CN208969936U - A comprehensive experimental platform for statics - Google Patents

Abstract

A statics comprehensive experimental platform includes a bench with a chute, a plane frame structure and a plane three-hinge arch structure installed at the front and rear ends of the bench, a loading column whose position is adjustable in the middle of the bench, and is arranged on the loading column A horizontal rod with adjustable orientation and capable of moving up and down, set at the pulley at the end of the horizontal rod; the connection between the plane frame structure and the platform can be fixed hinged at both ends or fixed hinged at one end and movable hinged at the other end , The rod material of the plane frame structure and the plane three-hinge arch structure can be made of materials with different elastic modulus, and the plane frame structure and the plane three-hinge arch structure use different loading positions during the experiment, and the transferability of the contrasting force is different. The influence of the structure on the restraint force and internal force, the position, height and orientation of the loading device can be adjusted conveniently, in addition to the convenient loading of the plane frame and the three-hinged arch, it can also independently complete the friction coefficient measurement experiment.

Description

A comprehensive experimental platform for statics

technical field

The utility model relates to the field of mechanical experiments, in particular to a statics comprehensive experimental platform.

Background technique

Most of the existing basic mechanics experimental platforms are aimed at the knowledge points in the material mechanics course, and the experimental platforms for the relevant knowledge points in the theoretical mechanics course are limited, and the experimental projects are outdated. The lack of a comprehensive experimental platform supports students to combine the knowledge points in the theoretical mechanics and material mechanics courses, carry out comprehensive experiments, and further understand the applicability of mechanical models and related principles.

SUMMARY OF THE INVENTION

In order to overcome the above problems, the purpose of this utility model is to propose a static comprehensive experimental platform, which can realize plane static indeterminacy, statically indeterminate structure restraint force, internal force measurement and friction coefficient measurement. The experiment includes statically indeterminate and hyperstatically indeterminate mechanical models composed of rods with different elastic moduli, loaded at different points, and compares the influence of force transferability on the restraint force and internal force of statically indeterminate and hyperstatically indeterminate structures to gain an in-depth understanding The application conditions of force transferability and its influence law, the loading device can independently measure the friction coefficient to verify the Euler friction formula. This comprehensive experiment has positive and important significance for strengthening the cultivation of students' comprehensive practical ability, and stimulating students to deeply understand the transferability of power, the difference between statically indeterminate and statically indeterminate models, and static sliding friction.

In order to achieve the above object, the technical scheme of the present utility model is achieved in this way:

A statics comprehensive experimental platform, comprising a bench 1 with a chute, a plane three-hinge arch structure 2 and a plane frame structure 3 are respectively installed at the front and rear ends of the bench 1, and a position-adjustable load cell is installed in the middle of the bench 1 Column 4, the loading column 4 is provided with a horizontal rod 5 that can be adjusted in orientation and can move up and down on the loading column 4, and the end of the horizontal rod 5 is provided with a pulley 6; the plane three-hinge arch structure 2 and the plane frame structure 3 are both There are two loading points, preferably two loading points are on the vertical rods of the plane three-hinge arch structure 2 and the plane frame structure 3, and must be located on the same horizontal line; the plane three-hinge arch structure 2 and the plane frame structure 3 are also set There are strain gauges attached to the strain tester that measure the strain of the member when loaded at two loading points.

The rods of the planar frame structure 3 and the planar three-hinge arch structure 2 can be replaced with rods with the same cross-sectional shape and size and different elastic moduli of materials.

The pulley 6 adopts a moving pulley in the plane frame and three-hinge arch loading experiments, and adopts a static pulley in the friction experiment.

The plane frame structure 3 is connected to the platform 1 by means of fixed hinge at both ends to form a statically indeterminate structure, or fixed hinge at one end and movable hinge at the other end to form a statically indeterminate structure.

The planar three-hinge arch structure 2 is a statically indeterminate three-hinge arch formed by two right-angle rods hinged through hinges 11 .

The static comprehensive experimental platform of the utility model can carry out the constraint force measurement and the internal force measurement experiment of the plane statically indeterminate structure and the statically indeterminate structure with different constraints and different materials. During the experiment, the students independently design the experiment according to the experiment assignment book. They can measure the change of the constraint force before and after the force slips along the action line and the change of the internal force of the rod, observe the effect of the force before and after the slip, and can also change the constraint type, compare The effect of the same size of force on the statically indeterminate structure and the super-statically indeterminate structure, replace the static pulley with different roughness, measure the static sliding friction coefficient, and verify the Euler friction formula. The utility model has the advantages of replaceable rod material, replaceable constraint type, replaceable loading position, simple structure and convenient operation. The experimental projects that can be set up are of great importance for strengthening the cultivation of students' comprehensive practical ability, stimulating students' in-depth understanding of the transferability inference, understanding the impact of loads on statically indeterminate structures, static sliding friction and friction coefficient measurement methods, etc. meaning.

Description of drawings

Figure 1 is a front view of the present invention.

FIG. 2 is a front view of the frame structure.

Figure 3 is a front view of a three-hinge arch.

Detailed ways

The structural principle and working principle of the present utility model are described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, Figure 2 and Figure 3, a statics comprehensive experimental platform includes a bench 1 with a chute, a plane three-hinge arch structure 2 is installed in the front of the bench 1, a plane frame structure 3 is installed at the back, and the platform A loading column 4 is installed in the middle of the frame 1, a horizontal rod 5 that can move up and down on the loading column 4 is installed on the loading column 4, and a pulley 6 is installed at the end of the horizontal rod 5, and the orientation of the horizontal rod 5 is adjustable. The plane where the radius of the pulley is located is coplanar with the plane frame structure 3, one end of the flexible cable is tied to the loading point of the plane frame structure 3, and the other end suspends the weight across the pulley 6. The plane frame structure 3D point is pasted with the plane frame strain gauge 14, the plane There are two loading points on the frame structure 3. The sliding loading column 4 is loaded in turn on the two loading points 7 and 8 on the vertical rod of the plane frame structure 3. The loading points 7 and 8 are on the same horizontal line, and the level is changed. The orientation of the rod 5 is such that the plane where the radius of the pulley is located is coplanar with the plane where the plane three-hinge arch structure 2 is located, and the weight is suspended across the pulley with a flexible cable, and two loading points 9 and 10 is loaded in sequence, the loading points 9 and 10 are on the same horizontal line, the plane three-hinge arch strain gauge 15 is pasted on the E point of the right rod of the plane three-hinge arch structure 2, and the pulley 6 in the loading device can be a moving pulley and a static pulley. Moving pulleys were used in the three-hinged arch and plane frame loading experiments, and static pulleys were used in the friction coefficient measurement experiments.

The plane frame structure 3 and the platform 1 can be connected by a fixed hinge support and a movable hinge support, or can be connected by two fixed hinge supports to realize statically indeterminate and super-statically indeterminate structures. The materials of the planar three-hinge arch structure 2 can be replaced, and materials with different elastic moduli are used to compare the influence of the elastic moduli of the materials on the experimental results. The pulley 6 can use static pulleys with different surface roughness, and measure different materials by hanging weights The static sliding friction coefficient between.

The working principle of the utility model is:

According to the self-designed and confirmed plan, the two ends of the plane frame structure 3 are connected to the bench 1 through fixed hinge supports to form a statically indeterminate structure, and the orientation of the pulley 6 is adjusted so that the plane where the pulley radius is located is the same as the plane frame structure 3. One end of the flexible cable is tied to the loading point of the plane frame structure 3, and the other end hangs the weight across the pulley 6, and is loaded in the horizontal direction at the two loading points 7 and 8 respectively, and the different loads are measured by the plane frame strain gauge 14. The strain of the rod at point D when the position is in the position, the signal of the plane frame strain gauge 14 at point D is connected to the strain tester placed next to the experimental device, and the connection is made according to the output characteristics of the Wheatstone bridge and the principle of internal force testing, and the axis of the test rod is Force and bending moment, the test results reflect the influence of force translation along its line of action in the statically indeterminate structure on the restraint force and internal force; the fixed hinge support at one end of the plane frame structure 3 is replaced with a movable hinge support, the plane The frame structure 3 becomes a statically indeterminate structure, and is loaded horizontally at two loading points 7 and 8 respectively. The strain at point D is measured, and the constraint force and internal force are calculated. The measurement results reflect the force on the statically indeterminate structure. and internal influence.

For the plane three-hinge arch structure 2, the fixed hinge support is installed on the bench 1 to form a plane statically indeterminate structure. The plane where the arch structure 2 is located is coplanar, and the weight is suspended by using a flexible cable across the pulley. The two loading points 9 and 10 on the vertical rod of the plane three-hinge arch structure 2 are loaded with the same load in the horizontal direction in turn. The three-hinged arch strain gauge 15 measures the strain at point E at different loading positions. The signal of the three-hinged arch strain gage 15 at point E is connected to the strain gauge placed next to the experimental device, and is wired according to the output characteristics of the Wheatstone bridge and the principle of internal force testing. , test the axial force and bending moment of the rod, and the measurement results reflect the influence of the force on the binding force at the hinge 11 and the influence of the internal force at E before and after the force slips along the action line. The materials of the two right-angle rods were replaced, and the restraint force and internal force were measured under the same loading conditions, and the restraint force and internal force of the statically indeterminate three-hinge arch of different materials under the same external load were compared.

The loading device used in this test bench, in the plane frame and three-hinged arch loading experiment, the pulley 6 adopts a movable pulley, and the weight of the weight suspended by the flexible cable is the size of the horizontal load. Except for the horizontal loading, the pulley is replaced with a static pulley. A flexible cable is crossed over the static pulley. One end of the flexible cable hangs a weight, the weight of the weight is G, and the other end is pulled by a force-measuring spring, and the weight is slowly lifted. The lifting process ensures that the reading of the force-measuring spring remains unchanged. The magnitude of the pulling force is F, the wrapping angle of the cable on the pulley is β, the weight of the weight G, the reading F of the force measuring spring, and the wrapping angle β of the flexible cable on the pulley are brought into the Euler friction formula F=Ge ^uβ , the static sliding friction coefficient u of the cable and the static pulley is calculated.

Claims (5)

1. a statics comprehensive experimental platform, is characterized in that, comprises the bench (1) with chute, the front and rear ends of the bench (1) are respectively installed with plane three-hinge arch structure (2) and plane frame structure (3) ), a position-adjustable loading column (4) is installed in the middle of the platform (1), and the loading column (4) is provided with a horizontal rod (5) whose orientation is adjustable and can move up and down on the loading column (4), The end of the horizontal rod (5) is provided with a pulley (6); the plane three-hinge arch structure (2) and the plane frame structure (3) have two loading points, and when the two loading points are in the plane three-hinge arch structure (2) and the vertical rod of the plane frame structure (3), they must be located on the same horizontal line; the plane three-hinge arch structure (2) and the plane frame structure (3) are also provided with a strain tester connected to measure at the two Strain gauge for member strain when loaded at one loading point. 2. A kind of comprehensive statics experimental platform according to claim 1, characterized in that: the rods of the plane frame structure (3) and the plane three-hinge arch structure (2) can be replaced with materials of the same cross-sectional shape and size Rods with different elastic moduli. 3. A kind of comprehensive statics experimental platform according to claim 1, is characterized in that: described pulley (6) adopts moving pulley in plane frame and three hinge arch loading experiment, adopts static pulley in friction experiment. 4. A kind of comprehensive statics experimental platform according to claim 1, is characterized in that: the connection mode of described plane frame structure (3) and platform (1) adopts both ends to be fixed and hinged to form a statically indeterminate structure, or One end is fixedly hinged and the other end is movable hinged to form a statically indeterminate structure, and the structure shape and size are exactly the same under the two connection modes. 5. A kind of statics comprehensive experimental platform according to claim 1, is characterized in that: described plane three-hinged arch structure (2) is a statically indeterminate three-hinge hinged by two right-angle rods through hinges (11) arch.