A method and device for calculating the interface friction coefficient of an ultrasonic assisted plastic forming process

Abstract

The application discloses an ultrasonic-assisted plastic forming process interface friction coefficient calculation method and device. The method is based on ultrasonic vibration-assisted forward and reverse extrusion forming processes of a tool and a workpiece, and interface friction coefficients in the extrusion process are calculated through different extrusion mechanical models, so that quantitative description of ultrasonic antifriction effects of different ultrasonic vibration modes is realized. The method can accurately quantitatively describe the mechanism of the effect of ultrasonic vibration on the interface friction effect of the plastic forming process, and is favorable for revealing the ultrasonic vibration-assisted machining forming mechanism and further improving machining part precision and machining performance.

Description

A method and apparatus for calculating the interfacial friction coefficient in ultrasonic-assisted plastic forming process Technical Field

[0001] This invention belongs to the field of ultrasonic vibration-assisted processing technology, specifically relating to a method and apparatus for calculating the interface friction coefficient in ultrasonic-assisted plastic forming processes. Background Technology

[0002] With the widespread application of precision manufacturing technology, the requirements for the machining accuracy of parts are becoming increasingly stringent. However, friction during the manufacturing process leads to defects such as increased surface roughness, reduced formability, and uneven forming of the formed samples. To address these forming defects caused by friction, ultrasonic energy fields are used in auxiliary machining processes, namely ultrasonic vibration-assisted machining.

[0003] Ultrasonic vibration-assisted machining technology has advantages such as improved surface quality, reduced friction, and increased processing efficiency, and has been widely used in important fields such as aerospace, shipbuilding, and military. To further improve the forming accuracy and mechanical properties of ultrasonic vibration-assisted machining, the mechanism by which ultrasound affects the interfacial friction coefficient needs to be precisely quantified and described.

[0004] Currently, existing methods for quantitatively describing the influence mechanism of ultrasound on the interfacial friction coefficient mainly focus on the tool-sample relationship, with few methods specifically for calculating the friction coefficient between the mold cavity and the sample. Existing methods for calculating the friction coefficient between the mold cavity and the sample are primarily based on finite element simulation calibration curves. However, finite element simulations cannot reflect the acoustic softening effect, leading to inaccurate friction coefficients.

[0005] Therefore, proposing a method and apparatus for calculating the friction coefficient of the mold cavity-sample interface has become a key technical problem that urgently needs to be solved to improve the accuracy and performance of machined parts. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is to propose a method and device for calculating the interface friction coefficient in the ultrasonic-assisted plastic forming process.

[0007] According to one aspect of the present invention, a method for calculating the interfacial friction coefficient in an ultrasonic-assisted plastic forming process is provided, comprising the following steps:

[0008] S1: A diameter of r is fixedly installed on the ultrasonic vibration platform. f The tool head with a bore diameter of r f The upper mold plate, with a center diameter of r r The lower die plate of the tool head is pressed down by the testing machine to achieve positive extrusion forming of the workpiece, obtaining a displacement-extrusion force dataset {x}. fi ,p fi}, and measured the height H of the extrusion cup under different displacements.fi Thus, the cup height-compression pressure dataset {H} is obtained. fi ,p fi};

[0009] S2: Activate the upper ultrasonic vibration platform to achieve tool vibration, and use the testing machine to press down to achieve positive extrusion forming of the workpiece, obtaining the displacement-extrusion force dataset {x}. tfi ,p tfi}, and measured the height H of the extrusion cup under different displacements. tfi Thus, the cup height-compression pressure dataset {H} is obtained. tfi ,p tfi};

[0010] S3: Activate the ultrasonic vibration platform to vibrate the workpiece, and use the testing machine to press down to achieve positive extrusion forming of the workpiece, obtaining the displacement-extrusion force dataset {x}. wfi ,p wfi}, and measured the height H of the extrusion cup under different displacements. wfi Thus, the cup height-compression pressure dataset {H} is obtained. wfi ,p wfi};

[0011] S4: Fix and install a diameter of r on the ultrasonic vibration platform. r Tool head, hole diameter r f The upper die plate and the lower die plate with a flat surface are used to achieve reverse extrusion forming of the workpiece by pressing down with a testing machine, thereby obtaining a displacement-extrusion force dataset {x}. ri ,p ri}, and measured the height H of the extrusion cup under different displacements. ri Thus, the cup height-compression pressure dataset {H} is obtained. ri ,p ri};

[0012] S5: Activate the upper ultrasonic vibration platform to achieve tool vibration, and use the testing machine to press down to achieve reverse extrusion forming of the workpiece, obtaining the displacement-extrusion force dataset {x}. tri ,p tri}, and measured the height H of the extrusion cup under different displacements. tri Thus, the cup height-compression pressure dataset {H} is obtained. tri ,p tri};

[0013] S6: Activate the ultrasonic vibration platform to vibrate the workpiece, and use the testing machine to press down to achieve reverse extrusion forming of the workpiece, obtaining the displacement-extrusion force dataset {x}. wri ,p wri}, and measured the height H of the extrusion cup under different displacements. wri Thus, the cup height-compression pressure dataset {H} is obtained. wri ,p wri};

[0014] S7: Based on the reverse extrusion coordinate system, perform registration calculations between the cup height-extrusion pressure data points and the reverse extrusion data points during forward extrusion to obtain the selected cup height point (H). ri =H fi The difference in extrusion pressure (f) i =p fi -p ri This refers to the interfacial friction force when there is no ultrasonic vibration.

[0015] S8: According to the Mises yield criterion, the formula for calculating friction is: Therefore, the coefficient of friction is: Obtain the cup height-interfacial friction coefficient dataset {H} fi ,μ i};

[0016] S9: Based on the tool vibration-assisted reverse extrusion coordinate system, perform registration calculations between the cup height-extrusion pressure data points and the reverse extrusion data points during workpiece vibration-assisted forward extrusion to obtain the selected cup height point (H). tri =H wfi The difference in extrusion pressure (f) wi =p wfi -p tri This refers to the interfacial friction force during ultrasonic vibration of the workpiece, and the coefficient of friction is calculated. Obtain the cup height-interfacial friction coefficient dataset {H} wfi ,μ wi};

[0017] S10: Based on the workpiece vibration-assisted reverse extrusion coordinate system, perform registration calculations between the cup height-extrusion pressure data points and the reverse extrusion data points during tool vibration-assisted forward extrusion to obtain the selected cup height point (H). wri =H tfi The difference in extrusion pressure (f) ti =p tfi -p wri This refers to the interfacial friction force during ultrasonic vibration of the tool, and the coefficient of friction is calculated. Obtain the cup height-interfacial friction coefficient dataset {H} tfi ,μ ti}

[0018] Furthermore, it also includes:

[0019] S11: Based on the selected cup height (H) fi =H wfi =H tfi ), calculate the reduction in friction coefficient (Δμ) under tool vibration. ti =μ ti -μ i ), to obtain the tool vibrating cup high-friction reduction dataset {Hwfi ,Δμ ti} Calculate the reduction in friction coefficient (Δμ) under workpiece vibration. wi =μ wi -μ i ), to obtain the workpiece vibration cup height-friction reduction dataset {H tfi ,Δμ wi}

[0020] Furthermore, the specific steps for obtaining the cup height-compression pressure dataset in steps S1-S6 include:

[0021] A1: Select different downward displacement amounts for forward and reverse extrusion forming, measure the cup height of the formed workpiece at the selected displacement amount, and obtain the displacement-cup height dataset {x}. i H i The displacement-cup height curve is obtained through linear fitting, and the displacement-cup height relationship function H is established. tfi =f(x) wri}, and substitute them into the displacement-compression force dataset to obtain the cup height-compression force dataset {H}. ri ,p ri};

[0022] A2: Using the same method as A1, obtain the cup height-extrusion force dataset {H} for both tool vibration and workpiece vibration-assisted forward and reverse extrusion processes. ri ,p ri}

[0023] Furthermore, the specific steps for registration calculation in step S7 include:

[0024] S7.1: In the absence of ultrasonic vibration, based on the high-compression force dataset {H} of the anti-compression cup ri ,p ri} Select the extrusion pressure corresponding to the cup height during the forward extrusion process; and calculate the difference in extrusion pressure between the forward and reverse extrusion, which is the friction force f under conditions without ultrasonication. i ,

[0025] S7.2: During ultrasonic vibration-assisted extrusion, based on the tool vibration-assisted reverse extrusion cup height-extrusion force dataset, select the extrusion force corresponding to the cup height during the workpiece vibration-assisted forward extrusion process, and calculate the extrusion force difference between forward and reverse extrusion, which is the friction force f under workpiece vibration conditions. wi Based on the workpiece vibration-assisted reverse extrusion cup height-extrusion pressure dataset, the extrusion pressure corresponding to the cup height is selected during the tool vibration-assisted forward extrusion process, and the difference in extrusion pressure between forward and reverse extrusion is calculated, which is the friction force f under tool vibration conditions. ti .

[0026] Preferably, in step S1, a bolt with a diameter of r is installed on the ultrasonic vibration platform. fThe tool head with a bore diameter of r f The upper mold plate, with a center diameter of r r The lower mold plate of the tool head.

[0027] Preferably, in step S4, a bolt with a diameter of r is installed on the ultrasonic vibration platform. r Tool head, hole diameter r f The upper mold plate has a flat surface, and the lower mold plate has a flat surface.

[0028] According to another aspect of the present invention, the present invention also provides a device for calculating the interface friction coefficient in an ultrasonic-assisted plastic forming process, comprising the following modules:

[0029] Module for acquiring high-pressure data set of conventional positive extrusion cup: used for fixing and installing a diameter r on an ultrasonic vibration platform. f The tool head with a bore diameter of r f The upper mold plate, with a center diameter of r r The lower die plate of the tool head is pressed down by the testing machine to achieve positive extrusion forming of the workpiece, obtaining a displacement-extrusion force dataset {x}. fi ,p fi}, and measured the height H of the extrusion cup under different displacements. fi Thus, the cup height-compression pressure dataset {H} is obtained. fi ,p fi};

[0030] Tool vibration-assisted positive extrusion cup height-extrusion pressure dataset acquisition module: Used to activate the upper ultrasonic vibration platform to achieve tool vibration, and to achieve positive extrusion forming of the workpiece by pressing down with the testing machine, thereby obtaining the displacement-extrusion pressure dataset {x tfi ,p tfi}, and measured the height H of the extrusion cup under different displacements. tfi Thus, the cup height-compression pressure dataset {H} is obtained. tfi ,p tfi};

[0031] Workpiece vibration-assisted positive extrusion cup height-extrusion pressure dataset acquisition module: Used to activate the ultrasonic vibration platform to achieve workpiece vibration, and to achieve positive extrusion forming of the workpiece by pressing down with the testing machine, thereby obtaining the displacement-extrusion pressure dataset {x wfi ,p wfi}, and measured the height H of the extrusion cup under different displacements. wfi Thus, the cup height-compression pressure dataset {H} is obtained. wfi ,p wfi};

[0032] Conventional anti-extrusion cup high-extrusion force dataset acquisition module: used for fixing and installing a diameter r on an ultrasonic vibration platform. r Tool head, hole diameter r fThe upper die plate and the lower die plate with a flat surface are used to achieve reverse extrusion forming of the workpiece by pressing down with a testing machine, thereby obtaining a displacement-extrusion force dataset {x}. ri ,p ri}, and measured the height H of the extrusion cup under different displacements. ri Thus, the cup height-compression pressure dataset {H} is obtained. ri ,p ri};

[0033] Tool vibration-assisted reverse extrusion cup high-extrusion pressure dataset acquisition module: Used to activate the upper ultrasonic vibration platform to achieve tool vibration, and to achieve reverse extrusion forming of the workpiece by pressing down with the testing machine, thereby obtaining the displacement-extrusion pressure dataset {x tri ,p tri}, and measured the height H of the extrusion cup under different displacements. tri Thus, the cup height-compression pressure dataset {H} is obtained. tri ,p tri};

[0034] Workpiece vibration-assisted reverse extrusion cup high-extrusion pressure dataset acquisition module: Used to activate the ultrasonic vibration platform to achieve workpiece vibration, and to achieve reverse extrusion forming of the workpiece by pressing down with a testing machine, thereby obtaining the displacement-extrusion pressure dataset {x wri ,p wri}, and measured the height H of the extrusion cup under different displacements. wri Thus, the cup height-compression pressure dataset {H} is obtained. wri ,p wri};

[0035] Registration Calculation Module: Used to perform registration calculations between cup height-extrusion pressure data points and reverse extrusion data points during forward extrusion, based on the reverse extrusion coordinate system, to obtain the selected cup height point (H). ri =H fi The difference in extrusion pressure (f) i =p fi -p ri This refers to the frictional force without ultrasonic vibration.

[0036] The cup height-interface friction coefficient dataset calculation module is used to calculate the friction force according to the Mises yield criterion. Therefore, the coefficient of friction is: Obtain the cup height-interfacial friction coefficient dataset {H} fi ,μ i};

[0037] Tool vibration-assisted extrusion cup height-interfacial friction coefficient dataset calculation module: This module calculates the registration of cup height-extrusion pressure data points with reverse extrusion data points during workpiece vibration-assisted forward extrusion based on the tool vibration-assisted reverse extrusion coordinate system, obtaining the selected cup height point (H). tri =Hwfi The difference in extrusion pressure (f) wi =p wfi -p tri This refers to the interfacial friction force during ultrasonic vibration of the workpiece, and the coefficient of friction is calculated. Obtain the cup height-interfacial friction coefficient dataset {H} wfi ,μ wi};

[0038] Workpiece vibration-assisted extrusion cup height-interfacial friction coefficient dataset calculation module: Based on the workpiece vibration-assisted reverse extrusion coordinate system, this module performs registration calculations between cup height-extrusion pressure data points and reverse extrusion data points during tool vibration-assisted forward extrusion to obtain the selected cup height point (H). wri =H tfi The difference in extrusion pressure (f) ti =p tfi -p wri This refers to the interfacial friction force during ultrasonic vibration of the tool, and the coefficient of friction is calculated. Obtain the cup height-interfacial friction coefficient dataset {H} tfi ,μ ti}

[0039] Furthermore, it also includes:

[0040] Tool / workpiece vibration friction reduction effect quantification module: used for quantification based on selected cup height (H) fi =H wfi =H tfi ), calculate the reduction in friction coefficient (Δμ) under tool vibration. ti =μ ti -μ i ), to obtain the tool vibrating cup high-friction reduction dataset {H wfi ,Δμ ti} Calculate the reduction in friction coefficient (Δμ) under workpiece vibration. wi =μ wi -μ i ), to obtain the workpiece vibration cup height-friction reduction dataset {H tfi ,Δμ wi}

[0041] The beneficial effects of the technical solution provided by this invention are as follows:

[0042] This invention relates to ultrasonic vibration-assisted forward and reverse extrusion forming processes for tools and workpieces. By calculating the interfacial friction coefficient during the extrusion process using different extrusion mechanics models, it achieves a quantitative description of the ultrasonic friction-reducing effect of different ultrasonic vibration modes. This method, by accurately quantifying the mechanism of ultrasonic vibration on the interfacial friction effect in the plastic forming process, is beneficial for revealing the mechanism of ultrasonic vibration-assisted machining and forming, and further improving the accuracy and performance of machined parts. Attached Figure Description

[0043] Figure 1 is a flowchart of a method for calculating the interface friction coefficient in an ultrasonic-assisted plastic forming process according to an embodiment of the present invention;

[0044] Figure 2 is a schematic diagram of ultrasonic vibration-assisted positive extrusion of the tool and workpiece;

[0045] Figure 3 is a schematic diagram of ultrasonic vibration-assisted reverse extrusion of the tool and workpiece;

[0046] Figure 4 is a schematic diagram of a device for calculating the interface friction coefficient in an ultrasonic-assisted plastic forming process according to an embodiment of the present invention.

[0047] In Figures 2 and 3: 1-upper die plate for forward extrusion, 2-tool head for forward extrusion, 3-tool vibration, 4-extrusion pressure during forward extrusion, 5-workpiece for forward extrusion, 6-interfacial friction, 7-lower die plate for forward extrusion, 8-workpiece vibration, 9-reaction force of forward extrusion, 10-upper die plate for reverse extrusion, 11-tool head for reverse extrusion, 12-extrusion pressure during reverse extrusion, 13-workpiece for reverse extrusion, 14-lower die plate for reverse extrusion, 15-reaction force of reverse extrusion. Detailed Implementation

[0048] The realization of the objectives, functional characteristics, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0049] Referring to Figure 1, this embodiment of the invention provides a method for calculating the interface friction coefficient in an ultrasonic-assisted plastic forming process, which mainly includes the following steps:

[0050] S1: As shown in Figure 2, a bolt with diameter r is installed on the ultrasonic vibration platform. f Tool head 2, hole diameter is r f The upper mold plate 1 has a center with a diameter of r. r The lower die plate 7 of the tool head is pressed down by the testing machine to achieve positive extrusion forming of the workpiece 5, obtaining the displacement-extrusion force dataset {x}. fi ,p fi}, and measured the height H of the extrusion cup under different displacements. fi Thus, the cup height-compression pressure dataset {H} is obtained. fi ,p fi};

[0051] S2: As shown in Figure 2, the upper ultrasonic vibration platform is activated to achieve tool vibration 3. The workpiece 5 is formed by positive extrusion by pressing down through the testing machine, and the displacement-extrusion force dataset {x} is obtained. tfi ,p tfi}, and measured the height H of the extrusion cup under different displacements. tfiThus, the cup height-compression pressure dataset {H} is obtained. tfi ,p tfi};

[0052] S3: As shown in Figure 2, the lower ultrasonic vibration platform is activated to achieve workpiece vibration 8. The workpiece 5 is then extruded and formed by pressing down with the testing machine, obtaining the displacement-extrusion force dataset {x}. wfi ,p wfi}, and measured the height H of the extrusion cup under different displacements. wfi Thus, the cup height-compression pressure dataset {H} is obtained. wfi ,p wfi};

[0053] S4: As shown in Figure 3, a bolt with diameter r is installed on the ultrasonic vibration platform. r Tool head 11, hole diameter r f The upper die plate 10 and the lower die plate 14, which have flat surfaces, are used to reverse-extrude the workpiece 13 by pressing it down with a testing machine, thereby obtaining a displacement-extrusion force dataset {x}. ri ,p ri}, and measured the height H of the extrusion cup under different displacements. ri Thus, the cup height-compression pressure dataset {H} is obtained. ri ,p ri};

[0054] S5: As shown in Figure 3, the upper ultrasonic vibration platform is turned on to realize tool vibration 3. The workpiece 13 is reverse extruded and formed by pressing down through the testing machine, and the displacement-extrusion force dataset {x} is obtained. tri ,p tri}, and measured the height H of the extrusion cup under different displacements. tri Thus, the cup height-compression pressure dataset {H} is obtained. tri ,p tri};

[0055] S6: As shown in Figure 3, the lower ultrasonic vibration platform is activated to achieve workpiece vibration 8. The workpiece 13 is then reverse-extruded and formed by pressing down with the testing machine, obtaining the displacement-extruded force dataset {x}. wri ,p wri}, and measured the height H of the extrusion cup under different displacements. wri Thus, the cup height-compression pressure dataset {H} is obtained. wri ,p wei};

[0056] S7: As shown in Figures 2 and 3, based on the reverse extrusion coordinate system, the registration calculation of the cup height-extrusion pressure data points and the reverse extrusion data points is performed to obtain the selected cup height point (H). ri =H fi The difference in extrusion pressure (f) i =p fi -pri ), which is the interfacial friction force when there is no ultrasonic vibration.

[0057] S8: According to the Mises yield criterion, the formula for calculating friction is: Therefore, the coefficient of friction is: Obtain the cup height-interfacial friction coefficient dataset {H} fi ,μ i}

[0058] S9: As shown in Figures 2 and 3, based on the tool vibration 3-assisted reverse extrusion coordinate system, the registration calculation of the cup height-extrusion pressure data points and the reverse extrusion data points in the workpiece vibration-assisted forward extrusion is performed to obtain the selected cup height point (H). tri =H wfi The difference in extrusion pressure (f) wi =p wfi -p tri ), that is, the interfacial friction force 6 during ultrasonic vibration of the workpiece, and calculate the coefficient of friction. Obtain the cup height-interfacial friction coefficient dataset {H} wfi ,μ wi}

[0059] S10: As shown in Figures 2 and 3, based on the workpiece vibration-assisted reverse extrusion coordinate system, the registration calculation of the cup height-extrusion pressure data points and the reverse extrusion data points in the tool vibration-assisted forward extrusion is performed to obtain the selected cup height point (H). wri =H tfi The difference in extrusion pressure (f) ti =p tfi -p wri ), that is, the interfacial friction force 6 during ultrasonic vibration of the tool, and calculate the coefficient of friction. Obtain the cup height-interfacial friction coefficient dataset {H} tfi ,μ ti}

[0060] S11: As shown in Figures 2 and 3, based on the selected cup height (H) fi =H wfi =H tfi ), calculate the reduction in friction coefficient (Δμ) under tool vibration. ti =μ ti -μ i ), to obtain the tool vibrating cup high-friction reduction dataset {H wfi ,Δμ ti}. Calculate the reduction in friction coefficient (Δμ) under workpiece vibration. wi =μ wi -μ i ), to obtain the workpiece vibration cup height-friction reduction dataset {H tfi ,Δμ wi}

[0061] Based on, but not limited to, the specific steps for obtaining the cup height-compression pressure dataset in steps S1-S6 include:

[0062] A1: Select different downward displacement amounts for forward and reverse extrusion forming, measure the cup height of the formed workpiece with the selected displacement amount, obtain the displacement-cup height dataset, obtain the displacement-cup height curve through linear fitting, establish the displacement-cup height relationship function, and substitute it into the displacement-extrusion pressure dataset to obtain the cup height-extrusion pressure dataset.

[0063] A2: Using the same method as A1, obtain the cup height-extrusion force datasets for the tool vibration and workpiece vibration-assisted forward and reverse extrusion processes, respectively.

[0064] Based on, but not limited to, the specific steps for registration calculation in step S7 include:

[0065] S7.1: In the absence of ultrasonic vibration, based on the reverse extrusion cup height-extrusion pressure dataset, select the extrusion pressure corresponding to the cup height during the forward extrusion process; and calculate the difference in extrusion pressure between the forward and reverse extrusion, which is the frictional force under conditions without ultrasonic vibration.

[0066] S7.2: During ultrasonic vibration-assisted extrusion, based on the tool vibration-assisted reverse extrusion cup height-extrusion force dataset, select the extrusion force corresponding to the cup height during the workpiece vibration-assisted forward extrusion process, and calculate the extrusion force difference between forward and reverse extrusion, which is the friction force under workpiece vibration conditions; based on the workpiece vibration-assisted reverse extrusion cup height-extrusion force dataset, select the extrusion force corresponding to the cup height during the tool vibration-assisted forward extrusion process, and calculate the extrusion force difference between forward and reverse extrusion, which is the friction force under tool vibration conditions.

[0067] Based on the above method, the specific calculation formulas in steps S1-S11 are as follows:

[0068] Formula for calculating friction coefficient:

[0069]

[0070] Dataset of cup height-friction coefficient during conventional extrusion:

[0071]

[0072] Dataset of cup height-friction coefficient during tool vibration-assisted extrusion:

[0073]

[0074] Dataset of cup height-friction coefficient during workpiece vibration-assisted extrusion:

[0075]

[0076] Quantitative model of ultrasonic friction reduction effect under tool vibration: (Δμ) wi =μ wi -μ i Dataset:

[0077] {H wfi ,Δμ wi}={H wfi ,μ wi}-{H fi ,μ i} (2)

[0078] Quantitative model of ultrasonic friction reduction effect under workpiece vibration: (Δμ) ti =μ ti -μ i Dataset:

[0079] {H tfi ,Δμ ti}={H tfi ,μ ti}-{H fi ,μ i}

[0080] The following describes a device for calculating the interface friction coefficient in an ultrasonic-assisted plastic forming process provided by the present invention. The device for calculating the interface friction coefficient in an ultrasonic-assisted plastic forming process described below can be referred to in correspondence with the method for calculating the interface friction coefficient in an ultrasonic-assisted plastic forming process described above.

[0081] Please refer to Figure 4. An embodiment of the present invention provides a device for calculating the interface friction coefficient in an ultrasonic-assisted plastic forming process, comprising the following modules:

[0082] Module for acquiring high-pressure data set of conventional positive extrusion cup: used for fixing and installing a diameter r on an ultrasonic vibration platform. f The tool head with a bore diameter of r f The upper mold plate, with a center diameter of r r The lower die plate of the tool head is pressed down by the testing machine to achieve positive extrusion forming of the workpiece, obtaining a displacement-extrusion force dataset {x}. fi ,p fi}, and measured the height H of the extrusion cup under different displacements. fi Thus, the cup height-compression pressure dataset {H} is obtained. fi ,p fi};

[0083] Tool vibration-assisted positive extrusion cup height-extrusion pressure dataset acquisition module: Used to activate the upper ultrasonic vibration platform to achieve tool vibration, and to achieve positive extrusion forming of the workpiece by pressing down with the testing machine, thereby obtaining the displacement-extrusion pressure dataset {x tfi ,P tfi}, and measured the height H of the extrusion cup under different displacements. tfi Thus, the cup height-compression pressure dataset {H} is obtained. tfi P tfi};

[0084] Workpiece vibration-assisted positive extrusion cup height-extrusion pressure dataset acquisition module: Used to activate the ultrasonic vibration platform to achieve workpiece vibration, and to achieve positive extrusion forming of the workpiece by pressing down with the testing machine, thereby obtaining the displacement-extrusion pressure dataset {x wfi ,p wfi}, and measured the height H of the extrusion cup under different displacements. wfi Thus, the cup height-compression pressure dataset {H} is obtained. wfi ,p wfi};

[0085] Conventional anti-extrusion cup high-extrusion force dataset acquisition module: used for fixing and installing a diameter r on an ultrasonic vibration platform. r Tool head, hole diameter r f The upper die plate and the lower die plate with a flat surface are used to achieve reverse extrusion forming of the workpiece by pressing down with a testing machine, thereby obtaining a displacement-extrusion force dataset {x}. ri ,p ri}, and measured the height H of the extrusion cup under different displacements. ri Thus, the cup height-compression pressure dataset {H} is obtained. ri ,p ri};

[0086] Tool vibration-assisted reverse extrusion cup high-extrusion pressure dataset acquisition module: Used to activate the upper ultrasonic vibration platform to achieve tool vibration, and to achieve reverse extrusion forming of the workpiece by pressing down with the testing machine, thereby obtaining the displacement-extrusion pressure dataset {x tri ,p tri}, and measured the height H of the extrusion cup under different displacements. tri Thus, the cup height-compression pressure dataset {H} is obtained. tri ,p tri};

[0087] Workpiece vibration-assisted reverse extrusion cup high-extrusion pressure dataset acquisition module: Used to activate the ultrasonic vibration platform to achieve workpiece vibration, and to achieve reverse extrusion forming of the workpiece by pressing down with a testing machine, thereby obtaining the displacement-extrusion pressure dataset {x wri ,p wri}, and measured the height H of the extrusion cup under different displacements. wri Thus, the cup height-compression pressure dataset {H} is obtained.wri ,p wri};

[0088] Registration Calculation Module: Used to perform registration calculations between cup height-extrusion pressure data points and reverse extrusion data points during forward extrusion, based on the reverse extrusion coordinate system, to obtain the selected cup height point (H). ri =H fi The difference in extrusion pressure (f) i =p fi -p ri This refers to the frictional force without ultrasonic vibration.

[0089] The cup height-interface friction coefficient dataset calculation module is used to calculate the friction force according to the Mises yield criterion. Therefore, the coefficient of friction is: Obtain the cup height-interfacial friction coefficient dataset {H} fi ,μ i};

[0090] Tool vibration-assisted extrusion cup height-interfacial friction coefficient dataset calculation module: This module calculates the registration of cup height-extrusion pressure data points with reverse extrusion data points during workpiece vibration-assisted forward extrusion based on the tool vibration-assisted reverse extrusion coordinate system, obtaining the selected cup height point (H). tri =H wfi The difference in extrusion pressure (f) wi =p wfi -p tri This refers to the interfacial friction force during ultrasonic vibration of the workpiece, and the coefficient of friction is calculated. Obtain the cup height-interfacial friction coefficient dataset {H} wfi ,μ wi};

[0091] Workpiece vibration-assisted extrusion cup height-interfacial friction coefficient dataset calculation module: Based on the workpiece vibration-assisted reverse extrusion coordinate system, this module performs registration calculations between cup height-extrusion pressure data points and reverse extrusion data points during tool vibration-assisted forward extrusion to obtain the selected cup height point (H). wri =H tfi The difference in extrusion pressure (f) ti =p tfi -p wri This refers to the interfacial friction force during ultrasonic vibration of the tool, and the coefficient of friction is calculated. Obtain the cup height-interfacial friction coefficient dataset {H} tfi ,μ ti};

[0092] Tool / workpiece vibration friction reduction effect quantification module: used for quantification based on selected cup height (H) fi =H wfi =H rfi), calculate the reduction in friction coefficient (Δμ) under tool vibration. ti =μ ti -μ i ), to obtain the tool vibrating cup high-friction reduction dataset {H wfi ,Δμ ti} Calculate the reduction in friction coefficient (Δμ) under workpiece vibration. wi =μ wi -μ i ), to obtain the workpiece vibration cup height-friction reduction dataset {H tfi ,Δμ wi}

[0093] Based on, but not limited to, the cup high-compression pressure dataset acquisition module is specifically used for:

[0094] Different downward displacements are selected for forward and reverse extrusion forming. The cup height of the formed workpiece with the selected displacement is measured to obtain the displacement-cup height dataset. The displacement-cup height curve is obtained by linear fitting. The displacement-cup height relationship function is established and substituted into the displacement-extrusion force dataset to obtain the cup height-extrusion force dataset.

[0095] The cup height-extrusion force datasets for the tool vibration and workpiece vibration-assisted forward and reverse extrusion processes were obtained using the same method described above.

[0096] Based on, but not limited to, the above-mentioned device, the registration calculation module is specifically used for:

[0097] Without ultrasonic vibration, based on the reverse extrusion cup height-extrusion pressure dataset, the extrusion pressure corresponding to the cup height during the forward extrusion process is selected; and the difference in extrusion pressure between the forward and reverse extrusion processes is calculated, which represents the frictional force under conditions without ultrasonic vibration.

[0098] During ultrasonic vibration-assisted extrusion, based on the tool vibration-assisted reverse extrusion cup height-extrusion force dataset, the extrusion force corresponding to the cup height is selected during the workpiece vibration-assisted forward extrusion process, and the difference in extrusion force between forward and reverse extrusion is calculated, which is the friction force under workpiece vibration conditions; based on the workpiece vibration-assisted reverse extrusion cup height-extrusion force dataset, the extrusion force corresponding to the cup height is selected during the tool vibration-assisted forward extrusion process, and the difference in extrusion force between forward and reverse extrusion is calculated, which is the friction force under tool vibration conditions.

[0099] Preferably, the tool head, upper mold plate, and lower mold plate are all fixed to the ultrasonic vibration platform by bolts.

[0100] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0101] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. In the unit claims listing several devices, several of these devices may be embodied by the same hardware item. The use of the terms first, second, and third, etc., does not indicate any order and can be interpreted as identifiers.

[0102] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for calculating the interfacial friction coefficient in an ultrasonic-assisted plastic forming process, characterized in that, Includes the following steps: S1: A diameter of r is fixedly installed on the ultrasonic vibration platform. f The tool head with a bore diameter of r f The upper mold plate, with a center diameter of r r The lower die plate of the tool head is pressed down by the testing machine to achieve positive extrusion forming of the workpiece, obtaining a displacement-extrusion force dataset {x}. fi p fi }, and measured the height H of the extrusion cup under different displacements. fi Thus, the cup height-compression pressure dataset {H} is obtained. fi p fi S2: Activate the upper ultrasonic vibration platform to achieve tool vibration, and use the testing machine to press down to achieve positive extrusion forming of the workpiece, obtaining the displacement-extrusion force dataset {x}. tfi p tfi }, and measured the height H of the extrusion cup under different displacements. tfi Thus, the cup height-compression pressure dataset {H} is obtained. tfi p tfi S3: Activate the ultrasonic vibration platform to vibrate the workpiece, and use the testing machine to press down to achieve positive extrusion forming of the workpiece, obtaining the displacement-extrusion force dataset {x}. wfi p wfi }, and measured the height H of the extrusion cup under different displacements. wfi Thus, the cup height-compression pressure dataset {H} is obtained. wfi ,p wfi S4: Fix and install a diameter of r on the ultrasonic vibration platform. r Tool head, hole diameter r f The upper die plate and the lower die plate with a flat surface are used to achieve reverse extrusion forming of the workpiece by pressing down with a testing machine, thereby obtaining a displacement-extrusion force dataset {x}. ri p ri }, and measured the height H of the extrusion cup under different displacements. ri Thus, the cup height-compression pressure dataset {H} is obtained. ri p ri S5: Activate the upper ultrasonic vibration platform to achieve tool vibration, and use the testing machine to press down to achieve reverse extrusion forming of the workpiece, obtaining the displacement-extrusion force dataset {x}. tri p tri }, and measured the height H of the extrusion cup under different displacements. tri Thus, the cup height-compression pressure dataset {H} is obtained. tri p tri S6: Activate the ultrasonic vibration platform to vibrate the workpiece, and use the testing machine to press down to achieve reverse extrusion forming of the workpiece, obtaining the displacement-extrusion force dataset {x}. wri p wri }, and measured the height H of the extrusion cup under different displacements. wri Thus, the cup height-compression pressure dataset {H} is obtained. wri p wri }; S7: Based on the reverse extrusion coordinate system, perform registration calculations between the cup height-extrusion pressure data points and the reverse extrusion data points during forward extrusion to obtain the selected cup height point (H). ri =H fi The difference in extrusion pressure (f) i =p fi -p ri This refers to the interfacial friction force when there is no ultrasonic vibration. S8: According to the Mises yield criterion, the formula for calculating friction is: Therefore, the coefficient of friction is: Obtain the cup height-interfacial friction coefficient dataset {H} fi ,μ i }; S9: Based on the tool vibration-assisted reverse extrusion coordinate system, perform registration calculations between the cup height-extrusion pressure data points and the reverse extrusion data points during workpiece vibration-assisted forward extrusion to obtain the selected cup height point (H). tri =H wfi The difference in extrusion pressure (f) wi =p wfi -p tri This refers to the interfacial friction force during ultrasonic vibration of the workpiece, and the coefficient of friction is calculated. Obtain the cup height-interfacial friction coefficient dataset {H} wfi μ wi S10: Based on the workpiece vibration-assisted reverse extrusion coordinate system, perform registration calculations between the cup height-extrusion pressure data points and the reverse extrusion data points during tool vibration-assisted forward extrusion to obtain the selected cup height point (H). wri =H tfi The difference in extrusion pressure (f) ti =p tfi -p wri This refers to the interfacial friction force during ultrasonic vibration of the tool, and the coefficient of friction is calculated. Obtain the cup height-interfacial friction coefficient dataset {H} tfi μ ti } 2. The method for calculating the interfacial friction coefficient in ultrasonic-assisted plastic forming process according to claim 1, characterized in that, Also includes: S11: Based on the selected cup height (H) fi =H wfi =H tfi ), calculate the reduction in friction coefficient (Δμ) under tool vibration. ti =μ ti -μ i ), to obtain the tool vibrating cup high-friction reduction dataset {H wfi , Δμ ti } Calculate the reduction in friction coefficient (Δμ) under workpiece vibration. wi =μ wi -μ i ), to obtain the workpiece vibration cup height-friction reduction dataset {H tfi , Δμ wi } 3. The method for calculating the interfacial friction coefficient in ultrasonic-assisted plastic forming process according to claim 1, characterized in that, The specific steps for obtaining the cup height-extrusion pressure dataset in steps S1-S6 include: A1: Selecting different downward displacement amounts for forward and reverse extrusion forming, measuring the cup height of the formed workpiece with the selected displacement amount, and obtaining the displacement-cup height dataset {x i H i The displacement-cup height curve is obtained through linear fitting, and the displacement-cup height relationship function H is established. tfi =f(x) wri ), and substitute them into the displacement-compression force dataset to obtain the cup height-compression force dataset {H ri p ri };A2: Using the same method as A1, obtain the cup height-extrusion force dataset {H} for both tool vibration and workpiece vibration-assisted forward and reverse extrusion processes. ri p ri } 4. The method for calculating the interfacial friction coefficient in ultrasonic-assisted plastic forming process according to claim 1, characterized in that, The specific steps for registration calculation in step S7 include: S7.1: In the absence of ultrasonic vibration, based on the anti-extrusion cup high-extrusion force dataset {H ri p ri } Select the extrusion pressure corresponding to the cup height during the forward extrusion process; and calculate the difference in extrusion pressure between the forward and reverse extrusion, which is the friction force f under conditions without ultrasonication. i S7.2: During ultrasonic vibration-assisted extrusion, based on the tool vibration-assisted reverse extrusion cup height-extrusion force dataset, select the extrusion force corresponding to the cup height during the workpiece vibration-assisted forward extrusion process, and calculate the extrusion force difference between forward and reverse extrusion, which is the friction force f under workpiece vibration conditions. wi Based on the workpiece vibration-assisted reverse extrusion cup height-extrusion pressure dataset, the extrusion pressure corresponding to the cup height is selected during the tool vibration-assisted forward extrusion process, and the difference in extrusion pressure between forward and reverse extrusion is calculated, which is the friction force f under tool vibration conditions. ti .

5. The method for calculating the interfacial friction coefficient in ultrasonic-assisted plastic forming process according to claim 1, characterized in that, In step S1, a bolt with a diameter of r is installed on the ultrasonic vibration platform. f The tool head with a bore diameter of r f The upper mold plate, with a center diameter of r r The lower mold plate of the tool head.

6. The method for calculating the interfacial friction coefficient in an ultrasonic-assisted plastic forming process according to claim 1, characterized in that, In step S4, a bolt with a diameter of r is installed on the ultrasonic vibration platform. r Tool head, hole diameter r f The upper mold plate has a flat surface, and the lower mold plate has a flat surface.

7. A device for calculating the interfacial friction coefficient in an ultrasonic-assisted plastic forming process, characterized in that, Includes the following modules: A module for acquiring a standard positive extrusion cup high-extrusion pressure dataset, used for fixing and installing a diameter r on an ultrasonic vibration platform. f The tool head with a bore diameter of r f The upper mold plate, with a center diameter of r r The lower die plate of the tool head is pressed down by the testing machine to achieve positive extrusion forming of the workpiece, obtaining a displacement-extrusion force dataset {x}. fi p fi }, and measured the height H of the extrusion cup under different displacements. fi Thus, the cup height-compression pressure dataset {H} is obtained. fi p fi }; Tool vibration-assisted positive extrusion cup high-extrusion pressure dataset acquisition module: used to activate the upper ultrasonic vibration platform to realize tool vibration, and to achieve positive extrusion forming of the workpiece by pressing down with the testing machine, thereby obtaining the displacement-extrusion pressure dataset {x tfi p tfi }, and measured the height H of the extrusion cup under different displacements. tfi Thus, the cup height-compression pressure dataset {H} is obtained. tfi p tfi }; Workpiece vibration-assisted positive extrusion cup high-extrusion pressure dataset acquisition module: used to activate the ultrasonic vibration platform to achieve workpiece vibration, and to achieve positive extrusion forming of the workpiece by pressing down with the testing machine, thereby obtaining the displacement-extrusion pressure dataset {x wfi ,p wfi }, and measured the height H of the extrusion cup under different displacements. wfi Thus, the cup height-compression pressure dataset {H} is obtained. wfi p wfi }; Conventional anti-extrusion cup high-extrusion force dataset acquisition module: used for fixing and installing a diameter r on an ultrasonic vibration platform. r Tool head, hole diameter r f The upper die plate and the lower die plate with a flat surface are used to achieve reverse extrusion forming of the workpiece by pressing down with a testing machine, thereby obtaining a displacement-extrusion force dataset {x}. ri p ri }, and measured the height H of the extrusion cup under different displacements. ri Thus, the cup height-compression pressure dataset {H} is obtained. ri p ri }; Tool vibration-assisted reverse extrusion cup high-extrusion pressure dataset acquisition module: used to activate the upper ultrasonic vibration platform to realize tool vibration, and to achieve reverse extrusion forming of the workpiece by pressing down with the testing machine, thereby obtaining the displacement-extrusion pressure dataset {x tri p tri }, and measured the height H of the extrusion cup under different displacements. tri Thus, the cup height-compression pressure dataset {H} is obtained. tri p tri}; Workpiece vibration-assisted reverse extrusion cup high-extrusion pressure dataset acquisition module: used to activate the ultrasonic vibration platform to achieve workpiece vibration, and to achieve reverse extrusion forming of the workpiece by pressing down with the testing machine, thereby obtaining the displacement-extrusion pressure dataset {x wri p wri }, and measured the height H of the extrusion cup under different displacements. wri Thus, the cup height-compression pressure dataset {H} is obtained. wri p wri }; Registration Calculation Module: Used to perform registration calculations between cup height-extrusion pressure data points and reverse extrusion data points during forward extrusion, based on the reverse extrusion coordinate system, to obtain the selected cup height point (H); ri =H fi The difference in extrusion pressure (f) i =p fi -p ri This refers to the frictional force without ultrasonic vibration; the cup height-interface friction coefficient dataset calculation module is used to calculate the frictional force according to the Mises yield criterion. The formula for calculating the frictional force is: Therefore, the coefficient of friction is: Obtain the cup height-interfacial friction coefficient dataset {H} fi μ i }; Tool vibration-assisted extrusion cup height-interfacial friction coefficient dataset calculation module: used to perform registration calculation of cup height-extrusion pressure data points and reverse extrusion data points in workpiece vibration-assisted forward extrusion based on the tool vibration-assisted reverse extrusion coordinate system, to obtain the selected cup height point (H tri =H wfi The difference in extrusion pressure (f) wi =p wfi -p tri This refers to the interfacial friction force during ultrasonic vibration of the workpiece, and the coefficient of friction is calculated. Obtain the cup height-interfacial friction coefficient dataset {H} wfi ,μ wi }; Workpiece vibration-assisted extrusion cup height-interfacial friction coefficient dataset calculation module: used to perform registration calculations between cup height-extrusion pressure data points and reverse extrusion data points in tool vibration-assisted forward extrusion based on the workpiece vibration-assisted reverse extrusion coordinate system, to obtain the selected cup height point (H wri =H tfi The difference in extrusion pressure (f) ti =p tfi -p wri This refers to the interfacial friction force during ultrasonic vibration of the tool, and the coefficient of friction is calculated. Obtain the cup height-interfacial friction coefficient dataset {H} tfi μ ti } 8. The device for calculating the interface friction coefficient in ultrasonic-assisted plastic forming process according to claim 7, characterized in that, Also includes: Tool / workpiece vibration friction reduction effect quantification module: used for quantification based on selected cup height (H) fi =H wfi =H tfi ), calculate the reduction in friction coefficient (Δμ) under tool vibration. ti =μ ti -μ i ), to obtain the tool vibrating cup high-friction reduction dataset {H wfi , Δμ ti } Calculate the reduction in friction coefficient (Δμ) under workpiece vibration. wi =μ wi -μ i ), to obtain the workpiece vibration cup height-friction reduction dataset {H tfi , Δμ wi }

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