CN107506506B - Threaded joint thread gluing risk prediction method based on finite element analysis - Google Patents
Threaded joint thread gluing risk prediction method based on finite element analysis Download PDFInfo
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- G06F30/20—Design optimisation, verification or simulation
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Abstract
The invention relates to a screwed joint thread gluing risk prediction method based on finite element analysis, which comprises the following steps: determining a dimension parameter of the threaded joint through the dimension of a part marked on a structural drawing of a threaded joint product or a way of surveying and mapping a threaded joint real object; determining screwing parameters of the threaded joint through an actual upper shackle test of the threaded joint; calculating the screwing length of the upper buckle of the threaded joint according to the dimension parameter and the screwing parameter of the threaded joint; calculating the contact stress of the upper buckle of the threaded joint according to the dimension parameter and the screwing parameter of the threaded joint by using a finite element analysis method; and calculating the thread gluing risk factor of the threaded joint by utilizing the screwing length and the contact stress of the upper thread of the threaded joint, and judging the thread gluing risk. The method can realize the prediction of the thread gluing of each part after the threaded connector is buckled, provides reference for the optimization design of products and the diagnosis of thread gluing problems, is favorable for reducing the development period and cost of the products, reduces the risk of thread gluing of the products and reduces various accidents caused by thread gluing when the products are used.
Description
Technical Field
The invention relates to a threaded connection technology in petroleum pipe engineering, in particular to a threaded joint thread gluing risk prediction method based on finite element analysis.
Background
The oil casing is a special pipe in oil exploitation engineering, supports the well wall after drilling, and conveys crude oil and natural gas to the surface of the earth by the oil pipe, and finally realizes oil and gas exploitation. In the process, the connection between the oil pipe and the connection between the casing and the casing are realized through threaded joints.
The sticking button is one of common failure modes of the oil casing in the production and use processes. The light person damages the thread surface, affects the repeated screwing-unscrewing capacity and screwing-in torque of the product, and can reduce the sealing property and the connection strength of the oil casing pipe in serious cases, so that the leakage or the tripping and well falling accidents of the threaded joint occur, and the operation production and the safety are affected.
According to the definition of the ISO13679(2002) standard, galling is a Cold welding (Cold welding) that occurs between metallic surfaces in contact with each other. During make-up of the oil casing, the contact surfaces of the interacting pin and box threads are not perfectly smooth, but have a certain roughness and form error. During screwing-in of the upper buckle, the corresponding contact surfaces of the male thread and the female thread are contacted from local points and gradually transited to surface contact. As the make-up process continues, contact unevenness caused by the presence of surface roughness, shape errors and the like causes different contact pressures at different parts, and the pressure at the local contact point is very high and exceeds the stress at the yield point of the steel matrix, thereby causing plastic deformation at the contact point. In the plastic deformation process, if no coating exists on the surface of the thread or the coating is cracked during tangential movement, metal on two sides of a contact point can be locally recrystallized, diffused or melted at normal temperature, the surfaces are easy to adhere, and therefore the cold welding phenomenon is generated. Once the oil casing has a serious thread gluing phenomenon, the structural integrity and the sealing integrity of the thread can be reduced sharply, and finally, slipping and well falling and underground leakage accidents are caused.
The thread gluing of the threaded joint is influenced by a plurality of factors, wherein the most important factors are as follows:
1. processing formed flanges and burrs: the phenomena of processing flanging, burrs and the like can be inevitable in the thread processing process. Improper treatment of the flanging and the burrs can scratch the thread surface in the process of screwing off, so that thread gluing is caused.
2. Machining errors: certain errors exist in the screw pitch, the taper, the tooth profile and the like in the joint machining process, the stress distribution is uneven after the joint is screwed, and the possibility of thread gluing in an area with overlarge local stress is increased.
3. Poor quality of thread surface treatment: the thread surface coating plays the roles of isolation and protection, and prevents the male and female thread matrixes from directly contacting in the screwing-in process, so that the thread gluing can be directly caused by the poor quality of the surface coating.
4. And (3) screwing torque: the increased make-up torque applied to the threaded connection translates into contact stresses within the connection. The greater the torque, the greater the contact stress and the higher the risk of galling.
Therefore, most of thread gluing is related to contact stress except for physical damages such as flanging, burrs, coating defects and the like, and therefore, the risk prejudgment of the thread joint gluing is feasible through analysis of the contact stress.
Disclosure of Invention
The invention aims to overcome the problems in the prior art, and provides a threaded joint thread gluing risk prediction method based on finite element analysis, so that thread gluing prediction of a threaded joint is realized.
The purpose of the invention is realized by the following technical scheme:
a screwed joint thread gluing risk prediction method based on finite element analysis comprises the following steps:
s1, determining the dimension parameter of the threaded joint through the dimension of the part marked on the structural drawing of the threaded joint product or the way of surveying and mapping the threaded joint object;
s2, determining screwing parameters of the threaded joint through an actual screwing-unscrewing test of the threaded joint;
s3, calculating the screwing length of the upper buckle of the threaded joint according to the dimension parameter and the screwing parameter of the threaded joint;
s4, calculating the contact stress of the upper buckle of the threaded joint according to the dimension parameter and the screwing parameter of the threaded joint by using a finite element analysis method;
and S5, calculating the thread gluing risk factor of the threaded joint by utilizing the screwing length and the contact stress of the upper thread of the threaded joint, and judging the thread gluing risk.
In step S1, the threaded joint size parameters include: the outer diameter D of the pipe body of the threaded joint, the wall thickness t and the diameter parameter D of the male end sealing surfaceSealing surface pinDiameter parameter d of pin threadThread pinDiameter parameter d of female end sealing surfaceSealing face boxDiameter parameter d of female end threadScrew thread boxAngle parameter theta of sealing surface of male end and female end, thread taper of male end and female endDegree parameter gamma and thread pitch parameter p of the male end and the female end;
in step S2, the screwing parameters include: upper buckling inflection point torque T of threaded joint1Number of turns n of buckling inflection point1Final make-up torque T2Finally, number of turns n is buckled2。
Step S3 is to select a plurality of calculation points on the shoulder surface, the sealing surface, and the threaded portion of the threaded joint, and then calculate the screwing contact length of each calculation point, and the calculation steps are as follows:
and S31, calculating the relative displacement of the threaded joint according to the following calculation formula:
d0＝p*(n2-n1)
in the formula: d0For screwing the threaded joint into the axial relative displacement, the screwing axial relative displacement d of the threaded joint at each calculation point0Are the same;
s32, calculating the contact interference of the threads of the threaded joint and the sealing surface part thereof, wherein the calculation formula is as follows:
screw thread＝dThread pin-dScrew thread box
Sealing surface＝dSealing surface pin-dSealing face box
In the formula:screw threadThe interference magnitude of the radial fit of the threads at the calculation points of the thread parts is the same;sealing surfaceCalculating the radial fit interference magnitude of the sealing surface of a point at the sealing surface part of the threaded joint;
s33, calculating the axial displacement of the thread, the sealing surface and the shoulder surface of the threaded joint;
for the thread part, the threads at the male end and the female end move relatively at an angle defined by the taper, and the axial displacement is calculated according to the following formula:
wscrew thread＝γ*Screw thread/2+d0
In the formula WScrew threadFor axial fitting displacement of the thread at a calculation point of the threaded portion of the threaded joint, the axial fitting displacement of the thread at said calculation point of the threaded portion is the same；
For the sealing surface part, the contact of the male end and the female end is relative movement of the sealing surface angle, the axial displacement is calculated according to the following formula:
in the formula WSealing surfaceCalculating axial matching displacement of a sealing surface at a point on the sealing surface of the threaded joint;
for the shoulder surface part, the contact of the male end and the female end occurs after the inflection point appears, and the axial displacement is as follows:
wshoulder surface＝d0
In the formula WShoulder surfaceCalculating axial matching displacement of a sealing surface at a point on the sealing surface of the threaded joint;
and S34, calculating the actual screwing contact length of the threads of the threaded joint according to the following calculation formula:
in the formula LEiCalculating the actual screw-on contact length for each respective point;
wherein W is the relative displacement, and if the relative displacement is at the calculation point of the threaded part of the threaded joint, W is equal to WScrew thread(ii) a If the calculated point is located at the sealing surface part of the threaded joint, W is equal to WSealing surface(ii) a W-W if at the calculated point of the threaded joint shoulder surface portionShoulder surface；
In the formula riFor the radius of the threaded joint pipe portion where each corresponding calculation point is located, where i is the number of each calculation point, and for the oil casing joint, the radius r of each portioniChange is not big, get riWhen D/2, then L isEiThe calculation formula of (2) is as follows:
the step S4 includes:
s41, establishing a threaded joint finite element model based on the threaded joint size parameters obtained in the step S1 and the threaded joint relative displacement relation obtained in the step S31;
s42, adding boundary conditions according to the screwing parameters of the threaded joint obtained in the step S2 and the displacement relation conditions of actual screwing in the step S31, wherein the boundary conditions mainly comprise material performance, axisymmetric characteristics, contact characteristics and the like and are added to a calculation model in the calculation process;
s43, completing finite element analysis and calculation;
s44, extracting the analysis result to obtain the contact stress sigma of each point contact partiWherein i is the number of each calculation point.
In the step S5, the actual screwing contact length L of each corresponding calculation point of the threaded joint is usedEiContact stress σ with contact portioniCalculating the thread gluing risk factor of the threaded joint, and judging the size of the thread gluing risk, wherein the formula is as follows:
Fzi＝σi*LEi
in the formula, FziAnd (3) sticking buckle risk factors of each corresponding calculation point, wherein i is the number of each calculation point.
The invention has the beneficial effects that:
according to the method for predicting the risks of the thread gluing of the threaded connector based on finite element analysis, prediction of all parts of thread gluing after the threaded connector is buckled can be achieved, reference is provided for product optimization design and diagnosis of thread gluing problems, the product development period and cost are reduced, the risks of the thread gluing of the product are reduced through the method and structure optimization, and various accidents caused by thread gluing during product use are reduced.
To further illustrate the above objects, structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings.
Drawings
FIG. 1 is a schematic flow chart of a method for predicting the risk of thread gluing of a threaded joint based on finite element analysis according to the present invention;
FIG. 2 is a schematic view showing the meaning of parameters of the male-end thread in the threaded joint according to the present invention;
FIG. 3 is a schematic representation of the meaning of the parameters indicated for the female thread in a threaded joint according to the invention;
FIG. 4 is a schematic view of the upper thread-up curve of the threaded joint of the present invention;
FIG. 5 is a schematic view of calculation points selected when calculating the length of the upper thread of the threaded joint according to the present invention;
FIG. 6 is a graph showing the results of contact stress analysis of the threaded joint according to the present invention.
Detailed Description
The following describes in detail a specific embodiment of the present invention with reference to the drawings of the embodiment.
The method determines the screwing contact length of each contact part of the threaded joint in the screwing process through the analysis and calculation of thread parameters; then determining the contact stress of the corresponding part after the threaded joint is screwed by using a finite element analysis method; and finally, determining the size of the thread gluing risk by comparing the screwing contact length and the contact stress of the determined part.
Referring to fig. 1, the method for predicting the galling risk of the threaded joint based on finite element analysis comprises the following steps:
s1, determining the dimension parameter of the threaded joint through the dimension of the part marked on the structural drawing of the threaded joint product or the way of surveying and mapping the threaded joint object;
s2, determining screwing parameters of the threaded joint through an actual screwing-unscrewing test of the threaded joint;
s3, calculating the screwing length of the upper buckle of the threaded joint according to the dimension parameter and the screwing parameter of the threaded joint;
s4, calculating the contact stress of the upper buckle of the threaded joint according to the dimension parameter and the screwing parameter of the threaded joint by using a finite element analysis method;
and S5, calculating the thread gluing risk factor of the threaded joint by utilizing the screwing length and the contact stress of the upper thread of the threaded joint, and judging the thread gluing risk.
One embodiment is described in detail below.
And selecting a threaded joint as an analysis object to predict the thread gluing risk.
In step S1, determining various dimensional parameters of the threaded joint structure according to the dimensions of the components marked on the product structure drawing or by means of tool-to-object mapping, and the like, with reference to fig. 2 to 3, the dimensional parameters of the threaded joint mainly include: the outer diameter D of the pipe body of the threaded joint, the wall thickness t and the diameter parameter D of the male end sealing surfaceSealing surface pinDiameter parameter d of pin threadThread pinDiameter parameter d of female end sealing surfaceSealing face boxDiameter parameter d of female end threadScrew thread boxThe parameters include a male end sealing surface angle parameter theta, a male end thread taper parameter gamma, a female end thread taper parameter gamma and a male end thread pitch parameter p and a female end thread pitch parameter p.
In step S2, the threaded joint screwing parameters are obtained by the actual unscrewing test of the threaded joint. Referring to fig. 4, the screwing parameters mainly include: upper buckling inflection point torque T of threaded joint1Number of turns n of buckling inflection point1Final make-up torque T2Finally, number of turns n is buckled2. The buckling inflection point is a point where a buckling torque curve of the threaded joint has a significant change in curvature, namely T in FIG. 41The corresponding point; final make-up is the point at which make-up of the connection ends, i.e. T in FIG. 42The corresponding point.
In step S3, calculating the screwing length of the threaded joint according to the dimension parameter and the screwing parameter, specifically, selecting a plurality of calculation points on the shoulder surface, the sealing surface and the threaded portion of the threaded joint, where the calculation points selected in this embodiment are 1-4 calculation points shown in fig. 5, where: selecting two calculation points at the thread part, namely a large thread end (calculation point 2) and a small thread end (calculation point 1); one calculation point (calculation point 4) is selected for the seal surface portion, and one calculation point (calculation point 3) is selected for the shoulder surface portion. And in the selection process, respectively selecting the point with the maximum contact stress of the part in each part as a calculation point. Then, the screwing contact length of each calculation point is calculated respectively, and the calculation steps are as follows:
and S31, calculating the relative displacement of the threaded joint according to the following calculation formula:
d0＝p*(n2-n1)
in the formula: d0Screwing the threaded joint to perform axial relative displacement; p is the thread pitch parameter of the male end and the female end; n is1The number of turns of the buckling inflection point is set; n is2For final number of make-up turns, i.e. screwing-in axial relative displacement d of threaded joint at each of 1-4 calculation points0Are the same;
s32, calculating the contact interference of the threads of the threaded joint and the sealing surface part thereof, wherein the calculation formula is as follows:
screw thread＝dThread pin-dScrew thread box
Sealing surface＝dSealing surface pin-dSealing face box
In the formula:screw threadIn order to obtain the thread radial fit interference at the calculation points (in this embodiment, calculation point 2 and calculation point 1) of the threaded part of the threaded joint, the thread radial fit interference at the calculation points (calculation point 2 and calculation point 1) of the threaded part is the same;sealing surfaceCalculating the radial fit interference of a sealing surface of a point (which is a calculation point 4 in the embodiment) at the sealing surface part of the threaded joint; dSealing surface pinThe diameter parameter of the sealing surface of the male end is obtained; dThread pinThe diameter parameter of the male end thread is shown; dSealing face boxThe diameter parameter of the sealing surface of the female end is shown; dScrew thread boxThe diameter parameter of the female end thread is shown.
S33, calculating the axial displacement of the thread, the sealing surface and the shoulder surface of the threaded joint;
for the thread part, the threads at the male end and the female end move relatively at an angle defined by the taper, so the axial displacement calculation formula is as follows:
wscrew thread＝γ*Screw thread/2+d0
In the formula WScrew threadThe axial matching displacement of the threads at the calculation points (in the embodiment, the calculation point 2 and the calculation point 1) of the thread part of the threaded joint is the same; gamma is the thread taper parameter of the male end and the female end;
for the sealing surface part, the male end and the female end are in relative motion by the angle of the sealing surface, so the axial displacement calculation formula is as follows:
in the formula WSealing surfaceThe axial matching displacement of the sealing surface of a calculation point (the calculation point 4 is referred to in the embodiment) at the sealing surface part of the threaded joint;
for the shoulder surface portion, the male-female end contact occurs after the inflection point occurs, so its axial displacement is:
wshoulder surface＝d0
In the formula WShoulder surfaceThe axial matching displacement of the sealing surface of a calculation point (the calculation point 4 is referred to in the embodiment) at the sealing surface part of the threaded joint;
and S34, calculating the actual screwing contact length of the threads of the threaded joint according to the following calculation formula:
in the formula LEiCalculating the actual screw-on contact length for each respective point; w is the relative displacement, and if it is at the calculation point of the screw part of the threaded joint (in this embodiment, calculation point 2 and calculation point 1), W is equal to WScrew thread(ii) a If the calculation point is located at the sealing surface part of the threaded joint (the calculation point 4 is referred to in the embodiment), W is equal to WSealing surface(ii) a If it is at the calculation point of the threaded joint shoulder surface portion (this embodiment means calculation point 3), W is W ═ WShoulder surface(ii) a p is the thread pitch parameter of the male end and the female end; r isiThe radius of the threaded joint pipe part where each corresponding calculation point is located, wherein i is the number of each calculation point (in the present embodiment, i is 1, 2, 3, 4), and for the oil casing joint, the radius r of each partiThe change is not large, and r can be takeniD/2, then:
in step S4, the contact stress of the thread end on the threaded joint is calculated according to the dimensional parameters and the screwing parameters by using a finite element analysis method. The contact stress is a problem of state nonlinearity, and the contact mechanism may be considered that when two solids are in contact, a portion where the sum of the heights of the asperities is the largest between the two surfaces is the first to contact due to the surface roughness. As the load increases, other pairs of microprotrusions correspondingly contact; each micro-convex body is elastically deformed after being contacted; when the load exceeds a certain critical value, plastic deformation occurs or the elastic-plastic deformation state is set.
The specific operation flow of S4 includes:
s41, establishing a threaded joint finite element model based on the threaded joint size parameters obtained in the step S1 and the threaded joint relative displacement relation obtained in the step S31;
s42, adding boundary conditions according to the screwing parameters of the threaded joint obtained in the step S2 and the displacement relation conditions of actual screwing in the step S31, wherein the boundary conditions mainly comprise material performance, axisymmetric characteristics, contact characteristics and the like and are added to a calculation model in the calculation process;
s43, completing finite element analysis and calculation;
s44, extracting the analysis result to obtain the contact stress sigma of each point contact partiWhere i is the number of each calculation point (in this embodiment, i is 1, 2, 3, 4), and fig. 6 shows the results of contact stress analysis at the threaded joint 1-4.
In step S5, the actual screwing contact length L of each corresponding calculation point of the threaded joint is usedEiContact stress σ with contact portioniAnd calculating the thread gluing risk factor of the threaded joint and judging the size of the thread gluing risk. There are multiple algorithms based on different failure mode thread gluing risk factors, and this embodiment selects a simplified algorithm, and the calculation formula is as follows:
Fzi＝σi*LEi
in the formula, FziFor each respective calculated point the sticking risk factor, LEiThe actual screwing contact length for each respective calculation point, where i is the number of each calculation point (in this embodiment, i is 1, 2, 3, 4); sigmaiIs the contact stress at each respective calculated point.
TABLE 1 Table for contact stress and thread gluing risk factor of each calculated point contact length
As can be seen from the calculation data (table 1) of the selection test of the threaded joint, in the comparison of the maximum contact stress nodes respectively selected from the four positions of the thread large end (calculation point 2), the thread small end (calculation point 1), the seal surface (calculation point 4), and the shoulder surface (calculation point 3), the contact stress of the shoulder surface (calculation point 3) is the maximum (1456MPa), but the galling factor is the minimum. The thread gluing factor appears at the small end part of the thread (calculation point 1) to the maximum extent, and corresponds to the initial thread part of the thread at the male end, and is consistent with the actual thread gluing result.
It should be understood by those skilled in the art that the above embodiments are for illustrative purposes only and are not intended to limit the present invention, and that changes and modifications to the above embodiments may fall within the scope of the appended claims.
Claims (3)
1. A screwed joint thread gluing risk prediction method based on finite element analysis is characterized by comprising the following steps:
s1, determining the dimension parameters of the threaded joint through the dimensions of the components marked on the structural drawing of the threaded joint product or the way of mapping the threaded joint, wherein the dimension parameters of the threaded joint comprise: the outer diameter D of the pipe body of the threaded joint, the wall thickness t and the diameter parameter D of the male end sealing surfaceSealing surface pinDiameter parameter d of pin threadThread pinDiameter parameter d of female end sealing surfaceSealing face boxDiameter parameter d of female end threadScrew thread boxAngle parameter theta of sealing surface of male end and female end, thread taper of male end and female endA parameter gamma and a thread pitch parameter p of the male end and the female end;
s2, determining screwing parameters of the threaded joint through a practical screwing-unscrewing test of the threaded joint, wherein the screwing parameters comprise: upper buckling inflection point torque T of threaded joint1Number of turns n of buckling inflection point1Final make-up torque T2Finally, number of turns n is buckled2；
S3, calculating the screwing length of the upper buckle of the threaded joint according to the dimension parameter and the screwing parameter of the threaded joint;
s4, calculating the contact stress of the upper buckle of the threaded joint according to the dimension parameter and the screwing parameter of the threaded joint by using a finite element analysis method;
s5, calculating the thread gluing risk factor of the threaded joint by utilizing the screwing length and the contact stress of the upper thread gluing of the threaded joint, judging the thread gluing risk,
step S3 is to select a plurality of calculation points on the shoulder surface, the sealing surface, and the threaded portion of the threaded joint, and then calculate the screwing contact length of each calculation point, and the calculation steps are as follows:
and S31, calculating the relative displacement of the threaded joint according to the following calculation formula:
d0＝p*(n2-n1)
in the formula: d0For screwing the threaded joint into the axial relative displacement, the screwing axial relative displacement d of the threaded joint at each calculation point0Are identical, n1For the number of turns of the upper buckle, n2The final number of the fastening turns is obtained;
s32, calculating the contact interference of the threads of the threaded joint and the sealing surface part thereof, wherein the calculation formula is as follows:
screw thread＝dThread pin-dScrew thread box
Sealing surface＝dSealing surface pin-dSealing face box
In the formula:screw threadThe interference magnitude of the radial fit of the threads at the calculation points of the thread parts is the same;sealing surfaceCalculating the interference of radial fit of the sealing surface at the point of the sealing surface of a threaded joint, dThread pinDiameter parameter of male end thread, dScrew thread boxIs a diameter parameter of the female end thread, dSealing surface pinIs the diameter parameter of the sealing surface of the male end, dSealing face boxThe diameter parameter of the sealing surface of the female end is shown;
s33, calculating the axial displacement of the thread, the sealing surface and the shoulder surface of the threaded joint;
for the thread part, the threads at the male end and the female end move relatively at an angle defined by the taper, and the axial displacement is calculated according to the following formula:
wscrew thread＝γ*Screw thread/2+d0
In the formula wScrew threadThe axial matching displacement of the threads at the calculation point of the thread part of the threaded joint is the same, and gamma is a thread taper parameter of a male end and a female end;
for the sealing surface part, the contact of the male end and the female end is relative movement of the sealing surface angle, the axial displacement is calculated according to the following formula:
in the formula wSealing surfaceCalculating axial matching displacement of a sealing surface at a sealing surface part of the threaded joint, wherein theta is an angle parameter of the sealing surface of the male end and the sealing surface of the female end;
for the shoulder surface part, the contact of the male end and the female end occurs after the inflection point appears, and the axial displacement is as follows:
wshoulder surface＝d0
In the formula wShoulder surfaceCalculating axial matching displacement of a sealing surface at a point on the sealing surface of the threaded joint;
and S34, calculating the actual screwing contact length of the threads of the threaded joint according to the following calculation formula:
in the formula LEiCalculating the actual screwing contact length of each corresponding calculation point, wherein p is a thread pitch parameter of the male end and the female end;
wherein w is the relative displacement, and if the w is at the calculation point of the threaded part of the threaded joint, the w is equal to wScrew thread(ii) a If the calculated point is located at the sealing surface part of the threaded joint, w is equal to wSealing surface(ii) a If at the calculated point of the threaded joint shoulder surface portion, w ═ wShoulder surface；
In the formula riFor the radius of the threaded joint pipe portion where each corresponding calculation point is located, where i is the number of each calculation point, and for the oil casing joint, the radius r of each portioniChange is not big, get riWhen D/2, then L isEiThe calculation formula of (2) is as follows:
in the formula: d is the outer diameter of the pipe body of the threaded joint.
2. A threaded joint galling risk prediction method based on finite element analysis according to claim 1, characterized in that: the step S4 includes:
s41, establishing a threaded joint finite element model based on the threaded joint size parameters obtained in the step S1 and the threaded joint relative displacement relation obtained in the step S31;
s42, adding boundary conditions according to the screwing parameters of the threaded joint obtained in the step S2 and the actual screwing displacement relation conditions in the step S31, wherein the boundary conditions mainly comprise material performance, axisymmetric characteristics and contact characteristics and are added to a calculation model in the calculation process;
s43, completing finite element analysis and calculation;
s44, extracting the analysis result to obtain the contact stress sigma of each point contact partiWherein i is the number of each calculation point.
3. A threaded joint galling risk prediction method based on finite element analysis according to claim 2, characterized in that:
in the step S5, the actual screwing contact length L of each corresponding calculation point of the threaded joint is usedEiContact stress σ with contact portioniCalculating the thread gluing risk factor of the threaded joint, and judging the size of the thread gluing risk, wherein the formula is as follows:
Fzi＝σi*LEi
in the formula, FziAnd (3) sticking buckle risk factors of each corresponding calculation point, wherein i is the number of each calculation point.
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| Title |
|---|
| 快速上扣螺纹接头的有限元分析及优化设计;孙建安等;《宝钢技术》;20130630;第19页 * |
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| CN107506506A (en) | 2017-12-22 |
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