CN109853763B

CN109853763B - U-T slope type variable friction damper

Info

Publication number: CN109853763B
Application number: CN201811231713.3A
Authority: CN
Inventors: 李澈; 闫维明
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2018-10-22
Filing date: 2018-10-22
Publication date: 2021-01-08
Anticipated expiration: 2038-10-22
Also published as: CN109853763A

Abstract

The invention discloses a U-T slope type variable friction damper, which comprises a plurality of steel plates stacked together, wherein at least one pair of adjacent steel plates are respectively provided with a U-part slope and a T-part slope, and the U-part slope and the T-part slope form a U-T slope mechanism; and the rest adjacent steel plates are in plane contact, and friction materials are bonded on the side surface of at least one steel plate in the side surfaces of the two adjacent steel plates which are attached to each other. The invention converts the axial deformation into the normal deformation, and the slope surface keeps continuous contact in the length direction in the axial deformation process, so that the local 'void' phenomenon does not exist, and the whole slope panel is uniformly pressed. The invention can adjust the additional rigidity generated by the device according to the requirement, even can achieve the effect of not increasing the additional rigidity, is flexible to use and provides larger selection space.

Description

U-T slope type variable friction damper

Technical Field

The invention relates to a damper, in particular to a variable friction damper for resisting earthquake, and belongs to the field of energy consumption and shock absorption control of building structures.

Background

With the continuous advance of the urbanization process, urban buildings are higher in height and denser, and earthquake disasters remind people again and again, so that the earthquake resistance of the building structure is emphasized while the extreme challenges of various buildings are created. Relevant standard criteria of structural earthquake resistance are made by countries in the world according to the economic development level of the countries and the geographical environmental conditions (whether the countries are near the earthquake zone), and the earthquake resistance requirements of building structures are continuously improved along with the improvement of the economic development level of the countries. The anti-seismic standard of China is subject to industrial and civil building anti-seismic design standard (TJ11-74, revised as TJ11-78 after the earthquake in Tangshan), < building anti-seismic design standard > (GBJ11-89), < building anti-seismic design standard > (GB50011-01, the latest revised version is GB 50011-2010-2016), the requirement on the anti-seismic performance of the building structure is continuously improved, and the appearance and use function requirements of the building are difficult to meet by adopting the traditional method for increasing the section and the reinforcement quantity of the structural member. Therefore, the energy consumption damper is additionally arranged in the structure to consume earthquake input energy, protect the safety of the main structural member and improve the earthquake-resistant performance of the structure, and has been widely proved to be an effective earthquake-resistant measure. The friction damper is used as a damper device for dissipating energy based on a friction principle, and has the advantages of clear principle, low manufacturing cost and the like, and is widely paid attention to and adopted. The variable friction damper has the characteristic of generating larger friction force along with the increase of deformation, can ensure that the structure provides gradually increased energy consumption performance under small deformation (frequently meeting earthquake action), medium deformation (fortifying earthquake action) and large deformation (rarely meeting earthquake action), and is more in line with the actual engineering. The main disadvantages of the existing friction dampers are:

1. the friction surface of the conventional friction damper for the building is always in a high stress state due to the fact that pretightening force needs to be applied, and the friction coefficient of the friction surface may change under the high stress state and deviate from an expected design value, so that the friction damper starts to slide too early or does not start to slide. For the bolt (or other structures) applying the pretightening force, a relaxation and creep phenomenon can be generated to cause pretightening force loss, and the pretightening force loss is further influenced.

2. The conventional single-joint sliding force friction damper has determined and unique damper output force, and the hysteresis curve of the damper is rectangular. However, in the actual engineering design, if the output force of the damper is designed under the action of strong shock, the damper does not work under the medium shock and the small shock, if the damper is designed under the medium shock, the small shock does not work, and the action is insufficient under the large shock. Due to the immaturity of earthquake prediction and earthquake zoning theory, the earthquake action of a building structure is often uncertain greatly. The adoption of not only the sliding force friction damper in the building structure can not only solve the dilemma that the large earthquake and the small earthquake can not be considered.

The existing spring-slope variable friction damper adopts a V-shaped slope to be matched with a spring to generate damping force which is increased along with the increase of deformation, overcomes the defects of the conventional friction damper with only one sliding force to a certain extent, but has a plurality of defects which cannot be overcome, such as:

1) the hysteresis curve of the pair of triangle or dog bone is not full enough, which limits the energy consumption capability.

2) When variable friction force is generated, the V-shaped slope surface plate of the main variable friction mechanism is in close contact with the slope surface on one side, and the slope surface on the other side is separated, so that the slope surface plate is bent and deformed in the length direction, the bolt-spring pretightening force in a separation area is lost, and the output force of the damper is reduced. If the sloping panel part is thin or the distance between the bolts is large, the panel part can be subjected to inelastic deformation, and the damper can be failed.

Disclosure of Invention

The invention designs a variable friction damper by adopting the principle of a U-T slope mechanism, which is characterized in that: the force of the damper is increased along with the increase of deformation, and a deformation-damping force curve (hysteresis curve) is in a shape of a right triangle or a butterfly (a structure with large two ends and small middle).

The principle of the U-T slope mechanism is as follows: the U-T slope mechanism consists of U, T two parts, wherein the U part has a concave groove in the length direction, and the groove bottom and the groove shoulder have slopes (slope i) with opposite directions but same angle in the length direction, and the U part is called as U part because the cross section shape is similar to letter U; the T-piece has a rectangular projecting edge in the length direction, and the projecting edge and the edge side shoulder have slopes (gradient i) with opposite directions but the same angle in the length direction, and the T-piece is called T-piece because its cross-sectional shape is similar to the letter "T". U, T the slope angles of the two parts are the same. And inserting the convex edge of the T part into the groove of the U part to form a U-T slope mechanism. Since U, T the two parts have the same slope angle, and the two slopes of each part (the bottom slope and shoulder slope of U part; the rib slope and shoulder slope of T part) have opposite directions, the U-T slope mechanism can find a point, so that the top slope of T part rib and the bottom slope of U part groove are completely jointed, and the shoulder slope of T part rib and the shoulder slope of U part groove are completely jointed, defining the point as the initial position of U-T mechanism, and the total height of U-T mechanism is Hd. When U, T parts are mutually dislocated in the gradient direction, assuming that U is at the lower position and T is at the upper position, the bottom slope surface of the U part is low at the left and high at the right (the bottom slope surface of the U groove is low at the right and high at the left), if the T part is dislocated to the right relative to the U part by a distance Ud, the bottom slope surface of the U part groove is continuously contacted with the rib slope surface, the groove shoulder slope surface of the U part is separated from the rib shoulder slope surface of the T part, the total height of the U-T mechanism is increased, and the increase is V; if the T part is staggered leftwards relative to the U part by a distance Ud, the groove shoulder slope surface of the U part is continuously contacted with the ridge shoulder slope surface of the T part, the groove bottom slope surface of the U part is separated from the ridge slope surface of the T part, the total height of the U-T mechanism is increased, and the increase is Vd which is Ud tan (i). According to the working principle of the U-T mechanism, U, T parts stagger in the slope direction, the total height of the U-T mechanism is increased no matter in the staggering direction, U, T parts are always in surface contact (the U groove shoulder contacts the T rib or the U groove bottom contacts the T rib) in the slope length direction, no 'void' area exists, and the U-T mechanism is unique in characteristic. The principle is the core of the U-T slope type variable friction damper.

The invention adopts the following technical scheme: the U-T slope type variable friction damper comprises a plurality of steel plates which are stacked together, wherein at least one pair of adjacent steel plates are respectively provided with a U-part slope and a T-part slope, and the U-part slope and the T-part slope form a U-T slope mechanism; and the rest adjacent steel plates are in plane contact, and friction materials are bonded on the side surface of at least one steel plate in the side surfaces of the two adjacent steel plates which are attached to each other.

The steel plate part (1) with the T-type slope, the steel plate part (2) with the U-type slope and the plurality of plane steel plate parts (3) are stacked together, wherein the steel plate part (1) with the T-type slope, the steel plate part (2) with the U-type slope, the T-type slope of the steel plate part (1) with the T-type slope and the U-type slope of the steel plate part (2) with the U-type slope are opposite and stacked together, and the slopes on the two parts are completely stacked to form a U-T slope mechanism. In order to avoid the cold bonding problem, the slope surface is plated with a corrosion-resistant isolation coating such as a Teflon material layer (polytetrafluoroethylene PTFE) or a zinc-chromium coating (Dacromet DACROMET).

The middle steel plate part (1) with a T-type slope, the middle steel plate part (2) with a U-type slope and the plurality of plane steel plate parts (3) are provided with bolt chutes matched with the bolt-spring pre-tightening devices (5).

Friction material interlayers (4) are arranged among the plane steel plate parts (3) which are stacked together, between the plane steel plate parts (3) and the plane of the steel plate part (1) with the T-type slope, and between the plane steel plate parts (3) and the plane of the steel plate part (2) with the U-type slope.

The steel plate part (1) with the T-type slope, the steel plate part (2) with the U-type slope and the plane steel plate parts (3) are divided into an L group and an R group in a staggered mode, the parts in each group are connected to an end connecting plate (7) at the end through a connecting pin key (6) at the end, and obviously, the steel plate part (1) with the T-type slope and the steel plate part (2) with the U-type slope belong to different groups. The surfaces of the components in the L group and the R group can slide mutually, and the components in each group are kept static.

One plate surface of the steel plate part (1) with the T-type slope surface is a plane, the other plate surface is a T-type slope surface, namely, the steel plate part is provided with a rectangular convex edge in the length direction, the convex edge and the edge side shoulder are slope surfaces with opposite directions but the same angle in the length direction, and the slope is i. One plate surface of the steel plate part (2) with the U-shaped slope surface is a plane, the other plate surface is a U-shaped slope surface, namely, the steel plate part is provided with a concave groove in the length direction, the groove bottom and the groove shoulder are provided with slope surfaces with opposite directions but the same angle in the length direction, and the slope is i. The T-shaped slope surface of the steel plate part (1) with the T-shaped slope surface can be completely attached to the U-shaped slope surface of the steel plate part (2) with the U-shaped slope surface to form a U-T slope surface mechanism.

The bolt-spring pre-tightening device (5) consists of a screw rod (51), a nut (52), a guide gasket (53) and a disc spring (54). The screw (51) sequentially penetrates through the guide gasket (53), the disc-shaped spring (54), the part (1) formed by overlapping a plurality of pieces, the bolt sliding groove on the part (2) and the part (3), the disc-shaped spring (54), the guide gasket (53), the anti-loosening washer (55) and the nut (52). The spring and the steel plate part are pressed together through the bolt-nut, but the disc-shaped spring is not pressed to the limit deformation.

The friction material interlayer (4) is composed of friction plates (41), positioning screws (42) and constraint purlines (43). One surface of the friction plate (41) is bonded with the plane steel plate part (3), and the other surface is contacted with the plane of the plane steel plate part (3) or the plane of the steel plate part (1) or the plane of the steel plate part (2), and can generate mutual dislocation. The restraining purlines (43) are tightly attached to the peripheries of the friction plates (41), and gaps are filled with bonding substances.

When the variable friction damper mechanism works, the L part group and the R part group mutually dislocate or slide, and friction force for blocking relative motion, namely damping force of the damper, is generated on contact surfaces of a steel plate part (1) with a T-type slope surface, a steel plate part (2) with a U-type slope surface and a plane steel plate part (3), and the magnitude of the damping force depends on the friction coefficient of the friction surface and normal pressure acting on the friction surface. The steel plate part (1) with the T-type slope and the steel plate part (2) with the U-type slope belong to different groups, so that a U-T slope mechanism is formed. When the mechanism is dislocated from the initial position, according to the principle of a U-T slope mechanism, the thickness of the superposed part set is increased, the disc spring (54) in the bolt-spring pre-tightening device (5) is further compressed, the normal pressure acting on each friction surface is increased, the friction force on the friction surface is increased, namely the damping force of the mechanism is increased, the steel plate part (1) with the T-type slope and the steel plate part (2) with the U-type slope are always in surface contact, no void area exists in the length direction, and the two parts are in a uniform compression state in the thickness direction; when the mechanism is dislocated from a certain position to an initial position, according to the principle of a U-T slope mechanism, the thickness of the superposed part set is reduced, the disc spring (54) in the bolt-spring pre-tightening device (5) is loosened, the normal pressure acting on each friction surface is reduced, the friction force on the friction surface is reduced, namely the damping force of the mechanism is reduced, the steel plate part (1) with the T-type slope and the steel plate part (2) with the U-type slope are always in surface contact, no void area exists in the length direction, and the two parts are in a uniform compression state in the thickness direction.

A loose-proof washer (55) in the bolt-spring pre-tightening device (5) can act together with the nut (52) to ensure that the bolt-spring pre-tightening device (5) is not loosened in the whole structural working process. The guide gasket (53) can ensure that the center of the disc spring (54) is always coincident with the center of the screw rod, namely the centers of the disc springs (54) on the upper surface and the lower surface are completely coincident.

The friction plate (41) in the friction material interlayer (4) is made of hard friction materials such as phenolic resin base and the like, is positioned and installed on the plane of the steel plate by a positioning screw (42), is restrained by a restraining purlin (43) around the friction plate (41), and the restraining purlin (43) is welded with steel plate parts. After the damper is assembled, the friction plate (41) is in a state that three surfaces are restrained, namely the friction plate is restrained by the bolt-spring pre-tightening device (5) in the thickness direction, the periphery of the friction plate is restrained by the restraining purlines (43), and the pressure resistance of the material is obviously enhanced.

Preferably, the number of the steel plate parts is six, the steel plate parts comprise a steel plate part (1) with a T-type slope surface and a steel plate part (2) with a U-type slope surface which are positioned in the middle to form a U-T slope surface mechanism, and the steel plate parts are respectively connected with the L end and the R end, and two plane steel plate parts (3) are respectively connected with the L end; two planar steel plate parts (3) are connected to the R end, and one side surface or two side surfaces of each planar steel plate part (3) are bonded with a lattice friction material layer. The middle parts of the part (1), the part (2) and the part (3) are provided with a strip bolt sliding groove.

Preferably, the steel plate part (1) with the T-shaped slope and the steel plate part (2) with the U-shaped slope have a plurality of groups of U-shaped grooves and T-shaped ribs which correspond to each other on the contact surfaces. The U-shaped groove is provided with a concave groove in the length direction of the part, the groove bottom and the groove shoulder are provided with slopes with opposite directions but same angles in the length direction, the slope is i, and the cross section of the U-shaped groove is similar to a letter U; the T-shaped rib is provided with a rectangular convex edge in the length direction of the part, and the convex edge and the side shoulder of the rib are provided with slopes with opposite directions but same angles in the length direction, the slope is i, and the cross section of the T-shaped rib is similar to the letter T. The slope angle of the U groove is the same as that of the T convex rib. And inserting the T-shaped convex edge into the U groove to form a U-T slope mechanism. Because all slope angles of the U groove and the T convex edge are the same, and the two slopes of the U groove and the T convex edge, the slope surface at the bottom of the U groove and the slope surface at the shoulder of the U groove are the same; the angle direction of the rib slope surface of the T-shaped rib is opposite to that of the rib shoulder slope surface, so that a U-T slope surface mechanism can find a point, the top slope surface of the T-shaped rib is completely attached to the bottom slope surface of the U groove, the shoulder slope surface of the T-shaped rib is completely attached to the shoulder slope surface of the U groove, and the point is the initial position of the mechanism.

Preferably, the concave-convex slope surface of the steel plate of the U-T slope surface mechanism is plated with corrosion-resistant isolation coatings such as a Teflon material layer (polytetrafluoroethylene PTFE) or a zinc-chromium coating (Dacromet DACROMET) and the like so as to avoid cold bonding between the metal plates.

Preferably, the springs are disc springs or other types of high stiffness, weakly-creeping-like springs.

Preferably, a loose-proof washer matched with the thread angle is adopted to play a role in loose prevention.

Preferably, the friction material is a phenolic resin-based hard friction material, and the creep amount is small under the action of long-term normal compressive stress; the temperature stability is good and the friction loss is small in the friction process.

Preferably, the U grooves and the T ribs are distributed on two sides of the bolt sliding groove in two groups.

Preferably, the variable friction damper is a support type friction damper or a shear type friction damper.

Preferably, the variable friction damper can be additionally provided with a protective sleeve with an anti-buckling function on the outer layer.

Compared with the prior art, the variable friction damper has the beneficial effects that:

1. the invention adopts the principle of a U-T slope mechanism, axial deformation is converted into normal deformation, and in the axial deformation process, the slope keeps continuous contact in the length direction, so that the phenomenon of local 'void' does not exist, and the whole slope panel is uniformly pressed. The variable-friction damper for the slope surface of the traditional damper avoids the phenomenon that the damper is unstable in output because the slope surface plate is out of the way to generate local bending deformation under the action of uniformly distributed pretightening force.

2. The variable friction damper utilizes the principle of a U-T slope mechanism to convert axial deformation into normal deformation, compresses/relaxes a pre-tightening spring, and further changes the normal pressure of a friction surface in the sliding process to realize the change of friction force under the condition of unchanged friction coefficient, thereby providing linear damping, so that the variable friction damper has good damping performance in small shock, medium shock and large shock.

3. After the variable friction damper is installed on a building structure, the additional rigidity generated by the variable friction damper can be adjusted according to the requirement, even the effect of not increasing the additional rigidity can be achieved, the variable friction damper is flexible to use, and a larger selection space is provided for designers.

4. The variable friction damper has wide potential application. The damper with triangular hysteresis curves or similar triangular hysteresis curves (such as butterfly shape) is adopted, and the damper can be independently used in a structure as a common damper and can also be used in a shock insulation layer of a shock insulation structure.

5. The variable friction damper has the advantages of simple structure, easily obtained materials and low manufacturing cost, and compared with the existing spring-slope mechanism, the slope part has no additional bending deformation in the whole length, so that the damping force is more stable. Meanwhile, the machining amount of slope parts is reduced (4 parts with slopes are needed for the spring-slope mechanism, but only 2 parts are needed for the spring-slope mechanism), so that the machining difficulty and the machining cost are reduced.

6. The invention can be in various forms, is suitable for various different structures, and can be arranged on various different structural parts according to requirements to realize the effects of energy dissipation and shock absorption.

7. The variable friction damper has strong applicability, the output and the appearance of the variable friction damper can be flexibly adjusted according to design requirements, the adjustable area of the variable friction damper is larger, and meanwhile, the variable friction damper has better energy consumption effect under various conditions.

Drawings

FIG. 1 is a sectional view of the assembly of a first embodiment of a variable friction damper according to the present invention.

FIG. 2 is a disassembled sectional view of a first embodiment of the variable friction damper of the present invention.

Fig. 3 is an exploded view of a bolt tightening system according to a first embodiment of the variable friction damper of the present invention.

Fig. 4 is a part view of a T-slope core plate of the first embodiment of the variable friction damper of the present invention.

Fig. 5 is a part view of a U-slope core plate of the first embodiment of the variable friction damper of the present invention.

FIG. 6 is a plan view of a steel plate component of a first embodiment of the variable friction damper of the present invention.

FIG. 7 is a diagram of a friction material sandwich of a first embodiment of the variable friction damper of the present invention.

FIG. 8 is a diagram of the application of the friction material sandwich of the first embodiment of the variable friction damper of the present invention.

FIG. 9 is a cross-sectional view A-A of a friction material sandwich application of a first embodiment of the variable friction damper of the present invention.

Fig. 10 is a view of the ramp, which is basically composed of parts.

Fig. 11U-T ramp mechanism schematic.

FIG. 12 is a schematic view of a loose washer bite tooth angle and a bolt thread angle.

In the figure: 1-steel plate parts with T-type slopes; 2-steel plate parts with U-type slopes; 3-a planar steel plate part; 4-a friction material interlayer; 5-bolt-spring pre-tightening device; 6-connecting pin key; 7-an end connection plate; 41-friction plate; 42-a set screw; 43-restraining purlins; -

51-screw rod; 51-a nut; 51-a guide pad; 54-disc spring; 55-a lock washer;

Detailed Description

As shown in fig. 1-12, the mechanism is divided into an L-part group and an R-part group, wherein the L-part group comprises a steel plate part (2) with a U-type slope surface and 2 plane steel plate parts (3) which are pinned together by a connecting pin key (6) (the thickness direction is free from constraint); the R part group comprises a steel plate part (1) with a T-type slope surface and 2 plane steel plate parts (3) which are connected together by pins through connecting pin keys (6) (the thickness direction is free of constraint); at the planar contact surfaces between the L, R component groups (i.e. all but the contact surfaces between the part (1) and the part (2)) there is a friction material sandwich (4) which is pressed together L, R component groups by a bolt-spring pretensioning device (5).

When the L-shaped part group and the R-shaped part group rub (slide) each other from the initial position (namely the position where the top slope surface of the T-shaped rib is completely attached to the bottom slope surface of the U-shaped groove and the shoulder slope surface of the T-shaped rib is completely attached to the shoulder slope surface of the U-shaped groove) along the length direction, the thickness of the part group is increased by contacting the T-shaped rib with the shoulder of the U-shaped rib or contacting the T-shaped rib with the bottom of the U-shaped groove according to the principle of the U-shaped rib, the disc spring (54) in the bolt-spring pre-tightening device (5) is further compressed, the normal pressure acting on each friction surface is increased, the friction force on the friction surface is increased, namely the damping force of the mechanism is increased, and the steel plate part (1) with the T-shaped slope surface and the steel plate part (2) with the U-shaped slope surface are always kept in face contact, there is no void region in the length direction and both parts are in a uniformly compressed state in the thickness direction. When the L-type part group and the R-type part group are twisted (slide) mutually from a certain position to an initial position along the length direction, the thickness of the part group is reduced by contacting a T-shaped rib shoulder with a T-shaped slope surface or a T-shaped rib with a U-shaped slope surface bottom through a U-shaped groove shoulder with a slope surface or a U-shaped groove bottom due to the principle of the U-T slope surface, a disc spring (54) in a bolt-spring pre-tightening device (5) is loosened, normal pressure acting on each friction surface is reduced, friction force on the friction surface is reduced, namely damping force of the mechanism is reduced, the steel plate part (1) with the T-type slope surface and the steel plate part (2) with the U-type slope surface are always kept in surface contact, no void area exists in the length direction, and the two parts are in a uniform state in the thickness direction.

When the initial pretightening force of a bolt-spring pretightening device (5) in the mechanism is 0, the structure generates a triangular hysteresis curve; when the initial pretightening force of a bolt-spring pretightening device (5) in the mechanism is not 0, the structure generates a butterfly-shaped hysteresis curve.

The above description is only for the essential features of the present invention, and not intended to limit the present invention in any way, and any modification, equivalent change and modification made within the spirit and principle of the present invention according to the technical spirit of the present invention should be regarded as the technical scope of the present invention, and should be included in the protection scope of the present invention.

Claims

U-T slope type variable friction damper, which is characterized in that: the steel plate stacking mechanism comprises a plurality of steel plates which are stacked together, wherein at least one pair of adjacent steel plates are respectively provided with a U-part slope surface and a T-part slope surface, and the U-part slope surface and the T-part slope surface form a U-T slope surface mechanism; the other adjacent steel plates are in plane contact, and in the side surfaces of the two adjacent steel plates which are attached to each other, the side surface of at least one steel plate is bonded with a friction material;

the steel plate part (1) with the T-type slope, the steel plate part (2) with the U-type slope and a plurality of plane steel plate parts (3) are stacked together, wherein the steel plate part (1) with the T-type slope, the steel plate part (2) with the U-type slope, the T-type slope of the steel plate part (1) with the T-type slope and the U-type slope of the steel plate part (2) with the U-type slope are oppositely stacked together, so that the slopes on the two parts are completely stacked to form a U-T slope mechanism; the slope surface is plated with a Teflon material layer or a zinc-chromium coating;

the middle steel plate part (1) with a T-type slope, the middle steel plate part (2) with a U-type slope and the plurality of plane steel plate parts (3) are provided with bolt chutes matched with the bolt-spring pre-tightening devices (5);

friction material interlayers (4) are arranged among the plane steel plate parts (3) which are stacked together, between the plane steel plate parts (3) and the plane of the steel plate part (1) with the T-type slope, and between the plane steel plate parts (3) and the plane of the steel plate part (2) with the U-type slope.
2. The U-T dome variable friction damper of claim 1, wherein: the steel plate part (1) with the T-type slope, the steel plate part (2) with the U-type slope and the plane steel plate parts (3) are divided into an L group and an R group in a staggered mode, the parts of the groups are connected to an end connecting plate (7) at the end through a connecting pin key (6) at the end, and obviously, the steel plate part (1) with the T-type slope and the steel plate part (2) with the U-type slope belong to different groups; the surfaces of the components in the L group and the R group can slide mutually, and the components in each group are kept static.
3. The U-T dome variable friction damper of claim 1, wherein: one plate surface of a steel plate part (1) with T-type slope surfaces is a plane, the other plate surface is a T-type slope surface, namely the steel plate part is provided with a rectangular convex edge in the length direction, the convex edge and the edge side shoulder are provided with slope surfaces with opposite directions but same angles in the length direction, and the slope is i; one plate surface of the steel plate part (2) with the U-shaped slope surface is a plane, the other plate surface is a U-shaped slope surface, namely the steel plate part is provided with a concave groove in the length direction, the groove bottom and the groove shoulder are provided with slope surfaces with opposite directions but the same angle in the length direction, and the slope is i; the T-shaped slope surface of the steel plate part (1) with the T-shaped slope surface can be completely attached to the U-shaped slope surface of the steel plate part (2) with the U-shaped slope surface to form a U-T slope surface mechanism.
4. The U-T dome variable friction damper of claim 1, wherein: the bolt-spring pre-tightening device (5) consists of a screw rod (51), a nut (52), a guide gasket (53) and a disc spring (54); the screw (51) sequentially penetrates through a guide gasket (53), a disc-shaped spring (54), a plurality of stacked steel plate parts (1) with T-type slopes, a steel plate part (2) with U-type slopes and a bolt sliding groove on a flat steel plate part (3), the disc-shaped spring (54), the guide gasket (53), a locking washer (55) and a nut (52); the spring and the steel plate part are pressed together through the bolt-nut, but the disc-shaped spring is not pressed to the limit deformation.
5. The U-T dome variable friction damper of claim 1, wherein: the friction material interlayer (4) consists of a friction plate (41), a positioning screw (42) and a restraining purline (43); one surface of the friction plate (41) is bonded with the plane steel plate part (3), and the other surface of the friction plate is contacted with the plane of the plane steel plate part (3) or the plane of the steel plate part (2) with the U-type slope of the steel plate part (1) with the T-type slope and can generate mutual dislocation; the restraining purlines (43) are tightly attached to the peripheries of the friction plates (41), and gaps are filled with bonding substances.
6. The U-T dome variable friction damper of claim 1, wherein: when the variable friction damper mechanism works, the L group of parts and the R group of parts are mutually dislocated or slide, and friction force for blocking relative motion, namely damping force of the damper, is generated on contact surfaces of a steel plate part (1) with a T-type slope, a steel plate part (2) with a U-type slope and a plane steel plate part (3), and the magnitude of the damping force depends on the friction coefficient of a friction surface and normal pressure acting on the friction surface; the steel plate part (1) with the T-type slope and the steel plate part (2) with the U-type slope belong to different groups, so that a U-T slope mechanism is formed; when the mechanism is dislocated from the initial position, according to the principle of a U-T slope mechanism, the thickness of the superposed part set is increased, the disc spring (54) in the bolt-spring pre-tightening device (5) is further compressed, the normal pressure acting on each friction surface is increased, the friction force on the friction surface is increased, namely the damping force of the mechanism is increased, the steel plate part (1) with the T-type slope and the steel plate part (2) with the U-type slope are always in surface contact, no void area exists in the length direction, and the two parts are in a uniform compression state in the thickness direction; when the mechanism is dislocated from a certain position to an initial position, according to the principle of a U-T slope mechanism, the thickness of the superposed part set is reduced, the disc spring (54) in the bolt-spring pre-tightening device (5) is loosened, the normal pressure acting on each friction surface is reduced, the friction force on the friction surface is reduced, namely the damping force of the mechanism is reduced, the steel plate part (1) with the T-type slope and the steel plate part (2) with the U-type slope are always in surface contact, no void area exists in the length direction, and the two parts are in a uniform compression state in the thickness direction.
7. The U-T dome variable friction damper of claim 1, wherein: a loose-proof washer (55) in the bolt-spring pre-tightening device (5) can act together with the nut (52) to ensure that the bolt-spring pre-tightening device (5) is not loosened in the whole structural working process; the guide gasket (53) can ensure that the center of the disc spring (54) is always coincident with the center of the screw rod, namely the centers of the disc springs (54) on the upper surface and the lower surface are completely coincident.
8. The U-T dome variable friction damper of claim 1, wherein: friction plates (41) in the friction material interlayer (4) are made of phenolic resin-based hard friction materials, are positioned and installed on a steel plate plane by positioning screws (42), are restrained by restraining purlins (43) around the friction plates (41), and the restraining purlins (43) are welded with steel plate parts; after the damper is assembled, the friction plate (41) is in a state that three surfaces are restrained, namely the friction plate is restrained by the bolt-spring pre-tightening device (5) in the thickness direction, the periphery of the friction plate is restrained by the restraining purlines (43), and the pressure resistance of the material is obviously enhanced.
9. The U-T dome variable friction damper of claim 1, wherein: the steel plate part (1) with the T-type slope and the steel plate part (2) with the U-type slope are respectively connected with the L end and the R end, and the two plane steel plate parts (3) are respectively connected with the L end; two plane steel plate parts (3) are connected to the R end, and one side surface or two side surfaces of each plane steel plate part (3) are bonded with a lattice friction material layer; the middle parts of the steel plate part (1) with the T-type slope, the steel plate part (2) with the U-type slope and the plane steel plate part (3) are provided with strip-shaped bolt sliding grooves.
10. The U-T dome variable friction damper of claim 1, wherein: the steel plate part (1) with the T-type slope and the steel plate part (2) with the U-type slope are provided with a plurality of groups of mutually corresponding U-shaped grooves and T-shaped ribs on contact surfaces; the U-shaped groove is provided with a concave groove in the length direction of the part, the groove bottom and the groove shoulder are provided with slopes with opposite directions but same angles in the length direction, the slope is i, and the cross section of the U-shaped groove is similar to a letter U; the T-shaped rib is provided with a rectangular convex edge in the length direction of the part, the convex edge and the side shoulder of the rib are provided with slopes with opposite directions but same angles in the length direction, the slope is i, and the cross section of the T-shaped rib is similar to the letter T; the slope angle of the U groove is the same as that of the T-shaped convex rib; inserting the T-shaped convex edge into the U groove to form a U-T slope mechanism; because all slope angles of the U groove and the T convex edge are the same, and the two slopes of the U groove and the T convex edge, the slope surface at the bottom of the U groove and the slope surface at the shoulder of the U groove are the same; the angle direction of the rib slope surface of the T-shaped rib is opposite to that of the rib shoulder slope surface, so that a U-T slope surface mechanism can find a point, the top slope surface of the T-shaped rib is completely attached to the bottom slope surface of the U groove, the shoulder slope surface of the T-shaped rib is completely attached to the shoulder slope surface of the U groove, and the point is the initial position of the mechanism.