LT4403B - A device for measuring of a curvature of a surface of a thin-walled anisotrppic shell - Google Patents

Abstract

This invention belongs to the branch of geometric measurements. The device consists of a unit for fitting the specimen, a unit for the deformation of the specimen and a unit for measuring the curvature of the formed shell. The unit for the deformation of the specimen consists of a hard punch, placed under the specimen, and a vertical pull mechanism with a pair of screws. The unit for measuring the curvature of the formed shell is mounted above the shell and consists of an angle sensor, placed on the vertical axis of the measured shell, the fixation for orienting the sensor, automatic vertical pull gear, which has a synchronized connection with registering device, and horizontally oriented sensor outcome axis, on which the lever tracker is mounted; it must attach to the surface of the measured shell.

Description

APPARATUS FOR MEASURING THE SURFACE CURVE OF ANISOTROPIC SHELLS

The invention relates to the field of material testing and measurement of geometrical parameters of thin structures and can be used in the design and manufacture of household products (soft containers, clothing), thin building structures (hangars) and flying machines (balloons, etc.).

A known device is used to measure the radii of curvature of thin anisotropic positive-curvature shells loaded with evenly distributed pneumatic or hydraulic loading. The apparatus consists of a shell fastening device, a linear displacement gauge and a two-lever lever with angle sensor and counterweight (see former USSR Certificate No. 602767, TPKG01 B 5/20, 1972).

This device can only be applied to convex or convex shells (positive curvature), devoid of concave or curved (concave) zones (negative curvature), i.e. "Operating" only under conditions of uniformly distributed pneumatic or hydraulic loading. And such conditions are very rare. The main disadvantage of this device is its narrow technological capabilities. In addition, the measurement performance is also low, as data deductions are made visually on the scales of two devices (angle sensor and displacement micrometer), performing auxiliary counterweight operations.

Also known is another device for a similar purpose consisting of a specimen clamping device, a specimen deformation device and a specimen deflection measuring device in which the specimen deflection measuring device is located below the specimen and consists of a vertical dagger fork, a micrometer, a disc with a rotation angle lock and a screw. with threads of different directions at the ends (see Pat. No. 4057, TPK G01 B 5/20; 13/16, 1995).

This device allows you to measure the surface curvature of the most complex shells, even when there are positive and negative areas of curvature in the same shell. However, this device is characterized by inadequate accuracy and low measurement performance, since finding the coordinates of each shell composite point depends on the accuracy of the fork contact with the soft shell, which is determined only visually, and may vary between sections of the shell or for quality (smoothness). However, despite its drawbacks, the device is considered a prototype of the present invention due to the similarity of its essential features.

The object of the invention is to improve the accuracy of measurements and to increase their speed.

This object is achieved by providing a device for measuring surface curvature of thin-walled anisotropic shells consisting of a specimen mounting device, a specimen deformation device and a formed shell forming curvature device having a mechanical surface tracker and an angle measuring transducer, consisting of a solid pouch, the specimen and its helical pair of propulsion mechanism, the formed shell forming curvature gauge being mounted above the shell and consisting of an angle transducer positioned along the vertical axis of the measured shell symmetry, the orientation of the transducer along the shell folding locking system, a recording device, and a horizontally oriented sensor output axis on which a lever follower is mounted which contacts the outer surface of the body to be measured.

The invention is illustrated in the drawings: FIG. 1 is a schematic diagram of the proposed device; FIG. 2 - Angle Sensor Hanger Assembly (Figure A-A).

The device (Fig. 1) consists of a specimen mounting device 1, a specimen deformation device 2, and a body curvature measuring device 3. All three parts 1,2 and 3 are arranged in one common vertical axis. The specimen clamping device 1 consists of two rings 4 and 5 between which a specimen 6 of a flat polymeric material with more or less pronounced anisotropic properties is compressed. The specimen deformation device 2 consists of a solid, e.g. a metallic pouch 7 which is connected via a stem 8 to a vertical push slider 9 having a nut 10, a screw 11, a rotary handle 12 thereof and a displacement measuring rod 13 of the pouch 7 placed above the pouch 6 to be measured and consisting of angle sensor 14, e.g. an inductive fixed to a vertical shaft 15 having an orientation 14 of a sensor 14 along any of the shell measuring discs 16 with an angle unit scale 17 and an arrow 18 (FIG. 2) connected by a screw 19 through a bracket 20 to a screw 22 enclosing a nut 21. coupled to an automated vertical-angle transducer 14 with an electric motor 23, e.g. a stepped control unit 24 with end stops 25, 26, a baseboard 27 and a feather 28 of a nut 21. A light lever 30 with a supporting roller 31 is mounted on the output shaft 29 of the sensor 14 at its lower end. The transducer 14 is coupled to the recording circuit 33 by means of an electrical circuit 32, which communicates synchronously with the control unit 24 via the electrical circuit 34.

If the specimen 6 exhibits a pronounced anisotropy (deformation unevenness in different directions), then the indenter 7 is pressed to form a complex thin-walled shell with positive and negative curvature, which in the area between the indenter 7 and the fastening rings 4-5 will be inclined in different directions. (unevenly crooked). The most divergent components will be at an angle of 90 ° to each other and will follow the principal axes of the specimen (eg longitudinal and transverse or warp and weft).

The device works as follows. The pre-cut specimen 6 (of film, fabric, or other material) is clamped firmly in the specimen mounting device 1 between the rings 4 and 5. Poisson 7 then occupies its lower position, i.e. it is in the plane of the intersection of the rings 4 and 5 and at the same time in the plane of the specimen 6 (the specimen 6 is flat in its attachment). The thin-walled shell 6 is then formed by puncturing the test piece 6 from the flat test piece 6 by deforming it into the shell as follows. By rotating the handle 12, the screw 11 through the nut 10, the slider 9 and the stem 8 puts a punch 7 perpendicular to the surface of the specimen 6 to form a complex shell 6. Once a certain height of the shell 6 is deducted from the displacement size of the nut 10. the twisting process of the handle 12 and the formation of the shell 6 is interrupted. Measurement of the shell curvature is performed by device 3. By pressing the corresponding button on control unit 24 (not shown), the angle sensor assembly 14 with lever 30 and support roller 31 is automatically lowered to its lower starting position (roller 31 is positioned at specimen mounting rings 4 and 5). leaning on the end stop 26). This is the initial starting position from which measurements of the curvature of the shell components begin. Upon actuation of the device control unit 24 (another button not shown in the drawing), the stepping motor 23 rotates a vertical screw 22 which raises the angle sensor 14 through the nut 21, the holder 20 and the stem 15, and the roller 31 is rolled by the lever lever 30. the angle α between the lever 30 and the vertical axis, which is recorded by the device 33 throughout the measurement, changes when the angle α becomes zero and the stylus 28 reaches the limiter 25 and the measurement process automatically stops. In order for the actual curvature of the shell 6 to correspond to the recorded curvature of the device 33, the lifting speed of the angle sensor 14 must be constant and synchronized with the device 33. Such a synchronizing role is performed by the electrical circuit 34.

In order to measure a strictly defined constituent of the shell 6 with respect to the axes of the specimen, e.g. the angle sensor 14 extending along the weft, having the bolt 19 released, together with the stem 15 and the disc 16 mounted on it having a scale 17 graduated in angular units, must be rotated so that the arrow 18 is at 0 ° (zero degrees). Consequently, when the curvature of the constituent is measured, the arrow 18 along the warp is fixed at 90 ° on the scale 17.

The claimed invention significantly improves the accuracy and speed of measurements when compared to the known

- a specimen deformation device consisting of a solid pouch placed underneath the specimen and a helical displacement pair which allows to obtain fixed shell height values from zero to full specimen piercing;

- a device for measuring the curvature of the skeleton is mounted above the skeleton;

- the curvature measuring device consists of an angle sensor;

- the angle sensor is placed on the vertical axis of symmetry of the hull to be measured;

- the curvature measuring device has an orientation sensor for orienting the angle sensor along the shell;

- Angle transducer has an automated vertical shift actuator that synchronizes with the recording device;

- The angle sensor has a horizontally oriented output axis with a lightweight lever follower mounted to measure very soft shells.

Claims (1)

DEFINITIONS OF INVENTION Apparatus for measuring the surface curvature of thin-walled anisotropic shells, consisting of a specimen mounting device, a specimen deformation device and a formed shell forming curvature device, a sensing mechanical surface tracker with an angle measuring transducer, characterized in that the specimen deformation device consists of a solid pouch, and its vertical feed mechanism having a helical pore and the formed shell forming curvature gauge mounted above the shell and comprising an angle transducer positioned along the vertical axis of the measured shell symmetry, an orientation of the sensor along the shell forming latch, automated vertical displacement drive, with a recording device, and a horizontally oriented sensor output axis on which a lever follower is mounted, touching the outer surface of the body to be measured.