Method for testing mechanical properties of hard and brittle material under action of ultrasonic energy field

Abstract

The invention discloses a method for testing the mechanical property of a hard and brittle material under the action of an ultrasonic energy field, particularly a SiC fiber-reinforced SiC ceramic-based composite material, and relates to the technical field of material mechanical property testing. According to the method, ANSYS finite element analysis software is used for carrying out modal analysis on a whole formed by an ultrasonic knife handle and a pressure head required by a test to obtain a pressure head material corresponding to amplitude and frequency required by the test, a pressure head overhanging amount and an output power of an ultrasonic power supply, and then the pressure heads required by different tests are processed according to a modal analysis result. And connecting ultrasonic device mechanical test equipment by using a connecting tool, and carrying out mechanical test to obtain the mechanical property of the hard and brittle material under the action of the ultrasonic energy field. The method is high in measurement precision and easy to implement, the defect that ultrasonic vibration cannot be introduced in a conventional mechanical property testing method is overcome, and the problem that the vibration frequency and amplitude are difficult to determine after an ultrasonic energy field is introduced is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of testing the mechanical properties of materials, and relates to a method for testing the mechanical properties of hard and brittle materials under the action of an ultrasonic energy field, and particularly relates to a method for testing the mechanical properties of SiC f / SiC ceramic matrix composites under the action of an ultrasonic energy field. Background Technique

[0002] SiC fiber reinforced SiC ceramic matrix composite (SiC f / SiC ceramic matrix composite) is a new type of fiber reinforced ceramic matrix composite, which has the characteristics of low density, high temperature resistance, high strength, high modulus, creep resistance, and corrosion resistance, and has broad application prospects in the fields of hot end components of advanced aeroengines, automotive brake systems, etc. However, the characteristics of large hardness and brittleness of SiC f / SiC ceramic matrix composites make it a difficult-to-machine material in machining. Therefore, ultrasonic vibration assisted machining is widely used in the machining of SiC f / SiC ceramic matrix composites. However, the introduction of the ultrasonic energy field will not only change the tool's movement trajectory, thereby reducing the cutting force and cutting heat during machining, thus improving the machining quality, but also change the mechanical properties of the material, thereby improving the machinability of the material.

[0003] Patent CN117782790A discloses a testing device and method based on the mechanical properties of composites. The device and method have a high degree of automation and can synchronously detect the tensile properties and bending properties of composite plates, getting rid of the traditional method of separately detecting with two separate devices, and shortening the detection cycle of the mechanical properties of composites. Patent CN116256248A discloses a testing device for the mechanical properties of carbon fiber composites. The device can shear carbon fiber material plates while adjusting the shearing size, and drives the control component through the movement of the carbon fiber material plates, improving the shearing accuracy of the carbon fiber material plate specimens.

[0004] However, both of the above two mechanical property testing devices can only test the mechanical properties of materials under normal conditions and cannot introduce ultrasonic vibration during the mechanical property testing process. Therefore, it is impossible to test the mechanical properties of materials under the action of an ultrasonic energy field. At the same time, since the vibration of an object is related to the natural frequency of the overall vibration. Therefore, after the ultrasonic device clamps the indenter for mechanical property testing, the overall vibration frequency and amplitude will change. It is difficult for the current technology to solve the matching problems of the indenter material, the indenter overhang, the output frequency and output power of the ultrasonic power supply, and it is difficult to introduce vibrations with the required frequency and amplitude during the mechanical property testing process. In summary, it is necessary to design a suitable auxiliary tooling to connect the ultrasonic device and the mechanical testing device, and use a suitable testing method to test the mechanical properties of materials under the action of an ultrasonic energy field. Summary of the Invention

[0005] Technical problems to be solved:

[0006] Existing mechanical property testing devices only target the original mechanical properties of materials and cannot introduce ultrasonic vibration during the testing process. Therefore, it is impossible to accurately test the mechanical properties of materials under the action of ultrasonic vibration.

[0007] To solve the above problems, the present invention adopts the following technical solutions.

[0008] A method for testing the mechanical properties of SiC fiber-reinforced SiC ceramic matrix composites under the action of an ultrasonic energy field, which includes the following steps:

[0009] Step 1: Use ANSYS finite element analysis software to perform modal analysis on the overall formed by the ultrasonic tool shank and the indenter required for the test to obtain the indenter material, indenter overhang, and output power of the ultrasonic power supply corresponding to the amplitude and frequency required for the test;

[0010] Step 2: Machine an indenter with the required dimensions based on the indenter material determined in Step 1, and finish the surface treatment of the indenter;

[0011] Step 3: Use a connecting tooling to connect the ultrasonic vibration machining system and the universal testing machine, where the connecting tooling is a columnar structure, one end of which is finished for clamping and fixing on the universal testing machine; the other end is machined with an external thread for connecting the ultrasonic tool shank in the ultrasonic vibration machining system;

[0012] Step 4: Clamp the indenter machined in Step 2 on the ultrasonic tool shank based on the indenter overhang obtained in Step 1, and adjust the ultrasonic power supply in the ultrasonic vibration machining system according to the frequency and output power obtained in Step 1 to obtain the required amplitude and vibration frequency;

[0013] Step 5: Start the ultrasonic power supply, and use an LV-S20 type self-focusing laser vibrometer to detect and confirm that it has been adjusted to the vibration frequency and amplitude required for the performance test;

[0014] Step 6: Place the SiC fiber-reinforced SiC ceramic matrix composite material specimen on the test bench of the universal testing machine, so that the specimen is aligned with the center of the indenter of the universal testing machine;

[0015] Step 7: Use the universal testing machine to conduct mechanical property tests on the composite material specimen, and analyze and process the test data to obtain the mechanical properties of the specimen.

[0016] Furthermore, the connecting tooling consists of a columnar structure and an external thread structure.

[0017] Furthermore, one end of the columnar structure is subjected to finishing treatment for clamping and fixing by the universal testing machine; one end of the external thread structure is used to connect the ultrasonic tool shank in the ultrasonic vibration processing system.

[0018] Furthermore, the size of the columnar structure of the connecting tooling is Φ12mm * 90mm, and the size of the external thread structure is M15 mm * 50mm.

[0019] Furthermore, the pitch of the external thread structure is 2.5mm.

[0020] Furthermore, in Step 7, a continuous test force is applied to the composite material specimen, and the critical load at the time of specimen compression failure is recorded.

[0021] Furthermore, in Step 7, the mechanical property is the compressive strength.

[0022] The present invention has achieved the following beneficial effects compared with the prior art:

[0023] The present invention uses the method of modal analysis to determine the indenter material, indenter overhang, and output power of the ultrasonic power supply, so that the ultrasonic amplitude and ultrasonic vibration frequency required for the mechanical property test can be accurately adjusted. At the same time, the present invention can introduce ultrasonic vibration during the mechanical property test, so that the load-displacement curve under the action of the ultrasonic energy field can be measured, and then the stress-strain relationship under the action of the ultrasonic energy field can be obtained, realizing a more comprehensive understanding of the mechanical properties of the specimen. Description of the Drawings

[0024] Figure 1 It is a modal analysis diagram of the ultrasonic tool shank with a compression indenter installed in the embodiment of the present invention;

[0025] Figure 2 It is a physical diagram of the connecting tooling in the embodiment of the present invention;

[0026] Figure 3 Schematic diagram of the connection tooling in the embodiment of the present invention;

[0027] Figure 4 Material compressive strength diagrams at different frequencies and amplitudes in the embodiment of the present invention. Detailed implementation manners

[0028] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in more detail below with reference to the accompanying drawings of the specification, but the present invention is not limited thereto.

[0029] The present invention provides a method for testing the mechanical properties of hard and brittle materials under the action of an ultrasonic energy field, which can solve the problems existing in the prior art. In this embodiment, only the compressive strength of SiC f / SiC ceramic matrix composite is described. In this embodiment, the universal testing machine used is an 8872-type electro-hydraulic servo universal material testing machine, and the ultrasonic device used is a CKN-XH11-BT40-type ultrasonic vibration processing system of Shaanxi Chaokeneng Electromechanical Technology Development Co., Ltd., and the frequency of ultrasonic vibration is 20 - 50 kHz.

[0030] The compressive strength test of SiC f / SiC ceramic matrix composite in this embodiment includes the following main technical measures:

[0031] Step 1: Use ANSYS finite element analysis software to perform modal analysis on the overall of the ultrasonic tool shank and the indenter required for the test, and obtain the indenter material, indenter overhang, and output power of the ultrasonic power supply corresponding to the required amplitude and frequency.

[0032] The analysis results show that the required vibration parameters can be obtained by adjusting the indenter made of high-speed steel according to the parameters shown in the following table:

[0033]

[0034] Step 2: Machine a compressive test indenter made of high-speed steel and finish the surface treatment of it.

[0035] Step 3: Use the connection tooling to connect the ultrasonic vibration processing system with the universal testing machine. The connection tooling is as Figure 2 and Figure 3 shown, which is composed of a columnar structure with a size of Φ12mm * 90mm and an external thread structure of M15mm * 50mm. One end with a diameter of Φ12mm is finished for clamping and fixing on the universal testing machine; the other end is machined with an external thread, the major diameter of the thread section is 15mm, the length is 50mm, and the pitch is 2.5mm, for connecting the ultrasonic tool shank in the ultrasonic vibration processing system.

[0036] Step 4: Clamp the compression test indenter made of high-speed steel on the ultrasonic tool holder according to the indenter overhang shown in Table 1, and adjust the ultrasonic power supply in the ultrasonic vibration machining system according to the frequency and output power in Table 1 to obtain the required amplitude and vibration frequency.

[0037] Step 5: Start the ultrasonic power supply, and use the LV-S20 type self-focusing laser vibrometer to detect and confirm that the vibration frequency and amplitude required for the performance test have been adjusted.

[0038] Step 6: Place the SiC fiber-reinforced SiC ceramic matrix composite material specimen with a size of Φ2mm×4mm on the test bench of the universal testing machine, and carefully adjust the specimen so that the centers of the specimen and the contact block can be aligned with the center of the indenter of the testing machine.

[0039] Step 7: Set the crossbeam displacement to a displacement rate of 0.2mm / min, apply a continuous test force to the specimen, and record the critical load when the specimen is compressed and damaged.

[0040] Step 8: After the test is completed, clean the specimen fragments on the test bench.

[0041] Step 9: Analyze and process the test data, and the mechanical properties of the obtained specimen are as Figure 4 shown.

[0042] It should be noted that the above-described embodiments are only the preferred embodiments of the present invention. For those of ordinary skill in the art, without departing from the principle of the present invention, several modifications, improvements, and equivalent replacements can be made to the present invention, and these modifications, improvements, and equivalent replacements are also considered to fall within the protection scope of the claims of the present invention.

Claims

1. A method for testing the mechanical properties of SiC fiber-reinforced SiC ceramic matrix composites under the action of an ultrasonic energy field, characterized in that, It includes the following steps: Step 1: Use ANSYS finite element analysis software to perform modal analysis on the overall structure formed by the ultrasonic tool shank and the indenter required for the test, and obtain the indenter material, indenter overhang, and output power of the ultrasonic power supply corresponding to the amplitude and frequency required for the test; Step 2: Machine an indenter with the required dimensions based on the indenter material determined in Step 1, and finish the surface treatment of the indenter; Step 3: Connect the ultrasonic vibration machining system to the universal testing machine using a connecting tooling. The connecting tooling is a columnar structure, one end of which is finished for clamping and fixing on the universal testing machine; the other end is machined with an external thread for connecting the ultrasonic tool shank in the ultrasonic vibration machining system; Step 4: Clamp the indenter machined in Step 2 on the ultrasonic tool shank based on the indenter overhang obtained in Step 1, and adjust the ultrasonic power supply in the ultrasonic vibration machining system according to the frequency and output power obtained in Step 1 to obtain the required amplitude and vibration frequency; Step 5: Start the ultrasonic power supply, and use an LV-S20 type self-focusing laser vibrometer to detect and confirm that the vibration frequency and amplitude required for the performance test have been adjusted; Step 6: Place the SiC fiber reinforced SiC ceramic matrix composite material specimen on the test bench of the universal testing machine so that the specimen is aligned with the center of the indenter of the universal testing machine; Step 7: Use the universal testing machine to perform mechanical property tests on the composite material specimen, and analyze and process the test data to obtain the mechanical properties of the specimen.

2. The mechanical property testing method of SiC fiber reinforced SiC ceramic matrix composite under the action of ultrasonic energy field according to claim 1, characterized in that, The connecting tooling is composed of a columnar structure and an external thread structure.

3. The mechanical property testing method of SiC fiber reinforced SiC ceramic matrix composite under the action of ultrasonic energy field according to claim 2, characterized in that, One end of the columnar structure is finished for clamping and fixing on the universal testing machine; one end of the external thread structure is used to connect the ultrasonic tool shank in the ultrasonic vibration machining system.

4. The method for testing the mechanical properties of SiC fiber reinforced SiC ceramic matrix composites under the action of an ultrasonic energy field according to claim 2 or 3, characterized in that, The size of the columnar structure of the connecting tooling is Φ12mm * 90mm, and the size of the external thread structure is M15 mm * 50mm.

5. The mechanical property testing method of SiC fiber reinforced SiC ceramic matrix composite under the action of ultrasonic energy field according to claim 2, characterized in that, The pitch of the external thread structure is 2.5mm.

6. The mechanical property testing method of SiC fiber reinforced SiC ceramic matrix composite under the action of ultrasonic energy field according to claim 1, characterized in that, In Step 7, apply a continuous test force to the composite material specimen and record the critical load at the time of specimen compression failure.

7. The mechanical property testing method of SiC fiber reinforced SiC ceramic matrix composite under the action of ultrasonic energy field according to claim 1, characterized in that, In Step 7, the mechanical property is the compressive strength.

Images