CN108692848B - Cable force testing method of inhaul cable under complex quality condition - Google Patents
Cable force testing method of inhaul cable under complex quality condition Download PDFInfo
- Publication number
- CN108692848B CN108692848B CN201810568530.4A CN201810568530A CN108692848B CN 108692848 B CN108692848 B CN 108692848B CN 201810568530 A CN201810568530 A CN 201810568530A CN 108692848 B CN108692848 B CN 108692848B
- Authority
- CN
- China
- Prior art keywords
- cable
- frequency
- cable force
- force
- jack
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/04—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands
- G01L5/045—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands for measuring the tension across the width of a band-shaped flexible member
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
- Bridges Or Land Bridges (AREA)
Abstract
The invention discloses a cable force testing method of a cable under a complex quality condition, wherein the cable force testing based on a frequency method is the most common method in the cable force testing of an arch bridge suspender, an anchorage device is frequently installed at the end part of the cable for facilitating the replacement of the suspender, and a jack which is bound during tensioning further changes the power characteristic of the cable, so that the cable force-frequency relation of the cable is greatly changed, and the cable force measuring precision of the conventional frequency method is influenced. The invention combines practical engineering to research the influence of the mass action of the end device of the stay cable and the jack bound on the stay cable on the vibration characteristic of the stay cable, and fits the cable force-frequency relation under the conditions of complex mass and rigidity. The engineering test result shows that the relation between the tension cable force and the actually measured frequency is consistent with the cable force-frequency relation under the condition of considering complex mass and rigidity, and the difference is larger than the conventional cable force-frequency relation, thereby verifying that the invention has certain engineering value.
Description
Technical Field
The invention relates to the technical field of cable force testing of inhaul cables, in particular to a cable force testing method of inhaul cables under complex quality conditions, and relates to a method for measuring cable force by using a frequency method of an anchorage device at the end part of an inhaul cable and a bound jack, namely aiming at a non-homogeneous suspender (the anchorage device in a non-tensioning stage, the jack quality action in a tensioning stage and the anchorage device action).
Background
Nowadays, the arch bridge of the half-through type and the through type is widely applied to China which becomes the world bridge and the big country. The hanger rod is used as an important force transmission component, and a plurality of bridge safety accidents are caused by corrosion, breakage and the like. Based on the research of many scholars, the diseases of the guy cable are summarized and corresponding maintenance measures are provided. Zhangxiu carries out research to jib detection, maintenance, proposes the suggestion that changes dangerous jib. The research on the anchor device of the suspension rod is carried out by the Sun's sea of shaking, and the extrusion type anchor is more applicable to the rapidity of replacing the suspension rod. Wenghui et al subsequently studied the particular advantages of an extruded anchorage for arch bridge boom replacement. With the wide use of the anchorage device on the suspender, the analytic method is too complicated and has low practical applicability, and different scholars study the frequency method for years, and although various practical formulas exist, the frequency method is mostly directed to the standard inhaul cable; the existing finite element method considers that the calculation deviation of the cable force of a stay cable with the end property under the condition of 30m is large. In addition, neither of them takes into account the action of the jack.
Currently, the current status and deficiencies of this research area are summarized as follows:
1. the existing literature only considers the action of an anchorage device aiming at a non-homogeneous suspender, and does not consider the quality action of a binding jack in a tensioning stage.
2. The existing finite element method of the heterogeneous suspender has larger cable force measurement error for the short cable, and the length of the suspender is mostly shorter.
3. The analytic method and the conventional finite element method are difficult to obtain an accurate cable force frequency relation, and the accuracy of the cable force frequency relation directly influences the accuracy of the actually measured cable force.
Disclosure of Invention
The invention aims to solve the defects in the prior art and provides a cable force testing method of a guy cable under a complex mass condition. Firstly, a corrected cable force frequency relation is obtained by establishing the heterogeneous suspension rod in finite element software, and then the actually measured cable force is obtained through the actually measured frequency, so that the accuracy of cable force testing is greatly improved.
The purpose of the invention can be achieved by adopting the following technical scheme:
a cable force testing method of a cable under a complex quality condition comprises the following steps:
s1, establishing two models of the non-homogeneous suspender (a tensioning stage and a non-tensioning stage) by using finite element software ANSYS to obtain a corresponding cable force frequency relation.
And S2, binding the vibration sensor on the stay cable, carrying out frequency domain analysis on the vibration signal, and picking up the peak frequency of each order of the spectrogram to obtain the natural vibration frequency of each order of the stay cable.
And S3, determining the measured cable force according to the measured frequency through the interpolation principle.
Further, in the step S1, the specific operation process is as follows:
(1) for convenience of inputting and outputting, the model parameter input and output results need to be stored in an ARRAY form, ARRAY numerical ARRAY definition is used, ARRAY parameters are defined by using a DIM command, and ARRAY parameter assignment is input by using a SET command.
(2) Establishing a cable geometric model and dividing grids, wherein for the cables with anchorage devices at the ends of non-homogeneous cables (in a non-tensioning stage), the mass and rigidity of section units of the anchorage devices need to be set according to actual engineering, and the structure is shown in figure 1; for the heterogeneous inhaul cable (tensioning stage), except for the anchorage device section, the jack section only needs to increase the linear density because the jack section only increases the mass effect, and the model is shown in figure 2.
(3) And applying boundary conditions and cable force, wherein the numerical value of the cable force needs to consider the cable.
(4) The initial internal force under the static effect of the cable force is calculated, and the geometric nonlinearity is required to be considered because the cable has a self-balancing state under the actions of self weight and prestress.
(5) And calculating a cable force frequency relation, wherein a concentrated mass matrix is adopted in dynamic analysis, an equation solver (EQSLV command) is appointed, a prestress switch is opened, and frequency solution under cyclic cable force is carried out.
Finite element models of two different tension states of the heterogeneous inhaul cable are shown in fig. 3 and 4.
Further, in step S2, the field frequency acquisition is as shown in fig. 5, a dynamic signal testing analyzer (donghua DHDAS5906) is used, the sensor is a piezoelectric sensor, and the stay cable is generally tensioned symmetrically and simultaneously according to the number of jacks during tensioning, so as to avoid mutual influence to the maximum extent. In addition, the spectrum analysis can be carried out in real time or afterwards, and the cable frequency in the tensioning stage can be efficiently obtained.
Further, in step S3, the linear interpolation principle is a simple interpolation method widely used in the fields of mathematics, computer graphics, and the like. The correspondence of the cable force frequency, e.g., (ω), is obtained through step S10,F0) And (omega)1,F1) To obtain [ omega ]0,ω1]F value (ω - ω) where a measured value ω is on a straight line in the interval0)/(ω1-ω0)*(F1-F0)+F0. (Note): omega refers to the measured frequency, omega0、ω1Refers to the frequency of finite element calculation, F refers to the actual measurement cable force, F0、F1Refers to the cable force exerted by the finite elements).
Compared with the prior art, the invention has the following advantages and effects:
1) the cable force frequency relation calculated by finite element software is fast, and the cable force testing efficiency is greatly improved;
2) the application of the technology considers the functions of the anchor device at the end part of the inhaul cable or the hanger and the binding jack, and the calculation accuracy of the cable force is higher.
Drawings
FIG. 1 is a schematic view of a non-homogeneous boom (non-tensioned phase);
FIG. 2 is a schematic view of a non-homogeneous boom (tension phase);
FIG. 3 is a schematic diagram of a finite element model of a non-homogeneous boom (non-tensioned phase);
FIG. 4 is a schematic diagram of a finite element model of a non-homogeneous boom (tension phase);
FIG. 5 is a schematic view of a non-homogeneous boom tension phase frequency test;
FIG. 6 is a flow chart of a finite element cable force-frequency relationship loop calculation;
FIG. 7 is a comparison diagram of the cable force calculation results of different modes of the suspension rod under different states.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Examples
In this embodiment, the method for measuring the cable force under abrupt change of end stiffness and mass is mainly established according to finite element software ANSYS, and specifically includes the following steps:
r1, measuring the vibration frequency f of the jack when the cable is tensioned and the jack is bound1；
R2, measuring the vibration frequency f when the jack is removed after the tension of the stay cable is finished2；
R3, establishing different models of the stay cable under the condition of the existence of the jack by finite elements, taking the diameter and the linear density of the end anchorage device into consideration in the modeling without the jack, and taking the increased linear density of the jack section into consideration besides the anchorage device by the existence of the jack, thereby calculating to obtain different cable force frequency relations;
r4, according to measured frequency f1And f2Substituting different cable force frequency relations to calculate the cable force value, and the cable force value before and after the binding of the jack is unchanged, so that the calculated cable force value deviation is not large.
The present invention is further verified by taking the non-homogeneous boom of a prosperous bridge as an example, and the boom parameters are shown in table 1.
TABLE 1 heterogeneous boom parameter table
Aiming at the steps R1 and R2, the measured values of the cable force before and after tensioning the heterogeneous suspender of the Xingwang bridge are analyzed, and the measured frequency of the heterogeneous suspender under the condition of tensioning with or without a jack is shown in Table 2
TABLE 2 boom parameters of Xingwang bridge
Aiming at the step R4, the calculation results of finite element cable force of the technology are compared under different tensioning states of the heterogeneous inhaul cable and under the same cable force state, and the calculation values of the cable force of the actually measured frequency under different tensioning states by different calculation methods are shown in the table 3.
TABLE 3 practical cable force value of Xingwang bridge
△ therein1＝(T1-T2)/T2，△2＝(T3-T4)/T4，△3＝(T3-T1)/T1，△4＝(T4-T2)/T2，T1Is f1The frequency is based on the cable force calculated by finite element of the heterogeneous inhaul cable (tensioning stage); t is2Is f2The frequency is based on the cable force calculated by finite element of the non-homogeneous cable (in a non-tensioning stage); t is3Is f1The frequency is based on the cable force calculated by the uniform cable; t is4Is f2The frequency is based on the cable force calculated for a uniform cable.
The above table shows the results of finite element calculation of two kinds of measured frequencies based on different models in different states of the cable as shown in fig. 7, and it can be seen that: 1) cable force T calculated based on text model1And T2The results are close, the deviation is within +/-10%, and the maximum deviation is 9.8%; 2) cable force T obtained by actually measured frequency calculation based on uniform cable force-frequency relation3And T4The deviation is large and is in the range of 12% -86%, wherein the deviation of the short cable is the largest, the deviation of the cable force of wd1 reaches 85.8%, and the deviation ratio of the cable force is obviously reduced as the cable length is gradually increased from 5.481m to 13.460 m; 3) f is measured based on the tension stage of the inhaul cable1The deviation of the cable force result calculated by the method and the uniform cable force-frequency mud scraping is in the range of 22% -92%, the cable force of the short cable is influenced obviously, the maximum deviation reaches 91.1%, the deviation proportion is reduced along with the increase of the cable length, but the minimum deviation proportion also reaches 22.8%, and the deviation amplitude is still unacceptable for the cable force measurement in the actual engineering; 4) f is measured based on the tension stage of the inhaul cable2The deviation of the calculation result of the method and the uniform inhaul cable model is in the range of 6% -45%, and the deviation is reduced along with the increase of the cable length.
The cable force value deviation obtained by calculation of the finite element model established at two different stages (with or without a jack) of the heterogeneous cable is small, which shows that under the conditions of the same cable force and different boundaries, the calculation method provided by the invention has small deviation, the calculation result has high closure degree and certain application value; the cable force result deviation range under the condition of the existence of the jack and the absence of the cable force frequency relation calculation of the homogeneous cable is large, which indicates that the existence of the jack and the anchorage has large change to the cable force-frequency relation of the cable, especially for a short cable, if the cable force-frequency relation of the traditional homogeneous cable is used for calculating the cable force-frequency relation, the precision requirement in the engineering can not be met; the cable force result deviation calculated by the method and the homogeneous cable model is large based on the frequency measured in the heterogeneous cable tensioning stage (with the jack), and the cable force result deviation calculated by the method and the homogeneous cable model is slightly smaller based on the frequency measured in the heterogeneous cable non-tensioning stage (without the jack), which indicates that for a short cable, the effects of an end anchorage device and the jack must be considered to obtain an accurate and reliable cable force test result, the anchorage device has small influence on the end of the long cable, but the jack effect is not negligible.
In summary, the finite element software ANSYS has the characteristics of convenience and rapidness in cable force-frequency analysis, can directly read a programmed file and write a calculation result into the file, and not only facilitates the modification of an original program, but also facilitates the processing of calculation data. The result of modal analysis can write the required frequency into an array through simple circulation, and each cable force change or cable length change can be obtained by deleting model reloading calculation, because each analysis speed is high, different cable force-frequency relations (thousands of data) of several cables with different lengths can be calculated in only ten minutes. Based on a set of frequencies obtained by cycling through a set of cable forces of the finite element software ANSYS, a set of cable forces obtained by cycling through a set of cable lengths, and outputting the resulting data in a fixed format to a 'command' file, as shown in figure 6.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.
Claims (5)
1. A cable force testing method of a cable under a complex quality condition is characterized by comprising the following steps:
s1, respectively establishing two models of the heterogeneous suspender in a tensioning stage and a non-tensioning stage to obtain corresponding cable force frequency relation, wherein the step process is as follows:
storing the input and output results of the model parameters in an ARRAY form, using ARRAY numerical ARRAY definition, using DIM command to define the ARRAY parameters, and using SET command to input the ARRAY parameters for assignment;
establishing a cable geometric model and dividing grids, wherein in a non-tensioning stage, for a non-homogeneous cable with an anchorage device at the end part, the mass and rigidity of a section unit of the anchorage device need to be set according to actual engineering; in the tensioning stage, the heterogeneous inhaul cable is considered except for the anchorage device section, and the jack section only needs to increase the linear density because the jack section only increases the mass effect;
applying boundary conditions and cable force, and preliminarily estimating the cable force range by using a use formula of an analytic method;
the initial internal force under the static effect of the cable force is calculated, and the geometric nonlinearity is required to be considered because the self-balancing state exists under the action of bearing the dead weight and the prestress of the cable;
calculating a cable force frequency relation, wherein a concentrated mass matrix is adopted in power analysis, an equation solver is designated, a prestress switch is turned on, and frequency solution under cyclic cable force is carried out;
s2, binding the vibration sensor on the stay cable, carrying out frequency domain analysis on the vibration signal, and picking up the peak frequency of each order of the spectrogram to obtain the natural vibration frequency of each order of the stay cable;
and S3, determining the measured cable force according to the measured frequency through the interpolation principle.
2. The method for testing the cable force of the inhaul cable under the complex mass condition according to claim 1, wherein in S1, finite element software ANSYS is used for respectively establishing two models of the heterogeneous suspender in a tensioning stage and a non-tensioning stage to obtain corresponding cable force frequency relation.
3. The method for testing the cable force of the cable under the complex mass condition as claimed in claim 1, wherein in the step S2, the vibration frequency f is measured when the jack is bound during the tensioning of the cable1After the tension of the guy cable is finished, the vibration frequency f of the jack is measured when the jack is unloaded2The finite element establishment of the guy cable adopts different models under the condition of existence of a jack, the modeling considers the diameter and the linear density of an end anchorage device when the jack does not exist, and the jack also needs to consider the linear density increased by a jack section besides considering the anchorage device, so that different guy force frequency relations are obtained through calculation.
4. The cable force testing method of the guy cable under the complex quality condition as claimed in claim 1, wherein in S2, a dynamic signal testing analyzer is adopted, wherein the dynamic signal testing analyzer can preset sampling frequency and channel information parameters for different testing environments, and a plurality of sets of simultaneous measurement are adopted in a testing field;
the sensor adopts a piezoelectric sensor, and the stay cable is simultaneously and symmetrically tensioned according to the number of jacks during tensioning.
5. The method for testing cable force of a cable under complex mass condition as claimed in claim 1, wherein in said S3, the corresponding relation of cable force frequency is obtained in advance through step S1: (omega)0,F0) And (omega)1,F1) Then [ omega ] is obtained0,ω1]F value of a certain measured value ω on a straight line in the interval, i.e., (ω - ω)0)/(ω1-ω0)*(F1-F0)+F0Where ω denotes the measured frequency, ω0、ω1Refers to the frequency of finite element calculation, F refers to the actual measurement cable force, F0、F1Refers to the cable force exerted by finite elements.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810568530.4A CN108692848B (en) | 2018-06-05 | 2018-06-05 | Cable force testing method of inhaul cable under complex quality condition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810568530.4A CN108692848B (en) | 2018-06-05 | 2018-06-05 | Cable force testing method of inhaul cable under complex quality condition |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108692848A CN108692848A (en) | 2018-10-23 |
| CN108692848B true CN108692848B (en) | 2020-01-24 |
Family
ID=63849330
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810568530.4A Active CN108692848B (en) | 2018-06-05 | 2018-06-05 | Cable force testing method of inhaul cable under complex quality condition |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108692848B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112985671B (en) * | 2021-02-23 | 2021-11-23 | 中冶建筑研究总院有限公司 | Damage judgment method based on full-cable-system cable force test and error adaptive analysis |
| CN113218556A (en) * | 2021-04-20 | 2021-08-06 | 广西大学 | Weight fixing device and method for measuring cable force of short cable by using weight |
| CN113322810A (en) * | 2021-04-22 | 2021-08-31 | 西北工业大学 | Debugging and installing system and method for stay cable of anti-seismic support |
| CN114878053B (en) * | 2022-06-02 | 2024-04-19 | 辽宁省交通高等专科学校 | Novel high-precision cable force device of piezoelectric type |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101504324B (en) * | 2009-02-26 | 2010-09-15 | 南京工业大学 | Intelligent judgment method and system for operation state of inhaul cable |
| KR100958405B1 (en) * | 2009-06-03 | 2010-05-18 | (주) 도담이앤씨종합건축사사무소 | Non-destructive measurement method of pullout resistance in cable structures and device for the same |
| CN101893497B (en) * | 2010-06-13 | 2012-01-11 | 东南大学 | Out-of-plane frequency method for testing cable force of planar cable rod system |
| CN103278279B (en) * | 2013-04-28 | 2015-10-28 | 华南理工大学 | A kind of cable force measurement method and apparatus |
| CN106932135B (en) * | 2017-05-17 | 2022-09-23 | 苏交科集团股份有限公司 | Flexible inhaul cable force testing method for identifying vibration frequency based on weighted narrow-band peak searching method |
| CN107588879B (en) * | 2017-09-11 | 2018-07-24 | 哈尔滨工业大学 | Rope supports the equal for hinged girder interpolation model method for building up of bridge cable group's cable force vibration method measurement |
-
2018
- 2018-06-05 CN CN201810568530.4A patent/CN108692848B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN108692848A (en) | 2018-10-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108692848B (en) | Cable force testing method of inhaul cable under complex quality condition | |
| CN106197970B (en) | A kind of bridge rope monitoring method and system based on optimization tensioning string model | |
| CN101641582B (en) | Vibrating wire sensor using spectral analysis | |
| CN105181200A (en) | Accurate algorithm for measuring cable force by using frequency method | |
| CN107300432B (en) | Method and device for realizing field self-adaptive cable force measurement | |
| CN103278279B (en) | A kind of cable force measurement method and apparatus | |
| CN101832813A (en) | Noise and Vibration-Measuring System based on virtual instrument technique | |
| CN108875120B (en) | Numerical iteration method for recognizing internal force of short bridge suspender | |
| CN106596100A (en) | Four-step machine tool spindle elastic modulus nondestructive detection method and device | |
| CN107862119B (en) | Vibration reliability testing method | |
| CN107145620B (en) | A kind of structural dynamic characteristic recognition methods based on Random Decrement Technique | |
| CN108090263B (en) | Verification method for pneumatic damping of deicing vibration scale test of power transmission line | |
| CN105222973A (en) | For the field calibration method of vibration signal order tracking technique | |
| JP2023107210A (en) | Critical point for test data preprocessing | |
| KR19990064682A (en) | An Apparatus for Measuring the Cable Tension Using the Dynamic Characteristics of Cable | |
| CN110333148B (en) | Soil dynamic shear modulus testing method based on fine analysis of vibration attenuation curve | |
| CN202929473U (en) | Closed loop control system dynamic performance index testing device | |
| CN211178306U (en) | Bridge type vibrating wire strain gauge based on online correction | |
| CN206450357U (en) | A kind of Suo Li dynamic testers | |
| CN110276045A (en) | Resolver | |
| CN110348160A (en) | A kind of dynamic triaxial tests actual seismic load applying method and system | |
| CN116878801B (en) | Structure state identification method, device and terminal under random excitation effect | |
| Campisi | Development of control system in LabVIEW environment for the study of the random fatigue behavior of metallic materials | |
| KR19990046801A (en) | A Measuring Method of Cable Tension Using the Dynamic Characteristics of Cable | |
| CN101599103B (en) | Material model influenced by weld thermal cycle and establishment method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20191211 Address after: 510640 Tianhe District, Guangdong, No. five road, No. 381, Applicant after: Xu Yufeng Applicant after: Guangzhou South China University of Technology science and Technology Park Co., Ltd. Address before: Nansha District Avenue South Ring of 511458 cities in Guangdong province Guangzhou City, No. 25 Hua Da Guangzhou production and Research Institute Applicant before: South China University of Technology |
|
| TA01 | Transfer of patent application right | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20191224 Address after: 528313 room 321, floor 3, block 22, Shunlian Machinery City, No. 18, Xingye 4th Road, Guanglong Industrial Park, Chihua neighborhood committee, Chencun Town, Shunde District, Foshan City, Guangdong Province (application for residence) Applicant after: Guangdong Huajiao Engineering Technology Co., Ltd. Address before: 510640 Tianhe District, Guangdong, No. five road, No. 381, Applicant before: Xu Yufeng Applicant before: Guangzhou South China University of Technology science and Technology Park Co., Ltd. |
|
| GR01 | Patent grant | ||
| GR01 | Patent grant |