CN115492887A

CN115492887A - Displacement-related memory damper device

Info

Publication number: CN115492887A
Application number: CN202211179408.0A
Authority: CN
Inventors: 张孝良; 朱伟安; 聂佳梅; 王风力
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2022-09-27
Filing date: 2022-09-27
Publication date: 2022-12-20

Abstract

The invention relates to a displacement-related memory damper device, which consists of a piston rod, a piston, a hydraulic cylinder and a hydraulic channel, wherein a group of pistons with radial through grooves on the surfaces and a variable-inner-diameter hydraulic cylinder or a group of cylindrical pistons and a variable-inner-diameter hydraulic cylinder with through grooves on the small inner-diameter end are used as core parts, a cylinder barrel is divided into a left cavity and a right cavity by the piston, the small inner diameter of the hydraulic cylinder is the same as the diameter of the excircle of the piston, the hydraulic channel with the length capable of changing along with the position of the piston is formed to communicate the left cavity and the right cavity, viscous damping media are filled in the cylinder, when the piston rod moves, the damping media flow through the hydraulic channel to achieve pressure balance at two ends of the hydraulic cylinder, the damping media generate damping force in the friction and extrusion of the hydraulic channel, the damping coefficient of the displacement-related memory damper device is continuously variable along with the displacement of the piston, and the memory characteristic defined by a memory element theory is possessed, and the displacement-related memory damper device belongs to a mechanical memory element.

Description

Displacement-related memory damper device

Technical Field

The invention relates to a damper device, in particular to a displacement-related memory damper device.

Background

The hydraulic damper is used as an energy consumption element and can effectively inhibit the vibration transmission of a vibration system. Patent CN 208565396U discloses a damper with damping parameters related to piston displacement, which realizes the change of the damping parameters by providing an additional set of bypass grooves and valves. However, the damping parameters of the above invention can only be changed when the relative displacement between the two ends of the damper reaches a set value, and the continuous change and adjustment of the damping coefficient cannot be realized.

On the basis of the nonlinear theory, the concept of "memory element" was derived. "memory element" means a non-linear element having in part a significant memory characteristic, embodied in that a parameter of the element can "memorize" the entire history of changes in its particular physical quantity. In the field of electronics, the relevant scholars give corresponding definitions and propose a triangular periodic table of circuit elements with instructive significance. Based on the electromechanical similarity theory, a triangular periodic table of mechanical elements is also proposed, predicting unknown mechanical memory elements. According to this table, patent CN 106051022A discloses a hydraulic memory inerter device, which is the first real mechanical memory element. However, since the oil produces parasitic damping during the movement of the hydraulic circuit, the device is actually a inertance-damping parallel device and cannot be used as a single element.

Disclosure of Invention

The invention aims to provide a memristor device with a continuously variable damping coefficient, provides an implementation device for an ideal model element of a memristor, obtains a force control characteristic that the damping coefficient changes along with relative displacement, and overcomes the problem that the damping coefficient of the current damper cannot change continuously.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a displacement-related memory damper device comprises a hydraulic cylinder, a piston, a hydraulic rod and a hydraulic channel, wherein the piston divides the hydraulic cylinder into a left cavity and a right cavity, the hydraulic channel communicates the left cavity and the right cavity of the hydraulic cylinder, and the length of the hydraulic channel can change along with the change of the relative displacement of the hydraulic cylinder and the piston. The damping coefficient of the displacement-related memory damper device continuously changes along with the displacement of the piston, a damping force-relative speed characteristic curve of the displacement-related memory damper device is a twisted hysteresis loop, and a momentum-relative displacement characteristic curve is a single-value mapping curve.

In the scheme, the hydraulic cylinder is bounded by a radial center and is provided with two inner circular surfaces with different diameters, namely a large inner circular surface and a small inner circular surface, a through groove is formed in the outer surface of the piston, the outer surface of the piston is matched with the small inner circular surface of the hydraulic cylinder to divide the cylinder barrel into a left cavity and a right cavity, and a hydraulic channel formed by the through groove and the small inner circular surface is communicated with the left cavity and the right cavity of the hydraulic cylinder.

The scheme can also be replaced by the following scheme: the hydraulic cylinder is bounded by a radial center and is provided with two inner circular surfaces with different diameters, namely a large inner circular surface and a small inner circular surface. The outer surface of the piston is matched with the small inner circular surface of the hydraulic cylinder to divide the cylinder barrel into a left cavity and a right cavity, the small inner circular surface is provided with a through groove, and the through groove and a hydraulic channel enclosed by the small inner circular surface are communicated with the left cavity and the right cavity of the hydraulic cylinder.

In the above scheme, the through grooves are equidistant through grooves or non-equidistant through grooves.

In the above solution, either one of the hydraulic cylinder or the piston of the displacement-dependent memristor device is fixed.

In the above scheme, a damping force-velocity characteristic curve of the displacement-related memory damper device is a twisted hysteresis loop, and a momentum-relative displacement characteristic curve of the memory damper is a single-value mapping curve. This is considered as a mark of the memory element, which indicates that the damper is a hydraulic type memory damper with a memory function.

The invention has the beneficial effects that: (1) The damping coefficient of the device changes along with the change of the relative displacement of the two end points, and the technical effect that the damping coefficient is continuously variable is realized. (2) The device is a passive element, has simple structure, can be equivalent to a semi-active damper with a load adaptive control strategy, and does not need additional energy. (3) The damping force-velocity characteristic of the device is a twisted hysteresis loop, which is electrically the sign of a memory element. (4) The momentum-displacement characteristic of the device is a single-valued mapping curve. The characteristics show that the device is an implementation device for ideal memory damper elements, and has important significance in the field of mechanical memory elements. The device can overcome the defect that the damping coefficient of the existing damper device cannot be continuously variable, and provides a force control characteristic that the damping coefficient changes along with the change of displacement, thereby improving the performance of a vibration damping system and better controlling or offsetting the vibration force.

Drawings

Fig. 1 is a schematic structural diagram of a memristor device with a piston with a through groove formed in the surface and a variable-inner-diameter hydraulic cylinder.

Fig. 2 is a schematic structural diagram of a membrake device using a cylindrical piston and a variable-inner-diameter hydraulic cylinder with a through groove.

FIG. 3 is a diagram of damping forces of all parts of a displacement-dependent memristor device.

FIG. 4 is a graph of damping coefficient-relative displacement of a displacement-dependent memdamper device.

FIG. 5 is a graph of damping force versus relative velocity of a displacement-dependent memberant device.

FIG. 6 is a momentum-relative displacement graph of a displacement-dependent memdamper device.

FIG. 7 is a graph of damping coefficient versus relative displacement of a displacement-dependent memb damper device and a linear damper.

FIG. 8 is a graph of damping force versus relative velocity for a displacement-dependent memb damper device and a linear damper.

FIG. 9 is a displacement-dependent memristor device and linear damper momentum-relative displacement comparison graph.

In the figure, 1-hydraulic cylinder, 2-straight through groove, 3-piston, 4-piston rod, 5-large inner circular surface, 6-small inner circular surface and 7-damping medium.

Detailed Description

The invention is further illustrated by the following examples in conjunction with the drawings.

In the implementation mode, a group of pistons with radial through grooves on the surfaces and a variable-inner-diameter hydraulic cylinder or a group of cylindrical pistons and a variable-inner-diameter hydraulic cylinder with through grooves on the small inner-diameter end are used as core components, a cylinder barrel is divided into a left cavity and a right cavity by the pistons, the small inner diameter of the hydraulic cylinder is the same as the diameter of the outer circle of the pistons, a hydraulic channel with the length capable of changing along with the position of the pistons is formed to communicate the left cavity and the right cavity, viscous damping media are filled in the cylinders, when the piston rods move, the damping media flow through the hydraulic channel to achieve pressure balance at the two ends of the hydraulic cylinder, the damping media generate damping force through friction and extrusion of the hydraulic channel, the damping coefficient of the displacement-related damper device is continuously variable along with the displacement of the pistons, and has the memory characteristic defined by the memory element theory, and belongs to a mechanical memory element.

Fig. 1 is an embodiment 1 of a displacement-related memristor, and is a memristor device applying a piston with a through groove formed on the surface and a variable-inner-diameter hydraulic cylinder, and the memristor device comprises a hydraulic cylinder 1, a piston 3 and a piston rod 4; the hydraulic cylinder 1 is bounded by a radial center and is provided with two inner circular surfaces with different diameters, namely a large inner circular surface 5 and a small inner circular surface 6, and the whole interior of the hydraulic cylinder 1 is filled with a damping medium 7; the outer surface of the piston 3 is provided with a through groove 2, the outer surface of the piston is matched with the small inner circular surface 6 of the hydraulic cylinder to divide the cylinder barrel into a left cavity and a right cavity, and the left cavity and the right cavity of the hydraulic cylinder are communicated through a hydraulic channel enclosed by the through groove 2 and the small inner circular surface 6. When the piston 3 moves relative to the cylinder 1, the piston 3 drives the fluid 7 from one chamber to the other via the hydraulic channel, which generates a damping force when flowing due to the damping medium squeezing, rubbing in the hydraulic channel. The hydraulic cylinder 1 is used as one end point, the piston 3 is used as the other end point, and the length of the hydraulic channel changes along with the change of the relative displacement of the two end points, so the ratio of the generated damping force to the relative speed of the two end points, namely the damping coefficient, continuously changes along with the change of the relative displacement of the two end points. In addition, the damping force-velocity characteristic of the device is a twisted hysteresis loop, and the momentum-displacement characteristic is a single-value mapping curve.

Fig. 2 shows an embodiment 2 of the damper device, which mainly differs from the embodiment 1 in that the radial through-grooves are provided on the surface of the piston 3, while the embodiment 2 shows the through-grooves on the small inner circular surface 6 of the cylinder.

In

embodiments

1 and 2, the cross-sectional shape of the through groove 2 is designed to be semicircular for the convenience of processing, and the cross-sectional shape is not limited to be semicircular, and can be designed to be other shapes as required. In addition, the hydraulic cylinder 1 may be a valve body or a housing containing a chamber.

The device shown in fig. 1 and 2 is implemented by using a double piston rod 4, but it is not limited thereto, and may be in the form of a single piston rod and a floating piston, a double cylinder, or the like, or other similar forms as long as they can drive the flow of liquid.

In the embodiment shown in fig. 1 and 2, the characteristic parameters of the device, i.e. the damping coefficient, are not constant but vary with the displacement, or the damping coefficient is a function of the displacement, which is determined by the diameter and width of the piston, the radius and number of through-grooves, the radius of the piston rod, the dynamic viscosity of the damping medium, etc.

The displacement-related hydraulic memristor devices provided in

embodiments

1 and 2 correspond to memristors in circuit elements, and provide an implementation method for ideal model elements of the memristor predicted in a triangular mechanical periodic table. Meanwhile, the device has the key characteristics of a mechanical memory element and belongs to a memory damper element corresponding to a p/x class in a triangular element periodic table. Moreover, the device has a simple structure, is easy to produce, can effectively improve the performance of the damping system, and has practical value.

The technical principles and effects of

embodiments

1 and 2 will be described below by taking the displacement-dependent memristor device of fig. 1 as an example.

The motion state of a conventional linear damping element can be defined by newton's second law:

f(t)＝c·v(t) (1)

in the formula: f (t) is the damping force of the damper, c is the damping coefficient, and v (t) is the relative velocity of the two end points.

Integrating equation (1) yields:

in the formula: p (t) is momentum.

It is easy to know that the equations (1) and (2) are equivalent, and both variables on both sides of the equal sign of any order derivative or differential plane are in a single-value mapping relationship. Therefore, the linear damper can be defined in any plane such as f-v, p-x, etc.

Let the relative speed and displacement between two end points of the displacement-related memory damper be v and x respectively, the damping coefficient be C (x), and the damping force output by the memory damper be f _C . Different from a linear damper, the displacement correlation type memristor cannot be freely defined in any f-v same-order integral or differential plane, namely cannot be defined by the following equation:

f _C ＝C(x)·v (3)

since formula (3) includes f _C X, v, which cannot satisfy the constraint of having and only two variables in the constitutive relation definition.

Integrating equation (3) in the time domain yields:

in the formula: p is _C Is the integral of momentum.

It can be seen that the left and right variables of equation (4) are only two, and are a single mapping relation, i.e., { P } _C And x, satisfying the definition that the variables in the constitutive relation have two variables, the memberane element can be correctly defined. This shows that the displacement-dependent memristor can only be used in P _C The x plane is defined by P _C And x.

The damping force generated by the oil flowing in the displacement-related memory damper mainly has three sources: (1) on-way pressure loss; (2) local pressure loss; (3) shear pressure loss. Thus, the damping force of the device can be expressed as:

Δp＝Δp _h +Δp _s +Δp _in +Δp _out (5)

in the formula: Δ p _h For on-way pressure loss, Δ p _s For shear pressure loss,. DELTA.p _in For inlet pressure loss, Δ p _out Is the outlet pressure loss.

Specifically, the terms on the right side of formula (5) can be respectively expressed as:

in the formula: mu is dynamic viscosity of oil, rho is liquid density, L (x) is length of the hydraulic channel, L (x) = L + x, L is initial length of the hydraulic channel, u is flow speed of oil in the hydraulic channel, A ₁ 、A ₂ Respectively the cross-sectional area of the hydraulic passage and the effective area of the piston, A _f Is the friction area of the hydraulic cylinder, d _e Is hydraulic radius of hydraulic channel, and deltar is clearance between piston and hydraulic cylinder.

Finally, the hydraulic type memb damper device damping force can be expressed as:

the mechanical properties of the devices described in examples 1 and 2 are illustrated below, taking the main parameters shown in table 1 as an example. The main parameters of the device are shown in table 1, and the total damping force and each component force of the damper can be obtained correspondingly, as shown in fig. 3. It can be seen that the on-way pressure dominates the total damping force, and the pressure loss is negligible in the other parts. Therefore, the displacement-dependent memberant damper damping force calculation formula can be approximated as:

wherein the damping coefficient can be expressed as:

integrating equation (8) in the time domain to obtain:

according to the formula (9), the damping coefficient C (x) of the memristor is linearly related to the relative displacement x of two ends of the device. The damping force and momentum of the devices described in examples 1 and 2 are shown by the equations (8) and (10), and the expression of the damping force contains x, u, f _C The three variables, and the momentum expression only contains x and p variables, accord with the definition of constitutive relation, and the constitutive relation can be defined only on a p-x plane, so that the definition of the memory damper device is satisfied.

To illustrate the mechanical properties of the devices described in examples 1 and 2, the displacement excitation v = Acos (2 pi ft), where the amplitude a is 0.05m and the frequency f is 2.5Hz, and the characteristic curves of the displacement-dependent memristor are shown in fig. 4, 5, 6, and the pairs of linear dampers are shown in fig. 7, 8, 9.

TABLE 1 Displacement-related MEMORY DAMPER DEVICE PARAMETERS

Fig. 4 shows that the damping coefficient of the device varies with the relative displacement of the two ends of the device, and that this variation is continuous, which demonstrates that the damping characteristics of the device are displacement-dependent. As can be seen in fig. 5, the curvature of the device in the F-v plane is a twisted hysteresis loop, which is a typical sign of a memory element, i.e., the devices described in examples 1 and 2 can be considered as a displacement-dependent memberator device. Since the F-v curve is not single-valued mapped, the memdamp characteristic of the device cannot be defined by the relation between the damping force F and the relative velocity v. And as can be seen from fig. 6, the characteristic curve of the device in the p-x plane is a single-value mapping curve, so that the relation between the momentum p and the relative displacement x in the graph, namely the expression (10), can be used for defining the memristive characteristic of the device.

Fig. 7, 8 and 9 clearly show the difference between the linear damper and the memristor device. As can be seen from fig. 7, the damping coefficient of a linear damper device is a constant, whereas the damping coefficient of a memristor device is related to the relative displacement of two end points of the device. It can be seen from fig. 8 that the damping force of the linear damper is proportional to the relative velocity of the two end points, and the mechanical characteristics of the memory damper are obviously different, and the relationship between the force and the velocity is a twisted hysteresis loop, so that the circulation process of energy in the device can be memorized. As can be seen from fig. 9, the p-x characteristic curve of the linear damper device is a straight line like the F-v curve, while the memristor device is a single-valued mapping curve, and only the single-valued mapping relation can be presented in this plane. It can be seen that the two devices are essentially different from each other, and the memristor and linear damper device is essentially different from the linear damper device in terms of displacement dependence, mechanical characteristics and essential characteristics of the devices, and the two devices are mechanical elements with different properties.

Claims

1. A displacement-related memory damper device comprises a hydraulic cylinder (1), a piston (3), a piston rod (4) and a hydraulic channel, and is characterized in that the piston (3) divides the hydraulic cylinder (1) into a left cavity and a right cavity, the hydraulic channel communicates the left cavity and the right cavity of the hydraulic cylinder, the length of the hydraulic channel can change along with the change of the relative displacement of the hydraulic cylinder (1) and the piston (3), the damping coefficient of the displacement-related memory damper device continuously changes along with the displacement of the piston, the damping force-relative speed characteristic curve of the displacement-related memory damper device is a twisted hysteresis loop, and the momentum-relative displacement characteristic curve is a single-value mapping curve.

2. A displacement correlation type memory damper device according to claim 1, characterized in that the hydraulic cylinder (1) is bounded by a radial center and has two inner circular surfaces with different diameters, namely a large inner circular surface (5) and a small inner circular surface (6), a through groove (2) is formed in the outer surface of the piston (3), the outer surface of the piston (3) is matched with the small inner circular surface (6) to divide a cylinder barrel of the hydraulic cylinder (1) into a left cavity and a right cavity, and a hydraulic channel formed by the through groove (2) and the small inner circular surface (6) is communicated with the left cavity and the right cavity of the hydraulic cylinder.

3. A displacement correlation type memory damper device as claimed in claim 1, wherein the hydraulic cylinder (1) is bounded by a radial center and is provided with two inner circular surfaces with different diameters, namely a large inner circular surface (5) and a small inner circular surface (6), the outer surface of the piston (3) is matched with the small inner circular surface (6) to divide the cylinder barrel into a left cavity and a right cavity, the small inner circular surface (6) is provided with a through groove (2), and a hydraulic channel formed by the through groove (2) and the small inner circular surface (6) is communicated with the left cavity and the right cavity of the hydraulic cylinder.

4. A displacement-dependent memdamper device as claimed in claim 2 or 3, wherein said through slots (2) are equidistant through slots or non-equidistant through slots.

5. A displacement-dependent memdamper device as claimed in claim 1, characterized in that either the hydraulic cylinder (1) or the piston (3) is fixed.