CN105206142B - A kind of experiment device for teaching for intuitively changing displacement method - Google Patents

Abstract

The invention provides a teaching experiment device which visualizes the displacement. The device comprises a rigid frame structure, a worm gear loading device, a supporting and restraining device, a rotation angle restraining and loading device and measuring equipment. The rigid frame structure is formed by connecting rectangular thin-walled rods perpendicular to each other through the rigid joint plate; the worm gear loading device realizes the loading and unloading of the rigid frame structure; the support and restraint device includes the restraint support of the rigid frame structure and the reaction frame , the constrained support of the rigid frame structure includes a fixed support and a hinged support, a reaction frame, a reaction frame and a base; the rotation angle constraint and loading device measures the angular displacement value through the rotation angle sensor; the measuring equipment includes force sensors, strain gauges and Corner sensor. The experimental model of the device is flexible and variable; according to the needs of the experimental content, different sub-experimental models can be assembled, and various methods of displacement method experiments can be carried out. The results obtained by various methods are convenient for mutual comparison and comparison with theoretical results.

Description

A Teaching Experimental Device Visualizing the Displacement Method

technical field

The invention belongs to the field of experimental teaching of structural mechanics for civil engineering specialty, and relates to an experimental device for visualizing displacement method.

Background technique

Structural mechanics is a compulsory subject for civil engineering majors in colleges and universities. The displacement method is the basic method of structural mechanics to solve the internal force and displacement of statically indeterminate structures under static loads.

The statically indeterminate structure is different from the statically indeterminate structure in calculation. The internal force of the hyperstatically indeterminate structure cannot be obtained from the static equilibrium condition alone, and the deformation coordination condition must be considered at the same time. For the convenience of calculating problems, a part of all the unknowns of the hyperstatically indeterminate structure is often selected as the basic unknowns. Displacement method is a method to solve statically indeterminate structures according to static equilibrium conditions by taking certain displacements as basic unknowns.

At present, the teaching method of structural mechanics in colleges and universities is mainly theoretical teaching. Due to the lack of experimental verification of relevant theories, some students do not have a deep understanding of the relevant theories, and even have doubts about the relevant theories. Introducing experimental content into the daily teaching of structural mechanics in colleges and universities is an inevitable trend in the development of structural mechanics teaching in the future.

Contents of the invention

Aiming at the deficiencies of the existing technology and changing the current situation of lack of relevant experimental content in the teaching of structural mechanics, a teaching experimental device that visualizes the displacement method is invented. This teaching experimental device can realize the experimentalization of the teaching content of the structural mechanics displacement method, and realize The verification of the displacement method theory, and the reason for the experimental error can be found out through the difference between the experiment and the theory, so that students can have a deeper understanding of the theoretical knowledge of the displacement method through personal practice and analysis.

Technical scheme of the present invention is as follows:

A teaching experiment device that visualizes the displacement method is composed of a rigid frame structure, a worm gear loading device, a rotation angle constraint and loading device, a support and constraint device, and a measuring device.

The rigid frame structure is composed of vertical rectangular thin-walled rods 3a, horizontal rectangular thin-walled rods 3b and rigid joint discs 4a. One end of the vertical rectangular thin-walled rod 3a is connected with the first rigid joint plate 4a with grooves through bolts; the other end is connected with the second rigid joint plate 4b with grooves through bolts, so as to realize the rigid frame structure and Fixed support connections. One end of the transverse rectangular thin-walled rod 3b is connected with the first rigid joint plate 4a with grooves through bolts; the other end is connected with the hinged joint plate 5 with grooves through bolts to realize the rigid frame structure and hinge support Connection. Both the rigid joint plate and the hinged joint plate adopt the same stiffness as the connected rods, and are connected to the joint plate by bolts to form an equal stiffness model.

The worm gear loading device is composed of a worm gear lifter 6 , a loading rod 9 , a ball joint 8 and a rod clamp 10 . One end of the worm gear lifter 6 is fixedly connected to the first trolley platform 12a through bolts, and the first trolley platform 12a is installed on the guide rail of the reaction frame 1 through the four slide blocks at the bottom, and the first trolley platform 12a can be arbitrarily moved along the guide rail of the reaction frame 1. Adjust the height; the other end of the worm lifter 6 is connected to the force sensor 7 through threads, and the worm lifter 6 applies a load to the rigid frame structure by rotating the hand wheel; the force sensor 7 is connected to the ball hinge 8 through threads, and the ball hinge 8 is connected to the load through threads. The rod 9 is connected, and the loading rod 9 is connected with the rod clamp 10 through threads, and the ball hinge 8 avoids the influence of the loading device on the rigid frame structure by the bending moment through its own free rotation; the rod clamp 10 includes a pin 23, a loading rod connector 22 and two rod clips 24 of different sizes; the large rod clip 24 has a pin hole on one side, and the loading rod connector 22 has a pin hole on one side, and the two are connected together by a pin 23; the rectangular thin-walled The rod 3a vertically passes through the groove formed by two rod clips 24, and each rod clip 24 has four bolt holes, and the rectangular thin-walled rod 3a is connected with the rod clip 24 by bolts; The clamp 10 can realize the connection of the loading device with the horizontal thin-walled rod 3b or the vertical thin-walled rod 3a, and at the same time, the pin structure of the rod clamp 10 can avoid the transmission of bending moments. The loading and unloading of the rigid frame structure is realized through the worm gear loading device. The worm gear loading device can manually control the application of tension and pressure, and the loaded load is displayed on the computer through the force sensor 7 to realize the loading and unloading of the rigid frame structure.

The rotation angle restraint and loading device is composed of XY-direction follow-up workbench 20, torque sensor 18 and lead screw reducer 19, and XY-direction follow-up workbench 20 is composed of horizontal guide rail 13d, vertical guide rail 13c, sixth trolley platform 12f and seventh The trolley platform consists of 12g. One end of the torque sensor 18 is fixed on the first rigid joint plate 4a by bolts, and the other end is inserted into the lead screw reducer 19; the lead screw reducer 19 is installed on the sixth trolley platform 12f by bolts, and the sixth trolley platform 12f passes The block is connected to the vertical guide rail 13c, the vertical guide rail 13c is connected to the seventh trolley platform 12g through bolts, the seventh trolley platform 12g is connected to the horizontal guide rail 13d through the slider, and the horizontal guide rail 13d is connected to the middle part of the side reaction force frame 21 plate through bolts connected. The XY-direction follow-up table 20 can make the rotation angle constraint and loading device move freely along the horizontal guide rail 13d and the vertical guide rail 13c with the structure; the rotation angle constraint and loading device can be used to constrain the rotation of the rigid frame structure on the first rigid joint disk 4a , the torque generated by the rigid frame structure at the joint can be measured by the torque sensor; the rotation angle restraint and loading device can also apply torque to the first rigid joint disk 4a of the rigid frame structure, so that the rigid frame structure generates an angle at the joint. Displacement, the angular displacement value can be measured by the rotation angle sensor.

The support and restraint device is composed of the reaction force frame and the restraint support of the rigid frame structure.

The reaction frame is in various forms such as "L"-shaped rigid frame, door-shaped rigid frame, etc., and is composed of a reaction force frame 1, a lateral reaction force frame 21 and a base 2. 1, the lower beam lower part is used to support the whole device. Described reaction force frame 1 is made up of two upper and lower crossbeams of built-in guide rail and two left and right columns of built-in guide rail, can fix worm gear and worm elevator 6 and dolly platform on each crossbeam and upright column, and lower crossbeam fixes the second dolly platform 12b, a The side column fixes the first trolley platform 12a; the lateral reaction force frame 21 is composed of a flat plate and a column, and the column is connected up and down with the upper and lower beams of the reaction frame 1 through a slider, and the flat plate is connected with the column through a slider, and the plate can slide up and down on the column The lateral reaction force frame 21 is used to install the corner restraint and loading device, and the middle part of the plate is connected with the horizontal guide rail 13d of the X-Y direction follow-up worktable through bolts.

The constraint support of the rigid frame structure includes a fixed support and a fixed hinge support. The fixed support is composed of the first horizontal support sensor 11a, the first vertical support sensor 11b, and the second rigid joint plate 4b; the bottom end of the adapter plate is connected with the second trolley platform 12b through bolts, and one side of the adapter plate Connect with the first horizontal support sensor 11a through bolts; the first horizontal support sensor 11a is inserted into the second rigid joint plate 4b arranged with grooves, and is connected with it by bolts; the upper end of the first vertical support sensor 11b is inserted into the second In the rigid joint plate 4b, the lower end is connected with the second trolley platform 12b through bolts, and the second trolley platform 12b is fixed on the lower beam of the reaction force frame. The fixed hinge support consists of the second horizontal support sensor 11c, the second vertical support sensor 11d, the hinge point plate 5, the hinge support horizontal guide rail 13a, the hinge support vertical guide rail 13b, the third trolley platform 12c, the second The four-car platform 12d, the fifth car platform 12e, the screw lifter 15 and the box-shaped platform 16 are composed of the second horizontal support sensor 11c, which makes the fixed hinge support into a movable hinge support; the second horizontal support One end of the seat sensor 11c and the second vertical support sensor 11d is inserted into the hinge point plate 5 arranged with grooves, and connected with it by bolts; The guide rails 13a are connected, and the other end of the second horizontal support sensor 11c is connected to the vertical guide rail 13b through the third trolley platform 12c. The horizontal guide rail 13a is installed on the box-shaped platform 16 through bolts; the vertical guide rail 13b is installed on one side of the adapter plate through bolts, the other side of the adapter plate is connected with the connector 14, and the bottom end of the adapter plate passes through the fifth trolley platform 12e Connected to the horizontal guide rail 13a. Lead screw lifter 15 is installed on one side of box-shaped platform 16, is connected with adapter plate by connector 14, can be used for rigid frame structure limit or impose horizontal displacement, and box-shaped platform 16 is fixed on the crossbeam under reaction force frame.

The measuring device includes a force sensor 7 , a strain gauge and a rotation angle sensor 17 . Strain gauges are pasted on different positions on both sides of the rectangular thin-walled rod, and the internal force of the rod is calculated through the measured strain value; the force sensor 7 measures the load value applied by the worm elevator 6 to the rigid frame structure; the rotation angle sensor 17 is fixed on the rigid frame structure. On the second rigid joint disk 4a of the frame structure, the rotation angle at the rigid joint disk can be measured; the above measuring equipment is connected with the computer through the data acquisition and analysis system, and the various data are monitored in real time by the computer.

The beneficial effects of the present invention are: according to the needs of the experiment content, the displacement method experimental device can be assembled into different partial experimental models, and the displacement method experiments of various methods can be carried out, and the results obtained by various methods are convenient for mutual comparison and comparison with theoretical results . The device integrates a structural mechanics experimental model, a loading device and a measuring device. According to the needs of the experiment, strain gauges can be pasted at different positions of the bar and loaded at different positions of the bar. The experimental model is flexible and variable. Through the experimental verification, the experimental results obtained by the displacement method experimental device have a small error compared with the theoretical value calculated by structural mechanics, which is suitable for colleges and universities to carry out relevant teaching experiments and further design and expansion.

Description of drawings

Figure 1 is a top view of the corner constraint and loading device.

Figure 2 is a detailed view of the worm gear loading device.

Figure 3 is a detailed view of the rod connecting device.

Figure 4 is a detailed view of the internal structure of the experimental device.

Figure 5 is the original structural diagram of the rigid frame without lateral displacement of the displacement method experimental device.

Figure 6 is a diagram of the displacement method experimental device where the load acts alone on the rigid frame without lateral displacement.

Fig. 7 is a diagram of the no-side-shift rigid frame acting solely on the node rotation angle of the displacement method experimental device.

Fig. 8 is the original structural diagram of the lateral movement rigid frame of the displacement method experimental device.

Figure 9 is a diagram of the displacement method experimental device load and horizontal line displacement acting on the rigid frame with lateral displacement.

Figure 10 is a diagram of the displacement method experimental device node rotation angle and horizontal line displacement acting on the rigid frame with side shift.

In the figure: 1 reaction force frame; 2 base; 3a vertical rectangular thin-walled rod; 3b horizontal rectangular thin-walled rod; 4a first rigid joint plate; 4b second rigid joint plate; 5 hinged joint plate; 6 Worm gear lifter; 7 Force sensor; 8 Ball hinge; 9 Loading rod; 10 Rod fixture; 11a first horizontal support sensor; 11b first vertical support sensor; Vertical support sensor; 12a first car platform; 12b second car platform; 12c third car platform; 12d fourth car platform; 12e fifth car platform; 12f sixth car platform; 12g seventh car platform; 13a hinge Support horizontal guide rail; 13b hinge support vertical guide rail; 13c vertical guide rail; 13d horizontal guide rail; 14 connector; 15 lead screw lift; 16 box platform; 17 corner sensor; 18 torque sensor; 20 X-Y direction follow-up table; 21 Lateral reaction force frame; 22 Loading rod connector; 23 Pin; 24 Rod clip.

Detailed ways

The invention measures the internal force and displacement of the structure in each subdivision experiment by applying loads on the structural members of the rigid frame or applying node rotation angles and line displacements at the joints of the rigid frame structure. Applying the principle of the displacement method, the internal force and displacement of the structure under the load and each displacement are superimposed to solve the internal force and displacement of the load acting on the rigid frame structure, and verify the correctness of the principle of the displacement method.

The embodiments of the present invention will be further described below in conjunction with the accompanying drawings and implementation examples. The specific installation and implementation of the experimental device are as follows:

Example 1: Displacement method experiment of rigid frame without lateral movement

Figure 5 is the original structural diagram of the rigid frame without lateral displacement of the displacement method experimental device.

The rigid frame structure is composed of a vertical rectangular thin-walled rod 3a, a transverse rectangular thin-walled rod 3b and a first rigid joint plate 4a. One end of the vertical rectangular thin-walled rod 3a is connected with the first rigid joint plate 4a with grooves through bolts; the other end is connected with the second rigid joint plate 4b with grooves through bolts, so as to realize the rigid frame structure and Fixed support connections. One end of the transverse rectangular thin-walled rod 3b is connected with the first rigid joint plate 4a with grooves through bolts; the other end is connected with the hinged joint plate 5 with grooves through bolts to realize the rigid frame structure and hinge support Connection.

The worm gear loading device is composed of a worm gear lifter 6, a force sensor 7, a ball joint 8, a loading rod 9 and a rod clamp 10, which are sequentially connected head to tail by threads. The bar clamp 10 is connected with the vertical thin-walled bar 3a, and applies load to the rigid frame structure.

Strain gauges are pasted at different positions on both sides of the rectangular thin-walled rods 3a and 3b, and the internal force of the rods is calculated through the measured strain values; the force sensor 7 measures the load value applied by the worm gear elevator 6 to the rigid frame structure; the rotation angle sensor 17 Fixed on the first rigid joint disc 4a of the rigid frame structure, the rotation angle at the first rigid joint disc 4a can be measured; the above measuring devices are all connected to the computer, and the various data are monitored in real time by the computer.

Figure 6 is a diagram of the displacement method experimental device where the load acts alone on the rigid frame without lateral displacement.

The installation method of the structure of Fig. 6 is on the basis of the structure of Fig. 5, on the lateral reaction force frame 21 behind the first rigid joint disc 4a, install the torque sensor 18, the lead screw speed reducer 19 as shown in Fig. 1 The rotation angle restriction and loading device composed of the XY direction follow-up table 20 restricts the rotation of the rigid frame structure at the rigid joint disk 4 . Apply load to the rigid frame through the above-mentioned worm gear loading device, and adjust the rotation angle constraint and the loading device so that the rotation angle of the rigid frame structure at the rotation angle sensor 17 is zero, and the torque borne by the torque sensor 18 is measured at the same time.

Fig. 7 is a diagram of the no-side-shift rigid frame acting solely on the joint rotation angle of the displacement method experimental device. The installation method of the structure in Fig. 7 is based on the structure in Fig. 6, and the above-mentioned worm gear loading device is removed. Torque is applied to the rigid frame structure at the rigid joint disk 4 through the rotation angle constraint and loading device, and the rotation angle of the rigid frame structure at the rigid joint disk 4 is measured through the rotation angle sensor 17 installed on the rigid joint disk 4 .

Embodiment 2: there is the displacement method experiment of laterally moving rigid frame

Fig. 8 is the original structural diagram of the lateral movement rigid frame of the displacement method experimental device. The installation method of the structure in Fig. 8 is based on the structure in Fig. 5, and the second horizontal support sensor 11c at the fixed hinge support is removed, so that the fixed hinge support is transformed into a movable hinge support. Apply load to the rigid frame structure through the above-mentioned worm gear loading device, and measure the rotation angle of the rigid frame structure at the first rigid joint disc 4a under the load by the rotation angle sensor 17 installed on the first rigid joint disc 4a .

Figure 9 is a diagram of the displacement method experimental device load and horizontal line displacement acting on the rigid frame with lateral displacement. The installation method of the structure in Fig. 9 is based on the structure in Fig. 6, and the second horizontal support sensor 11c at the fixed hinge support is removed, so that the fixed hinge support is transformed into a movable hinge support. Apply load to the rigid frame through the above-mentioned worm gear loading device, and adjust the rotation angle constraint and the loading device so that the rotation angle of the rigid frame structure at the rotation angle sensor 17 is zero, and the torque borne by the torque sensor 18 is measured at the same time.

Figure 10 is a diagram of the displacement method experimental device node rotation angle and horizontal line displacement acting on the rigid frame with lateral movement. The installation method of the structure in Fig. 10 is based on the structure in Fig. 7, and the second horizontal support sensor 11c at the fixed hinge support is removed, so that the fixed hinge support is transformed into a movable hinge support. Torque is applied to the rigid frame structure at the rigid joint disk 4 through the rotation angle constraint and loading device, and the rotation angle of the rigid frame structure at the rigid joint disk 4 is measured through the rotation angle sensor 17 installed on the rigid joint disk 4 .

Claims (3)

1. a kind of experiment device for teaching for intuitively changing displacement method, it is characterised in that including rigid-framed structure, worm and gear loading dress Put, restricted joint angle and loading device, support and restraint device and measuring apparatus；

The rigid-framed structure is by vertical rectangular thin-wall rod member (3a), horizontal rectangular thin-wall rod member (3b) and the first rigid joint disk (4a) Composition；Vertical rectangular thin-wall rod member (3a) one end is fixedly connected with the first rigid joint disk (4a), the other end and the second rigid joint disk (4b) is fixedly connected, and realizes the connection of rigid-framed structure and hold-down support；Just tied with first horizontal rectangular thin-wall rod member (3b) one end Point disk (4a) is fixedly connected, and the other end is fixedly connected with pin joint disk (5), realizes being fixedly connected for rigid-framed structure and hinged-support； First rigid joint disk, the second rigid joint disk and pin joint disk use with institute's link member identical rigidity, pass through bolt and node Disk connects the rigidity model such as to form；

The worm and gear loading device is by worm and gear lift (6), load bar (9), ball pivot (8) and rod member fixture (10) group Into；Worm and gear lift (6) one end is fixedly connected with trolley platform (12a), and the first trolley platform (12a) is installed to reaction frame (1) on guide rail, the first trolley platform (12a) can adjust height, worm and gear lift (6) other end along reaction frame (1) guide rail It is connected with force snesor (7), worm and gear lift (6) is further applied load by rotation hand wheel to rigid-framed structure；Force snesor (7), ball pivot (8), load bar (9) and rod member fixture (10) pass sequentially through threaded connection；Rod member fixture (10) realizes loading device With the connection of horizontal thin-walled bar (3b) or vertical thin-walled bar (3a), rod member fixture (10) includes pin (23), load bar connects Fitting (22) and rod member intermediate plate (24), loading joint element for bar (22) are connected with rod member intermediate plate (24) by pin (23), Thin Rectangular Wall rod member (3a) passes perpendicularly through the groove of rod member intermediate plate (24) formation and is fixedly connected with rod member intermediate plate (24)；Control worm gear manually Worm screw loading device applies pulling force and pressure to rigid-framed structure, shown on computers by force snesor (7) added by load；

The restricted joint angle and loading device are from X-Y to follow-up work bench (20), torque sensor (18) and leading screw reductor (19) form, X-Y to follow-up work bench (20) by horizontal guide rail (13d), upright guide rail (13c), the 6th trolley platform (12f) and 7th trolley platform (12g) forms；Torque sensor (18) one end is fixedly connected with the first rigid joint disk (4a), and the other end is inserted Enter in leading screw reductor (19)；Leading screw reductor (19) is installed on the 6th trolley platform (12f), the 6th trolley platform (12f) Be connected with upright guide rail (13c), upright guide rail (13c) is connected with the 7th trolley platform (12g), the 7th trolley platform (12g) with Horizontal guide rail (13d) connects, and horizontal guide rail (13d) in the middle part of lateral reaction frame (21) flat board with being connected；X-Y is to follow-up work bench (20) restricted joint angle and loading device are realized along horizontal guide rail (13d) and upright guide rail (13c) free movement, restricted joint angle and is added Carry and put by applying moment of torsion to the first rigid joint disk (4a), angular displacement is produced at node in rigid-framed structure, is passed by corner Sensor (17) measures angular displacement numerical value；

The support and restraint device are made up of the constraint support of reaction frame and rigid-framed structure；

The reaction frame is made up of reaction frame (1), lateral reaction frame (21) and base (2), and base (2) is fixed on reaction frame (1) sill bottom, for supporting whole device；Reaction frame (1) by built-in guide rail two crossbeams and built-in guide rail up and down Left and right two columns composition, each crossbeam or column can fix worm and gear lift (6) and trolley platform, sill are fixed Second trolley platform (12b), a heel post fix the first trolley platform (12a)；Lateral reaction frame (21) is by flat board and column group Into column is connected down through sliding block with reaction frame (1) lower and upper cross-member, and flat board is connected by sliding block with column, and flat board can be Slided up and down on column；Lateral reaction frame (21) is used for installing angle constraint and loading device, passes through bolt and X-Y in the middle part of flat board It is connected to the horizontal guide rail (13d) of follow-up work bench；

The constraint support of the rigid-framed structure includes hold-down support and fixed-hinged support；Hold-down support is sensed by first level bearing Device (11a), the first vertical bearing sensor (11b) and the second rigid joint disk (4b) composition；Put down with the second dolly pinboard bottom Platform (12b) connects, and pinboard side is connected with first level bearing sensor (11a), first level bearing sensor (11a) and Second rigid joint disk (4b) connects, and the first vertical bearing sensor (11b) upper end is connected with the second rigid joint disk (4b), lower end and Second trolley platform (12b) is connected, and the second trolley platform (12b) is fixed on reaction frame sill；Fixed-hinged support is by second Horizontal seat sensor (11c), the second vertical bearing sensor (11d), pin joint disk (5), hinged-support horizontal guide rail (13a) and Hinged-support vertical guide (13b) forms；Second vertical bearing sensor (11d) and second horizontal seat sensor (11c) one end It is connected with pin joint disk (5), second vertical bearing sensor (11d) other end passes through the 4th trolley platform (12d) and hinged-support Horizontal guide rail (13a) connects, and second horizontal seat sensor (11c) other end passes through the 3rd trolley platform (12c) and hinged-support Vertical guide (13b) connects；Hinged-support horizontal guide rail (13a) is arranged on box platform (16), hinged-support vertical guide (13b) Installed in pinboard side, pinboard opposite side is connected with connector (14), and pinboard bottom passes through the 5th trolley platform (12e) It is connected on hinged-support horizontal guide rail (13a)；Screw-threaded shaft elevator (15) is arranged on box platform (16) side, passes through connector (14) it is connected with pinboard, available for limiting rigid-framed structure or applying horizontal displacement, box platform (16) is fixed on reaction frame On sill；

The measuring apparatus includes force snesor (7), foil gauge, rotary angle transmitter (17)；Strain gauge adhesion is in rectangular thin-wall bar Part (3a, 3b) both sides diverse location, pass through surveyed strain value and calculate rod member internal force size；Force snesor (7) measures worm and gear The payload values that lift (6) is applied to rigid-framed structure；Rotary angle transmitter (17) is fixed on the first rigid joint disk of rigid-framed structure On (4a), the corner at first rigid joint disk (4a) place is surveyed；Above measuring apparatus is all connected to computer, by computer to items Data are monitored in real time.

A kind of 2. experiment device for teaching for intuitively changing displacement method as claimed in claim 1, it is characterised in that the rigid frame knot Structure is " L " shape rigid frame OR gate shape rigid frame.

3. a kind of experiment device for teaching for intuitively changing displacement method as claimed in claim 1 or 2, it is characterised in that described the Detachably, fixed-hinged support is changed into removable hinged-support to two horizontal seat sensors (11c) after removal.