CN105352715A - Separation testing method for axial force, bending moment and torque of load for a drilling tool - Google Patents

Abstract

The invention relates to a separation testing method for axial force, bending moment and torque of load for a drilling tool. The method comprises: selecting three points at equal intervals on the cross section of a cylinder rod with the same size to a drilling tool; respectively placing strain sensors at the three points to measure the axial strain; placing a strain sensor at other directions of any point to measure the strain of the direction; establishing a threaded rod model and a cylinder rod model in finite element simulation software so as to obtain the difference between the axial stress value of the drilling tool and the axial stress value of the cylinder rod and the shear stress ratio of the drilling tool to the cylinder rod on the same slope; and then obtaining the axial force, the bending moment and the torque of the drilling tool through calculation. Compared with the prior art, the separation testing method for axial force, bending moment and torque of load for a drilling tool takes the drilling tool as a product obtained by overlaying screw threads on the cylinder rod with the same size to the drilling tool, and can realize a separation test of the axial force, the bending moment and the torque of the composite load by measuring the axial strain at the three points and the strain of other directions from any point, and is simple, accurate and reliable.

Description

The method of testing that a kind of drilling tool load pressure bending is separated

Technical field

The present invention relates to mechanical engineering field, the method for testing of particularly a kind of drilling tool load pressure bending separation.

Background technology

Drilling apparatus is widely used in the industry such as oil and geologic prospecting, building and mine coal mining, the drilling tool that in drilling process, drill bit and drilling rod form can be subject to the effect of axle pressure (being called for short " axle power "), moment of flexure and moment of torsion simultaneously, and the size of three kinds of parameters relates to the smooth degree of drilling process and the height of drilling efficiency.

Existing research method or technology mainly concentrate the compound action measuring moment of flexure and moment of torsion, axle power and moment of torsion, such as with ohmer, moment of flexure under combined deformation and moment of torsion are detected, axle power moment of torsion is measured, axle power, moment of flexure are not carried with the power of moment of torsion three coupling and are separated by this method of testing, therefore lack the method for testing that above-mentioned three mechanics parameters of drilling rod under a kind of actual condition are separated.

Summary of the invention

The technical matters that the present invention solves is: overcome the deficiencies in the prior art, provides a kind of method of testing that axial strain realizes combined load situation lower shaft power with the strain on other direction at any point place, moment of flexure is separated with the drilling tool load pressure bending of moment of torsion discrete testing being positioned at 3, same interface place by measuring drilling rod lateral surface.

Technical solution of the present invention is: the method for testing that a kind of drilling tool load pressure bending is separated, and comprises the steps:

(1) with drilling tool with the cylindrical bar xsect of size and side hand over A, B and C of circumferentially getting and equidistantly distributing at 3, A, B and C place strain transducer 1, strain transducer 2, strain transducer 3 respectively, are that a strain transducer 4 is placed at γ Angle Position place in A side, some place and with axis;

(2) use strain transducer 1, strain transducer 2, strain transducer 3 correspondence to measure the axial strain at A, B, C 3 place respectively, and be designated as ε respectively _a, ε _b, ε _c, use strain transducer 4 is measured A side, some place and is the strain stress of γ angular direction with axis _γ;

(3) in finite element emulation software, drilling tool length is inputted, external diameter, internal diameter, screw wing height, width, pitch, head number, set up threaded rod model, then input material, material characteristic parameter, load, the way of restraint, obtain drilling tool side any point axial stress, input and the cylindrical bar length of drilling tool with size in finite element emulation software, external diameter, internal diameter, set up cylindrical bar model, then input material, material characteristic parameter, load and the way of restraint, obtain the axial stress with any point position, drilling tool side identical point on cylindrical bar side, and two axial stresses are done the difference DELTA that difference obtains drilling tool axial tension stress and cylindrical bar axial tension stress,

(4) to finite element emulation software input drilling tool length, external diameter, internal diameter, screw wing height, width, pitch, head number, set up threaded rod model, then input material, material characteristic parameter, load, the way of restraint, draw the shear Stress Distribution of drilling tool, to finite element emulation software input and the cylindrical bar length of drilling tool with size, external diameter, internal diameter, set up cylindrical bar model, then input material, material characteristic parameter, load, the way of restraint, obtain the shear Stress Distribution of cylindrical bar, and then obtain drilling tool and the shearing stress axially in side, γ angular direction, cylindrical bar and the shearing stress ratio k axially in side, γ angular direction,

(5) the axle power F of drilling tool is calculated _nfor

$F_n=(\mathrm{\Δ}-\frac{({\mathrm{E\ϵ}}_A+{\mathrm{E\ϵ}}_B+{\mathrm{E\ϵ}}_C)}{3})S$

Moment M is

$M=\frac{I_z}{R}\sqrt{\frac{{({\mathrm{E\ϵ}}_C-{\mathrm{E\ϵ}}_B)}^2}{3}+{\left(\frac{2{\mathrm{E\ϵ}}_A-{\mathrm{E\ϵ}}_B-{\mathrm{E\ϵ}}_C}{3}\right)}^2}$

Torque T is

$T=k\[\frac{{\mathrm{E\ϵ}}_A}{2a(1+\mathrm{\μ})}\left(1-b-\mathrm{\μ}-\mathrm{\μ}b\right)-\frac{{\mathrm{E\ϵ}}_{\mathrm{\γ}}}{a(1+\mathrm{\μ})}\]\frac{{\mathrm{\πR}}^3}{2}$

Wherein, S is and the cylindrical bar xsect of drilling tool with size, and E is the Young's modulus of elasticity of drilling tool material, and R is and the cylindrical bar cross sectional radius of drilling tool with size, I _zfor with the moment of inertia of drilling tool with the cylindrical bar of size, sin (2 γ)=a, μ are the Poisson ratio of drilling tool material, cos (2 γ)=b.

Be ANSYS in described finite element emulation software.

Described material characteristic parameter comprises density, elastic modulus, Poisson ratio, yield strength.

The present invention's advantage is compared with prior art:

(1) the present invention is positioned at the strain on the axial strain at 3, same interface place and other direction at any point place by measurement drilling rod lateral surface, just can realize the discrete testing of the axle power of combined load, moment of flexure and moment of torsion, solve axle power, the power of moment of flexure and moment of torsion three coupling carry separation problem, have method simply, advantage accurately and reliably;

(2) the present invention to be carried with the power of moment of torsion three coupling by axle power, moment of flexure and is separated, solve the problem of drilling tool complex load decoupling zero test in Practical Project, range of application comprises the structures such as cylinder drilling rod, pipe drilling rod, screw thread column drilling rod, threaded tubular drilling rod, and having can the advantage of on-line real-time measuremen;

(3) the present invention compared with prior art, drilling tool is superposed the product after screw thread as with drilling tool with the cylindrical bar of size, obtain drilling tool, the axial stress of cylindrical bar, shear strain distribution correction by simulation software, and then obtain drilling tool axle power, moment of flexure and moment of torsion solution.

Accompanying drawing explanation

Fig. 1 is cylindrical bar force diagram in the method for testing of a kind of drilling tool load pressure of the present invention bending separation;

Fig. 2 is sensing station force diagram in the method for testing that is separated of a kind of drilling tool load pressure of the present invention bending, and sensor 1, sensor 2, sensor 3 are used for surveying drilling rod axial strain, and sensor 4 is used for surveying the strain with sensor 3 one-tenth γ angular direction.

Embodiment

The present invention is directed to the deficiencies in the prior art, propose a kind of based on the method for strain monitoring realization to drilling tool axle power, moment of flexure and moment of torsion discrete testing, by to same size cylindrical bar strain monitoring, realize the separation of its combined load mechanics parameter, then correction is obtained by emulation, and then the separation realized screw rod mechanics parameter, below in conjunction with accompanying drawing, the inventive method is described in detail.

One, the separation of cylindrical bar mechanics parameter

As shown in Figure 1, with drilling apparatus with the cylindrical bar xsect of size and side hand over A, B and C of circumferentially getting and equidistantly distributing at 3, the center of circle is O, invention introduces 4 strain transducers as shown in Figure 2, wherein three (strain transducer 1, strain transducer 2, strain transducer 3) is affixed on A, B, C 3 point respectively vertically, remembers that 3 axial stresses are respectively σ _Α, σ _Β, σ _c, a strain transducer 4 is pasted, then the axle power F suffered by cylindrical bar with axial in γ angular direction in any point (as the A point) side, place in A, B, C are 3 _nbe respectively with moment M

$F_n=-\frac{1}{3}({\mathrm{\σ}}_A+{\mathrm{\σ}}_B+{\mathrm{\σ}}_C)S---\left(1\right)$

$M=\frac{I_z}{R}\sqrt{\frac{{({\mathrm{\σ}}_C-{\mathrm{\σ}}_B)}^2}{3}+{\left(\frac{2{\mathrm{\σ}}_A-{\mathrm{\σ}}_B-{\mathrm{\σ}}_C}{3}\right)}^2}---\left(2\right)$

Wherein, R, S=π R ²and I _z=π R ⁴/ 4 section radius being respectively cylindrical bar, sectional area and moment of inertia, the central angle of note AO and moment of flexure couple application point line to be measured is α, then

$\mathrm{\α}=arctan\[\frac{\sqrt{3}({\mathrm{\σ}}_C-{\mathrm{\σ}}_B)}{2{\mathrm{\σ}}_A-{\mathrm{\σ}}_B-{\mathrm{\σ}}_C}\]---\left(3\right)$

The strain transducer detected object that A, B, C 3 place axially places is strain, and A, B, C 3 point, remembers that 3 axial strains are respectively ε _a, ε _b, ε _c, the Young's modulus of elasticity of drilling tool material is E, utilizes the relation of stress and strain can obtain the stress value of this position, is respectively

σ _A＝Eε _A(4)

σ _B＝Eε _B(5)

σ _C＝Eε _C(6)

Recycling formula (1) and formula (2), just separable go out the axle power F of cylindrical bar _nand moment M.

Meanwhile, the stress of 3 also can use axle power F _nrepresent with moment M:

${\mathrm{\σ}}_A=-\frac{F_n}{S}+\frac{MRcos\mathrm{\α}}{I_z}---\left(7\right)$

${\mathrm{\σ}}_B=-\frac{F_n}{S}+\frac{MR}{I_z}(-\frac{\sqrt{3}}{2}sin\mathrm{\α}-\frac{1}{2}cos\mathrm{\α})---\left(8\right)$

${\mathrm{\σ}}_C=-\frac{F_n}{S}+\frac{MR}{I_z}(\frac{\sqrt{3}}{2}sin\mathrm{\α}-\frac{1}{2}cos\mathrm{\α})---\left(9\right)$

Note shearing stress is τ, then the torque T being applied to cylindrical bar is

T＝τ·W _ρ(10)

Wherein, W _ρfor Torsion Section coefficient.

Under pure torsion effect, the shearing stress τ of cylindrical bar is directly proportional to shear strain, and its ratio is shear modulus, but under Action of Combined Loads, the relation of shearing stress τ and shear strain meets generalized Hooke law.

Any point (as A point) side, place in A, B, C are 3 pastes a strain transducer with axial in γ angular direction, and the strain recorded is ε _γ, the Young's modulus of elasticity of note drilling tool material is E, and Poisson ratio is μ, shearing stress

$\mathrm{\τ}=\frac{{\mathrm{E\ϵ}}_A}{2\left(1+\mathrm{\μ}\right)sin2\mathrm{\γ}}(1-cos2\mathrm{\γ}-\mathrm{\μ}-\mathrm{\μ}cos2\mathrm{\γ})-\frac{{\mathrm{E\ϵ}}_{\mathrm{\γ}}}{\left(1+\mathrm{\μ}\right)sin2\mathrm{\γ}}$

Note sin (2 γ)=a, cos (2 γ)=b, cylindrical bar Torsion Section coefficient W _ρ=π R ³/ 2, this pattern (10) becomes

$T=\[\frac{{\mathrm{E\ϵ}}_A}{2a(1+\mathrm{\μ})}(1-b-\mathrm{\μ}-\mathrm{\μ}b)-\frac{{\mathrm{E\ϵ}}_{\mathrm{\γ}}}{a(1+\mathrm{\μ})}\]\frac{{\mathrm{\πR}}^3}{2}---\left(11\right)$

To sum up, by same position both direction strain detecting, the moment of torsion of this position of cylindrical bar can be determined.

(1), (2) and (3) formula shows, measure the strain of 3 A, B, C place axial strains and any point (as: A point) any γ angular direction, drilling rod side, place that same cross section and bar side circumferential boundary lines equidistantly distribute, the separation of cylindrical bar at Action of Combined Loads lower shaft power, moment of flexure and moment of torsion can be realized.

Two, the separation of threaded drillpipe mechanics parameter

General drilling tool is external thread structure, considers screw rod complex structure, is difficult to provide the analytic expression accurately describing the distribution of its mechanics parameter, therefore, measures the strain value of limited Nodes, directly cannot provide the value of drilling tool axle power, moment of flexure and moment of torsion.

Consider that threaded rod is the product that cylindrical bar is superimposed with screw thread, on the basis of cylindrical bar mechanics parameter expression formula, by revising the approximate analytic solution that can obtain axle power, moment of flexure and moment of torsion on external spiral drilling rod.

On cylindrical bar basis, after considering screw thread, A, B, C 3 axial stresses need introduce correction amount, with former stress σ _a, σ _b, σ _csuperimposed, note three is respectively σ ' _a, σ ' _b, σ ' _c, obtained by (7), (8) and (9) formula

${{\mathrm{\σ}}_A}^{\′}={\mathrm{\σ}}_A+\mathrm{\Δ}=-\frac{F_n}{S}+\frac{MRcos\mathrm{\α}}{I_z}+\mathrm{\Δ}---\left(12\right)$

${{\mathrm{\σ}}_B}^{\′}={\mathrm{\σ}}_B+\mathrm{\Δ}=-\frac{F_n}{S}+\frac{MR}{I_z}\left(-\frac{\sqrt{3}}{2}sin\mathrm{\α}-\frac{1}{2}cos\mathrm{\α}\right)+\mathrm{\Δ}---\left(13\right)$

${{\mathrm{\σ}}_C}^{\′}={\mathrm{\σ}}_C+\mathrm{\Δ}=-\frac{F_n}{S}+\frac{MR}{I_z}\left(\frac{\sqrt{3}}{2}sin\mathrm{\α}-\frac{1}{2}cos\mathrm{\α}\right)+\mathrm{\Δ}---\left(14\right)$

The axle power of threaded drillpipe, moment of torsion and moment of flexure are respectively

$F_n=\left(\mathrm{\Δ}-\frac{({{\mathrm{\σ}}_A}^{\′}+{{\mathrm{\σ}}_B}^{\′}+{{\mathrm{\σ}}_C}^{\′})}{3}\right)S---\left(15\right)$

$M=\frac{I_z}{R}\sqrt{\frac{{\left({{\mathrm{\σ}}_C}^{\′}-{{\mathrm{\σ}}_B}^{\′}\right)}^2}{3}+{\left(\frac{2{{\mathrm{\σ}}_A}^{\′}-{{\mathrm{\σ}}_B}^{\′}-{{\mathrm{\σ}}_C}^{\′}}{3}\right)}^2}---\left(16\right)$

Wherein, correction amount depends on helicitic texture and material, also relevant with α, asks the difference between threaded rod axial tension stress and cylindrical bar axial stress theoretical value, can obtain Δ by emulation.Equally, emulate the shear Stress Distribution of spiral drill pipe, trying to achieve with axis is the stress of side, γ angular direction and the ratio k of the equidirectional shearing stress τ theoretical value of same size cylindrical bar, (10) formula is modified to

$T=k\mathrm{\τ}\·W_{\mathrm{\ρ}}=k\[\frac{{\mathrm{E\ϵ}}_A}{2a(1+\mathrm{\μ})}\left(1-b-\mathrm{\μ}-\mathrm{\μ}b\right)-\frac{{\mathrm{E\ϵ}}_{\mathrm{\γ}}}{a(1+\mathrm{\μ})}\]\frac{{\mathrm{\πR}}^3}{2}---\left(17\right)$

Visible, measure 3 A, B, C place axial strains that the same cross section of threaded drillpipe and bar sideline equidistantly distribute, utilization (15) and (16) separable go out axle power in combined load and moment of flexure; In conjunction with the strain of any point (as: A point) any γ angular direction, drilling rod side, place, utilize (17) formula, separable go out moment of torsion.For hollow drilling tool, in (15) and (16) formula, give corresponding sectional area and moment of inertia, give corresponding Torsion Section coefficient in (17) formula, the separation of combined load can be realized equally.When changing drilling tool structure, the thought that above-mentioned load is separated is applicable equally, and just correction amount and k have difference.

In finite element emulation software, (such as ANSYS) inputs threaded rod length, external diameter, internal diameter, screw wing height, width, pitch, head number, set up threaded rod model, input cylindrical bar length, external diameter, internal diameter, set up cylindrical bar model, input material (such as 45 steel), material characteristic parameter (comprises density, elastic modulus, Poisson ratio, yield strength), (such as bar two ends freely-supported is fixed for load and the way of restraint, front end applies 20Nm moment of torsion and 600N axial force), draw the stress result of threaded rod and cylindrical bar identical point, then the poor difference DELTA obtained between threaded rod axial tension stress and cylindrical bar axial stress theoretical value is done to the two.Equally, to finite element emulation software input threaded rod length, external diameter, internal diameter, screw wing height, width, pitch, head number, set up threaded rod model, input cylindrical bar length, external diameter, internal diameter, set up cylindrical bar model, input material (such as 45 steel), material characteristic parameter (comprises density, elastic modulus, Poisson ratio, yield strength), (such as bar two ends freely-supported is fixed for load and the way of restraint, front end applies 20Nm moment of torsion and 600N axial force), draw the shear Stress Distribution to spiral drill pipe, try to achieve threaded rod and the shearing stress axially in side, γ angular direction and the equidirectional shearing stress ratio k of same size cylindrical bar.

The content be not described in detail in instructions of the present invention belongs to the known technology of those skilled in the art.

Claims (3)

1. a method of testing for drilling tool load pressure bending separation, is characterized in that comprising the steps:

(1) with drilling tool with the cylindrical bar xsect of size and side hand over A, B and C of circumferentially getting and equidistantly distributing at 3, A, B and C place strain transducer 1, strain transducer 2, strain transducer 3 respectively, are that a strain transducer 4 is placed at γ Angle Position place in A side, some place and with axis;

(2) use strain transducer 1, strain transducer 2, strain transducer 3 correspondence to measure the axial strain at A, B, C 3 place respectively, and be designated as ε respectively _a, ε _b, ε _c, use strain transducer 4 is measured A side, some place and is the strain stress of γ angular direction with axis _γ;

(3) in finite element emulation software, drilling tool length is inputted, external diameter, internal diameter, screw wing height, width, pitch, head number, set up threaded rod model, then input material, material characteristic parameter, load, the way of restraint, obtain drilling tool side any point axial stress, input and the cylindrical bar length of drilling tool with size in finite element emulation software, external diameter, internal diameter, set up cylindrical bar model, then input material, material characteristic parameter, load and the way of restraint, obtain the axial stress with any point position, drilling tool side identical point on cylindrical bar side, and two axial stresses are done the difference DELTA that difference obtains drilling tool axial tension stress and cylindrical bar axial tension stress,

(4) to finite element emulation software input drilling tool length, external diameter, internal diameter, screw wing height, width, pitch, head number, set up threaded rod model, then input material, material characteristic parameter, load, the way of restraint, draw the shear Stress Distribution of drilling tool, to finite element emulation software input and the cylindrical bar length of drilling tool with size, external diameter, internal diameter, set up cylindrical bar model, then input material, material characteristic parameter, load, the way of restraint, obtain the shear Stress Distribution of cylindrical bar, and then obtain drilling tool and the shearing stress axially in side, γ angular direction, cylindrical bar and the shearing stress ratio k axially in side, γ angular direction,

(5) the axle power F of drilling tool is calculated _nfor

$F_n=(\mathrm{\Δ}-\frac{({\mathrm{E\ϵ}}_A+{\mathrm{E\ϵ}}_B+{\mathrm{E\ϵ}}_C)}{3})S$

Moment M is

$M=\frac{I_z}{R}\sqrt{\frac{{({\mathrm{E\ϵ}}_C-{\mathrm{E\ϵ}}_B)}^2}{3}+{\left(\frac{2{\mathrm{E\ϵ}}_A-{\mathrm{E\ϵ}}_B-{\mathrm{E\ϵ}}_C}{3}\right)}^2}$

Torque T is

$T=k\[\frac{{\mathrm{E\ϵ}}_A}{2a(1+\mathrm{\μ})}\left(1-b-\mathrm{\μ}-\mathrm{\μ}b\right)-\frac{{\mathrm{E\ϵ}}_{\mathrm{\γ}}}{a(1+\mathrm{\μ})}\]\frac{{\mathrm{\πR}}^3}{2}$

Wherein, S is and the cylindrical bar xsect of drilling tool with size, and E is the Young's modulus of elasticity of drilling tool material, and R is and the cylindrical bar cross sectional radius of drilling tool with size, I _zfor with the moment of inertia of drilling tool with the cylindrical bar of size, sin (2 γ)=a, μ are the Poisson ratio of drilling tool material, cos (2 γ)=b.

2. the method for testing of a kind of drilling tool load pressure bending separation according to claim 1, is characterized in that: be ANSYS in described finite element emulation software.

3. the method for testing of a kind of drilling tool load pressure bending separation according to claim 1, is characterized in that: described material characteristic parameter comprises density, elastic modulus, Poisson ratio, yield strength.