CN201666845U - Testing platform for stiffness of member - Google Patents

Abstract

The utility model discloses a testing platform for stiffness of a member. The testing platform is characterized in that: two end points of the member are respectively provided with a total reflection mirror M0 and a total reflection mirror M1; the laser beam emitted by a laser respectively passes through a total reflection mirror M4 and a half-reflecting mirror M3 to be then reflected respectively to the total reflection mirror M0 and the total reflection mirror M1; after reflected by the total reflection mirror M0 and the total reflection mirror M1, the beam is projected to a screen to form light spots A0' and A1'; and the screen reads the coordinate values of the light spots A0' and A1'. After load P is exerted at the free end of the member, the beam is reflected by the total reflection mirror M0 and the total reflection mirror M1 and then projected to the screen to form light spots A0'' and A1'', the screen reads the coordinate values of the light spots A0'' and A1'', the coordinate values of the light spots A0' and A1' are respectively subtracted from the coordinate values of the light spots A0'' and A1'' to obtain displacement differences Delta 0 and Delta, the relative rigidity of the mounting position of the total reflection mirror M1 to the mounting position of the total reflection mirror M0 can be obtained by subtracting the displacement difference Delta 0 from the displacement difference Delta, and according to the calculated displacement differences, the bending or torsional rigidity of the member can be calculated. The testing platform disclosed by the utility model is high in testing accuracy and can test the deformation in micro-nanometer magnitude.

Description

The test platform of stiffness of structural member

Technical field

The utility model relates to a kind of test platform of stiffness of structural member, and particularly the rigidity test and the analysis of higher, the deflection small construction assembly of rigidity belong to construction package rigidity test field.

Background technology

Stiffness of structural member is meant the ability of member resistance to deformation, and its expression formula is the ratio that puts on its corresponding deformation of member of the caused internal force of effect on the member.The rigidity of analytical structure is an important process in the engineering design.For the structure of an a little strict restrained deformation,, must come controlled deformation by stiffness analysis as wing, high-precision assembly parts etc.Many structures, as buildings, machinery etc., also will be by control rigidity to prevent vibration, flutter or unstability.In addition, as spring balance, ring type dynamometer etc., must be that a certain reasonable value is to guarantee its specific function by controlling its rigidity.In addition, in the displacement method of structural mechanics is analyzed,, also to analyze the rigidity of its each several part usually for determining the distortion and the stress of structure.

For the member under the arm-type beam type flecition, the test philosophy of conventional bending stiffness as shown in Figure 1.Bending stiffness K _MxFor:

$K_{\mathrm{Mx}}=\frac{P}{f}---\left(1\right)$

Wherein f is by displacement meter (2) test gained.

Summary of the invention

A kind of stiffness of structural member test platform comprises member (3), laser instrument (4), completely reflecting mirror M ₀, completely reflecting mirror M ₁, half-reflecting mirror M ₃, completely reflecting mirror M ₄, screen (5), the stiff end A of member (3) ₀, free end A ₁Completely reflecting mirror M is installed respectively ₀, completely reflecting mirror M ₁, the laser beam that laser instrument (4) sends is respectively by completely reflecting mirror M ₄, half-reflecting mirror M ₃After respectively with beam reflection to completely reflecting mirror M ₀, completely reflecting mirror M ₄On, light beam is through completely reflecting mirror M ₀, completely reflecting mirror M ₁Project screen (5) after the reflection and go up formation hot spot, the free end A of member (3) ₁Before the imposed load, light beam is through completely reflecting mirror M ₀, completely reflecting mirror M ₁Project screen (5) after the reflection and go up formation hot spot A ₀', A ₁', read hot spot A by screen (5) ₀', A ₁' coordinate figure, as the free end A of member (3) ₁Imposed load, light beam is through completely reflecting mirror M ₀, completely reflecting mirror M ₁Project screen (5) after the reflection and go up formation hot spot A ₀", A ₁", read hot spot A by screen (5) ₀", A ₁" coordinate figure, hot spot A ₀", A ₁" coordinate figure deduct described hot spot A respectively ₀', A ₁' coordinate figure obtains the displacement difference DELTA ₀, Δ, described displacement difference DELTA deducts Δ ₀Can obtain completely reflecting mirror M ₁The relative completely reflecting mirror M in installation site ₀The relative rigidity of installation site;

When the free end imposed load of member (3) is concentrated force P, then moment M _x=PL, wherein L is the M of completely reflecting mirror ₀To completely reflecting mirror M ₁Distance, the free end A of member (3) then ₁Point relative member (3) stiff end A ₀The relative rotation α of point is:

$\mathrm{\α}={\mathrm{\α}}_1-{\mathrm{\α}}_0=\frac{\mathrm{\Δ}}{2S_1}-\frac{{\mathrm{\Δ}}_0}{2S_0}---\left(2\right)$

S wherein ₀, S ₁Be respectively A ₀, A ₁Point is to the distance of screen, and then the bending stiffness of member (3) is k _MxFor

$k_{\mathrm{Mx}}=\frac{M_x}{\mathrm{L\Δ\α}}---\left(3\right)$

Wherein L is A ₁Point is to A ₀The distance of point;

Wherein the stiffness of structural member test platform also is included in the free end installation connecting lever (6) of member (3), at described connecting lever (6) imposed load P, then moment of torsion M _z=Pa, wherein a is that connecting lever (6) imposed load is put member (3) free end A ₁Distance, member (3) free end A then ₁Point relative fixed end A ₀The torsion angle φ of point is:

$\mathrm{\φ}={\mathrm{\φ}}_1-{\mathrm{\φ}}_0=\frac{\mathrm{\Δ}-{\mathrm{\Δ}}_0}{2S}---\left(4\right)$

S is completely reflecting mirror M in the formula ₀Or completely reflecting mirror M ₁To the distance of screen (5), the torsional rigidity K of member (3) _MzFor:

$K_{\mathrm{Mz}}=\frac{M_z}{\mathrm{\φ}}---\left(5\right)$

Wherein member (3) is that an end is fixed, and the other end is semi-girder fixed form freely;

Laser instrument (4) can be adjusted the incident angle of laser beam.

The utility model can accurately be measured the distortion of this micro-nano magnitude.

Description of drawings

The conventional bending stiffness test platform of Fig. 1 synoptic diagram.

Bending stiffness test platform synoptic diagram in Fig. 2 the utility model.

Torsional rigidity test platform synoptic diagram in Fig. 3 the utility model.

Embodiment

The synoptic diagram of the utility model bending stiffness test platform as shown in Figure 2.Member (3) one ends are fixed other end center imposed load P, then moment M _x=PL, wherein the other end of member (3) adopts the semi-girder fixed form.In (3) two terminal A of member ₀, A ₁Completely reflecting mirror M is installed respectively ₀, completely reflecting mirror M ₁, the laser beam that laser instrument sends is by completely reflecting mirror M ₄, half-reflecting mirror M ₃Light beam is reflexed to completely reflecting mirror M respectively ₀, M ₁On, light beam is through completely reflecting mirror M ₀, completely reflecting mirror M ₁Project screen (5) after the reflection and go up formation hot spot A ₀', A ₁', apply moment of flexure after, hot spot is respectively from A ₀', A ₁' move on to A ₀", A ₁", the displacement difference that moves is respectively Δ ₀, Δ.Member A ₁The relative A of point ₀The relative rotation α of point is:

$\mathrm{\α}={\mathrm{\α}}_1-{\mathrm{\α}}_0=\frac{\mathrm{\Δ}}{2S_1}-\frac{{\mathrm{\Δ}}_0}{2S_0}---\left(2\right)$

S in the following formula ₀, S ₁Be respectively A ₀, A ₁Point is to the distance of screen.Then bending stiffness is k _MxHave:

$k_{\mathrm{Mx}}=\frac{M_x}{\mathrm{L\Δ\α}}---\left(3\right)$

Wherein L is A ₁Point is apart from A ₀The distance of point.Adopt in this platform test process S ₀, S ₁Big more, Δ ₀, Δ is big more, helps improving the measuring accuracy of slight curves deflection.

The synoptic diagram of the utility model torsional rigidity test platform as shown in Figure 3.One end of member (3) is fixed, and the other end is by connecting lever (6)

Imposed load P, then moment of torsion M _z=Pa, wherein a is that connecting lever (6) imposed load is put the free-ended distance of member (3).In two terminal A of member ₀, A ₁Completely reflecting mirror M is installed respectively ₀, M ₁, the laser beam that laser instrument sends is by completely reflecting mirror M ₄, half-reflecting mirror M ₃Light beam is reflexed to M respectively ₀, M ₁On the completely reflecting mirror, reflex to again and form A on the screen ₀', A ₁' hot spot.After applying moment of torsion, hot spot is respectively from A ₀', A ₁' move on to A ₀", A ₁", the displacement difference that moves is respectively Δ ₀, Δ.Member A ₁The relative A of point ₀The torsion angle φ of point is:

$\mathrm{\φ}={\mathrm{\φ}}_1-{\mathrm{\φ}}_0=\frac{\mathrm{\Δ}-{\mathrm{\Δ}}_0}{2S}---\left(4\right)$

S is M in the formula ₀, M ₁Completely reflecting mirror is to the distance of screen.The torsional rigidity K of member _MzFor:

$K_{\mathrm{Mz}}=\frac{M_z}{\mathrm{\φ}}---\left(5\right)$

Adopt in this platform test process, S is big more, Δ ₀, Δ is big more, helps improving the measuring accuracy of small torsional deflection amount.

The above, it only is preferred embodiment of the present utility model, be not that the utility model is done any pro forma restriction, though the utility model discloses as above with preferred embodiment, yet be not in order to limit the utility model, any those skilled in the art, in the scope that does not break away from technical solutions of the utility model, when the technology contents that can utilize above-mentioned announcement is made a little change or is modified to the equivalent embodiment of equivalent variations, in every case be not break away from the technical solutions of the utility model content, foundation technical spirit of the present utility model is to above any simple modification that embodiment did, equivalent variations and modification all still belong in the scope of technical solutions of the utility model.

Claims (3)

1. a stiffness of structural member test platform comprises member (3), laser instrument (4), completely reflecting mirror M ₀, completely reflecting mirror M ₁, half-reflecting mirror M ₃, completely reflecting mirror M ₄, screen (5), it is characterized in that: the stiff end A of described member (3) ₀, free end A ₁Completely reflecting mirror M is installed respectively ₀, completely reflecting mirror M ₁, the laser beam that described laser instrument (4) sends is respectively by completely reflecting mirror M ₄, half-reflecting mirror M ₃After respectively with beam reflection to completely reflecting mirror M ₀, completely reflecting mirror M ₄On, light beam is through completely reflecting mirror M ₀, completely reflecting mirror M ₁Project screen (5) after the reflection and go up formation hot spot, the free end A of described member (3) ₁Imposed load, light beam is through completely reflecting mirror M ₀, completely reflecting mirror M ₁Project screen (5) after the reflection and go up the formation hot spot.

2. stiffness of structural member test platform according to claim 1 is characterized in that: the free end of described member (3) is installed connecting lever (6).

3. stiffness of structural member test platform according to claim 1 is characterized in that: described member (3) is that an end is fixed, and the other end is semi-girder fixed form freely.

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