CN204924166U - Two sensitive grid interdigital metal strain gauge of lateral deviation of horizontal local derviation but measured surface meets an emergency - Google Patents

Abstract

The utility model provides a two sensitive grid interdigital metal strain gauge of lateral deviation of horizontal local derviation but measured surface meets an emergency, includes basement and two sensitive grids, a lead -out wire is connected respectively at the both ends of every sensitive grid, two fixed sensitive grids in the basement, each sensitive grid includes sensitive segment and changeover portion, and the axis of all sensitive segments is straight line, parallel arrangement and in same plane, in the plane is confirmed to the sensitive segment axis, follow the sensitive segment axis direction is the axial, is horizontal with axial vertical's direction, two sensitive gate resistance are unanimous, and resistance variation is unanimous under the same meeting an emergency, along transversely from last to being called sensitive grid and lower sensitive grid down respectively, on each sensitive segment plane that the axis is confirmed, going up the sensitive grid and are interdigital arranging down between the sensitive grid, two sensitive grid center zero deflections in the axial have the deviation on horizontal. The utility model discloses can measure and to change the horizontal first -order local derviation of can effective measuring surface meeting an emergency.

Description

The lateral deviation sensitive grid interdigitated metal foil gauge of horizontal local derviation can be strained by measured surface

Technical field

The utility model relates to sensor field, especially a kind of metal strain plate.

Background technology

The principle of work of metal resistance strain gauge is resistance strain effect, and namely tinsel is when being subject to effects of strain, and its resistance, along with the size of occurred mechanically deform (stretching or compression), corresponding change occurs.The theoretical formula of resistance strain effect is as follows:

$R=\mathrm{\ρ}\frac{L}{S}---\left(1\right)$

Wherein R is its resistance value, and ρ is metal material resistivity, and L is metal material length, and S is metal material sectional area.Tinsel occurs in the process of mechanically deform bearing strain, and ρ, L, S three will change, thus will inevitably cause the change of metal material resistance value.When metal material is stretched, length increases, and sectional area reduces, and resistance value increases; When by compression, length reduces, and sectional area increases, and resistance value reduces.Therefore, as long as the change of resistance value can be measured, just known strained situation wiry.Metal material resistance change rate formula can be derived by relevant knowledges such as formula (1) and the mechanics of materials

$\frac{\mathrm{\Δ}R}{R}=K\frac{\mathrm{\Δ}L}{L}=K\mathrm{\ϵ}---\left(2\right)$

Wherein Δ R is resistance variation amount, and Δ L is the variable quantity of metal material length on pulling force or pressure action direction, and ε is that the strain on same direction is usually called axial strain, and K is metal material ga(u)ge factor.

In actual applications, metal resistance strain gauge is pasted onto the surface of Sensor Elastic Element or tested mechanical component.When the flexible member in sensor or tested mechanical component produce strain by acting force, also there is identical mechanically deform in the foil gauge pasted thereon thereupon, causes foil gauge resistance that corresponding change occurs.At this moment, mechanical quantity is just converted to the variable quantity output of resistance by resistance strain gage.

But we also need the partial derivative understanding workpiece strain sometimes, such as have three kinds of occasions below, but are not limited thereto three, need to use surface of the work strain partial derivative:

The first, concentrate owing to there will be strain near workpiece shapes sudden change place, often become workpiece and first occur damaging part, the strain partial derivative near sudden change place of monitoring shape, this place strain intensity can be obtained intuitively.

Second, exist in a large number by comer pieces in building, bridge, plant equipment, mechanics of materials relevant knowledge tells us, bent beam surface axial strain is directly proportional to section turn moment, the axial partial derivative of section turn moment is directly proportional to cross section shearing strain, namely can know cross section shearing strain by the axial partial derivative of surperficial axial strain, and this shearing strain directly cannot measure at surface of the work with foil gauge;

3rd, during applied elasticity research workpiece strain, internal strain is decided by partial differential equation, and equation solution needs boundary condition, and surface of the work strain partial derivative is exactly one of boundary condition, and this is that general foil gauge cannot provide.

Summary of the invention

The deficiency of strain local derviation cannot be detected in order to overcome existing metal strain plate, the utility model provide a kind of can monitor strain more effectively can detect the horizontal local derviation of surface strain can strain the lateral deviation sensitive grid interdigitated metal foil gauge of horizontal local derviation by measured surface.

The utility model solves the technical scheme that its technical matters adopts:

A kind ofly can strain the lateral deviation sensitive grid interdigitated metal foil gauge of horizontal local derviation by measured surface, comprise substrate, described metal strain plate also comprises two sensitive grids, be respectively lower sensitive grid and upper sensitive grid, the two ends of each sensitive grid connect an extension line respectively, described substrate are fixed described two sensitive grids;

Each sensitive grid comprises sensitive segment and transition section, the two ends of described sensitive segment are transition section, described sensitive segment is elongated strip shaped, described transition section is tubbiness shape, the resistance of described sensitive segment is much larger than the resistance of described transition section, under same strain state, the increased resistance value of described sensitive segment is much larger than the increased resistance value of described transition section, and the increased resistance value of described transition section is close to 0;

All xsect centres of form of each sensitive segment form sensitive segment axis, this sensitive segment axis is straight line section, the axis being parallel of each sensitive segment and be arranged in same plane, and sensitive segment axis is determined in plane, along described sensitive segment axis direction namely axially, be laterally with axially vertical direction; All shape of cross section consistent size of each sensitive segment; Get the axis point midway of each sensitive segment and with this sensitive segment resistance value for nominal mass is formed the nominal particle of place sensitive segment, the centroid position that the nominal particle of each sensitive segment is formed jointly is the center of sensitive grid;

The sensitive segment all-in resistance of two sensitive grids is consistent, described two sensitive grids all-in resistance changing value of sensitive segment under identical strain is consistent, two sensitive grids be centrally located on straight line, this straight line is perpendicular to two any sensitive segment axis of sensitive grid, and two sensitive grids are called upper sensitive grid and lower sensitive grid from top to bottom along this rectilinear direction; Each sensitive segment axis is determined in plane, in interdigital layout between upper sensitive grid and lower sensitive grid;

Two sensitive grid center bias frees in the axial direction, have deviation in the horizontal, and the distance at upper sensitive grid center and lower sensitive grid center is Δ y.

In the utility model, the line of centres of two sensitive grids should be vertical with two any sensitive segment axis directions of sensitive grid, claims two sensitive grids to have lateral deviation for this reason.The distance at the center of two sensitive grids is Δ y, and lateral deviation is in other words Δ y.Δ y is generally less than even much smaller than the length of each sensitive segment.Described interdigital layout refers to: each sensitive segment axis institute of two sensitive grids in the plane, in the sensitive segment distribution straggly with two sensitive grids on sensitive segment axes normal direction.The order occur respectively the sensitive segment of two sensitive grids in the direction in which and number of times do not limit.Utilize the linear relationship between metal material increased resistance value and strain, on the one hand, as common foil gauge, may be used for monitor strain; On the other hand, the ratio of distances constant at the resistance difference of two sensitive grids and the center of two sensitive grids reflects the horizontal local derviation of strain.

Technique should being noted, keeping each sensitive grid transition section all-in resistance and the transition section resistance variable quantity one under external strain to show heightens measuring accuracy, if the resistance of transition section and the lower resistance change of strain be can not ignore, also can be eliminated when detecting as systematic error.

Further, described metal strain plate also comprises cover plate, and described cover plate is covered in described sensitive grid and substrate.

Further again, described sensitive grid is wire form, foil, diaphragm type or thick-film type sensitive grid.

Further, described substrate is glued membrane substrate, glass fabric substrates, asbestos substrate, metallic substrates or temporary substrate.

Described two sensitive grids are arranged in substrate up and down.Certainly, also can be other arrangement.

The beneficial effects of the utility model are mainly manifested in: can not only measuring workpieces surface strain, more effectively can detect the horizontal partial derivative of surface strain.

Accompanying drawing explanation

Fig. 1 can strain the schematic diagram of the lateral deviation sensitive grid interdigitated metal foil gauge of horizontal local derviation by measured surface.

Fig. 2 can strain the lateral deviation sensitive grid interdigitated metal foil gauge vertical view of horizontal local derviation by measured surface.

Fig. 3 is measuring bridge schematic diagram.

Embodiment

Below in conjunction with accompanying drawing, the utility model is further described.

With reference to Fig. 1 ~ Fig. 3, a kind ofly can strain the lateral deviation sensitive grid interdigitated metal foil gauge of horizontal local derviation by measured surface, comprise substrate, described metal strain plate also comprises two sensitive grids, be respectively lower sensitive grid and upper sensitive grid, the two ends of each sensitive grid connect an extension line respectively, described substrate are fixed described two sensitive grids;

Each sensitive grid comprises sensitive segment and transition section, the two ends of described sensitive segment are transition section, described sensitive segment is elongated strip shaped, described transition section is tubbiness shape, the resistance of described sensitive segment is much larger than the resistance of described transition section, under same strain state, the increased resistance value of described sensitive segment is much larger than the increased resistance value of described transition section, and the increased resistance value of described transition section is close to 0;

All xsect centres of form of each sensitive segment form sensitive segment axis, this sensitive segment axis is straight line section, the axis being parallel of each sensitive segment and be arranged in same plane, and sensitive segment axis is determined in plane, along described sensitive segment axis direction namely axially, be laterally with axially vertical direction; All shape of cross section consistent size of each sensitive segment; Get the axis point midway of each sensitive segment and with this sensitive segment resistance value for nominal mass is formed the nominal particle of place sensitive segment, the centroid position that the nominal particle of each sensitive segment is formed jointly is the center of sensitive grid;

The sensitive segment all-in resistance of two sensitive grids is consistent, described two sensitive grids all-in resistance changing value of sensitive segment under identical strain is consistent, two sensitive grids be centrally located on straight line, this straight line is perpendicular to two any sensitive segment axis of sensitive grid, and two sensitive grids are called upper sensitive grid and lower sensitive grid from top to bottom along this rectilinear direction; Each sensitive segment axis is determined in plane, in interdigital layout between upper sensitive grid and lower sensitive grid;

Two sensitive grid center bias frees in the axial direction, have deviation in the horizontal, and the distance at upper sensitive grid center and lower sensitive grid center is Δ y.

The present embodiment can strain the lateral deviation sensitive grid interdigitated metal foil gauge of horizontal local derviation by measured surface, comprise substrate 1, described metal strain plate also comprises two sensitive grids, and the two ends of each sensitive grid connect an extension line respectively, described substrate 1 is fixed described two sensitive grids.

Lower sensitive grid 2 and upper sensitive grid 3 can be fixed on substrate 1, for keep each sensitive grid fixing shape, position and size; Substrate 1 is very thin, thus the strain of surface of test piece is delivered to lower sensitive grid 2 and upper sensitive grid 3 exactly.Substrate 1 can be glued membrane substrate, glass fabric substrates, asbestos substrate, metallic substrates and temporary substrate.Usually with cohering, weld, substrate is fixed on the tested position of test block by the mode such as ceramic spraying.Substrate 1 also can be printed on the lines that some are located for foil gauge.

The materials such as cover plate paper using or glue are made, and are covered in lower sensitive grid 2, upper sensitive grid 3 and substrate 1, play the protective seam of the effects such as protection against the tide, corrosion protection, loss prevention.

Lead-in wire is 4 for connecting sensitive grid and metering circuit, and lower sensitive grid 2 or upper sensitive grid 3 respectively have two to go between 4, to foil and membrane type foil gauge, the lower sensitive grids 2 that lead-in wire 4 is connected with it or upper sensitive grid 3 combine as a whole.

Lower sensitive grid 2 and upper sensitive grid 3, according to the difference of its metal sensitive material and processing technology, can be wire form, foil, diaphragm type, thick-film type.No matter the thickness of which kind of lower sensitive grid 2 or upper sensitive grid 3 is all very little, make the axial length of lower sensitive grid 2 and upper sensitive grid 3 with it depend on the deformation of workpiece and change.The basic innovation of the utility model is the cooperation between lower sensitive grid 2 and upper sensitive grid 3, has following main points:

The first, two sensitive grids are arranged in substrate, is called lower sensitive grid 2, upper sensitive grid 5.

The second, lower sensitive grid 2 and upper sensitive grid 3 all can be divided into multiple sensitive segment 5 and multiple transition section 6, and each sensitive segment 5 is connected to form sensitive grid by each transition section 6.Comparatively speaking, sensitive segment 5 is in elongated shape, and resistance is comparatively large and its resistance is comparatively responsive to strain; Described transition section 6, substantially in tubbiness shape, makes the resistance of described transition section very little and insensitive to strain, and under duty, resistance variations is close to 0, and therefore the summation of sensitive segment resistance is the all-in resistance of single sensitive grid substantially.Fig. 2 has marked sensitive segment 5 and transition section 6 in more detail from angle more clearly.

3rd, lower sensitive grid 2 is all identical with sensitive segment 5 shape of cross section of upper sensitive grid 3, and the summation of lower sensitive grid 2 and respective sensitive segment 5 length of upper sensitive grid 3 is identical.Ignore the resistance of transition section 6, the all-in resistance of lower-left sensitive grid 2 and upper sensitive grid 3 is all equal, and two sensitive grids under identical strain, sensitive segment all-in resistance variable quantity should be consistent.

4th, the sensitive segment of each sensitive grid 5 is in elongated strip, and all xsect centres of form of each sensitive segment 5 form sensitive segment axis, and this sensitive segment 5 axis is straight line section, the axis being parallel of each sensitive segment 5 and be arranged in same plane.All xsects of each sensitive segment 5 are consistent along the projection of shape of sensitive segment axis direction.Get the axis point midway of each sensitive segment and with this sensitive segment resistance value for nominal mass is formed the nominal particle of place sensitive segment, the centroid position that the nominal particle of each sensitive segment is formed jointly is the center of sensitive grid.

5th, overlook all sensitive segments 5 of lower sensitive grid 2 and upper sensitive grid 3, they all have axis of symmetry and axis of symmetry overlaps (y-axis in Fig. 2), lower sensitive grid 2 sensitive segment 5 respective with upper sensitive grid 3 is all vertical with this axis of symmetry, the sensitive segment 5 of each sensitive grid all distributes about this rotational symmetry, and lower sensitive grid 2 starts identical with end position with each sensitive segment 5 in upper sensitive grid 3 along the x-axis direction.Therefore, lower sensitive grid 2 and upper sensitive grid 3 only have lateral deviation without axial deviation, and the center of lower sensitive grid 2 and upper sensitive grid 3 is all in y-axis.According to the vertical view of foil gauge in Fig. 2, the center of lower sensitive grid 2 is at y-axis and x _lthe intersection point of axle, the center of upper sensitive grid 3 is at y-axis and x _uthe intersection point of axle.The line mid point at the center of lower sensitive grid 2 and the center of upper sensitive grid 3 is the intersection point of x-axis and y-axis.

6th, lower sensitive grid 2 and the interdigital layout of upper sensitive grid 3, the center of two sensitive grids is all in same axis of symmetry y-axis.Can notice, the direct result that interdigital layout causes is that lower sensitive grid 2 center and upper sensitive grid 3 center are comparatively close, and lateral separation is Δ y, as shown in Figure 2.Because the relative position of lower sensitive grid 2 and upper sensitive grid 3 is ensured quite accurately to be secured by foil gauge production technology, this is also that the utility model can detect the key one of of workpiece strain axis to partial derivative.

In sum, sensitive grid 2 and upper sensitive grid 3 equal and opposite in direction under the utility model, sensitive grid center axial distance is 0, lateral separation is very closely Δ y.

Under making free state, lower sensitive grid 2 resistance is R _l0, upper sensitive grid 3 resistance is R _r0, should R be had _l0=R _r0=R ₀.Foil gauge of the present utility model is placed in certain have strain surface time, lower sensitive grid 2 resistance is R ₀+ Δ R _l, upper sensitive grid 3 resistance is R ₀+ Δ R _u; On the other hand, the center of lower sensitive grid 2 and upper sensitive grid 3 lays respectively at y-axis and x in Fig. 2 _lintersection point and y-axis and x _uintersection point, two sensitive grid centers are in the horizontal at a distance of Δ y, and described transverse direction is x-axis.Lower sensitive grid 2 and upper sensitive grid 3 center stress different cause the different of lower sensitive grid 2 and upper sensitive grid 3 resistance.The relation of sensitive grid resistance and surface strain is utilized to have:

$\frac{\∂\mathrm{\ϵ}}{\∂y}{|}_{y=\stackrel{\‾}{y}}=\underset{\mathrm{\Δ}y\→0}{\lim }\frac{{\mathrm{\ϵ}}_U-{\mathrm{\ϵ}}_L}{\mathrm{\Δ}y}\≈\frac{K({\mathrm{\ΔR}}_U-{\mathrm{\ΔR}}_L)}{\mathrm{\Δ}y}---\left(3\right)$

Wherein be two sensitive grid line of centres point midways, ε _lfor the strain of lower sensitive grid 2 center, ε _ufor the strain of upper sensitive grid 3 center.Namely this is the principle that the utility model measured surface strains horizontal local derviation.

Coordinated by the present embodiment electric bridge to can be used for monitor strain, strain horizontal local derviation, suppose that bridge input voltage is u _i, output voltage is u _o, Fig. 3 is shown in by the schematic diagram of measuring bridge.When without workpiece effects of strain, each arm resistance of electric bridge is labeled as R respectively according to clockwise direction ₁, R ₂, R ₃, R ₄, when obscuring also with these sign flag resistance place electric bridges.Each electric bridge can be laid sensitive grid or the resistance of foil gauge.Arrange identical with general foil gauge, if settle sensitive grid on multiple brachium pontis, to the order of each installation position, the requirement of strain difinite quality.During without workpiece effects of strain, the Output Voltage Formula of electric bridge is

$u_o=\frac{R_1{R}_3-R_2{R}_4}{(R_1+R_2)(R_3+R_4)}{u}_i;---\left(4\right)$

Now, bridge balance i.e. u is required _o=0, so so-called bridge balance condition R must be met ₁r ₃-R ₂r ₄=0, the electric bridge of employing meets further

R ₁=R ₂=R ₃=R ₄, (5) because, the first, satisfy condition (5) time, the highest according to relevant theoretical foil gauge sensitivity; The second, monitor strain or strain horizontal local derviation the equal requirement condition of method (5) set up.When foil gauge, with external world's strain, strain also occurs, above-mentioned bridge balance condition is generally no longer set up, now

$\begin{array}{c}{u}_o=\frac{(R_1+{\mathrm{\ΔR}}_1)(R_3+{\mathrm{\ΔR}}_3)-(R_2+{\mathrm{\ΔR}}_2)(R_4+{\mathrm{\ΔR}}_4)}{(R_1+{\mathrm{\ΔR}}_1+R_2+{\mathrm{\ΔR}}_2)(R_3+{\mathrm{\ΔR}}_3+R_4+{\mathrm{\ΔR}}_4)}{u}_i\\ \≈\frac{R_3{\mathrm{\ΔR}}_1+R_1{\mathrm{\ΔR}}_3-R_4{\mathrm{\ΔR}}_2-R_2{\mathrm{\ΔR}}_4+{\mathrm{\ΔR}}_1{\mathrm{\ΔR}}_3-{\mathrm{\ΔR}}_2{\mathrm{\ΔR}}_4}{(R_1+R_2)(R_3+R_4)}{u}_i\\ \≈\frac{({\mathrm{\ΔR}}_1-{\mathrm{\ΔR}}_2)+({\mathrm{\ΔR}}_3-{\mathrm{\ΔR}}_4)}{4R_1}{u}_i\end{array}---\left(6\right)$

Due to Δ R _i< < R _i(i=1,2,3,4 events) first ≈, part Δ R that second ≈ ignores ₁Δ R ₃-Δ R ₂Δ R ₄also very little, and it can be made in engineering much smaller than comparatively reserve part.The voltage measurement strain that general available formula (6) obtains; Can convolution (3) and formula (6) to the horizontal local derviation of strain, reasonable design arranges each brachium pontis sensitive grid and resistance can obtain the magnitude of voltage u linear with straining horizontal local derviation _o, this voltage is that feeble signal need be amplified.

Claims (5)

1. one kind can strain the lateral deviation sensitive grid interdigitated metal foil gauge of horizontal local derviation by measured surface, comprise substrate, it is characterized in that: described metal strain plate also comprises two sensitive grids, be respectively lower sensitive grid and upper sensitive grid, the two ends of each sensitive grid connect an extension line respectively, described substrate are fixed described two sensitive grids;

Each sensitive grid comprises sensitive segment and transition section, the two ends of described sensitive segment are transition section, described sensitive segment is elongated strip shaped, described transition section is tubbiness shape, the resistance of described sensitive segment is much larger than the resistance of described transition section, under same strain state, the increased resistance value of described sensitive segment is much larger than the increased resistance value of described transition section, and the increased resistance value of described transition section is close to 0;

All xsect centres of form of each sensitive segment form sensitive segment axis, this sensitive segment axis is straight line section, the axis being parallel of each sensitive segment and be arranged in same plane, and sensitive segment axis is determined in plane, along described sensitive segment axis direction namely axially, be laterally with axially vertical direction; All shape of cross section consistent size of each sensitive segment; Get the axis point midway of each sensitive segment and with this sensitive segment resistance value for nominal mass is formed the nominal particle of place sensitive segment, the centroid position that the nominal particle of each sensitive segment is formed jointly is the center of sensitive grid;

The sensitive segment all-in resistance of two sensitive grids is consistent, described two sensitive grids all-in resistance changing value of sensitive segment under identical strain is consistent, two sensitive grids be centrally located on straight line, this straight line is perpendicular to two any sensitive segment axis of sensitive grid, and two sensitive grids are called upper sensitive grid and lower sensitive grid from top to bottom along this rectilinear direction; Each sensitive segment axis is determined in plane, in interdigital layout between upper sensitive grid and lower sensitive grid;

Two sensitive grid center bias frees in the axial direction, have deviation in the horizontal, and the distance at upper sensitive grid center and lower sensitive grid center is Δ y.

2. can strain the lateral deviation sensitive grid interdigitated metal foil gauge of horizontal local derviation by measured surface as claimed in claim 1, it is characterized in that: described metal strain plate also comprises cover plate, described cover plate is covered in described sensitive grid and substrate.

3. can strain the lateral deviation sensitive grid interdigitated metal foil gauge of horizontal local derviation by measured surface as claimed in claim 1 or 2, it is characterized in that: described sensitive grid is wire form, foil, diaphragm type or thick-film type sensitive grid.

4. can strain the lateral deviation sensitive grid interdigitated metal foil gauge of horizontal local derviation by measured surface as claimed in claim 1 or 2, it is characterized in that: described substrate is glued membrane substrate, glass fabric substrates, asbestos substrate, metallic substrates or temporary substrate.

5. can strain the lateral deviation sensitive grid interdigitated metal foil gauge of horizontal local derviation by measured surface as claimed in claim 1 or 2, it is characterized in that: described two sensitive grids are arranged in substrate up and down.