measurement gauge for a hull stress monitoring device according to the present invention, in which FIG. 1a is a plan view and FIG. 1b is a front view.

2 is a schematic diagram showing the interior of a linear variable differential transducer body.

3 shows a state in which the strain measurement gauge of FIG. 1 is installed on the girder of the hull, in which FIG. 3a is a plan view and FIG. 3b is a front view.

4 is a schematic representation of a conventional point strain gauge.

<Explanation of symbols for main parts of drawing>

1 strain gauge 3 rod member

5: hull (girder) 7: rod fastening plate

11: rod clamp 15: bracket plate

19: L-bracket 21: guide bush

23: linear variable differential transducer 25: linear variable differential transducer fixed clamp

47: spring 49: zero adjustment bar

51: amplifier 53: amplifier plate

55: amplifier fixing clamp 59: cover

EMBODIMENT OF THE INVENTION Hereinafter, with reference to an accompanying drawing, the strain measuring gauge for ship hull stress monitoring apparatus of this invention is demonstrated in detail. The following specific examples merely illustrate the strain measurement gauge for the hull stress monitoring device of the present invention, but are not intended to limit the scope of the present invention.

The strain measuring gauge for hull stress monitoring device according to the present invention receives a linear displacement amount of a rod member to a movable other end of a rod member having a predetermined length, one end of which is fixed to the hull and the other end of which is freely movable from side to side. Linear variable differential transducers (LVDTs) are installed in series to convert them into electrical quantities, a zeroing bar for zeroing the strain gauge to zero at the other end of the rod member, and amplifying the electrical quantities converted by the linear variable differential transducers. An amplifier is electrically connected to a linear variable differential transducer, and the linear displacement of the rod member due to the deformation of the hull transmitted to the linear variable differential transducer is converted into an electric quantity, and the stress of the hull is converted from the electric quantity. Characterized in that.

1 shows a strain measurement gauge for a hull stress monitoring device according to the present invention, in which FIG. 1A is a plan view, FIG. 1B is a front view, and FIG. 2 is a schematic view showing the inside of the linear variable differential transducer body. 3 is a state where the strain measurement gauge of FIG. 1 is installed in a ship body, FIG. 3A is a top view and FIG. 3B is a front view.

As shown, the rod member 3 of the strain measurement gauge 1 is, for example, a rod clamp coupled to the rod fastening plate 7 welded to the girder 5, which forms the main skeleton of the hull. 11) one end is fixed. The rod fastening plate 7 is in the shape of a recess having a leg portion which is welded to the girder 5 and a flat plate portion formed with bolt holes for bolting the rod clamp 11. The rod clamp 11 is composed of two fastening members 13 and 13 'having bolt holes formed therein, and by inserting the rod member 3 between the fastening members 13 and 13' to tighten the bolt 9. The rod member 3 is fixed to the rod fastening plate 7.

The other end of the rod member 3 is movably supported from side to side on an L-shaped bracket 19 coupled to a bolt 17 to a bracket plate 15 having a welding shape attached to the girder 5. The bracket plate 15 differs only in size from the rod fastening plate 7, and its basic shape is the same. The L-shaped bracket 19 has a long horizontal leg with a bolt hole for bolting a clamp 25 for fixing the linear variable differential transducer 23 to be described later, and a rod member 3 on the rod member side of the horizontal leg. It consists of a vertical leg formed with a bush mounting hole is inserted into the guide bush (21) to facilitate the horizontal movement of the.

That is, the rod member 3 is fixed so that one end thereof cannot be moved by the rod clamp 11 and the rod fastening plate 7, and the other end thereof is an L-shaped bracket 19 provided with the guide bush 21. And since it is supported so that it can be moved to the left and right freely by the bracket plate 15, when the girder 5 is deformed by an external force, the other end, which is the free end, is moved to the left and right by the deformation of the girder.

The rod member 3 used for the strain measuring gauge 1 of the present invention is not particularly limited in its material and size, but according to the experiments of the present inventors, the strain measuring gauge 1 is considered in consideration of the thermal stress effect. It is preferable to use the steel material of the same component as the steel which comprises the ship body in which) is installed, and to use the rod of 1.58m length from a viewpoint of the precision of a measurement.

The linear variable differential transducer LVDT 23 receives a linear displacement of the rod member 3 according to the deformation of the girder 5 and converts it into an electric quantity such as a voltage on an extension line of the other movable end of the rod member 3. Is fixed to the rod member 3 by a clamp 25 bolted to the L-shaped bracket 19 described above. The linear variable differential transducer 23 may be a known linear variable differential transducer, and as shown in FIG. 1 and FIG. 2, the probe tip may move in contact with the rod member 3 and move along the lateral movement of the rod member. a probe tip; 27), a tubular body 35 having a primary coil 31 and a secondary coil 33 that are not moved, wound around a core 29 that is connected to and move with the probe tip; And a spring relief 37. When the probe tip 27 is pushed or pulled by the displacement amount of the rod member 3 according to the deformation of the girder 5, the electrical change is generated by the action of the primary coil and the secondary coil in the main body 35, As a result, the displacement of the rod member 3 is converted into an electrical change.

The clamp 25 which fixes the main body 35 of the linear variable differential transducer 23 to the L-shaped bracket 19 is composed of an upper and lower member. That is, the linear variable by fastening the upper member 43 with the bolt 45 in a state where the linear variable differential transducer 23 is mounted on the lower member 41 fastened to the L-shaped bracket 19 with the bolt 39. The differential transducer is fixed. Here, by inserting the spring 47 inside the bolt 45 which fastens the upper member, when the linear variable differential transducer is fixed with the bolt 45, elasticity is given to the tightening force so that the linear variable differential transducer is not damaged. It is desirable to.

At the other end of the rod member 3 which the linear variable differential transducer 23 is in contact with, a zero adjustment bar 49 for adjusting the zero point before measuring the stress of the girder 5 is provided. The zero adjustment bar 49 is screwed to the rod member 3. Manually turning the zero adjustment bar 49 moves the zero adjustment bar to the left and right, for example, the length of the rod member 3 can be adjusted up to ± 5 mm, and the zero adjustment bar can be installed so that the minimum adjustable displacement amount becomes 0.01 mm. .

The linear variable differential transducer 23 is electrically connected by an electric wire 52 to an amplifier 51 which amplifies the displacement of the rod member 3 converted into an electric quantity by the linear variable differential transducer. This amplifier 51 is fastened by the clamp 55 to the amplifier plate 53 fixed to the girder 5, and performs the function of amplifying the amount of electrical change output in a weak amount.

The amplified electrical quantity is sent to a device programmed to convert it to hull stress, and finally the body stress is output.

The strain measurement gauge 1 for the hull stress monitoring device of the present invention consisting of a rod member 3, a linear variable differential transducer 23, a zeroing bar 49, and an amplifier 51 is preferably By providing the cover 59 provided on the girder 5 by a plurality of bolts 57, it is possible to prevent this material from penetrating into the strain gauge and damaging the strain gauge.

In the present invention, four strain gauges are provided at positions having an important meaning on the strength of a ship, such as a girder, and the data measured by these strain gauges are connected to the hull stress monitoring device of the central control room to stress the hull. Can be monitored.

According to the strain measurement gauge for hull stress monitoring device of the present invention described above, it is possible to continuously measure and monitor the stress of the hull for the entire life of the ship, which is not only useful for the safe navigation of the ship, but also the work of the hull There is an effect that a long-baseline strain gauge operated by a mechanical mechanism is provided that can obtain stress data over a long baseline corresponding to at least the entire length of the rod member of the strain measurement gauge, rather than local stress data about the point, It also has the effect of lower manufacturing and maintenance costs compared to the existing point strain gauges.

Claims (4)

A rod member having a predetermined length, the one end of which is fixed to the hull, and the other end of which is supported to be movable freely from side to side; A linear variable differential transducer connected to an extension line of the other movable end of the rod member and fixed to the hull, and receiving a linear displacement amount of the rod member according to the deformation of the hull and converting the linear member into an electrical quantity; A zero adjustment bar installed at the other end of the rod member that is movable; And an amplifier electrically connected to the linear variable differential transducer for amplifying the amount of electricity converted by the linear variable differential transducer. The rod member of claim 1, wherein the rod member is fixed to a rod clamp bolted to a rod fastening plate welded to the hull, and the other end is bolted to a bracket plate welded to the hull and guided. A strain measurement gauge for a hull stress monitoring device, which is supported by a bush-mounted L-shaped bracket so as to be movable from side to side. 3. The clamp according to claim 2, wherein the linear variable differential transducer comprises a lower member fastened to the L-shaped bracket by bolts and an upper member fastened to the lower member by a linear variable differential transducer mounted on the lower member. And a spring is attached to the bolt of the upper member, the strain measuring gauge for the hull stress monitoring device. The strain measurement gauge according to any one of claims 1 to 3, wherein the strain measurement gauge is protected by a cover provided on the hull by bolts.