Disclosure of Invention
The invention aims to solve the technical problems, and a first object of the invention is to provide a method for evaluating the failure of a bolt in random vibration, which considers the coupling effect of pretightening force and random vibration, performs linear superposition analysis on equivalent external force and bolt pretightening force, can evaluate the residual pretightening force of the bolt in the vibration process, has high accuracy of evaluation results, and can well guide the improvement design of products by researching the random vibration process and rule of the bolt through a simulation means.
A second object of the present invention is to provide a failure evaluation device for a bolt in random vibration.
The technical scheme adopted by the invention is as follows:
in order to achieve the above object, a first embodiment of the present invention provides a method for evaluating failure of a bolt in random vibration, including the following steps: performing random vibration mechanics simulation to obtain the maximum axial response displacement U of the bolt and the maximum acceleration a of the connected piece relative to the radial direction of the bolt; performing statics simulation to obtain an equivalent external force of the bolt meeting the maximum axial response displacement U; acquiring bolt pretightening force f0, applying pretightening force f0 to the bolt and analyzing the bolt pretightening force; applying the equivalent external force to the bolt, and performing the static simulation analysis to obtain the residual pretightening force f1 of the bolt; calculating a static friction force f2 between the bolt and the connected piece under the action of the residual pretightening force f1 according to the residual pretightening force f 1; calculating the maximum vibration force F of the connected piece under the condition of the maximum acceleration a; and performing failure evaluation on the bolt according to the static friction force F2 and the maximum vibration force F.
According to one embodiment of the invention, the static friction force f2 between the bolt and the connected piece under the action of the residual pretightening force f1 is calculated according to the following formula (1):
f2=f1×μ (1);
wherein f1 is the residual pretightening force, f2 is the static friction force between the bolt and the connected piece under the action of the residual pretightening force f1, and mu is the friction coefficient of the contact area between the bolt and the connected piece.
According to one embodiment of the present invention, the maximum vibration force F of the attached member under the condition of the maximum acceleration a is calculated according to the following formula (2):
wherein a is the maximum acceleration of the connected piece relative to the radial direction of the bolt, F is the maximum vibration force of the connected piece under the condition of the maximum acceleration a, M is the total mass of the connected piece, and n is the number of bolts connected with the connected piece.
According to one embodiment of the invention, the failure evaluation of the bolt is performed according to the static friction force F2 and the maximum vibration force F, and comprises the following steps: comparing the maximum vibratory force F to a preset multiple β of a static friction force F2, wherein β is less than 1; if F is more than or equal to beta multiplied by F2, judging that the bolt is loosened; if F < β × F2 is present, the bolt is judged to be fastened.
According to an embodiment of the invention, the value range of β is 0.8-0.9.
In order to achieve the above object, a second aspect of the present invention provides a failure evaluation device for a bolt in random vibration, including: the first acquisition module is used for carrying out random vibration mechanics simulation so as to acquire the maximum axial response displacement U at the bolt and the maximum acceleration a of the connected piece relative to the radial direction of the bolt; the second acquisition module is used for performing statics simulation to acquire an equivalent external force at the bolt under the condition that the maximum axial response displacement U is met; the first applying module is used for acquiring bolt pretightening force f0, applying the pretightening force f0 to the bolt and analyzing the pretightening force of the bolt; the second applying module is used for applying the equivalent external force to the bolt and carrying out the statics simulation analysis to obtain the residual pretightening force f1 of the bolt; a first calculation module, which is used for calculating a static friction force f2 between the bolt and the connected piece under the action of the residual pretightening force f1 according to the residual pretightening force f 1; a second calculation module for calculating a maximum vibration force F of the connected member under a maximum acceleration a condition; an evaluation module for performing a failure evaluation of the bolt as a function of the static friction force F2 and the maximum vibration force F.
According to one embodiment of the invention, the first calculation module calculates the static friction force f2 between the bolt and the connected piece under the action of the residual pretightening force f1 according to the following formula (1):
f2=f1×μ (1);
wherein f1 is the residual pretightening force, f2 is the static friction force between the bolt and the connected piece under the action of the residual pretightening force f1, and mu is the friction coefficient of the contact area between the bolt and the connected piece.
According to an embodiment of the present invention, the second calculation module calculates the maximum vibration force F of the attached member under the condition of the maximum acceleration a according to the following formula (2):
wherein a is the maximum acceleration of the connected piece relative to the radial direction of the bolt, F is the maximum vibration force of the connected piece under the condition of the maximum acceleration a, M is the total mass of the connected piece, and n is the number of bolts connected with the connected piece.
According to an embodiment of the invention, the evaluation module is specifically configured to: comparing the maximum vibratory force F to a preset multiple β of a static friction force F2, wherein β is less than 1; if F is more than or equal to beta multiplied by F2, judging that the bolt is loosened; if F < β × F2 is present, the bolt is judged to be fastened.
According to an embodiment of the invention, the value range of β is 0.8-0.9.
The invention has the beneficial effects that:
(1) the invention mainly adopts a simulation means to carry out virtual evaluation in the product design stage, and can play the roles of saving research and development expenses, shortening development period and improving product quality.
(2) According to the method, the coupling effect of the pretightening force and the random vibration is considered, the equivalent external force and the bolt pretightening force are subjected to linear superposition analysis, the residual pretightening force of the bolt in the vibration process can be estimated, and the accuracy of the estimation result is high.
(3) The invention can research the random vibration process and rule of the bolt by a simulation means and can well guide the improved design of products.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is a flowchart of a method for evaluating a failure of a bolt in random vibration according to an embodiment of the present invention. As shown in fig. 1, the method comprises the steps of:
and S1, performing random vibration mechanics simulation to obtain the maximum axial response displacement U at the bolt and the maximum acceleration a of the connected piece relative to the radial direction of the bolt.
And S2, performing statics simulation to obtain the equivalent external force of the bolt meeting the maximum axial response displacement U.
S3, acquiring bolt pretightening force f0, applying pretightening force f0 to the bolt and analyzing the bolt pretightening force.
The pretightening force f0 is mainly related to the performance grade, the specification and the like of the bolt and can be obtained by inquiring a related manual.
And S4, applying equivalent external force to the bolt, and performing statics simulation analysis to obtain the residual pretightening force f1 of the bolt.
S5, calculating static friction force f2 between the bolt and the connected piece under the action of the residual pretightening force f1 according to the residual pretightening force f 1.
In one embodiment of the invention, the static friction force f2 between the bolt and the connected piece under the action of the residual pretightening force f1 is calculated according to the following formula (1):
f2=f1×μ (1);
f1 is residual pretightening force, f2 is static friction force between the bolt and the connected piece under the action of the residual pretightening force f1, and mu is a friction coefficient of a contact area between the bolt and the connected piece.
And S6, calculating the maximum vibration force F of the connected piece under the condition of the maximum acceleration a.
In one embodiment of the present invention, the maximum vibration force F of the connected member under the condition of the maximum acceleration a is calculated according to the following formula (2):
wherein a is the maximum acceleration of the connected piece relative to the radial direction of the bolt, F is the maximum vibration force of the connected piece under the condition of the maximum acceleration a, M is the total mass of the connected piece, and n is the number of the bolts connected with the connected piece.
And S7, performing failure evaluation of the bolt according to the static friction force F2 and the maximum vibration force F.
According to one embodiment of the invention, the failure evaluation of the bolt is performed according to the static friction force F2 and the maximum vibration force F, and comprises the following steps: comparing the maximum vibratory force F to a predetermined multiple β of the static friction force F2, wherein β is less than 1; if F is more than or equal to beta multiplied by F2, judging that the bolt is loosened; if F < β × F2 is present, the bolt is judged to be fastened.
In the embodiment of the invention, the value range of β is 0.8-0.9, for example, 0.85.
Specifically, the bolt connection diagram can be seen in fig. 2, where 1 is a connected component, 2 is a connected component, and 3 is a bolt.
As shown in fig. 3, random vibration analysis is performed on the bolt through simulation software, and the maximum axial displacement U at the bolt and the maximum acceleration a of the connected piece relative to the radial direction of the bolt are obtained. And carrying out statics analysis on the product, and applying an equivalent external force to one side of the shaft end of the bolt to enable the axial displacement of the bolt to be equal to the maximum axial displacement U. And statically analyzing the product, inquiring the bolt pretightening force f0 suitable for loading according to relevant parameters such as the performance grade and the specification of the bolt, and calculating the simulation result of the product when the pretightening force f0 is applied. On the basis, the equivalent external force obtained in the previous step is applied to one side of the shaft end of the bolt, and the residual pretightening force f1 of the bolt is obtained through calculation. The static friction force f2 between the bolt and the connected member is calculated according to the formula f2 ═ f1 × μ, where μ is the friction coefficient of the contact area between the bolt and the connected member. The maximum vibration force F under the maximum acceleration a condition is calculated by the formula F ═ a × m. Finally, F is compared with beta xf 2, and when F is larger than or equal to 1.3 xf 2, the bolt is judged to be loosened, and otherwise, the bolt is judged to be fastened.
Therefore, the method considers the coupling effect of the pretightening force and the random vibration, carries out linear superposition analysis on the equivalent external force and the pretightening force of the bolt, can evaluate the residual pretightening force of the bolt in the vibration process, has high accuracy of an evaluation result, can partially research the random vibration process and rule of the bolt by a simulation means, and can well guide the improved design of a product.
In the present invention, the maximum axial response displacement U at the bolt and the maximum acceleration a of the connected member with respect to the radial direction of the bolt are both maximum values under the condition of 3 σ. And the failure assessment method described above does not involve material non-linearity of the bolt. Random vibromechanical and hydrostatic simulations can be performed in software such as Abaqus.
In summary, according to the failure evaluation method for the bolt in the random vibration of the embodiment of the invention, the random vibration mechanics simulation is performed to obtain the maximum axial response displacement U at the bolt and the maximum acceleration a of the connected piece relative to the radial direction of the bolt; obtaining an equivalent external force at the position of the bolt meeting the maximum axial response displacement U; acquiring bolt pretightening force f0, applying pretightening force f0 to the bolt and analyzing the pretightening force of the bolt; applying an equivalent external force to the bolt to obtain the residual pretightening force f1 of the bolt; calculating the static friction force f2 between the bolt and the connected piece under the action of f1 according to f 1; calculating the maximum vibration force F of the connected piece under the condition of the maximum acceleration a; the bolt failure evaluation was performed according to F2 and F. The method considers the coupling effect of the pretightening force and the random vibration, carries out linear superposition analysis on the equivalent external force and the pretightening force of the bolt, can evaluate the residual pretightening force of the bolt in the vibration process, has high accuracy of an evaluation result, can research the random vibration process and the rule of the bolt by a simulation means, and can well guide the improved design of products.
Corresponding to the failure evaluation method of the bolt in random vibration, the invention also provides a failure evaluation device of the bolt in random vibration. Since the device embodiment of the present invention corresponds to the method embodiment described above, details that are not disclosed in the device embodiment may refer to the method embodiment described above, and are not described again in the present invention.
Fig. 4 is a block diagram schematically showing a failure evaluation device for a bolt in random vibration according to an embodiment of the present invention. As shown in fig. 4, the apparatus includes: a first acquisition module 10, a second acquisition module 20, a first application module 30, a second application module 40, a first calculation module 50, a second calculation module 60, an evaluation module 70.
The first obtaining module 10 is configured to perform random vibration mechanics simulation to obtain a maximum axial response displacement U at the bolt and a maximum radial acceleration a of the connected component relative to the bolt; the second obtaining module 20 is configured to perform statics simulation to obtain an equivalent external force at the bolt position that meets the maximum axial response displacement U; the first applying module 30 is used for acquiring bolt pretightening force f0, applying pretightening force f0 to the bolt and analyzing the pretightening force of the bolt; the second applying module 40 is used for applying an equivalent external force to the bolt and performing statics simulation analysis to obtain the residual pretightening force f1 of the bolt; the first calculation module 50 is used for calculating the static friction force f2 between the bolt and the connected piece under the action of the residual pretightening force f1 according to the residual pretightening force f 1; the second calculating module 60 is used for calculating the maximum vibration force F of the connected piece under the condition of the maximum acceleration a; the evaluation module 70 is used to perform a failure evaluation of the bolt based on the static friction force F2 and the maximum vibratory force F.
According to one embodiment of the invention, the first calculation module 50 calculates the static friction force f2 between the bolt and the connected piece under the action of the residual pretightening force f1 according to the following formula (1):
f2=f1×μ (1);
f1 is residual pretightening force, f2 is static friction force between the bolt and the connected piece under the action of the residual pretightening force f1, and mu is a friction coefficient of a contact area between the bolt and the connected piece.
According to one embodiment of the present invention, the second calculation module 60 calculates the maximum vibration force F of the connected member under the condition of the maximum acceleration a according to the following formula (2):
wherein a is the maximum acceleration of the connected piece relative to the radial direction of the bolt, F is the maximum vibration force of the connected piece under the condition of the maximum acceleration a, M is the total mass of the connected piece, and n is the number of the bolts connected with the connected piece.
According to an embodiment of the invention, the evaluation module 70 is specifically configured to: comparing the maximum vibratory force F to a preset multiple β of the static friction force F2, wherein β is less than 1; if F is more than or equal to beta multiplied by F2, judging that the bolt is loosened; if F < β × F2 is present, the bolt is judged to be fastened.
Further, the value range of beta is 0.8-0.9.
According to the failure evaluation device of the bolt in the random vibration of the embodiment of the invention, the first acquisition module is used for carrying out random vibration mechanics simulation to acquire the maximum axial response displacement U at the bolt and the maximum acceleration a of the connected piece relative to the radial direction of the bolt, the second acquisition module is used for carrying out statics simulation to acquire the equivalent external force at the bolt meeting the maximum axial response displacement U, the first application module is used for acquiring the bolt F0, applying the pretightening force F0 to the bolt and carrying out bolt pretightening force analysis, the second application module is used for applying the equivalent external force to the bolt and carrying out statics simulation analysis to acquire the residual pretightening force F1 of the bolt, the first calculation module is used for calculating the static friction force F2 between the bolt and the connected piece under the action of the residual pretightening force F1 according to the residual pretightening force F1, and the second calculation module is used for calculating the maximum vibration force F of the connected piece under the condition of the maximum acceleration a, the evaluation module performs a failure evaluation of the bolt based on the static friction force F2 and the maximum vibratory force F. Therefore, the failure evaluation device considers the coupling effect of the pretightening force and the random vibration, carries out linear superposition analysis on the equivalent external force and the pretightening force of the bolt, can evaluate the residual pretightening force of the bolt in the vibration process, has high accuracy of an evaluation result, can research the random vibration process and rule of the bolt through a simulation means, and can well guide the improved design of a product.
In the present invention, any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing steps of a custom logic function or process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the embodiments of the present invention.
The logic and/or steps represented in the flowcharts or otherwise described herein, e.g., an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Further, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.
It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
It will be understood by those skilled in the art that all or part of the steps carried out in the method of implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and the program, when executed, includes one or a combination of the steps of the method embodiments.
In addition, functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.