CN104897460A - A test-piece clamp for multi-load coupling loading and a multi-physics field coupling loading method thereof - Google Patents

Abstract

The invention relates to a test-piece clamp for multi-load coupling loading and a multi-physics field coupling loading method thereof, and belongs to the field of material micro-mechanical property testing. By machining a groove in the clamp, putting a test piece into the groove and compacting through pressing plates, application of stretching, bending, torsion, and other mechanical loads onto the test piece by the clamp is achieved. Conductive heating is performed by bringing a silicon nitride heating sheet and the test piece into contact, and temperature feedback is achieved by a thermocouple, thus achieving application of thermal-field loading onto the test piece to be tested. Electric-field loading to the test piece is achieved by providing the test piece with a controllable electric current. Magnetic-field loading to the test piece to be tested is achieved through two magnetic induction coils. The structure is simple and compact, the method is scientific and reasonable, and properties are stable and reliable. Large-range temperature loading, accurate electric current loading and controllable magnetic field loading for a test piece material to be tested can be achieved. Composite-load loading and stimulation of a thermal field, an electric field and a magnetic field, which are closer to service conditions, for material testing can be provided. The test-piece clamp and the method have important theoretical significance and application value.

Description

Specimen fixture for multi-load coupling loading and its multi-physics field coupling loading method

technical field

The invention relates to the technical field of material microscopic properties, in particular to testing of material micromechanical properties, in particular to a multi-load coupled loading specimen fixture and a multi-physics field coupled loading method in the testing of material micromechanical properties. It belongs to precision instrument components and precision drive transmission unit components.

Background technique

    In recent years, the research work on the testing of material micromechanical properties under multiple loads and multi-physics field coupling conditions has attracted more and more attention from the international academic and engineering communities. In the field of engineering, the accidental damage and failure of materials and their products often lead to economic losses and even serious accidents. The reason why materials and their products have usually been tested for mechanical properties but accidental failures may occur, one of which is very The important reason is that the load application state and the physical field environment under service conditions are not truly simulated during the mechanical performance test. The most common material tensile testing machine can only achieve a single tensile test, and the torsion testing machine can only provide a single torsional load, while mechanical parts are often subjected to composite loads under service conditions. Similarly, traditional material testing machines are difficult to provide simulations of electric field environment, thermal field environment, and magnetic field environment close to service conditions. Therefore, it is difficult for traditional material testing machines to provide tests close to service conditions. The material performance test under the composite load multi-physics field is a test that is closer to the material under service conditions, and the test data is more real and reliable. This kind of testing is of great significance for the development of new materials and the development of high-end precision equipment manufacturing industry.

At present, there is no relatively mature specimen fixture and multi-physics coupling loading method suitable for multi-load coupling loading. Under the condition of pre-clamping, traditional wedge-shaped clamps have limited transmission torque; threaded clamps are difficult to clamp and can only be twisted in one direction. The difficulties of multi-physics field coupling loading are mainly reflected in the following aspects: First, the observation problem. For in-situ material mechanical performance testing, a good field of view must be provided for the microscope, and enough observation space must be left. It is required that the loading of the electric field, thermal field, and magnetic field cannot interfere with the observation path of the microscope; second, the resistance wire heating method usually used is difficult to reach a very high temperature, and a small range of temperature changes is of little significance for material testing; third, The electric field loading and cooling water cannot be carried out at the same time. Most of the fixtures are metal conductors. Loading will cause thermal deformation of the fixture, and it must be ensured that the fixture can still clamp the specimen reliably under high temperature. To sum up, a set of reliable multi-load coupled loading specimen fixtures and multi-physics field coupled loading methods is of great significance for testing the micromechanical properties of materials.

Contents of the invention

The object of the present invention is to provide a multi-load coupled loading specimen fixture and a multi-physics field coupled loading method thereof, which solve the above-mentioned problems existing in the prior art. The multi-load coupled load test piece fixture of the present invention can simply, reliably and efficiently transmit tensile, bending and torsional composite loads. The multi-physics field coupling loading method solves the interference problem between multi-physics field loading and in-situ observation, has a large temperature range, can carry out electric field loading and cooling at the same time, and can ensure reliable clamping of specimens under high temperature conditions.

Above-mentioned purpose of the present invention is achieved through the following technical solutions:

The multi-load coupling loaded specimen fixture is used to clamp the specimen sample under the conditions of tensile, bending, torsion and other loads on the specimen 17. At the same time, the fixture can also pass the thermal field loading module, electric field loading module, magnetic field The loading module realizes the coupled loading of the thermal field, electric field and magnetic field of the material sample to be tested. Its specific structure is: the heating plate pressing plate 4 compresses the silicon nitride heating plate 25 and fixes it in the groove of the upper pressing plate 3. The three Connected as a whole, the upper pressing plate 3 and the lower pressing plate 5 are hinged through the left cylindrical pin 18, the lower pressing plate 5 is provided with a groove with the same dimensions as the clamping end of the test piece, the upper pressing plate 3 rotates upward to open the fixture, and the test piece Put the clamping end into the groove, then rotate the upper platen 3 downwards to stick to the test piece 17, and finally lock the nuts on the swing bolts respectively to realize the clamping of the test piece 17;

The thermal field loading module is: the silicon nitride heating plate 25 is in contact with the clamping end of the test piece 17, the thermocouple 16 measures the temperature of the test piece 17, and the temperature signal is fed back to the controller 22, and the controller 22 then sends a steady state signal to the controller 22. The piezoelectric source 23 sends a signal to change the voltage applied to the silicon nitride heating sheet 25, and then control the heating power of the heating sheet, so that the test piece reaches the set temperature; the hard mica plate 6 slows down the heat propagation speed to the right, and increases Large temperature gradient, the cooling connection seat 7 is provided with a flow channel, the cooling water flows in from the water inlet 11, and flows out from the water outlet on the other side after absorbing heat; the heat shield 9 connects the cooling connection seat 7 and the sensor behind;

The electric field loading module is: the lower pressing plate 5 is fixedly connected to the electrode 13 through the copper screw 14, the electric field power supply 21 outputs the current through the lower pressing plate 5 and is introduced into the test piece 17, and the clamp at the other end is connected with a negative pole to form a closed loop;

The magnetic field loading module is as follows: the magnetic field power supply 24 supplies current to the solenoid coil 1 to make the test piece 17 in the magnetic field, and the solenoid coil 1 is fixed on the lower platen 5 through the solenoid coil fixing cylinder 2 . According to the Biot-Savart law, the current element The magnetic induction at any point is

In the formula is the magnetic permeability N/A ² in vacuum; is the current intensity A passing through the current element; is the line element vector of the current element; is the vector m of the current element to any point.

The groove on the lower pressing plate 5 is provided with a tapered part, and it matches with the tapered transition part of the test piece. In the tapered part of the groove, the tensile load is applied to the test piece; when the clamping end of the test piece 17 is fully clamped, the clamping end of the test piece 17 has a fixed position relative to the fixture. unchanged, when the other fixture moves according to the curved trajectory of the specimen 17, the cantilever bending load is applied to the specimen 17; the two clamping ends of the specimen 17 are plate-shaped, when its two clamping ends After being clamped by the two clamps, the clamping end will rotate synchronously with the two clamps respectively, and when the two clamps rotate relative to each other, a torsional load is applied to the test piece 17 .

The parallel length portion of the test piece 17 is cylindrical, and the clamping ends on both sides are plate-shaped with a thickness equal to the diameter of the cylinder, and there is a tapered transition portion between the clamping end and the parallel length portion.

The hard mica board 6 can not only realize heat insulation, but also realize insulation, which can not only reduce the heat conduction rate, increase the temperature gradient, but also realize the compatibility between the water cooling module and the electric field loading module, and avoid passing through the cooling water. Leakage. It has a high density and high processing accuracy, and will not affect the overall accuracy of the device.

The lower pressing plate 5 is processed from austenitic stainless steel, which can ensure the normal use under high temperature conditions, and the lower pressing plate 5 is processed with a groove matching the clamping end of the test piece to ensure the transfer to the test piece (17). Tensile force, torque and bending moment.

The cooling connection seat 7 has a cooling function on the one hand, and a connection function on the other hand. The left side passes through the hard mica plate 6 and is connected to the lower pressure plate 5 through a screw 20. The part is directly inserted into the corresponding bolt hole, in order to install the screw 20, there is a passage hole 10 on the right side of the cooling connection seat 7, and the screw 20 passes through the passage hole 10 on the right side and is inserted into the corresponding bolt hole; cooling The right side of the connection seat 7 is connected with the sensor through a stud 8 .

The electric field loading module can realize the loading of different currents by changing the voltage of the electric field power supply 21. The hard mica plate 6 ensures the front and rear insulation, the lower pressure plate 5, the hard mica plate 6 and the cooling connection seat 7 are connected by screws 20, and the bolt insulation sleeve 19 It is used in conjunction with the screw 20 to achieve insulation while ensuring effective connection.

The magnetic field loading module can change the strength of the magnetic field by changing the current of the magnetic field power supply 24 .

The solenoid coil 1 is fixed on the lower platen 5 through the coil fixing cylinder 2. When the magnetic loading module is not required, it can be disassembled from the lower platen 5, and a solenoid coil 1 is installed at each end of the test piece 17, Ensure a high magnetic field strength, the length of the solenoid coil 1 is appropriate, ensure that the test piece 17 has a sufficient observation range, the solenoid coil 1 does not contact the test piece 17, and ensure that the test piece 17 can be stretched, bent, and twisted freely.

Another object of the present invention is to provide a multi-physics coupling loading method for a specimen fixture loaded with multi-load coupling, and the specific steps are as follows:

Step 1: setting the loading conditions of the multi-physics field through the computer;

Step 2: The computer generates driving signals for controlling thermal field, electric field, and magnetic field through the signal generation module;

Step 3: amplify the driving signal output in step 2 by a power amplifier, and output a current signal;

Step 4: With the current signal output in step 3, drive the regulated power supply 23 to output a preset voltage and load it on the silicon nitride heating plate 25 to realize the loading of the thermal field; with the current signal output in step 3, drive the electric field power supply 21 to output The preset current realizes the loading of the electric field; the current signal output by step 3 drives the magnetic field power supply 24 to output the preset current to realize the loading of the magnetic field;

Step 5: collect multi-physics field sensor signals by A/D acquisition card;

Step 6: Input the collected sensor signal into the computer and compare it with the set value of the computer. If the test conditions are met, the multiphysics field reaches the set value; otherwise, return to step 2 to adjust the multiphysics field driving signal.

The beneficial effect of the present invention is that: the multi-load coupled load test piece fixture can simply, reliably and efficiently transmit tensile, bending and torsional composite loads; the heating module is integrated inside the fixture, avoiding the interference of the heating module and the observation module, At the same time, avoid the observation lens from being subjected to high temperature; the silicon nitride heating plate has the characteristics of fast heating and high temperature, which can ensure that the high temperature can be reached quickly; the electric field loading and cooling water are separated by an insulating plate to ensure that the two can be carried out at the same time ;The lower platen is made of austenitic steel, which can ensure the performance under high temperature conditions; the magnetic field loading module does not interfere with the observation module, and does not affect the tensile, bending, and torsion tests of the specimen.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention, and constitute a part of the application. The schematic examples and descriptions of the present invention are used to explain the present invention, and do not constitute improper limitations to the present invention.

Fig. 1 is the overall appearance schematic diagram of the present invention;

Figure 2 is an overall sectional view of the present invention;

Fig. 3 is the schematic diagram of thermal field principle of the present invention;

Fig. 4 is the electric field principle schematic diagram of the present invention;

Fig. 5 is the schematic diagram of magnetic field principle of the present invention;

Fig. 6 is a circuit connection diagram of the present invention;

Fig. 7 is a schematic structural view of the upper platen of the present invention;

Fig. 8 is a structural schematic diagram of the lower platen of the present invention;

Fig. 9 is a cross-sectional view of the cooling connection seat of the present invention.

In the figure: 1. Solenoid coil, 2. Coil coil fixing cylinder, 3. Upper platen, 4. Heating plate platen, 5. Lower platen, 6. Hard mica plate, 7. Cooling connection seat, 8. Double-ended stud, 9. Heat shield, 10. Through hole, 11. Water inlet, 12. Swing bolt, 13. Electrode, 14. Copper screw, 15. Right cylindrical pin, 16. Thermocouple, 17. Test piece, 18. Left cylindrical Pin, 19. Bolt insulation sleeve, 20. Screw, 21. Electric field power supply, 22. Controller, 23. Stabilized voltage power supply, 24. Magnetic field power supply, 25. Silicon nitride heating sheet.

Detailed ways

The detailed content of the present invention and its specific implementation will be further described below in conjunction with the accompanying drawings.

Referring to Fig. 1 to Fig. 9, the multi-load coupled loading test piece fixture of the present invention is suitable for clamping the test piece sample under the conditions of applying tension, bending, torsion and other loads to the test piece 17, and the fixture is also The coupling loading of the thermal field, electric field and magnetic field of the material sample to be tested can be realized through the thermal field loading module, the electric field loading module and the magnetic field loading module.

Referring to Fig. 1 and Fig. 2, the specific structure of the multi-load material in-situ test fixture is: the heating plate pressing plate 4 compresses the silicon nitride heating plate 25, and fixes it in the groove of the upper pressing plate 3, the three Connected as a whole, the upper pressing plate 3 and the lower pressing plate 5 are hinged through the left cylindrical pin 18, the lower pressing plate 5 is processed with a groove having the same dimensions as the clamping end of the test piece, the upper pressing plate 3 rotates upward to open the fixture, and the test piece The clamping end is inserted into the groove of the lower pressing plate 5, and then the upper pressing plate 3 is rotated downward to be close to the test piece 17, and finally the nuts on the swinging bolts are respectively locked to realize the clamping of the test piece 17.

For the application of the tensile load, the groove on the lower platen 5 has a tapered portion that matches the tapered transition portion of the test piece 17. When the test piece 17 bears the tensile force, the tapered transition portion of the test piece 17 is stuck on the lower platen In the tapered part of the groove of 5, a tensile load can be applied to the test piece 17.

In the application of the bending load, when the clamping end of the test piece 17 is fully clamped, the clamping end of the test piece 17 has a fixed position relative to the fixture. Bending load can be applied to the test piece 17 when the test piece moves along a curved track.

For the application of the torsional load, the two clamping ends of the test piece 17 are plate-shaped. When the two clamping ends of the test piece 17 are respectively clamped by two clamps, the clamping ends of the test piece 17 will be As the two clamps rotate synchronously, when the two clamps rotate relative to each other, a torsional load can be applied to the test piece 17 .

Referring to Fig. 2, Fig. 5 and Fig. 6, the described thermal field loading module is directly contacted with the clamping end of the test piece 17 by the silicon nitride heating plate 25 for heating, so that the test piece reaches the test temperature as soon as possible, and the thermocouple 16 measures The temperature of the test piece 17, and the temperature signal is fed back to the controller 22, and the controller 22 sends a signal to the stabilized power supply 23 to change the voltage applied to the silicon nitride heating chip 25, and then control the heating power of the heating chip. The hard mica plate 6 slows down the heat propagation speed to the right, and increases the temperature gradient. There is a flow channel in the cooling connection seat 7, and the cooling water flows in from the water inlet 11. After absorbing heat, it flows out from the water outlet on the other side and takes away The heat conducted by the heating part to the rear, the heat shield 9 connects the cooling connection seat 7 and the sensor behind, reduces the heat conduction rate, and increases the temperature gradient.

Referring to Fig. 4, the described electric field loading module fixes the electrode 13 on the lower pressing plate 5 by the copper screw 14, the electric current output by the electric field power supply 21 is introduced into the test piece 17 through the lower pressing plate 5, and the clamp at the other end is connected with Negative pole, forming a closed circuit. The circuit connection of the electric field is shown in FIG. 6 , changing the voltage of the electric field power supply 21 can realize loading of different currents. The insulation of the electric field is shown in Figure 2. The hard mica plate 6 ensures the front and rear insulation. The lower pressure plate 5, the hard mica plate 6 and the cooling connection seat 7 are connected by screws 20. The bolt insulating sleeve 19 is used in conjunction with the screw 20, so as to ensure effective connection. while achieving insulation.

The principle of magnetic field loading is shown in FIG. 5 . The magnetic field power supply 24 supplies current to the solenoid coil 1 to make the test piece 17 in the magnetic field. The circuit connection of the magnetic field is shown in FIG. 6 . Changing the current of the magnetic field power supply 24 can realize the change of the strength of the magnetic field. The installation of the magnetic field is shown in Figure 2. The coil fixing cylinder 2 fixes the solenoid coil 1 on the lower platen 5. According to the Biot-Savart law, the distance from the current element The magnetic induction at any point is

In the formula is the magnetic permeability in vacuum (N/A ² ); is the current intensity (A) passing through the current element; is the line element vector of the current element; is the vector radius (m) from the current element to any point.

Referring to Fig. 2, the solenoid coil 1 is fixed on the lower platen 5 through the coil fixing cylinder 2. When the magnetic loading module is not needed, it can be disassembled from the lower platen 5, and the two ends of the test piece 17 are respectively Install a solenoid coil 1 to ensure a high magnetic field strength. The length of the solenoid coil 1 is appropriate to ensure that the test piece 17 has a sufficient observation range. The solenoid coil 1 is not in contact with the test piece 17 to ensure that the test piece 17 can be stretched and bent freely. , to reverse.

Referring to FIG. 2 , the hard mica board 6 can realize both heat insulation and insulation, so as to ensure that the cooling water and the electric field can be loaded at the same time without leakage through the cooling water.

The silicon nitride heating plate 25 has a high heating temperature and a fast heating speed.

The lower pressing plate 5 is made of austenitic stainless steel, which can ensure the normal use under high temperature conditions, and the lower pressing plate 5 is milled with a groove suitable for the clamping end of the test piece, so as to ensure the transmission of tension and bending force to the test piece. moment and torque.

The cooling connection seat 8 has a cooling effect on the one hand, and a connection effect on the other hand, and the left side is connected with the lower pressing plate 5 through the hard mica plate 6 through the screw 20 . The screw 20 is too long and cannot be directly inserted into the corresponding bolt hole from the middle part of the cooling connection seat 7 with a smaller diameter. Pass through the hole 10 and insert into the corresponding bolt hole. The right side of the cooling connection seat 7 is connected with the sensor through a stud 8 .

The described electric field loading module can realize the loading of different currents by changing the voltage of the electric field power supply 21, the hard mica plate 6 ensures the front and rear insulation, the lower pressure plate 5, the hard mica plate 6 and the cooling connection seat 7 are connected by screws 20, and the bolts The insulating sleeve 19 is used in conjunction with the screw 20, so as to realize insulation while ensuring an effective connection.

Referring to the circuit connection diagram shown in Figure 6, the electric field power supply 21 supplies power to the electrodes 13, the voltage-stabilizing power supply 23 supplies power to the silicon nitride heating plate 25, and the magnetic field power supply 24 supplies power to the solenoid coil 1, and the three power supplies are all controlled by the controller 22 , and the controller 22 also needs to receive the signal from the thermocouple 16 to realize the closed-loop control of the thermal field.

The solenoid coil 1 is fixed on the lower platen 5 through the coil fixing cylinder 2. When the magnetic loading module is not required, it can be disassembled from the lower platen 5, and a solenoid coil 1 is installed at each end of the test piece 17, Ensure a high magnetic field strength, the length of the solenoid coil 1 is appropriate, ensure that the test piece 17 has a sufficient observation range, the solenoid coil 1 does not contact the test piece 17, and ensure that the test piece 17 can be stretched, bent, and twisted freely.

Referring to Figure 6, the specific steps of the multi-physics loading method are as follows:

Step 1: setting the loading conditions of the multi-physics field through the computer;

Step 2: The computer generates driving signals for controlling thermal field, electric field, and magnetic field through the signal generation module;

Step 3: amplify the driving signal output in step 2 by a power amplifier, and output a current signal;

Step 4: With the current signal output in step 3, drive the regulated power supply 23 to output a certain voltage and load it on the silicon nitride heating plate 25 to realize the loading of the thermal field; with the current signal output in step 3, drive the electric field power supply 21 to output a certain voltage The electric current realizes the loading of the electric field; the current signal output by step 3 drives the magnetic field power supply 24 to output a certain current to realize the loading of the magnetic field;

Step 5: collect multi-physics field sensor signals by A/D acquisition card;

Step 6: Input the collected sensor signal into the computer and compare it with the set value of the computer. If the test conditions are met, the multiphysics field reaches the set value; otherwise, return to step 2 to adjust the multiphysics field driving signal.

Referring to Fig. 7, the upper platen 4 is characterized in that it is made of stainless steel, which can ensure the normal use under high temperature conditions. The upper end has a groove suitable for the shape of the silicon nitride heating plate 25, and the surrounding four A bolt hole is used to install the heating sheet pressing plate 4, and the silicon nitride heating sheet 25 is pressed by the heating sheet pressing plate 4. The pin hole of bottom is used for realizing the hinge connection of upper pressing plate 4 and lower pressing plate 5.

Referring to Figure 8, the lower pressing plate 5 is characterized in that it is made of austenitic stainless steel, which can ensure the normal use under high temperature conditions, and the lower pressing plate 5 is milled with a concave hole suitable for the clamping end of the test piece. The groove ensures the transmission of tensile, bending and torsional combined loads to the specimen. The pin hole on the left side is used for installing the left cylindrical pin 18, and the interference fit realizes the hinge connection between the upper pressing plate 3 and the lower pressing plate 5. The pin hole on the right is used to install the right cylindrical pin 15, and the interference fit realizes the hinge connection between the swing bolt 12 and the lower pressing plate 5.

Referring to Fig. 9, the cooling connection seat 7 is characterized in that on the one hand, it has a cooling effect, and there is a cooling flow channel inside, and the flow direction of the cooling water is shown by the arrow; Pass through the hard mica plate 6 and connect with the lower pressing plate 5. The screw 20 is too long and cannot be directly inserted into the corresponding bolt hole from the middle part of the cooling connection seat 7 with a smaller diameter. Pass through the hole 10 and insert into the corresponding bolt hole. The right side of the cooling connection seat 7 is connected with the sensor through a stud 8 .

The outstanding feature of the present invention is to provide a multi-load coupled loading test piece fixture, which can simply, reliably and efficiently transfer tensile, bending and torsional composite loads; provide a multi-physical field coupling loading method, which integrates the heating module into the The interior of the fixture avoids the interference between the heating module and the observation module, and at the same time prevents the observation lens from being subjected to high temperature; the silicon nitride heating plate 25 has the characteristics of fast temperature rise and high temperature, which can ensure that the high temperature can be reached quickly; the electric field loading and The cooling water is separated by an insulating plate to ensure that both can be carried out at the same time; the lower platen 5 is made of austenitic steel, which can ensure the performance under high temperature conditions; the magnetic field loading module does not interfere with the observation module and does not affect the test piece 17 Tensile, bending, torsion tests.

The above descriptions are only preferred examples of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made to the present invention shall be included within the protection scope of the present invention.

Claims (7)

1. the piece fixture of a multi-load coupling loading, it is characterized in that: for applying to stretch to test specimen (17), bending, to the clamping of test specimen under torsional load condition, simultaneously by thermal field load-on module, electric field load-on module, magnetic field load-on module realizes the thermal field to measured material sample, electric field loads with being coupled of magnetic field, silicon nitride heating sheet (25) compresses by heating plate pressing plate (4), be fixed in the groove of top board (3), three connects into an entirety, top board (3) and lower platen (5) are by left straight pin (18) chain connection, lower platen (5) is provided with the groove identical with specimen holder end physical dimension, top board (3) rotates up opens fixture, specimen holder end is inserted groove, be rotated down top board (3) again and be adjacent to test specimen (17), finally locking swings the nut on bolt respectively, realize the clamping of test specimen (17),

Described thermal field load-on module is: silicon nitride heating sheet (25) contacts with the bare terminal end of test specimen (17), the temperature of test specimen (17) measured by thermopair (16), and temperature signal is fed back to controller (22), controller (22) sends signal to stabilized voltage supply (23) again, change the voltage be applied on silicon nitride heating sheet (25), and then control the heating power of heating plate, make test specimen reach design temperature; Hard micarex (6) slows down heat velocity of propagation to the right, and increases thermograde, is provided with runner in cooling Connection Block (7), and chilled water flows into from water inlet (11), flows out after absorbing heat from opposite side water delivering orifice; Thermal insulation board (9) connects cooling Connection Block (7) and sensor below;

Described electric field load-on module is: lower platen (5) is fixedly connected with electrode (13) by brass screw (14), the electric current that electric field power supply (21) exports imports in test specimen (17) by lower platen (5), the fixture of the other end is connected to negative pole, forms closed-loop path;

Described magnetic field load-on module is: magnetic field power supply (24) passes into electric current to solenoid (1), and make test specimen (17) be among magnetic field, solenoid (1) is fixed on lower platen (5) by solenoid stationary magazine creel (2).

2. the piece fixture of multi-load coupling loading according to claim 1, it is characterized in that: the groove on described lower platen (5) is provided with conical section, and it matches with test specimen tapered intermediate portion, when test specimen (17) bears pulling force, the tapered intermediate portion of test specimen is stuck in the groove conical section of lower platen (5), namely realizes applying drag load to test specimen; After the bare terminal end of test specimen (17) is clamped completely, the bare terminal end opposed jaw of test specimen (17) has determines constant position, when fixing, a chucking position is constant, when another fixture is according to the orbiting motion that test specimen (17) is bending, namely realizes applying cantilever bending loads to test specimen (17); Two bare terminal ends of test specimen (17) are all tabular, and after its two bare terminal ends are respectively by two clamp, bare terminal end can, respectively along with two fixture synchronous axial system, when two fixtures relatively rotate, namely realize applying torsional load to test specimen (17).

3. the piece fixture of multi-load coupling loading according to claim 1 and 2, it is characterized in that: the parallel length part of described test specimen (17) is cylindric, the bare terminal end on both sides is the tabular that thickness is equal with body diameter, has tapered intermediate portion between bare terminal end and parallel length part.

4. the piece fixture of multi-load coupling loading according to claim 1 and 2, it is characterized in that: described lower platen (5) is processed by austenitic stainless steel, lower platen (5) is processed with the groove matched with specimen holder end, ensures to transmit pulling force, moment of torsion and moment of flexure to test specimen (17).

5. the piece fixture of multi-load coupling loading according to claim 1, it is characterized in that: described cooling Connection Block (7) left side is connected with lower platen (5) through hard micarex (6) by screw (20), cooling Connection Block (7) right side has passing hole (10), screw (20) passes from passing hole (10), is inserted in bolt hole; Cooling Connection Block (7) the right is connected with sensor by studs (8).

6. the piece fixture of multi-load coupling loading according to claim 1, it is characterized in that: described solenoid (1) is fixed on lower platen (5) by solenoid stationary magazine creel (2), a solenoid (1) is respectively installed at the two ends of test specimen (17) ,solenoid (1) does not contact with test specimen (17), ensures that test specimen (17) freely stretches, bends, reverses.

7. a multiple physical field coupling loading method for the piece fixture of multi-load coupling loading according to claim 1, is characterized in that: concrete steps are as follows:

Step 1: by the loading environment of computer settings multiple physical field;

Step 2: computing machine produces the drive singal controlling thermal field, electric field, magnetic field by signal generating module;

Step 3: by power amplifier, the drive singal exported in step 2 is amplified, output current signal;

Step 4: the current signal exported by step 3, drives stabilized voltage supply (23) to export default voltage-drop loading on silicon nitride heating sheet (25), realizes the loading of thermal field; The current signal exported by step 3, drives electric field power supply (21) to export the electric current preset, realizes the loading of electric field; The current signal exported by step 3, driving magnetic field power supply (24) exports the electric current preset, and realizes the loading in magnetic field;

Step 5: gather multiple physical field sensor signal by A/D capture card;

Step 6: be input in computing machine by the sensor signal of collection, compares with the setting value of computing machine, if meet test condition, then multiple physical field reaches setting value; Otherwise, return step 2 pair multiple physical field drive singal and adjust.