SU913049A1 - Strain gauge for measuring large deformations - Google Patents

Description

The invention relates to measuring, engineering, and in particular to electric strain gauges for measuring severe deformations.

Known strain gauge for measuring large deformations, containing a sensing element in the form of a rubber cord with a wound strain gauge and supports for installation on the sample [1].

The disadvantage of this strain gauge is the low measurement accuracy associated with low sensitivity and the possibility of non-uniform deformation of the rubber cord.

Closest to the invention is a strain gauge for measuring large deformations, containing a sensing element in the form of a spiral spring with a microwire wound on it and plates for mounting on a sample [2].

The disadvantage of the known strain gauge is the low measurement accuracy associated with the possibility of the loss of stability of the sensitive element when measuring in compression, as well as the relatively narrow measurement range associated with the need to pre-stretch the springs when tested in compression.

2

The aim of the invention is to improve the accuracy and expansion of the measurement range.

This goal is achieved by the fact that the strain gauge is provided with two U-shaped brackets placed one 5 in the other, directed open ends facing one another so that their crossbars are parallel, two rigid rods of rectangular cross section, the plates are made with ₁₀ straight holes plates and each are connected respectively with the crossbar of the U-shaped bracket turned to it.

FIG. 1 shows a strain gauge, a general view; in fig. 2 and 3 - work of the strain gauge during testing, respectively, of tensile and

compression.

The strain gauge consists of a sensing element containing a coil spring 1 and a microwire 2, wound on a spring, plates 3 with rectangular holes, P-about ²⁰ different brackets 4 directed towards each other with their open ends parallel and two crossbars of rectangular sections placed in the holes of the plates 3 and connected each so3

913049

responsibly with the crossbar of the U-shaped bracket turned to it 4.

The strain gauge works as follows.

Traction 5 is fixed on the surface of the deformable part.

When tensile tests (Fig. 2) ₅

the deformation of the part through the thrust 5, the crossbar of the U-shaped brackets 4 and the plate 3 re ^; given by the spring 1, which is experiencing tensile deformation and its length increases with it.

When tested for compression (Fig. 3) ^de-1C formation parts 5 through traction, the free ends of the U-shaped brackets 4 and the plate 3 is transmitted to the spring I, which undergoes tensile deformation, and its length is increased.

Thus, the deformation of the part, both in tensile tests and in compression tests, is transformed into a tensile strain of the spring.

Together with the spring I, the microwire 2, wound on the spring, is deformed, which causes a change in its electrical resistance. An electrical signal proportional to the change in resistance of the sensitive element of the strain gauge, and, consequently, to the deformation, is amplified and fed to the recording equipment.

The proposed strain gauge allows you to increase the accuracy of strain measurement by eliminating the possibility of loss of stability of the sensitive element and ensuring its work only in tension.

Claims (1)

Claim A strain gauge for measuring large deformations, containing a spiral spring sensitive element with a microwire wound on it and plates for mounting on a sample, characterized in that, in order to improve accuracy and extend the measurement range, it is equipped with two U-shaped brackets placed one another. , directed open ends towards each other so that their crossbars are parallel, with two rigid rods of rectangular cross section, the plates are made with rectangular holes, the rods are placed in the holes of the plastic in and each respectively associated with its crossbar facing the U-shaped bracket.