A double-arm bending and twisting combined experimental method and device

Abstract

The present invention belongs to the technical field of bending combination test, and discloses a double-arm bending-torsion combination test method and device. The test method is that the loading arms installed on the bending-torsion tube are symmetrically arranged, and by adjusting the size and direction of the load applied to the two loading arms, bending, torsion, and bending-torsion loading can be achieved. During bending-torsion loading, the bending-torsion ratio can be adjusted arbitrarily to verify the principle of stress superposition. The test method and device can realize pure bending test, bending-torsion combination test, and bending-torsion combination test, and the ratio of bending and torsion can be adjusted arbitrarily.

Description

Technical Field

[0001] The invention relates to the technical field of material mechanics experiments, and in particular to a double-arm bending and torsion combined experimental method and device. Background Art

[0002] The bending and torsion combination experiment of thin-walled circular tube (bending and torsion tube) is one of the required experiments stipulated in the experimental teaching syllabus of material mechanics course. At present, the equipment used for these experiments is mostly single-arm bending and torsion combination experimental devices, which cannot change the ratio of bending and torsion load combination, nor can they complete bending stress test, torsion G measurement experiment and other projects. For example, Chinese patent CN104359754A discloses a beam component bending and torsion combination loading test device and method, which includes a simple support-torsion combination support and a combination loading component. The simple support-torsion combination support is installed at both ends of the beam component sample, and a certain length is taken in the middle area of ​​the sample as a test section. The combination loading component is set on the test section, specifically: a horizontal reverse loading arm is installed at both ends of the test section, and the free ends of the two loading beams are fixedly connected by a distribution beam. Although the above patent realizes the bending and torsion combination experiment, it cannot arbitrarily change the ratio of bending and torsion load combination, nor can it realize pure bending or pure torsion experiment. In order to facilitate students to understand the principle of stress superposition, it is necessary to develop an experimental device and experimental method for material mechanics experiment that is easy to operate, multi-purpose, and low in cost. Summary of the invention

[0003] In order to solve the problem that the double-arm bending and torsion combined experimental device in the prior art cannot realize pure bending or pure torsion experiments, the present invention provides a double-arm bending and torsion combined experimental method.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A double-arm bending and torsion combined experimental method, the present invention symmetrically arranges the loading arms installed on the bending and torsion tube, and realizes bending, torsion, and bending and torsion loading by adjusting the size and direction of the load applied to the two loading arms. The bending and torsion ratio can be adjusted arbitrarily during bending and torsion loading, which is used to verify the principle of stress superposition, and specifically includes the following steps:

[0006] a. The load applied by the symmetrically installed loading arms is of the same magnitude and direction, and the bending-torsion tube is a bending deformation member similar to a cantilever beam, thereby realizing a pure bending test;

[0007] b. The loads applied by the symmetrically installed loading arms are of the same magnitude but opposite directions. The bending-torsion tube is only subjected to torque at the connection. The torque is twice the product of the unilateral load and the unilateral force arm. At this time, the bending-torsion tube is a torsion deformation member. The bending-torsion tube is only subjected to torque at the connection of the loading beam, thereby realizing a pure torsion experiment;

[0008] c. The loads applied to the symmetrically installed loading arms are different in magnitude. The concentrated force applied to the bending-torsion tube at the connection is the sum of the loads applied by the two worm gear handwheels, and the torque applied is the product of the difference between the two loads and the unilateral force arm. At this time, the bending-torsion tube is a bending-torsion combined deformation component, thereby realizing a bending-torsion combined experiment, and the ratio of bending and torsion can be adjusted arbitrarily according to the different loads applied on both sides.

[0009] Another inventive object of the present invention is to provide a double-arm bending and torsion combination experimental device, comprising a base plate, a vertical plate installed on the base plate, a horizontal bending and torsion tube installed on the vertical plate, two loading arms symmetrically installed on the bending and torsion tube, and a tensile and compressive loading device installed at one end of each loading arm; the loading device comprises a worm gear, a force sensor and a lead screw, the worm gear is installed on the base plate through a guide device, the force sensor is connected to the worm gear, the lead screw is connected to the force sensor, and the lead screw is hinged to the loading arm.

[0010] The guide device includes a guide rail plate fixedly mounted on the bottom plate, a guide rail fixedly mounted on the guide rail plate, and a sliding trolley mounted on the guide rail and capable of sliding on the guide rail, and the worm gear is fixedly mounted on the sliding trolley. There is no specific limitation on the worm gear, and a manual worm gear can be selected. The loading mechanism can adjust the loading position of the bending and torsion tube along the guide device. The loading mechanism can realize both tensile loading and pressure loading on the loading beam, and can realize alternating tensile and compressive loading on the loading beam.

[0011] Preferably, the lead screw is hinged to the loading arm via a connecting piece and a pin.

[0012] Furthermore, a strain gauge is pasted on the bending and torsion tube and is connected to a strain meter. After the device applies a load, the load value can be read on the strain meter.

[0013] Furthermore, the two loading arms are connected together by screws and nuts, and are respectively connected to the bending and torsion tubes by flat keys.

[0014] In order to realize the arbitrarily adjustable internal pressure stress test area and the segmented internal pressure stress test experiment, this improved scheme can apply internal pressure by using a manual oil pump or a manual screw mechanism. Specifically, the double-arm bending and torsion combination experimental device described in the present invention also includes an internal pressure applying device for providing internal pressure to the bending and torsion tube, and the internal pressure applying device is a manual oil pump or a manual screw mechanism arranged in one end of the bending and torsion tube; the manual screw mechanism is a screw, and the screw is inserted into the bending and torsion tube, and a piston is arranged in the bending and torsion tube, and the screw is connected to the piston screw, and the screw is engaged with a nut fixed on the bending and torsion tube.

[0015] Preferably, the double-arm bending and torsion combined experimental device described in the present invention also includes an oil pressure sensor installed on the bending and torsion tube for collecting internal pressure, and a pressure gauge for displaying pressure, so as to facilitate stress distribution experiments on thin-walled circular tubes subjected to internal pressure.

[0016] Compared with the prior art, the present invention provides a double-arm bending and torsion combined test method and device, which can realize bending, torsion, and bending and torsion loading by means of two loading beams respectively arranged on both sides of the bending and torsion tube. The bending and torsion ratio can be adjusted arbitrarily during bending and torsion loading, which is used to verify the principle of stress superposition. When loads of the same magnitude and direction are applied on both sides, the bending and torsion tube is only subjected to concentrated force at the connection of the loading beams. The bending and torsion tube is a bending and deformation component similar to a cantilever beam, realizing a pure bending test; when loads of the same magnitude and opposite directions are applied on both sides, the bending and torsion tube is only subjected to torque at the connection of the loading beams, realizing a pure torsion test; when loads of different magnitudes are applied on both sides, a bending and torsion combined test can be realized, and the ratio of bending and torsion can be adjusted arbitrarily according to the different magnitudes of the loads applied on both sides. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of the double-arm bending and twisting combined experimental device provided by the present invention;

[0018] Figure 2 This is a schematic diagram of the side structure of the double-arm bending and twisting combined experimental device provided by the present invention;

[0019] Figure 3 A cross-sectional view of a loading arm provided by the present invention;

[0020] Figure 4 This is a schematic structural diagram of the manual screw mechanism provided by the present invention. DETAILED DESCRIPTION

[0021] The present invention aims to provide a double-arm bending and twisting combined experimental device to solve the problem that the double-arm bending and twisting combined experimental method and device in the prior art cannot realize pure bending or pure twisting experiments.

[0022] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below in conjunction with specific implementation methods and drawings.

[0023] Figure 1-Figure 4 Shown is a preferred embodiment of the present invention, as shown in the figure:

[0024] A double-arm bending and torsion combined experimental device, comprising a bottom plate 1, a vertical plate 2 fixedly mounted on the bottom plate, a horizontal bending and torsion tube 4 fixedly mounted on the vertical plate 2, two loading arms 5 symmetrically mounted on the bending and torsion tube 4, and a tension and compression loading device mounted on one end of each loading arm 5, wherein the two loading arms 5 are connected together by screws and nuts 21, and are respectively connected to the bending and torsion tube 4 by flat keys 20; the loading device comprises a worm gear 9, a force sensor 10 and a lead screw 11, and the worm gear 9 is mounted on the bending and torsion tube 4 through a guide device On the base plate 1, the force sensor 10 is connected to the worm gear 9, the lead screw 11 is connected to the force sensor 10, and the lead screw 11 is hinged to the loading arm 5 through a connecting piece 12 and a pin 13; the guiding device includes a guide plate 6 fixedly mounted on the base plate 1, a guide rail 7 fixedly mounted on the guide plate 6, and a sliding trolley 8 mounted on the guide rail 7 and capable of sliding on the guide rail, and the worm gear 9 is fixedly mounted on the sliding trolley 8; a strain gauge (not shown) is connected to the bending and torsion tube 4.

[0025] In another preferred embodiment, the double-arm bending and torsion combined experimental device of the present invention further includes an internal pressure applying device for providing internal pressure to the bending and torsion tube, and the internal pressure applying device is a manual oil pump 16 or a manual screw mechanism 14 arranged in one end of the bending and torsion tube; the manual screw mechanism 14 is a screw 22, and the screw 22 is inserted into the bending and torsion tube, and the screw is meshed with a nut 23 fixed on the bending and torsion tube, and a piston 24 is provided in the bending and torsion tube, and the screw 22 is screwed to the piston 24, and a sealing ring can be arranged between the piston 24 and the bending and torsion tube 4, and the piston 24 is pushed and pulled by rotating the screw 22 to complete the application or release of internal pressure to the bending and torsion tube. The double-arm bending and torsion combined experimental device of the present invention further includes an oil pressure sensor 18 installed on the bending and torsion tube for collecting internal pressure, and a pressure gauge 17 for displaying pressure, and the oil pressure sensor 18 is electrically connected to the strain gauge.

[0026] The preferred embodiment of the double-arm bending and twisting combined experimental method provided by the present invention is as follows:

[0027] a. If the loads applied by the worm gear handwheels on both sides to the two loading arms 5 are of the same magnitude and direction, the bending and torsion tube 4 is only subjected to concentrated force at the connection, and the concentrated force is the sum of the loads applied by the two worm gear handwheels. At this time, the bending and torsion tube 4 is a bending deformation member similar to a cantilever beam, so a pure bending test can be achieved;

[0028] b. If the loads applied by the worm gear handwheels on both sides to the two loading arms 5 are of the same magnitude but in opposite directions, the bending and torsion tube 4 is only subjected to torque at the connection, and the torque is twice the product of the unilateral load and the unilateral force arm. At this time, the bending and torsion tube is a torsion deformation member, and the bending and torsion tube is only subjected to torque at the connection of the loading beam, realizing a pure torsion experiment;

[0029] c. If the loads applied by the worm gear handwheels on both sides to the two loading arms 5 are different in magnitude, the concentrated force applied to the bending and torsion tube 4 at the connection point is the sum of the loads applied by the two worm gear handwheels, and the torque applied is the product of the difference between the two loads and the unilateral force arm. At this time, the bending and torsion tube is a bending-torsion combined deformation component, which can realize bending-torsion combined experiments, and the ratio of bending and torsion can be adjusted arbitrarily according to the different loads applied on both sides.

[0030] The above is a detailed introduction to a double-arm bending and twisting combined experimental method and device provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and central idea of ​​the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A double-arm bending and twisting combined test method, characterized in that The loading arms installed on the bending and torsion tube are symmetrically arranged. By adjusting the size and direction of the load applied to the two loading arms, bending, torsion, and bending-torsion loading can be achieved. The bending-torsion ratio can be adjusted arbitrarily during bending-torsion loading to verify the principle of stress superposition; The double-arm bending and twisting combined experimental method specifically comprises the following steps: a. The load applied by the symmetrically installed loading arms is of the same magnitude and direction, and the bending-torsion tube is a bending deformation member similar to a cantilever beam, thereby realizing a pure bending test; b. The loads applied by the symmetrically installed loading arms are of the same magnitude but opposite directions. The bending-torsion tube is only subjected to torque at the connection. The torque is twice the product of the unilateral load and the unilateral force arm. At this time, the bending-torsion tube is a torsion deformation component. The bending-torsion tube is only subjected to torque at the connection of the loading beam, thereby realizing a pure torsion experiment; c. The loads applied to the symmetrically installed loading arms are different in magnitude. The concentrated force applied to the bending-torsion tube at the connection is the sum of the loads applied by the two worm gear handwheels, and the torque applied is the product of the difference between the two loads and the unilateral force arm. At this time, the bending-torsion tube is a bending-torsion combined deformation component, thereby realizing a bending-torsion combined experiment, and the ratio of bending and torsion can be adjusted arbitrarily according to the different magnitudes of the loads applied on both sides.

2. A double-arm bending and twisting combined experimental device for implementing the double-arm bending and twisting combined experimental method according to claim 1, characterized in that , including a bottom plate, a vertical plate installed on the bottom plate, a horizontal bending and twisting tube installed on the vertical plate, two loading arms symmetrically installed on the bending and twisting tube, and a tensile and compressible loading device installed at one end of each loading arm; The loading device comprises a worm gear, a force sensor and a lead screw. The worm gear is mounted on the base plate through a guide device. The force sensor is connected to the worm gear. The lead screw is connected to the force sensor. The lead screw is hinged to the loading arm.

3. The double-arm bending and twisting combined experimental device as claimed in claim 2, characterized in that The guiding device includes a guide rail plate fixedly mounted on the base plate, a guide rail fixedly mounted on the guide rail plate, and a sliding trolley mounted on the guide rail and capable of sliding on the guide rail, and the worm gear is fixedly mounted on the sliding trolley.

4. The double-arm bending and twisting combined experimental device as claimed in claim 2, characterized in that: The lead screw is hinged to the loading arm through a connecting piece and a pin shaft.

5. The double-arm bending and twisting combined experimental device as claimed in claim 2, characterized in that , also includes an internal pressure applying device for providing internal pressure to the bending and twisting tube, the internal pressure applying device is a manual oil pump or a manual screw mechanism arranged in one end of the bending and twisting tube; the manual screw mechanism is a screw rod, the screw rod is inserted into the bending and twisting tube, a piston is arranged in the bending and twisting tube, the screw rod is connected to the piston screw, and the screw rod is engaged with a nut fixed on the bending and twisting tube.

6. The double-arm bending and twisting combined experimental device as claimed in claim 5, characterized in that , also includes an oil pressure sensor installed on the bending and torsion pipe to collect internal pressure, and a pressure gauge to display pressure.

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