Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B5/00—Measuring arrangements characterised by the use of mechanical techniques
  • G01B5/30—Measuring arrangements characterised by the use of mechanical techniques for measuring the deformation in a solid, e.g. mechanical strain gauge

Definitions

• the invention concerns a gauge for measuring linear strain of materials, consisting at least of two measuring marks created with certain spacing on the material; the invention also concerns a method of production of this gauge.
• tensiometers such as mechanical, optical, electrical, acoustic, pneumatic and other.
• the disadvantages of mechanical, optical, acoustic and pneumatic tensiometers are similar to those of the above-mentioned microscopes.
• Electrical tensiometers do not have some of these disadvantages, but their large setback is that they can only work within certain temperature ranges. In case of higher or lower temperatures electrical tensiometers have to be adjusted and their acquisition price then grows any times.
• a gauge for measuring linear strain of materials comprising at least two measuring elements fitted with measuring blades with mutually parallel axes, attachable to the measured material, and a portable scanning body with an impression surface made from a dimensionally stable material with hardness lower than the hardness of the material of the measuring blades and/or the portable measuring device pursuant to this invention.
• the measuring body is located, on the side facing away from the measuring blades, in a hole of a lug and is attached to it using resin-based glue; the lugs are connected to the surface of the measured material with a weld.
• the lugs are beneficially connected to the surface of the measured material using a weld made under electric arc.
• the lugs may be cylinder- shaped and the hole is then located in the direction of the cylinder axis, and is beneficially fitted with internal threading.
• the measuring blades are beneficially equipped with fittings and the measuring elements may be fitted with necks and cone- shaped ends in the bottom section.
• PatXML 3 PCT-ZEMAN (PV2004-1088)
• the measuring elements and/or lugs are beneficially lodged in a transport rig comprising a transport board with holes for measuring elements and/or lugs after the mutual accurate parallel adjustment of the axes of measuring blades, and the joint between the measuring elements and/or lugs and the transport rig has lower strength than the joint between the measuring elements and/or lugs and the measured material.
• the gauge described above is beneficially made so that the measuring elements and/or lugs are lodged in the holes in the transport preparation and the accurate mutual distance and parallelism of the blade axes are set and fixed in this position using glue with lower strength than the glue between the measuring elements and/or lugs and the measured material, and after that the measuring elements are connected to the measured material using the lugs, with the transport rig being removable.
• the measuring elements are beneficially located in the holes of the lugs before inserting in the holes in the transport rig and connected to the lugs using resin-based glue; when the accurate mutual distance and parallelism of the blade axes are set, the lugs are welded to the measured material and the transport rig is removed.
• the lugs are welded to the measured material and the measuring elements located in the transport rig are inserted in the lugs and connected to them using resin-based glue; when the joint hardens, the transport rig is removed.
• the measuring elements are fitted with measuring blades whose axes are in a mutually parallel position, it is possible to measure their accurate distance and the bend of the measured material, if any. Thanks to the fixed connection to the surface of the measured material it is possible to place the separate measuring elements on various structures where other measuring devices cannot be commonly connected, such as airplane structures, surfaces of power devices and the like.
• the material of the impression surface of the scanning body allows keeping the impressions for a long time thanks to its dimensional stability, which basically enables the monitoring and comparison of the measured material during its whole lifetime. Thanks to its lower hardness than the hardness of PatXML 4, PCT-ZEMAN (PV2004-1088)
• the measuring elements are not worn out even after many measurement repetitions.
• the measuring element on the side facing away from the measuring blades is placed in a lug hole, it can be connected to it using resin-based glue; in that case the joint transfers shearing stress as well as tensile stress and its strength is therefore much higher.
• the resin-based glue provides for permanent connection even under extreme conditions, such as large temperature differences, external influences and the like.
• the lugs may be in this case connected to the surface of the measured material using a weld, optimally a weld that influences the properties of the measured material to the minimum extent possible. This especially refers to a weld made by electric arc. Current technology makes it possible to make a weld within a couple of milliseconds and the necessary equipment is small and light, and as such can be transported anywhere.
• the hole is located in the direction of the cylinder axis and if the hole is fitted with internal threading, a larger contact surface is created and the joint between the measuring element and the lug has a higher strength.
• the measuring blades may have fitting in their central section, which allows for reducing the strength necessary to create the impression and reducing the contact surface between the measuring element and the lug and between the lug and the measured material, because these joints are exposed to smaller stress during measurement. If the measuring elements are fitted with necks and a cone-shaped end in the bottom section, they create conditions for increasing the strength of the joint between the measuring elements and the lugs. PatXML 5 PCT-ZEMAN(PV2004-1088)
• measuring elements and/or lugs are lodged in a transport rig following mutual precision setting, it is possible to transport and install the measuring elements basically in any place if the precision setting is kept and the measuring elements can be easily disconnected from the transport rig after their placement on the measured material.
• the mentioned method of gauge production makes it possible to set the measuring elements in the transport rig and on the measured material precisely, with the joint between the measuring elements and the measured material being strong and with a long lifetime.
• the gauge as specified in the invention gives the possibility of accurate measurement of permanent material deformations on the measured sections by using high-precision measuring equipment, such as measuring microscopes. Since this large and heavy device cannot be installed directly on a bridge, pipeline, ship or another structure where the condition has to be monitored after an excessive burden, for instance an earthquake, it is beneficial to use the gauge according to this invention where the measurement of the spacing of the measuring elements before and after the load is carried out using a measuring microscope on the impressions of measuring points created on a collected impression body.
• figure 1 shows a plan view of the location of two measuring elements and figure 2 a sectional side view of the measuring element in the lug, including the impression body.
• the exemplary linear strain gauge for materials comprises at least two measuring elements 1_ fitted with measuring blades 2 with parallel axes. These measuring elements 1_ are attachable to the measured material.
• the gauge also comprises a portable scanning body 3 with an impression surface 4 made of a dimensionally stable material with hardness lower than the hardness of the material of the measuring blades 2, or the scanning body 3 may be replaced or supplemented with a portable measuring device.
• On the side facing away from the measuring blades 2 the measuring elements 1_ are placed in a hole ⁇ O of a lug V ⁇ and are attached to it using resin-based glue.
• the lugs 1_1_ are cylinder-shaped and the hole 10[ is placed in the direction of the cylinder axis and is fitted with internal threading ⁇ 12.
• the lugs ⁇ _ are attached to the surface of the measured material using a weld made by electric arc.
• the measuring blades 2 have fitting 5 and the measuring elements 1_ are fitted with necks 6 and a cone-shaped end 7 in their lower section.
• the measuring elements 1_ are lodged in a transport rig 8, comprising a transport board with holes 9 for the measuring elements 1_, and the joint between the measuring elements " ⁇ _ and the transport rig 8 has lower strength than the joint between the measuring elements 1_ and the measured material.
• the gauge is manufactures so that the measuring elements 1_ are inserted in holes 9 in the transport rig 8 and the precise mutual distance and parallelism of the axes of the blades 2 are set; after that that measuring elements 1_ are fixed in this position using glue with lower strength than that of the glue used between the measuring elements 1_ and the measured material. After that the measuring elements 1_ are attached to the measured material using the lugs V[ and the transport rig 8 can be removed after connecting the measuring elements 1_.
• the measuring elements 1_ are placed in holes 10 of the lugs V ⁇ and connected to the lugs IM using resin-based glue before inserting into holes 9 in the transport rig 8 and after setting the precise PatXML 7, PCT ⁇ ZEMAN(PV2004-1088)
• the lugs 11_ are first welded to the measured material and the measuring elements 1_ placed in the transport rig 8 are inserted in the lugs Y_ ⁇ and connected to them using resin-based glue; when the joint hardens, the transport rig 8 is removed.
• impressions of the measuring elements 1_ fixed to the surface of the measured material are created on the impression surface 4 of the scanning body 3 and the precise distance of the identified sites of both impressions is measured in the spacing of the measuring elements X ⁇ the first pair of impressions is created before the strain and another pair of impressions of the measuring elements 1_ is created after the critical strain, and the distances between the first pair and the second pair of impressions are compared.
• the gauge therefore comprises a fixed part attached to the measured section of the material and a portable part.
• the gauge for measuring linear strain of materials and method of its production according to this invention can be applied in various fields of industry, especially aerospace, ship, power, construction and the like.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Length Measuring Devices With Unspecified Measuring Means (AREA)
• A Measuring Device Byusing Mechanical Method (AREA)
• Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

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ID=35385433

Family Applications (1)

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Cited By (2)

Citations (4)

Family Cites Families (3)

• 2004
  • 2004-11-02 CZ CZ20041088A patent/CZ301142B6/cs not_active IP Right Cessation
• 2005
  • 2005-09-14 WO PCT/CZ2005/000069 patent/WO2006047970A1/en active Application Filing
  • 2005-09-14 JP JP2007538251A patent/JP2008519249A/ja not_active Withdrawn
  • 2005-09-14 EA EA200700992A patent/EA010533B1/ru not_active IP Right Cessation

Patent Citations (4)

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