CN113029408A - Non-contact type wharf fender pressure measuring method and device - Google Patents
Non-contact type wharf fender pressure measuring method and device Download PDFInfo
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- CN113029408A CN113029408A CN202110336024.4A CN202110336024A CN113029408A CN 113029408 A CN113029408 A CN 113029408A CN 202110336024 A CN202110336024 A CN 202110336024A CN 113029408 A CN113029408 A CN 113029408A
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- 238000000034 method Methods 0.000 title claims abstract description 24
- 239000000463 material Substances 0.000 claims abstract description 29
- 238000012545 processing Methods 0.000 claims abstract description 25
- 238000006073 displacement reaction Methods 0.000 claims abstract description 10
- 230000008569 process Effects 0.000 claims abstract description 8
- 238000004422 calculation algorithm Methods 0.000 claims abstract description 5
- 238000000691 measurement method Methods 0.000 claims abstract description 4
- 229920001971 elastomer Polymers 0.000 claims description 18
- 238000009530 blood pressure measurement Methods 0.000 claims 1
- 238000004364 calculation method Methods 0.000 abstract description 3
- 239000002699 waste material Substances 0.000 abstract description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 239000002184 metal Substances 0.000 description 2
- 239000003190 viscoelastic substance Substances 0.000 description 2
- 230000005483 Hooke's law Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 239000013013 elastic material Substances 0.000 description 1
- 239000000806 elastomer Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005381 potential energy Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
- G01L1/248—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet using infrared
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Abstract
The invention discloses a method and a device for measuring pressure of a contactless wharf fender, wherein an image acquisition device is arranged outside the wharf fender in a contactless manner to acquire displacement of the fender in a direction vertical to a wharf quay wall, and the acquired image is input into an image processing server, and the image processing server calculates deformation of the fender after being extruded by a ship through an image processing algorithm; and converting the pressure borne by the fender according to the stress-strain curves corresponding to different fender form materials by combining the temperature information detected by the infrared thermometer, and outputting and displaying the pressure result in a display through a data output module. According to the method, redundant equipment does not need to be installed on the fender, the pressure on the fender is deduced and calculated through a formula by adopting an indirect measurement method, and the pressure on the fender at any time in the collision process can be calculated. The invention has accurate calculation result, simple and reliable structure and no waste of redundant resources.
Description
Technical Field
The invention relates to a pressure measuring method and a pressure measuring device, in particular to a non-contact type method and a non-contact type device for measuring the pressure of a wharf fender.
Background
The fender is also called as the fender of ship, and is an elastic buffer device used at the edge of wharf or ship, mainly used for reducing the impact force between ship and wharf or ship in the course of landing or mooring, and reducing or eliminating the damage to ship and wharf. The conventional fender is mainly classified into a rubber fender made of a rubber material or a rubber and metal skeleton, and a metal fender, according to the material, and the conventional fender mainly comprises a rubber tire directly used as the fender, and a rubber fender prepared into a specific shape according to the shape of a ship board. The stress of the material increases with the increase of the external force, and the increase of the stress is limited, and beyond the limit, the material is damaged. For safe use, the material should have a stress below its ultimate stress during use, otherwise the material will fail during use. Therefore, in order to prolong the service life of the fender, the pressure borne by the fender needs to be measured in real time to prevent the fender from being damaged and prevent the ship from being dangerous when in berthing, although the pressure measuring instrument can be installed on the fender to directly measure the pressure borne by the fender, the pressure measuring instrument is seriously damaged in the testing process, the service life of the pressure measuring instrument is short, the direct measuring method is high in cost, and the resource waste is serious.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides a non-contact type method and a device for measuring the pressure of a wharf fender.
The technical scheme adopted by the invention for solving the technical problems is as follows: a non-contact type device for measuring the pressure of a wharf fender comprises image acquisition equipment, an image processing server, a display and an infrared thermometer, wherein the image acquisition equipment is connected with the image processing server through an electric signal; and the image processing server processes and analyzes information transmitted by the image acquisition equipment and the infrared thermometer and outputs and displays the information on the display. The image processing server is used for running an image processing algorithm; the display is used for outputting and displaying data of the pressure of the dock fender, and the infrared temperature measuring instrument is used for detecting the temperature of the fender.
Further, the method specifically comprises the following steps during measurement:
1) the image acquisition equipment acquires fender state information;
2) the image processing server processes an algorithm to judge the deformation epsilon of the fender;
3) the infrared thermometer transmits the temperature information to the image processing server;
4) the image processing server converts the pressure borne by the fender according to the stress-strain curve of the corresponding fender material and the temperature information transmitted by the infrared thermometer;
5) the pressure data is output on a display.
Further, the above operation steps mainly obtain the following parameters:
when the ship does not collide with the fender, the displacement L of the fender in the direction vertical to the quay wall of the wharf0，
When the ship collides with the fender, the displacement L of the fender in the direction vertical to the quay wall of the wharf1，
Before and after the ship collides with the fender, the deformation epsilon of the fender,
model parameters C of fenderi，
And (4) the fender temperature T.
In the above parameters, the displacement L of the fender perpendicular to the quay wall direction0、L1The image acquisition device acquires the image. The fenderModel parameter C ofiIs determined by the fender material and the fender temperature. And the fender temperature T is detected by an infrared thermometer.
The invention has the beneficial effects that: according to the method, redundant equipment does not need to be installed on the fender, the pressure on the fender is deduced and calculated through a formula by adopting an indirect measurement method, and the pressure on the fender at any time in the collision process can be calculated. The invention has accurate calculation result, simple and reliable structure and no waste of redundant resources.
Drawings
FIG. 1 is a flow chart of the operation of the present invention.
FIG. 2 is a stress-strain diagram of a viscoelastic material.
Fig. 3 is a fender diagram measured in accordance with the present invention.
Fig. 4 is a working principle diagram of the present invention.
In the figure, 1, an image acquisition device, 2, an image processing server, 3, a display and 4, an infrared thermometer are arranged.
Detailed Description
The following describes embodiments of the present invention with reference to the drawings and examples, and parts not described in the present invention can be implemented by using or referring to the prior art.
It should be noted that the structures, proportions, sizes, and other dimensions shown in the drawings and described in the specification are only for the purpose of understanding and reading the present disclosure, and are not intended to limit the scope of the present disclosure, which is defined by the following claims, and any modifications of the structures, changes in the proportions and adjustments of the sizes, without affecting the efficacy and attainment of the same, are intended to fall within the scope of the present disclosure.
In addition, the terms "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the terms is not to be construed as a scope of the present invention.
As shown in fig. 1-4, a contactless dock fender pressure measuring method and device, an image acquisition device 1 is installed outside the dock fender in a contactless manner, and the image acquisition device 1 needs to be capable of acquiring the displacement of the dock fender in the direction perpendicular to the dock quay wall. The image acquisition equipment 1 respectively acquires images before and after the ship extrudes a fender; and inputs the acquired image to the image processing server 2. The image processing server 2 calculates the deformation amount of the fender after being extruded by the ship through an image processing algorithm; the image processing server 2 converts the pressure borne by the fender according to the relevant parameters corresponding to different fender materials by combining the temperature information detected by the infrared thermometer 4, and outputs and displays the pressure result in the display 3 through the data output module.
The stress and strain of an ideal elastic solid are linear according to hooke's law, as shown in equation (1). Where ε represents strain, σ represents stress, and λ represents a material parameter.
σ＝με (1)
According to newton's law of flow, ideal viscous liquid stress is directly proportional to strain rate and viscosity. And the properties of the elastomer are between the two. They are neither ideal elastic solids nor ideal liquids, elastic materials have both the elastic properties of solids and the viscous properties of liquids under the action of external forces, and their mechanical properties relax with time, a phenomenon also known as viscoelastic behavior. In actual use, the fender mostly comprises a rubber material, which is a viscoelastic material, when the fender is subjected to a sinusoidally varying stress, the strain of the fender always lags behind the stress, and the strain always lags behind the stress by a phase angle δ (δ is also referred to as a lagging phase angle), and the stress-strain relationship of the rubber material can be represented by fig. 2.
Compared with the mechanical property of a metal material, the stress-strain relation of the rubber material has nonlinearity, and in order to describe the stress-strain nonlinearity of the rubber material, a model capable of reflecting the functional relation between the deformation gradient and the strain potential energy is introduced, and the model is called as a superelasticity constitutive model. In the case of evaluating the non-linear elasticity of rubber materials in a superelastic constitutive model, it is generally assumed that the compound is isotropic and incompressible, i.e. that the material parameters do not change with the deformation of the rubber. The relationship between the strain energy and the engineering stress and strain of the known rubber material in uniaxial tension can be expressed as follows:
in the formula: w represents strain energy; ε represents strain, σ represents stress, I1、I2Two substantially invariant functions representing the Cauchy-Green deformation tensor.
Different constitutive models have different degrees of representation of the mechanical properties of the rubber, and the commonly used constitutive models comprise: Mooney-Rivlin model, Yeoh model, Arruda-Boyce model, Ogden model, Neo-Hookean model, etc. The invention selects a Yeoh superelasticity constitutive model to express the relation between strain energy and deformation tensor, and the Yeoh superelasticity strain energy function is as follows:
Ci: the unit of the model material parameter is MPA; c1: initial shear modulus in a small deformation state; c2: softening of the material at medium deformation; c3: hardening of the material in the state of large deformation.
For carbon black filled rubber materials, much smaller, and approximately zero. By combining the formulas (2) and (3), the relationship between stress and strain under the Yeoh superelastic constitutive model can be obtained, as shown in the formula (4).
In the formula (4), C1、C2、C3The values of (a) are related to the rubber material and the temperature.
The temperature T of the fender is measured by the infrared thermometer 4, and the C under the determined material can be calculated1、C2、C3The numerical value of (c).
C1＝λ(T)C1″+C1′
C2＝ζ(T)C2″+C2′ (5)
C3＝λ(T)C3′
C1′、C2′、C3' determined by the rubber material, C of the same material1′、C2′、C3' same.
The epsilon in the formula (4) can be calculated according to the displacement of the fender acquired by the image acquisition equipment 1 in the direction vertical to the quay wall, where epsilon is L0-L1Wherein L is0When the ship does not collide with the fender, the fender is displaced in the direction vertical to the quay wall of the wharf; l is1The displacement of the fender in the direction perpendicular to the quay wall of the wharf when the ship collides with the fender.
Combining the above description and the derivation of the related equations, the following equation (6) is obtained,
the pressure of the fender when the ship collides with the fender can be calculated through the formula (6).
The stress curve of the fender in the process of the ship colliding with the fender is shown in figure 3. The invention can calculate the pressure at any time in the collision process.
The pressure on the fender is deduced and calculated through a formula by an indirect measurement method, the calculation result is accurate, the structure is simple and reliable, and no redundant resource is wasted.
Claims (5)
1. A non-contact measurement method for wharf fender pressure is characterized by comprising the following steps: the method comprises the following steps:
1) when the ship does not collide with the fender, measuring the displacement L of the fender in the direction vertical to the quay wall of the wharf0；
2) When the ship collides with the fender, the direction of the fender perpendicular to the quay wall of the wharf is measuredUpper displacement amount L1；
3) Before and after the ship collides with the fender, the deformation amount epsilon and epsilon of the fender are changed into L through a formula epsilon1-L0Calculating to obtain;
4) measuring the fender temperature T;
5) model parameters C of fenderi，CiComprising C1、C2、C3，
C1＝λ(T)C1″+C1′，
C3＝λ(T)C3′，
C1′、C2′、C3' is determined by the rubber material;
6) the fender pressure sigma is expressed by the formula:
and (4) calculating.
2. The utility model provides a contactless pier fender pressure's measuring device which characterized in that: the system comprises image acquisition equipment (1), an image processing server (2), a display (3) and an infrared thermometer (4), wherein the image acquisition equipment (1) is connected with the image processing server (2) through an electric signal, the infrared thermometer (4) is connected with the image processing server (2) through an electric signal, and the image processing server (2) is connected with the display (3) through an electric signal; the image processing server (2) processes and analyzes information transmitted by the image acquisition equipment (1) and the infrared thermometer (4) and then outputs and displays the information on the display (3).
3. The contactless dock fender pressure measurement device of claim 2, wherein:
the image acquisition equipment (1) is used for acquiring fender state information;
the image processing server (2) is used for processing an algorithm to judge the deformation epsilon of the fender;
the infrared thermometer (4) transmits the temperature information to the image processing server (2);
the image processing server (2) converts the pressure borne by the fender according to the stress-strain curve of the corresponding fender material and the temperature information transmitted by the infrared temperature measuring instrument (4);
the display (3) is used for outputting pressure data.
4. The method for measuring the pressure of the wharf fender in the non-contact mode according to claim 1, wherein the method comprises the following steps: the fender is perpendicular to the displacement L in the quay wall direction of the wharf0、L1Acquired by an image acquisition device (1).
5. The method for measuring the pressure of the wharf fender in the non-contact mode according to claim 1, wherein the method comprises the following steps: model parameters C of the fenderiIs determined by the fender material and the fender temperature.
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| CN202110336024.4A CN113029408A (en) | 2021-03-29 | 2021-03-29 | Non-contact type wharf fender pressure measuring method and device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113654789A (en) * | 2021-10-20 | 2021-11-16 | 江苏弘业检测技术有限公司 | Fender compression performance detection device |
| CN114235239A (en) * | 2021-12-20 | 2022-03-25 | 北京有竹居网络技术有限公司 | Pressure detection method and device and electronic equipment |
-
2021
- 2021-03-29 CN CN202110336024.4A patent/CN113029408A/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113654789A (en) * | 2021-10-20 | 2021-11-16 | 江苏弘业检测技术有限公司 | Fender compression performance detection device |
| CN113654789B (en) * | 2021-10-20 | 2021-12-24 | 江苏弘业检测技术有限公司 | Fender compression performance detection device |
| CN114235239A (en) * | 2021-12-20 | 2022-03-25 | 北京有竹居网络技术有限公司 | Pressure detection method and device and electronic equipment |
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