An experimental teaching device for measuring the inverse bending moment at the supports of a continuous beam.

Abstract

An experimental teaching device for determining the inverse bending moment at the supports of a continuous beam belongs to the field of mechanics experimental teaching device research and development. The device includes a force loading and measurement structure mounted on a support and two sets of symmetrically arranged simply supported beam model structures; it can be used to determine the inverse bending moment at the supports of a continuous beam teaching model. The device uses simply supported ends as constraints, coupled with high-stiffness loading rods to avoid deformation interference, effectively reducing experimental errors and ensuring accurate and reliable experimental data. An angle indicator fixed to the beam ends allows for direct observation of the rotation angle change at the supports. Combined with a fixed pulley system guiding the loading and a rotating handwheel, the rotational torque is smoothly applied. Loading adjustment is convenient and operation is simple. It can accurately complete the experiment of determining the inverse bending moment at the supports of continuous beams, intuitively demonstrating abstract mechanics principles, and facilitating students' understanding and mastery of structural force laws. The overall structure is simple and practical, easy to build and use, and reliable, fully meeting the experimental teaching needs of structural mechanics-related courses.

Description

Technical Field

[0001] This invention relates to the field of research and development of experimental teaching devices for mechanics, and in particular to an experimental teaching device for measuring the inverse bending moment at the support of a continuous beam. Background Technology

[0002] Mechanics is a fundamental and compulsory course for engineering majors, and mechanics experimental teaching is a required course for university engineering students. The teaching of mechanics experiments is inseparable from relevant experimental teaching instruments and equipment. Continuous beams are a type of load-bearing component frequently used in engineering. How to enable students to intuitively understand the force patterns of continuous beams is crucial for strengthening their understanding and mastery of theoretical knowledge.

[0003] Based on the above problems, it is necessary to develop a mechanical experimental teaching device for continuous beams. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides an experimental teaching device for measuring the inverse bending moment at the support of a continuous beam, which can be used to measure the inverse bending moment at the support of a teaching model of a continuous beam.

[0005] An experimental teaching device for determining the inverse bending moment at the support of a continuous beam teaching model. The device includes a force loading and measurement structure set on a support and two sets of simply supported beam model structures.

[0006] The support includes side supports on both sides and a middle support. A loading beam is provided on the middle support, and a loading handle is provided on the loading beam. A force sensor is provided at the end of the loading handle that passes through the loading beam, and the other side of the force sensor contacts the loading plate.

[0007] In the simply supported beam model structure, the fixed hinge support is set on the middle support, and the movable hinge support is set on the side support. Both the fixed hinge support and the movable hinge support are structures that can rotate around the support axis. A simply supported beam model is set between the fixed hinge support and the movable hinge support, with one end fixedly connected to the fixed hinge support and the other end movably resting on the movable hinge support. Loading weights are set on the simply supported beam model.

[0008] A loading rod and an angle measuring plate are fixedly mounted on the fixed hinge support; a dial indicator is fixedly mounted on the intermediate support, with the measuring rod of the dial indicator in contact with the angle measuring plate; the simply supported beam model drives the fixed hinge support to rotate, thereby causing the loading rod and the angle measuring plate to rotate synchronously. The rotation of the angle measuring plate causes the measuring rod to produce relative displacement, and the amount of displacement is measured by the dial indicator.

[0009] The loading rod is connected to one end of a steel wire rope, and the other end of the steel wire rope, which passes over a fixed pulley, is mounted on the loading plate.

[0010] Furthermore, the two sets of simply supported beam model structures are symmetrically arranged, and the steel wire ropes of the two sets of simply supported beam model structures are respectively connected to the two ends of the loading plate.

[0011] Furthermore, the simply supported beam model includes a left span simply supported beam model and a right span simply supported beam model, and the dial gauge includes a left span dial gauge and a right span dial gauge.

[0012] Furthermore, a left-span simply supported beam model is set between the fixed hinge support and the movable hinge support, with one end fixedly connected to the fixed hinge support and the other end movably resting on the movable hinge support; a left-span loading weight is set on the left-span simply supported beam model; the measuring rod of the left-span dial indicator is in contact with the angle measuring plate.

[0013] Furthermore, a right-span simply supported beam model is set between the fixed hinge support and the movable hinge support, with one end fixedly connected to the fixed hinge support and the other end movably resting on the movable hinge support; a right-span loading weight is set on the right-span simply supported beam model; the measuring rod of the dial indicator of the right span is in contact with the angle measuring plate.

[0014] Furthermore, the left-span simply supported beam model and the right-span simply supported beam model have the same cross-sectional shape and the same cross-sectional dimensions, and the cross-section adopts a rectangular cross-section, an I-shaped cross-section, or a box-shaped cross-section.

[0015] Furthermore, the left-span simply supported beam model and the right-span simply supported beam model are made of the same material, and the material is ensured to remain in an elastic state during operation.

[0016] The experimental teaching device for measuring the inverse bending moment at the support of a continuous beam includes: a single-span beam teaching model, a loading device, an angle indicator device, and a fixed pulley system for guiding the loading.

[0017] There are two single-span beam teaching models. The two single-span beam teaching models must have the same cross-sectional shape and the same cross-sectional dimensions. The cross-section can be rectangular, I-shaped, box-shaped, or other similar shapes.

[0018] The single-span beam teaching model must be made of the same material, such as steel or other materials, but it must be ensured that the material remains in an elastic state during operation.

[0019] The boundary constraint condition for the single-span beam teaching model is that both ends are simply supported. One end, used for angle measurement, is connected to a loading rod, which must have sufficient stiffness to ensure that no significant deformation occurs during the experiment.

[0020] The pointer of the angle indicator must be tightly fixed to the simply supported end of the single-span beam, and at the same time, it can display the changes caused by the rotation of the simply supported end at the support during the loading process.

[0021] The fixed pulley block guiding loading system consists of a pull wire, fixed pulleys, loading plate, etc., and can apply rotational torque to the end of a simply supported beam.

[0022] The loading device is a rotary handwheel.

[0023] The measurement method for the experimental teaching device used to determine the inverse bending moment at the support of a continuous beam teaching model includes the following steps:

[0024] S1. The lower end of the loading handle is connected to a force sensor, the lower end of the force sensor is fixed to the loading plate, and both ends of the loading plate are connected to steel wire ropes. The steel wire ropes pass over fixed pulleys, and the other end of the steel wire ropes is connected to the loading rod. The distance from the connection point of the steel wire rope and the loading rod to the left span simply supported beam model is H, and the distance from the connection point of the steel wire rope and the loading rod to the right span simply supported beam model is also H, that is, the lever arms H of the two are equal.

[0025] S2. When the loading handle is rotated, a torque is applied to the fixed hinge support through the loading plate, wire rope and loading rod, and the fixed hinge support rotates.

[0026] S3. When the fixed hinge support rotates, the angle measuring plate produces the same angle; the angle measuring plate is in close contact with the measuring rod. When the angle measuring plate rotates, the measuring rod produces a relative displacement, which reflects the magnitude of the rotation angle; the relative displacement is measured by the left span dial indicator and the right span dial indicator respectively.

[0027] S4. When the relative displacement readings of the dial gauges on the left and right spans are the same, it means that φ1=φ=φ2; at this time, the corresponding force value F is read by the force sensor.

[0028] The product of the force value F / 2 and the lever arm H, FH / 2, is the support inverse moment at the fixed hinge support of the double-span continuous simply supported beam model.

[0029] The beneficial effects of this invention are as follows: The device uses two single-span beam teaching models with identical cross-sections, dimensions, and materials, which always maintain an elastic state. It is constrained by simply supported ends and equipped with high-stiffness loading rods to avoid deformation interference, effectively reducing experimental errors and ensuring accurate and reliable experimental data. The angle indicator device fixed to the beam end allows for direct observation of the rotation angle change at the support. Combined with the fixed pulley group guiding loading system and rotating handwheel, the rotational torque is applied smoothly. The loading adjustment is convenient and the operation is simple. It can accurately complete the experiment of measuring the inverse bending moment of continuous beam support, intuitively demonstrating the abstract mechanical principles, and making it easier for students to understand and master the structural force law. The overall structure is simple and practical, and it is convenient to build and use, which can fully meet the experimental teaching needs of structural mechanics-related courses. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure provided for an embodiment of the present invention.

[0031] Figure 2 A front view of the overall structure provided for an embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram illustrating the simply supported beam model provided in an embodiment of the present invention.

[0033] Figure 4 This is a schematic diagram of a continuous beam model provided in an embodiment of the present invention.

[0034] In the diagram: 1. Left span simply supported beam model; 2. Right span simply supported beam model; 3. Left span loading weight; 4. Right span loading weight; 5. Movable hinge support; 6. Fixed hinge support; 7. Angle measuring plate; 8. Left span dial indicator; 9. Measuring rod; 10. Fixed pulley; 11. Loading handle; 12. Support; 12a. Side support; 12b. Middle support; 12c. Loading crossbeam; 13. Steel wire rope; 14. Loading plate; 15. Force sensor; 16. Right span dial indicator; 17. Mechanical model of a double-span continuous simply supported beam; 18. Loading rod. Detailed Implementation

[0035] To make the technical problems solved by this invention, the technical solutions adopted, and the technical effects achieved clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings, not all of them.

[0036] Figure 1 This is a schematic diagram of the overall structure provided for an embodiment of the present invention. Figure 1 As shown in the figure, this invention provides an experimental teaching device for determining the inverse bending moment at the support of a continuous beam, comprising: a single-span beam teaching model, a loading device, an angle indicating device, and a fixed pulley system for guiding the loading. The single-span beam teaching model consists of two pieces, both of which must have the same cross-sectional shape and dimensions. The cross-section can be rectangular, I-shaped, box-shaped, or similar.

[0037] The single-span beam teaching model must be made of the same material, such as steel or other materials, but it must be ensured that the material remains in an elastic state during operation.

[0038] The boundary constraint condition for the single-span beam teaching model is that both ends are simply supported. One end, used for angle measurement, is connected to a loading rod, which must have sufficient stiffness to ensure that no significant deformation occurs during the experiment.

[0039] The pointer of the angle indicator must be in close contact with the simply supported end extension plate of the single-span beam, and can simultaneously display the changes caused by the rotation of the simply supported end at the support during the loading process.

[0040] The fixed pulley block guiding loading system consists of a pull wire, fixed pulleys, loading plate, etc., and can apply rotational torque to the end of a simply supported beam.

[0041] The loading device is a rotary handwheel.

[0042] The present invention will be further described below with reference to the embodiments:

[0043] An experimental teaching device for determining the inverse bending moment at the support of a continuous beam teaching model. The device includes a force loading and measurement structure set on a support 12 and two sets of simply supported beam model structures: a left simply supported beam model structure and a right simply supported beam model structure.

[0044] The bracket 12 includes side brackets 12a on both sides and a middle bracket 12b. A loading beam 12c is provided on the middle bracket 12b. A loading handle 11 is provided on the loading beam 12c. A force sensor 15 is provided at the end of the loading handle 11 that passes through the loading beam 12c. The other side of the force sensor 15 is in contact with the loading plate 14.

[0045] In the left simply supported beam model structure, the fixed hinge support 6 is set on the middle support 12b, and the movable hinge support 5 is set on the side support 12a. Both the fixed hinge support 6 and the movable hinge support 5 are structures that can rotate around the support axis. The left span simply supported beam model 1 is set between the fixed hinge support 6 and the movable hinge support 5. One end of the model is fixedly connected to the fixed hinge support 6, and the other end is movably placed on the movable hinge support 5. The left span loading weight 3 is set on the left span simply supported beam model 1.

[0046] A loading rod 18 and an angle measuring plate 7 are fixedly mounted on the fixed hinge support 6. A left-span dial indicator 8 is fixedly mounted on the intermediate support 12b, with its measuring rod 9 in contact with the angle measuring plate 7. The left-span simply supported beam model 1 drives the fixed hinge support 6 to rotate, causing the loading rod 18 and the angle measuring plate 7 to rotate synchronously. The rotation of the angle measuring plate 7 causes a relative displacement of the measuring rod 9, which is measured by the left-span dial indicator 8. One end of the loading rod 18 is connected to a steel wire rope 13, and the other end of the steel wire rope 13, which passes over a fixed pulley 10, is located at the left end of the loading plate 14.

[0047] Similarly, in the right simply supported beam model structure, the fixed hinge support 6 is set on the middle support 12b, and the movable hinge support 5 is set on the side support 12a. Both the fixed hinge support 6 and the movable hinge support 5 are structures that can rotate around the support axis. The right span simply supported beam model 2 is set between the fixed hinge support 6 and the movable hinge support 5. One end of the model is fixedly connected to the fixed hinge support 6, and the other end is movably placed on the movable hinge support 5. The right span loading weight 4 is set on the right span simply supported beam model 2.

[0048] A loading rod 18 and an angle measuring plate 7 are fixedly mounted on the fixed hinge support 6. A right-span dial indicator 16 is fixedly mounted on the intermediate support 12b, with its measuring rod 9 in contact with the angle measuring plate 7. The right-span simply supported beam model 2 drives the fixed hinge support 6 to rotate, causing the loading rod 18 and the angle measuring plate 7 to rotate synchronously. The rotation of the angle measuring plate 7 causes a relative displacement of the measuring rod 9, which is measured by the right-span dial indicator 16. One end of the loading rod 18 is connected to a steel wire rope 13, and the other end of the steel wire rope 13, which passes over a fixed pulley 10, is located at the right end of the loading plate 14.

[0049] Figure 1 The experimental teaching device shown is for simulating Figure 4 The double-span continuous simply supported beam model 17 is shown. Figure 4 This is a common double-span continuous beam model in engineering. Figure 4 In the double-span continuous simply supported beam model 17, both the left and right ends are movable hinged supports 5, and a fixed hinged support 6 is provided in the middle. Assuming the span of the left-span simply supported beam 1 is L1, and the span of the right-span simply supported beam 2 is L2 (L1 and L2 can be equal or unequal), a left-span loading weight 3 is applied at the mid-span of the left-span simply supported beam 1, and a right-span loading weight 4 is applied at the mid-span of the right-span simply supported beam 2 (weights 3 and 4 can be equal or unequal, and their positions on the spans of the simply supported beams can be the same or different), then the double-span continuous simply supported beam model 17 will experience the following... Figure 4 The bending deformation is shown. An angle φ will be generated at the fixed hinge support 6.

[0050] If the double-span continuous simply supported beam model 17 is disconnected from the fixed hinge support 6, as follows: Figure 1 , Figure 2 and Figure 3 As shown. The left span of the double-span continuous simply supported beam model 17 will become the left span simply supported beam model 1, and the right span of the double-span continuous simply supported beam model 17 will become the right span simply supported beam model 2. Assume that the rotation angle of the left span simply supported beam model 1 at the fixed hinge support 6 is φ1, and the rotation angle of the right span simply supported beam model 2 at the fixed hinge support 6 is φ2. At this time, φ1≠φ, φ2≠φ.

[0051] If the same end moment is applied to the fixed hinge support 6 of the left span simply supported beam model 1 and the fixed hinge support 6 of the right span simply supported beam model 2 respectively, and the magnitude of the end moment is adjusted so that φ1=φ=φ2, the corresponding end moment is equal to the reverse moment at the support corresponding to the fixed hinge support 6 of the double span continuous simply supported beam model 17.

[0052] like Figure 1 and Figure 2The device shown has a force sensor 15 connected to the lower end of the loading handle 11. The lower end of the force sensor 15 is fixed to the loading plate 14. Steel wire ropes 13 are connected to both ends of the loading plate 14, passing over a fixed pulley 10. The other end of the steel wire rope 13 is connected to the loading rod 18. The distance H from the connection point of the steel wire rope 13 and the loading rod 18 to the left span simply supported beam model 1 is equal to the distance H from the connection point of the steel wire rope 13 and the loading rod 18 to the right span simply supported beam model 2; that is, the lever arms H of both are equal.

[0053] When the loading handle 11 is rotated, a torque is applied to the fixed hinge support 6 through the loading plate 14, wire rope 13, and loading rod 18, causing the fixed hinge support 6 to rotate. Because the loading rod 18, the fixed hinge support 6, and the angle measuring plate 7 are fixed together, the angle measuring plate 7 will produce the same angle when the fixed hinge support rotates. The angle measuring plate 7 is in close contact with the measuring rod 9. When the angle measuring plate 7 rotates, the measuring rod 9 will produce a relative displacement. This displacement reflects the magnitude of the rotation angle, which can be measured using the left span dial gauge 8 and the right span dial gauge 16. When the relative displacement readings of the left span dial gauge 8 and the right span dial gauge 16 are the same, it means that φ1=φ=φ2. At this time, the corresponding force value F can be read by the force sensor 15. The product of this force value F / 2 and the lever arm H, FH / 2, is the support reaction moment of the double-span continuous simply supported beam model 17 at the fixed hinge support 6.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions for some or all of the technical features, do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An experimental teaching device for measuring the inverse bending moment at the support of a continuous beam teaching model, characterized in that, The device includes a force loading and measurement structure mounted on a support (12) and a symmetrically arranged simply supported beam model structure; The bracket (12) includes two side brackets (12a) and a middle bracket (12b). A loading beam (12c) is provided on the middle bracket (12b). A loading handle (11) is provided on the loading beam (12c). A force sensor (15) is provided at the end of the loading handle (11) that passes through the loading beam (12c). The other side of the force sensor (15) is in contact with the loading plate (14). In the simply supported beam model structure, the fixed hinge support (6) is set on the middle support (12b), and the movable hinge support (5) is set on the side support (12a). Both the fixed hinge support (6) and the movable hinge support (5) are structures that can rotate around the support axis. A simply supported beam model is set between the fixed hinge support (6) and the movable hinge support (5), with one end fixedly connected to the fixed hinge support (6) and the other end movably resting on the movable hinge support (5). Loading weights are set on the simply supported beam model. A loading rod (18) and an angle measuring plate (7) are fixedly installed on the fixed hinge support (6); a dial indicator is fixedly installed on the intermediate support (12b), and the measuring rod (9) of the dial indicator is in contact with the angle measuring plate (7); the simply supported beam model drives the fixed hinge support (6) to rotate, and then the loading rod (18) and the angle measuring plate (7) rotate synchronously. The rotation of the angle measuring plate (7) causes the measuring rod (9) to produce relative displacement, and the displacement is measured by the dial indicator; The loading rod (18) is connected to one end of the wire rope (13), and the other end of the wire rope (13) is placed on the loading plate (14) after passing over the fixed pulley (10).

2. The experimental teaching device for determining the inverse bending moment at the support of a continuous beam teaching model according to claim 1, characterized in that, Two sets of simply supported beam model structures are symmetrically arranged, and the steel wire ropes (13) of the two sets of simply supported beam model structures are respectively connected to the two ends of the loading plate (14).

3. The experimental teaching device for determining the inverse bending moment at the support of a continuous beam teaching model according to claim 2, characterized in that, The simply supported beam model includes a left span simply supported beam model (1) and a right span simply supported beam model (2), and the dial gauge includes a left span dial gauge (8) and a right span dial gauge (16).

4. The experimental teaching device for determining the inverse bending moment at the support of a continuous beam teaching model according to claim 3, characterized in that, A left-span simply supported beam model (1) is set between the fixed hinge support (6) and the movable hinge support (5). One end of the model is fixedly connected to the fixed hinge support (6), and the other end is movably placed on the movable hinge support (5). A left-span loading weight (3) is set on the left-span simply supported beam model (1). The measuring rod (9) of the left-span dial gauge (8) is in contact with the angle measuring plate (7).

5. The experimental teaching device for determining the inverse bending moment at the support of a continuous beam teaching model according to claim 4, characterized in that, A right-span simply supported beam model (2) is set between the fixed hinge support (6) and the movable hinge support (5). One end of the model is fixedly connected to the fixed hinge support (6), and the other end is movably placed on the movable hinge support (5). A right-span loading weight (4) is set on the right-span simply supported beam model (2). The measuring rod (9) of the right-span dial gauge (16) is in contact with the angle measuring plate (7).

6. The experimental teaching device for determining the inverse bending moment at the support of a continuous beam teaching model according to claim 5, characterized in that, The left-span simply supported beam model (1) and the right-span simply supported beam model (2) have the same cross-sectional form and the same cross-sectional dimensions. The cross-section adopts a rectangular cross-section, an I-shaped cross-section, or a box-shaped cross-section.

7. The experimental teaching device for determining the inverse bending moment at the support of a continuous beam teaching model according to claim 6, characterized in that, The left-span simply supported beam model (1) and the right-span simply supported beam model (2) are made of the same material, and the material is always kept in an elastic state during operation.

8. The measurement method of the experimental teaching device for determining the inverse bending moment at the support of a continuous beam teaching model according to claim 6, characterized in that, Includes the following steps: S1. The lower end of the loading handle (11) is connected to the force sensor (15). The lower end of the force sensor (15) is fixed on the loading plate (14). The two ends of the loading plate (14) are connected to the wire rope (13). The wire rope (13) passes over the fixed pulley (10). The other end of the wire rope (13) is connected to the loading rod (18). The distance from the connection point of the wire rope (13) and the loading rod (18) to the left span simply supported beam model (1) is H. The distance from the connection point of the wire rope (13) and the loading rod (18) to the right span simply supported beam model (2) is also H. That is, the lever arms H of the two are equal. S2. When the loading handle (11) is rotated, a torque is applied to the fixed hinge support (6) through the loading plate (14), the wire rope (13) and the loading rod (18), and the fixed hinge support (6) rotates. S3. When the fixed hinge support rotates, the angle measuring plate (7) produces the same angle. The angle measuring plate (7) is in close contact with the measuring rod (9). When the angle measuring plate (7) rotates, the measuring rod (9) produces a relative displacement, which reflects the magnitude of the rotation angle. The relative displacement is measured by the left span dial indicator (8) and the right span dial indicator (16) respectively. S4. When the relative displacement readings of the left span dial gauge (8) and the right span dial gauge (16) are the same, it means that φ1=φ=φ2; at this time, the corresponding force value F is read by the force sensor (15). The product of the force value F / 2 and the lever arm H, FH / 2, is the support inverse moment of the double-span continuous simply supported beam model (17) at the fixed hinge support (6).

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