CN112077584B - Method for assembling bolt connection of composite material component - Google Patents
Method for assembling bolt connection of composite material component Download PDFInfo
- Publication number
- CN112077584B CN112077584B CN202010908836.7A CN202010908836A CN112077584B CN 112077584 B CN112077584 B CN 112077584B CN 202010908836 A CN202010908836 A CN 202010908836A CN 112077584 B CN112077584 B CN 112077584B
- Authority
- CN
- China
- Prior art keywords
- bolt
- composite material
- pretightening force
- material member
- torque
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000002131 composite material Substances 0.000 title claims abstract description 101
- 238000000034 method Methods 0.000 title claims abstract description 53
- 230000006378 damage Effects 0.000 claims abstract description 71
- 230000008569 process Effects 0.000 claims abstract description 40
- 238000005553 drilling Methods 0.000 claims abstract description 4
- 238000009659 non-destructive testing Methods 0.000 claims description 10
- 230000008859 change Effects 0.000 claims description 8
- OIGNJSKKLXVSLS-VWUMJDOOSA-N prednisolone Chemical compound O=C1C=C[C@]2(C)[C@H]3[C@@H](O)C[C@](C)([C@@](CC4)(O)C(=O)CO)[C@@H]4[C@@H]3CCC2=C1 OIGNJSKKLXVSLS-VWUMJDOOSA-N 0.000 claims description 8
- 238000012544 monitoring process Methods 0.000 claims description 7
- 239000000919 ceramic Substances 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 238000001514 detection method Methods 0.000 abstract 1
- 230000007547 defect Effects 0.000 description 7
- 239000000463 material Substances 0.000 description 5
- 238000004364 calculation method Methods 0.000 description 4
- 239000011229 interlayer Substances 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 230000032798 delamination Effects 0.000 description 2
- 239000003292 glue Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- 206010061245 Internal injury Diseases 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 230000036316 preload Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000565 sealant Substances 0.000 description 1
- 239000003566 sealing material Substances 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P19/00—Machines for simply fitting together or separating metal parts or objects, or metal and non-metal parts, whether or not involving some deformation; Tools or devices therefor so far as not provided for in other classes
- B23P19/04—Machines for simply fitting together or separating metal parts or objects, or metal and non-metal parts, whether or not involving some deformation; Tools or devices therefor so far as not provided for in other classes for assembling or disassembling parts
- B23P19/06—Screw or nut setting or loosening machines
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D21/00—Measuring or testing not otherwise provided for
- G01D21/02—Measuring two or more variables by means not covered by a single other subclass
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)
Abstract
The invention relates to an assembly method for bolt connection of a composite material component, which comprises the following steps: determining technological parameters required by assembly according to the type of a composite material member and the type and size of a bolt; secondly, positioning and clamping the composite material member to be assembled on a fixture, drilling at a preset connecting position, and installing various detection devices; and step three, starting the electric tightening shaft to tighten the bolt, measuring various process parameters in real time all the time in the bolt tightening process, and controlling the assembling process according to the process parameters. The invention can improve the assembly quality of the composite material member during bolt connection and avoid the damage of the composite material member during assembly.
Description
Technical Field
The invention relates to an assembling method for bolt connection of a composite material component, and belongs to the technical field of composite material assembly.
Background
The composite material is widely applied to airplane structures by virtue of excellent mechanical properties. Compared with metal materials, the composite material has higher specific strength and specific modulus, and better fatigue resistance and breakage safety. Therefore, the use ratio of the composite material in various airplanes is higher and higher (for example, the use amount of the composite material in the Boeing B787 type reaches 50%, and the use amount of the composite material in the airbus A350 type reaches 52%), and the use ratio of the composite material becomes one of important marks for measuring the advancement of the airplane.
When the composite material member is assembled, bolt connection is mostly adopted. Compared with connection methods such as riveting, cementing and the like, the bolt connection quality is more stable and reliable, larger load can be borne, the assembly quality is easy to check, and repeated disassembly and assembly are facilitated. Therefore, bolting is used to assemble a large number of composite structures, especially critical areas and critical joints that are subjected to large loads. When the bolt connector is assembled, two operation modes of manually tightening the bolt and installing the bolt by a power tightening shaft are generally available. However, since the process of manually tightening bolts has a large dispersion and a low production efficiency, more electric tightening shaft mounting bolts are used in assembly. The electric tightening shaft can accurately control torque T, rotating speed n and a rotating angle theta, a certain pre-tightening force is obtained after torque is input into the bolt, reliable connection of an assembly structure is achieved, and the pre-tightening force is one of important parameters for measuring connection quality of the bolt.
In the conventional bolt connection process, whether the bolt connection is qualified or not is generally judged by monitoring the magnitude of the tightening torque, namely, the bolt connection is considered to be qualified when a certain torque is reached. However, this method has revealed major disadvantages when joining composite material members. The composite material is an anisotropic material, the interlayer strength is low, the material brittleness is high, local damage or overlarge assembling stress can be generated due to improper process parameter setting during bolt connection, the bearing capacity of the structure is weakened, the torque at the moment can be in a qualified range, and misjudgment on the assembling quality is easily caused. After the tightening is finished, the embedded tiny bulges on the contact surface can cause the relaxation of the pretightening force in a short time due to the creep phenomenon of the sealing material. Therefore, during the assembly process, monitoring and control is required for the bolting process of the composite material members.
Disclosure of Invention
The invention aims to solve the technical problems that: the assembling method can improve the assembling quality of the composite material member during bolt connection and avoid damage of the composite material member during assembling.
In order to solve the technical problems, the technical scheme provided by the invention is as follows: a method of assembling a bolted composite component comprising the steps of:
step one, determining process parameters required for assembly according to the type of the composite material component and the type and size of the bolt, wherein the process parameters comprise an expected interval F' ═ F of bolt pretightening force F1,F2]Target bolt pretightening force value FtThe expected section k' of the torque coefficient k ═ k1,k2]Allowable maximum value f of surface damage factor fmaxInternal damage stateAllowable maximum value s of smaxWherein 0.8 XF2≤Ft≤0.9×F2；
At the same time, the initial rotation speed n of the power tightening shaft is determinedstartAnd a stop speed nend；
Secondly, positioning and clamping the composite material connecting piece to be assembled on a fixture, and then drilling at a preset connecting position;
attaching a piezoelectric ceramic piece to the tail end of the bolt required for connection, installing an electric tightening shaft, and installing an ultrasonic sensor on the electric tightening shaft for measuring the pretightening force F of the bolt in real time;
manufacturing speckles on the surface of the composite material member, and building a 3D-DIC measuring system for measuring the surface strain field of the composite material member in real time to obtain a surface damage factor f;
constructing an ultrasonic nondestructive testing device for measuring the internal damage state s in real time;
starting the electric tightening shaft to tighten the bolt, and measuring the obtained bolt pre-tightening force F in real time all the time in the tightening process;
in the idle screwing stage, the bolt pretightening force F is equal to 0, the torque coefficient k is equal to 0, and the rotating speed of the electric screwing shaft is controlled to be nstart；
After the idle screwing stage is finished, when the pretightening force F of the bolt is detected to be greater than 0, the screwing is suspended; then the rotation speed of the electric tightening shaft is controlled to be nendContinuing the tightening operation, and calculating a real-time torque coefficient k as T/(F.d) according to the real-time torque T of the electric tightening shaft and the diameter d of the bolt; simultaneously, detecting the surface damage factor f and the internal damage state s in real time;
according to the bolt pretightening force F, the torque coefficient k, the surface damage factor F and the internal damage state s which are obtained in real time, the following control is carried out:
1) if the bolt pretightening force F reaches the target bolt pretightening force value FtThe assembly process of the composite material member is normally ended;
2) if the torque coefficient k exceeds the expected interval k', when k is less than k1When the torque is applied, the rotating speed n and the real-time torque T of the electric tightening shaft are reduced,when k is greater than k2Increasing the rotating speed n and the real-time torque T of the electric tightening shaft;
3) if the surface damage factor f of the composite component reaches the maximum permissible value fmaxThe surface of the composite material member is seriously abraded, and the assembly process of the composite material member is stopped;
4) if the internal damage state s of the composite component reaches the maximum allowable value smaxThe internal damage of the composite material member is serious, and the assembly process of the composite material member is terminated.
The composite material is an anisotropic heterogeneous material, and the performance of the composite material is different from that of a metal material. The composite laminated board has high in-plane strength, but low interlayer strength, and is easy to generate delamination damage in the assembling and service processes, so that the bearing capacity of the structure is reduced. When the bolt is connected, if the connection process parameters are improperly set, overlarge interlayer stress and even delamination damage are easily caused, and the surface layer of the composite material directly contacted with the bolt head is also easily abraded to influence the structure safety. Therefore, to evaluate the quality of the composite material structure bolted connection, the following four physical quantities need to be analyzed:
1) pretightening force F
The torque T input by electrically tightening the axial bolt is mainly converted into three parts including the torque T consumed by the relative sliding of the bolt head and the surface of the connected piecebTorque T consumed by friction between threadsthAnd the torque T consumed by stretching the bolt rod1Wherein, T1To generate the effective component of the preload, it generally accounts for about 10% of the input torque T. The pretightening force F has a great influence on the mechanical property of the composite material assembling structure, and researches show that the tensile and fatigue mechanical properties of the joint can be improved by increasing the pretightening force F within a certain range, but after the pretightening force F exceeds the range, the pretightening force F is continuously increased, so that more obvious damage can be caused during assembling, and the mechanical property of the connecting structure is weakened. When the tightening is completed, the loosening phenomenon of the connection structure can also be directly evaluated through the change of the pretightening force, so that the pretightening force F is one of key physical quantities for measuring the bolt connection.
When the bolt is pre-tightenedF is less than a predetermined interval F ═ F1,F2]And when the pretightening force of the bolt is about to exceed the preset interval, reducing the rotating speed n to 0, namely stopping inputting the torque T to the bolt. F1Minimum pre-tightening force (such as sealing structure, minimum clamping force required for ensuring sealing performance and the like) designed according to the bearing condition of the structure, F2To achieve maximum damage-prone pretension, normally when the pretension F exceeds F2The composite material member is inevitably damaged. F1、F2Can be obtained by calculation (this is the prior art, and the relevant literature can be referred to), or the empirical value can be taken.
2) Coefficient of torque k
In a traditional empirical formula, a torque coefficient k is T/(F · d), where T is a tightening shaft input torque, F is a bolt tightening force, and d is a bolt diameter. The torque coefficient k mainly reflects the magnitude of the friction coefficient in the bolt connection structure and the change rule thereof, including the friction coefficient of the bearing surface and the friction coefficient between threads. When the friction coefficient is lower, the torque coefficient k is also lower, and the required pretightening force F can be obtained by inputting a smaller torque T; when the friction coefficient is higher, the torque coefficient k is also higher, and a larger torque T must be input to obtain the required pretightening force F. The torque coefficient k is affected by a number of factors, including the manner of lubrication, the nature of the coating, the temperature and humidity of the assembly, etc. The torque coefficient k directly reflects the slope of the F-T curve, i.e. the friction characteristics of the connection system, which is also one of the physical quantities affecting the quality of the assembly.
When the bolt is tightened, the torque coefficient k must be maintained within a certain range k ═ k according to the tightening specifications of the bolt1,k2]To ensure that the friction coefficient of each part of the joint system remains within a reasonable interval, k1、k2Are empirical values. When k is smaller than a preset interval, the friction coefficient is smaller, the rotating speed n needs to be reduced, and the torque T is controlled not to be too large; and when k is larger than the preset interval, the friction coefficient is larger at the moment, the rotating speed n needs to be increased, and the torque T is ensured to be large enough to obtain the required pretightening force.
3) Surface damage factor f
When the composite material member is in bolt connection, the strain field epsilon of the surface of the member can be obtained by a 3D-DIC full-field strain measurement systemijAnd substituting each strain component into a failure criterion based on the strain to obtain the damage factor f of the component. When f is 0, the member is not stressed; when 0 is present<f<1, indicating that the component is stressed but is not damaged; when f is 1, the damage of the area is shown to occur, and most of the bearing capacity is lost. Current measurement techniques can only obtain strain values and calculate the damage factor f for the surface region of the composite material. The stress condition of the surface layer of the composite material is complex, the extrusion and friction effects of the bolt head are strong, and the composite material is easy to damage in the composite material laminated plate firstly. Therefore, the damage factor f of the surface of the composite material is monitored, the stress and the damage state of the composite material can be presumed, and therefore, the surface damage factor f is one of physical quantities for measuring the assembly quality.
First, the maximum value f of the surface damage factor needs to be determinedmaxIf the surface damage factor f reaches the maximum value during the tightening process, the electric tightening shaft is controlled to stop rotating, the rotating speed n is equal to 0, and the torque T is not increased any more.
4) Internal injury state s
Various defects can be generated inside the composite material component in the forming process, including air holes, poor glue, rich glue, fiber buckling and the like. During bolt connection, the internal defects are easy to develop into internal damage under the action of pretightening force, and the structural performance is influenced. When the bolt is connected, nondestructive testing equipment (including ultrasonic nondestructive testing, X-ray nondestructive testing and the like) can be used for monitoring the internal damage state s of the component in real time, so that information such as a damaged area and a damaged area can be obtained, and the bolt connection quality can be evaluated.
According to the internal molding defects and the service performance requirements of the composite material, determining the allowable internal maximum damage state s during assemblymaxIf the internal damage state s reaches the maximum value during tightening, the electric tightening shaft is controlled to stop rotating, and the rotation speed n is 0, at which time the torque T does not increase any more.
In summary, it can be known that, the quality of assembling the composite material member (the quality of bolt connection) can be evaluated by starting with the above four physical quantities (the methods and the devices for measuring the above four physical quantities are prior art, and refer to the related documents, which are not described again), including the bolt pretightening force F, the torque coefficient k, the surface damage factor F and the internal damage state s, and after obtaining the four physical quantities, the parameters such as the torque T, the rotation speed n and the like of the electric tightening shaft are controlled by calculation and judgment, so that the quality of assembling the composite material member (the quality of bolt connection) can be controlled. The invention controls the assembly quality of the composite material member by monitoring a plurality of parameters, and compared with the prior art, the invention avoids the situation that local damage or overlarge assembly stress is often generated due to improper process parameter setting, thereby preventing the bearing capacity of the assembled composite material member from being weakened and improving the assembly quality of the composite material member during bolt connection.
In addition, the applicant found that, assuming that the electric tightening shaft stops working when the proper tightening force F is reached, the bolt tightening force is significantly lost in a short time, and the loss amount after the bolt tightening force is stabilized is Δ F (refer to a measurement time limit of 10 min). And then, secondary screwing is carried out, and after the secondary screwing is loosened, stable and proper pretightening force F can be just obtained. Therefore, the improvement of the technical scheme is as follows: after the third step is finished, if the assembling process of the composite material member is normally finished, entering a relaxation measuring stage of the bolt pretightening force, continuously monitoring the change of the bolt pretightening force by using an ultrasonic sensor, and obtaining a change value delta F of the bolt pretightening force after the bolt pretightening force is gradually reduced and stabilized; the electric tightening shaft again tightens the bolt, and when the bolt pretightening force F is reached (F)t+ Δ F) or F2And when the electric tightening shaft stops working, the second tightening is finished. As mentioned above, the bolt pretension F must always be less than F2。
Drawings
FIG. 1 is a schematic diagram of a system for measuring various process parameters in an embodiment of the present invention.
Reference numerals: the device comprises a power tightening shaft 1, a bolt 2, a composite material component 3, an ultrasonic sensor 4, a 3D-DIC measuring system 5, an ultrasonic nondestructive testing device 6, a controller 7 and a complex interface 8 between two layers of composite material components.
Detailed Description
Examples
In the embodiment, the carbon fiber epoxy resin composite material laminated board 977-2 is selected as a composite material component to be assembled, the thickness of a single layer is 0.188mm, 20 layers are symmetrically laid, and the total thickness reaches 3.76 mm. The bolt is made of alloy steel bolt and self-locking nut, and is made of A286 and has nominal diameter of 6.35 mm. The power tightening shaft can provide a torque in the range of 0-220Nm, which can satisfy the torque required for tightening the bolt. The shaft is tightened by power (the torque T, the rotating speed n and the rotating angle theta can be controlled and recorded), the surface strain field of the composite material member is measured by a 3D-DIC measuring system, and the internal damage of the composite material member is measured by an ultrasonic nondestructive testing device (so as to obtain the internal damage state s of the composite material).
The assembling method for bolt connection of the composite material member comprises the following steps:
step one, determining process parameters required for assembly according to the type of the composite material component and the type and size of the bolt, wherein the process parameters comprise an expected interval F' ═ F of bolt pretightening force F1,F2]Target bolt pretightening force value FtThe expected section k' of the torque coefficient k ═ k1,k2]Allowable maximum value f of surface damage factor fmaxAllowable maximum value s of internal damage state smax；
At the same time, the initial rotation speed n of the power tightening shaft is determinedstartAnd a stop speed nend。
The expected interval of the bolt pretightening force F is within an acceptable pretightening force range and is smaller than F1The bolt connection is easy to loose and lose efficacy which is larger than F2The damage is easy to occur, and the self-relaxation amount is generally not more than 90% of the pretightening force F in consideration of the subsequent relaxation problem, so the target value F of the pretightening force of the bolt istCan take 0.8-0.9F2。
The expected range of the pre-tightening force in the embodiment is F' ═ 12kN,16kN]，Ft＝0.85F2The target pretightening force required by 13.6kN tightening is generally determined according to the load-bearing capacity, the tensile fatigue performance and the structural load-bearing requirement of the composite plateIt is determined that, in the present case, the pretension needs to be guaranteed to be [12kN,16kN ] according to the relevant assembly requirements and experience]And when the thickness exceeds 16kN, the composite board is easy to damage.
The expected interval of the torque coefficient k is a stable range which needs to be ensured by k in the tightening process, and the k value needs to be adjusted back to the interval by adjusting the rotating speed and the like outside the interval to ensure the stability of the tightening process. In the present embodiment, the expected interval of the torque coefficient k is k' ═ 0.15,0.25, the torque coefficient value is related to the fastener (bolt, nut), the value is mainly affected by the surface roughness of the fastener, the machining precision, the elastic modulus, the yield strength and the like, the value is fluctuated, and the fluctuation range of the torque coefficient is generally determined by performing a tightening experiment on the fastener in advance. In this example, the torque coefficient k' ranges between [0.15,0.25] according to the tightening specifications of the bolt.
The maximum allowable value of the surface damage factor f in this embodiment is fmaxThis is an empirical value, 0.8, and can also be obtained in advance by finite element analysis. Theoretical damage factor 0<f<And 1, the surface of the composite material is not damaged, and a certain safety margin needs to be set for a surface damage factor to ensure that the surface of the composite material is not damaged.
The maximum allowable value of the internal damage state in this embodiment is dmax＝0.1mm2This is an empirical value, and can be obtained in advance by finite element analysis. The composite material is inevitably subjected to defects during molding, and the defects are extruded by pretightening force in the screwing process and are easy to expand. In order to prevent the defect expansion from affecting the use performance of the whole composite material, the defect area size is set not to exceed 0.1mm in the example2。
The initial rotation speed of the power tightening shaft in this embodiment is nstart100r/min, and a final rotation speed nendThis is an empirical value, i.e. the initial rotational speed is set to 100r/min during idle screwing, and the rotational speed is reduced to 30r/min after the tightening element is engaged to generate the pretension force. The rotational speed of the power tightening shaft is generally set to be fast forward and slow backward. The screwing time can be shortened at the front end, and the screwing efficiency is improved; the latter slowing is to reduceThe moment of inertia generated during small screwing rotation avoids the phenomenon that the generated pretightening force exceeds a set value.
And step two, positioning and clamping the composite material connecting piece to be assembled on the fixture, and then drilling at a preset connecting position.
As shown in fig. 1, the composite material connecting piece to be assembled is firstly positioned and clamped on a jig, then holes are drilled at the preset connecting position of the fastener, bolts and nuts of the required fastener are prepared, the bolts and nuts are manually and simply screwed through hole positions manually, and then the electric tightening shaft is moved to be right above the hole positions, so that the positioning of the tightening shaft for the fastener is completed. The method comprises the following steps that a piezoelectric ceramic piece is attached to the tail end of a bolt required for connection, an electric tightening shaft is installed, an ultrasonic sensor is installed on the electric tightening shaft and used for measuring bolt pretightening force F in real time, and the piezoelectric ceramic piece and the ultrasonic sensor are used for measuring the bolt pretightening force F in the prior art;
manufacturing speckles on the surface of a composite material member, and building a 3D-DIC measuring system for measuring a surface strain field of the composite material member in real time to obtain a surface damage factor f, wherein the calculation of the surface damage factor f through the surface strain field of the composite material member is the prior art and is not repeated;
the ultrasonic nondestructive testing device is set up and used for measuring the internal damage state s in real time, after the ultrasonic nondestructive testing device detects data, the internal damage state s can be obtained through subsequent calculation, the internal damage state can be regarded as the maximum continuous damage area, and the ultrasonic nondestructive testing device is also the prior art and can refer to related documents.
Starting the electric tightening shaft to tighten the bolt, and measuring the obtained bolt pre-tightening force F in real time all the time in the tightening process;
in the idle screwing stage, the bolt pretightening force F is equal to 0, the torque coefficient k is equal to 0, and the rotating speed of the electric screwing shaft is controlled to be nstart＝100r/min；
After the idle screwing stage is finished, when the bolt pretightening force F is detected to reach the lower limit 12N of the expected interval F', controlling the rotating speed of the electric screwing shaft to be 30r/min, and calculating a real-time torque coefficient k to be T/(F.d) according to the real-time torque T of the electric screwing shaft and the diameter d of the bolt; simultaneously, detecting the surface damage factor f and the internal damage state s in real time;
according to the bolt pretightening force F, the torque coefficient k, the surface damage factor F and the internal damage state s which are obtained in real time, the following control is carried out:
1) if the bolt pretightening force F reaches the target bolt pretightening force value Ft13.6kN, the assembly process of the composite material member is normally finished;
2) if the torque coefficient k exceeds the expected interval k' [0.15,0.25]]If the assembly process of the composite material member is abnormal, the torque coefficient k needs to be adjusted; when k is less than k1When the friction coefficient is smaller, the rotating speed n of the electric tightening shaft is reduced (to be less than 30r/min) and the real-time torque T is reduced, and when k is greater than k2Increasing the rotating speed n (making the rotating speed n greater than 30r/min) and the real-time torque T of the electric tightening shaft;
3) if the surface damage factor f of the composite component reaches the maximum permissible value fmaxWhen the surface abrasion of the composite material component is more serious, the assembling process of the composite material component is stopped;
4) if the internal damage state s of the composite component reaches the maximum allowable value smax＝0.1mm2The internal damage of the composite material member is serious, and the assembly process of the composite material member is terminated.
After the tightening is finished, all measuring devices of the electric tightening shaft can be removed.
In the embodiment, four key physical quantities (the pretightening force F, the torque coefficient k, the surface damage factor F and the internal damage state s) are monitored in real time, and judgment is performed according to the four physical quantities, so that the torque T, the rotating speed n and the rotating angle theta of the electric tightening shaft are controlled, and the assembly quality is further controlled.
After the tightening is completed, a relatively significant reduction in the pretension force generally occurs within a short time, thereby affecting the predetermined assembly level. The pre-tightening force reduction in a short time is caused by the deformation of the material, such as the plastic deformation generated after the micro-protrusions on the contact surface of the screw thread and the contact surface of the material are pressed; and complex viscoelasticity such as coating sealant layer, liquid gasket and the like in the connectedThe interface is subject to creep deformation. Therefore, the present embodiment can be further modified as follows: after the third step is finished, if the assembling process of the composite material member is normally finished, entering a relaxation measuring stage of the bolt pretightening force, continuously monitoring the change of the bolt pretightening force by using an ultrasonic sensor, and obtaining a change value delta F of the bolt pretightening force after the bolt pretightening force is gradually reduced and stabilized; the electric tightening shaft again tightens the bolt, and when the bolt pretightening force F is reached (F)t+ Δ F) or F2And when the electric tightening shaft stops working, the second tightening is finished. Because the bolt pretension force F cannot exceed F2Otherwise damage to the composite component, therefore when (F)t+ΔF)>F2When the bolt pretightening force F reaches F2The operation is stopped.
After the tightening is finished, the ultrasonic pretightening force measuring sensor is continuously used for measuring a stable value of the pretightening force after the pretightening force is loosened for a short time, the pretightening force loss delta F is used as a compensation value of the pretightening force loading during the secondary tightening, the pretightening force is further tightened to offset the influence caused by the pretightening force loosening, and the bolt connection achieves stable assembly quality.
The present invention is not limited to the specific technical solutions described in the above embodiments, and other embodiments may be made in the present invention in addition to the above embodiments. It will be understood by those skilled in the art that various changes, substitutions of equivalents, and alterations can be made without departing from the spirit and scope of the invention.
Claims (2)
1. A method of assembling a bolted composite component comprising the steps of:
step one, determining process parameters required for assembly according to the type of the composite material component and the type and size of the bolt, wherein the process parameters comprise an expected interval F' ═ F of bolt pretightening force F1,F2]Target bolt pretightening force value FtThe expected section k' of the torque coefficient k ═ k1,k2]Allowable maximum value f of surface damage factor fmaxAllowable maximum value s of internal damage state smaxWherein 0.8 XF2≤Ft≤0.9×F2；
At the same time, the initial rotation speed n of the power tightening shaft is determinedstartAnd a stop speed nend；
Secondly, placing the composite material member to be assembled on a jig to complete positioning and clamping, and then drilling at a preset connecting position of the composite material member;
attaching a piezoelectric ceramic piece to the tail end of the bolt required for connection, installing an electric tightening shaft, and installing an ultrasonic sensor on the electric tightening shaft for measuring the pretightening force F of the bolt in real time;
manufacturing speckles on the surface of the composite material member, and building a 3D-DIC measuring system for measuring the surface strain field of the composite material member in real time to obtain a surface damage factor f;
constructing an ultrasonic nondestructive testing device for measuring the internal damage state s in real time;
starting the electric tightening shaft to tighten the bolt, and measuring in real time all the time in the tightening process to obtain bolt pre-tightening force F; in the idle screwing stage, the bolt pretightening force F is equal to 0, the torque coefficient k is equal to 0, and the rotating speed of the electric screwing shaft is controlled to be nstart(ii) a After the idle screwing stage is finished, when the pretightening force F of the bolt is detected to be greater than 0, the screwing is suspended; then the rotation speed of the electric tightening shaft is controlled to be nendContinuing the tightening operation, and calculating a real-time torque coefficient k as T/(F.d) according to the real-time torque T of the electric tightening shaft and the diameter d of the bolt; simultaneously, detecting the surface damage factor f and the internal damage state s in real time;
according to the bolt pretightening force F, the torque coefficient k, the surface damage factor F and the internal damage state s which are obtained in real time, the following control is carried out:
1) if the bolt pretightening force F reaches the target bolt pretightening force value FtThe assembly process of the composite material member is normally ended;
2) if the torque coefficient k exceeds the expected interval k', wherein when k is less than k1When the k is larger than k, the rotating speed n and the real-time torque T of the electric tightening shaft are reduced2Increasing the rotating speed n and the real-time torque T of the electric tightening shaft;
3) if the surface damage factor f of the composite component reaches the maximum permissible value fmaxThe surface of the composite material member is seriously abraded, and the assembly process of the composite material member is stopped;
4) if the internal damage state s of the composite component reaches the maximum allowable value smaxThe internal damage of the composite material member is serious, and the assembly process of the composite material member is terminated.
2. A method of assembling a bolted composite structural member according to claim 1, wherein: after the third step is finished, if the assembling process of the composite material member is normally finished, entering a relaxation measuring stage of the bolt pretightening force, continuously monitoring the change of the bolt pretightening force by using an ultrasonic sensor, and obtaining a change value delta F of the bolt pretightening force after the bolt pretightening force is gradually reduced and stabilized; the electric tightening shaft again tightens the bolt, and when the bolt pretightening force F is reached (F)t+ Δ F) or F2And when the electric tightening shaft stops working, the second tightening is finished.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010908836.7A CN112077584B (en) | 2020-09-02 | 2020-09-02 | Method for assembling bolt connection of composite material component |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010908836.7A CN112077584B (en) | 2020-09-02 | 2020-09-02 | Method for assembling bolt connection of composite material component |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112077584A CN112077584A (en) | 2020-12-15 |
| CN112077584B true CN112077584B (en) | 2021-06-25 |
Family
ID=73732407
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010908836.7A Active CN112077584B (en) | 2020-09-02 | 2020-09-02 | Method for assembling bolt connection of composite material component |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112077584B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115031942A (en) * | 2022-05-27 | 2022-09-09 | 南京航空航天大学 | Method for determining bolt tightening process parameters for assembling composite material structure |
| CN114872067A (en) * | 2022-06-01 | 2022-08-09 | 南京航空航天大学 | Bolt tightening robot with composite material structure |
| CN117943825B (en) * | 2024-03-27 | 2024-06-25 | 黎明职业大学 | Bolt assembly machine capable of detecting integrity and preventing accidental injury of bolts and assembly method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001150253A (en) * | 1999-11-26 | 2001-06-05 | Nitto Seiko Co Ltd | Automatic screw fastener |
| CN102699675B (en) * | 2011-03-28 | 2015-04-22 | 北汽福田汽车股份有限公司 | Wheel tightening method, wheel tightening control device and wheel tightening system |
| CN106329399B (en) * | 2016-11-01 | 2019-01-15 | 广东电网有限责任公司电力科学研究院 | A kind of control method and controller of transmission line of electricity bolt fastening machine people |
| DE102017219477A1 (en) * | 2017-11-02 | 2019-05-02 | Bayerische Motoren Werke Aktiengesellschaft | Assembly of a screw connection |
| CN109968012B (en) * | 2019-04-16 | 2020-06-30 | 西安航天动力研究所 | Helium turbine shafting tightening method and axial loading type tightening tool |
| CN111458123A (en) * | 2020-04-12 | 2020-07-28 | 北京工业大学 | Measuring device for friction coefficient and torque coefficient of threaded fastener |
-
2020
- 2020-09-02 CN CN202010908836.7A patent/CN112077584B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN112077584A (en) | 2020-12-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112077584B (en) | Method for assembling bolt connection of composite material component | |
| Hu et al. | An experimental study on mechanical response of single-lap bolted CFRP composite interference-fit joints | |
| Ireman et al. | On damage development in mechanically fastened composite laminates | |
| EP2138716A1 (en) | Blade insert | |
| WO2015154614A1 (en) | Double-bolt loose proof method | |
| US20100065688A1 (en) | Method and apparatus for reinforcing composite structures | |
| EP3036445B1 (en) | Replacing an aperture with an annular bushing in a composite laminated composite component | |
| CN108535101B (en) | Method for measuring interlayer tensile strength of composite laminated plate | |
| CN105588759B (en) | The test method of pin load distribution ratio in a kind of indirect determination composite Multi-fasteners joint structure failure history | |
| CN109372882A (en) | It is a kind of can be with the washer of monitoring bolt pretightning force | |
| US20090084197A1 (en) | Method and apparatus for mounting a sensor | |
| Nijgh | Loss of preload in pretensioned bolts | |
| US6421902B1 (en) | Method and device for producing and checking screwed connections | |
| CN110500350B (en) | Construction method for automatically controlling preload of bolt connection pair | |
| US7121780B2 (en) | Multiple load path fastener systems | |
| CN106644237B (en) | Integrated pressure-torsion compound sensor measuring device of multifunctional bolt fastening analysis system | |
| CN105333844B (en) | Riveting spot size detection online rapid measurement device and riveting point measuring method | |
| Van de Velde et al. | The effect of the setting force on the fatigue resistance of a blind rivet nut set in CFRP | |
| CN219551745U (en) | Device for testing stress relaxation of threaded fastener | |
| Mori et al. | A new tightening method for bolted joints by the simultaneous application of torque and compressive force | |
| CN219798676U (en) | Calibration fixture and calibration system | |
| US20230038777A1 (en) | Method of manufacturing adhered components | |
| RU2502896C2 (en) | Bolt joint with radial interference | |
| FI12249U1 (en) | Clamp bolt and dynamically loaded joint | |
| EP3797227B1 (en) | Fastener including a transition zone and method of use thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB03 | Change of inventor or designer information | ||
| CB03 | Change of inventor or designer information |
Inventor after: Yue Huide Inventor after: An Luling Inventor after: Wang Chufan Inventor after: Cai Yuebo Inventor after: Liu Qingbo Inventor after: Gao Guoqiang Inventor after: Yang Haoran Inventor before: Yue Xuande Inventor before: An Luling Inventor before: Wang Chufan Inventor before: Cai Yuebo Inventor before: Liu Qingbo Inventor before: Gao Guoqiang Inventor before: Yang Haoran |
|
| GR01 | Patent grant | ||
| GR01 | Patent grant |