CN106599496B - Method for measuring residual stress by ring core method based on numerical calculation - Google Patents
Method for measuring residual stress by ring core method based on numerical calculation Download PDFInfo
- Publication number
- CN106599496B CN106599496B CN201611185415.6A CN201611185415A CN106599496B CN 106599496 B CN106599496 B CN 106599496B CN 201611185415 A CN201611185415 A CN 201611185415A CN 106599496 B CN106599496 B CN 106599496B
- Authority
- CN
- China
- Prior art keywords
- residual stress
- milling
- stress
- calculating
- milling ring
- 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
- 238000000034 method Methods 0.000 title claims abstract description 56
- 238000004364 calculation method Methods 0.000 title claims abstract description 29
- 238000003801 milling Methods 0.000 claims abstract description 71
- 239000000463 material Substances 0.000 claims abstract description 29
- FGUUSXIOTUKUDN-IBGZPJMESA-N C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 Chemical compound C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 FGUUSXIOTUKUDN-IBGZPJMESA-N 0.000 claims description 2
- 238000000691 measurement method Methods 0.000 abstract 1
- 238000005259 measurement Methods 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 238000002050 diffraction method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 238000009659 non-destructive testing Methods 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/06—Power analysis or power optimisation
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Computer Hardware Design (AREA)
- Evolutionary Computation (AREA)
- Geometry (AREA)
- General Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
the invention relates to the technical field of residual stress measurement methods, in particular to a method for measuring residual stress by a ring core method based on numerical calculation, which comprises the following steps: a. establishing a homogeneous material stress-free flat plate model in numerical calculation software, and applying a unidirectional tensile load to obtain a stress field and a strain field which are uniformly distributed in the flat plate model; b. removing materials at the milling ring grooves layer by layer in the center of the flat plate model, and calculating stress values and strain increments at the ring core corresponding to the depths of the milling ring grooves after each layer of materials at the milling ring grooves is removed; c. calculating a residual stress release coefficient corresponding to the depth of each milling annular groove; d. calculating an equivalent residual stress release coefficient corresponding to each milling annular groove depth increment; e. calculating a simplified residual stress release coefficient; f. and calculating the residual stress value corresponding to the depth of each milling ring groove. The residual stress release coefficients corresponding to different milling ring groove depths can be obtained, and the distribution characteristics of the residual stress in the depth direction can be accurately measured.
Description
Technical Field
the invention relates to the technical field of residual stress measuring methods, in particular to a method for measuring residual stress by using a ring core method based on numerical calculation.
background
residual stress is the stress that exists inside a component when there is no external force or moment. The existence of residual stress not only affects the static strength, corrosion resistance, fatigue strength and the like of the parts, but also can cause the parts to deform or break in the assembling and using processes, and affect the normal use of the parts. Therefore, it is very important to know the residual stress distribution in the part accurately.
The methods for measuring residual stress mainly include a nondestructive detection method and a destructive detection method. The nondestructive testing method mainly comprises a Chinese character diffraction method, an X-ray diffraction method, an ultrasonic method and the like, and has the advantages that the tested workpiece is not damaged, the cost is high, and the volume of the tested workpiece is required to be small. The method for detecting the damage mainly comprises a blind hole method, a ring core method, a cutting method and the like, and has the advantages of mature technology, convenient use and damage to parts.
the ring core method is one of the most common methods for measuring the residual stress of the rotor of a steam turbine of a power station. An annular groove is processed on the surface of a workpiece to be measured, and an annular core is arranged in the middle of the annular groove. The processed ring core is hardly affected by external force, and the residual stress is fully released. And measuring the strain released at the ring core by using a specific strain flower, and obtaining the magnitude and the direction of the residual stress at the ring core through a corresponding calculation formula. The existing ring core method measurement standard defines the increment of the milling ring groove in the depth direction, and the average stress in the drilled depth direction is obtained, so when the gradient of the stress in the depth direction is large, the measurement result cannot well reflect the characteristic.
Disclosure of Invention
the technical problem to be solved by the invention is to provide a method for measuring residual stress by using a ring core method based on numerical calculation, which can obtain the residual stress release coefficients and the residual stress corresponding to different milling ring groove depths so as to overcome the defects in the prior art.
In order to solve the technical problems, the invention adopts the following technical scheme: a method for measuring residual stress by a ring core method based on numerical calculation comprises the following steps:
Step a, establishing a homogeneous material stress-free flat plate model in numerical calculation software, and applying a unidirectional tensile load on the flat plate model to obtain a stress field and a strain field which are uniformly distributed in the flat plate model;
B, removing materials at the milling ring grooves layer by layer in the center of the flat plate model, and obtaining stress values and strain increments at the ring core corresponding to the depths of the milling ring grooves after each layer of materials at the milling ring grooves is removed through balance calculation;
Step c, calculating a residual stress release coefficient corresponding to the depth of each milling ring groove according to the stress value and the strain increment calculated in the step b;
D, calculating to obtain an equivalent residual stress release coefficient corresponding to the depth increment of each milling ring groove after removing the material at each layer of the milling ring groove according to the residual stress release coefficient obtained by calculation in the step c;
E, calculating a simplified residual stress release coefficient according to the equivalent residual stress release coefficient calculated in the step d;
and f, calculating to obtain a residual stress value corresponding to the depth of each milling ring groove according to the simplified residual stress release coefficient calculated in the step e.
Preferably, in step a, the strain gauge on the flat plate model is a cross-shaped strain gauge and is attached along the main stress direction, wherein the main stress direction is the axial direction and the circumferential direction of the flat plate model.
Preferably, in step c, the residual stress relief coefficient is calculated by:
In the formula, Δ ε0、Δε90is the strain increment of two main stress directions; delta z is the milling ring groove depth increment; k is a radical of1、k2Residual stress release coefficients in two main stress directions corresponding to the depths of the corresponding milling ring grooves; sigma1、σ2Stress values in two main stress directions corresponding to the depths of the corresponding milling ring grooves; e is the Young's modulus of the material(ii) a μ is the Poisson's ratio of the material.
Preferably, in step d, the equivalent residual stress relief coefficient is calculated by:
in the formula, delta z is the depth increment of the milling ring groove; k1、K2equivalent residual stress release coefficients in two main stress directions corresponding to the depth increment of the corresponding milling ring groove; k is a radical of1、k2And the residual stress release coefficients in the two main stress directions corresponding to the depths of the corresponding milling ring grooves.
preferably, in step e, the simplified calculation method of the residual stress relief coefficient is as follows:
In the formula, delta A and delta B are simplified residual stress release coefficients; delta z is the milling ring groove depth increment; k1、K2Equivalent residual stress release coefficients in two main stress directions corresponding to the depth increment of the corresponding milling ring groove; μ is the Poisson's ratio of the material.
preferably, in step f, the residual stress value is calculated by:
In the formula, σ1‘、σ2' residual stress values in two principal stress directions corresponding to the depths of the corresponding milling ring grooves; e is the Young's modulus of the material; delta epsilon0、Δε90Is the strain increment of two main stress directions; Δ a, Δ B are simplified residual stress relief coefficients.
Compared with the prior art, the invention has the remarkable progress that:
The invention adopts a numerical calculation method to simply and conveniently obtain the residual stress release coefficients and the residual stress values corresponding to different milling ring groove depths, compared with the residual stress release coefficients in the existing ring core method measurement theoretical calculation formula which are determined by experiments, and the residual stress release coefficients only correspond to the specific milling ring groove depths. The advantages of the invention are particularly apparent in the case of varying inner and outer diameters of the milling ring groove. In addition, the invention has the advantage of simple and feasible implementation.
drawings
FIG. 1 is a schematic diagram of a flat plate model of a homogeneous material created by an embodiment of the present invention.
Fig. 2 is a schematic diagram of the flat panel model shown in fig. 1 after meshing.
Fig. 3 is a graph of strain at the ring core as a function of milling pocket depth, obtained by measuring residual stress using the flat plate model simulation ring core method shown in fig. 1.
Fig. 4 is a curve of the residual stress release coefficient of a certain nickel-based alloy sample plate, which is calculated according to the method for measuring the residual stress by using the ring core method based on numerical calculation in the embodiment of the invention, along with the change of the depth of the milling ring groove.
Detailed Description
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present invention and are not intended to limit the present invention.
In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
in the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.
As shown in fig. 1 to 4, one embodiment of the method for measuring residual stress based on the numerical calculation ring core method of the present invention. The method for measuring the residual stress based on the numerical calculation ring core method is suitable for measuring the residual stress of various workpieces, and is particularly suitable for measuring the residual stress of the surface of a rotor of a steam turbine of a power station. The following description will take the example of measuring the residual stress on the surface of a rotor of a steam turbine of a power station.
Specifically, the method for measuring the residual stress based on the numerical calculation ring core method of the present embodiment includes the following steps:
Step a, as shown in fig. 1 and fig. 2, establishing a flat plate model of a homogeneous material without stress in numerical calculation software, and applying a unidirectional tensile load sigma on the flat plate modelaAnd obtaining a stress field and a strain field which are uniformly distributed in the flat plate model. In the embodiment, as the main directions of the residual stress on the surface of the power station steam turbine rotor are distributed along the axial direction and the circumferential direction, the strain gauge on the flat plate model adopts a cross-shaped strain gauge and is pasted along the main stress direction, and the main stress directions are the axial direction and the circumferential direction of the flat plate model. Numbers used in the present exampleThe value calculation software was ABAQUS software.
And b, removing the materials at the milling ring grooves layer by layer in the center of the flat plate model, and obtaining the stress value and the strain increment at the ring core corresponding to the depth of each milling ring groove after removing the material at each layer of the milling ring groove through balance calculation by using the numerical calculation software according to the established flat plate model. Fig. 3 shows the strain of the ring core in the two principal stress directions as a function of the depth of the milling pocket during the removal of material from the milling pocket layer by layer in the center of the flat model.
and c, calculating a residual stress release coefficient corresponding to the depth of each milling ring groove according to the stress value and the strain increment calculated in the step b. The method for calculating the residual stress release coefficient in the embodiment comprises the following steps:
In the formula, Δ ε0、Δε90Is the strain increment of two main stress directions; delta z is the milling ring groove depth increment; k is a radical of1、k2Residual stress release coefficients in two main stress directions corresponding to the depths of the corresponding milling ring grooves; sigma1、σ2Stress values in two main stress directions corresponding to the depths of the corresponding milling ring grooves; e is the Young's modulus of the material; μ is the Poisson's ratio of the material.
And d, calculating to obtain an equivalent residual stress release coefficient corresponding to the depth increment of each milling ring groove after removing the material at each layer of milling ring groove according to the residual stress release coefficient obtained by calculation in the step c. The method for calculating the equivalent residual stress release coefficient in the embodiment comprises the following steps:
in the formula, delta z is the depth increment of the milling ring groove; k1、K2equivalent residual stress release coefficients in two main stress directions corresponding to the depth increment of the corresponding milling ring groove; k is a radical of1、k2For milling the depth of the groove correspondinglyThe residual stress relief factor in the corresponding two principal stress directions. FIG. 4 shows the equivalent residual stress relief coefficient K of a nickel-base alloy test piece plate1、K2Curve as a function of milling pocket depth.
And e, calculating to obtain a simplified residual stress release coefficient according to the equivalent residual stress release coefficient calculated in the step d. The simplified method for calculating the residual stress release coefficient in this embodiment is as follows:
In the formula, delta A and delta B are simplified residual stress release coefficients; delta z is the milling ring groove depth increment; k1、K2Equivalent residual stress release coefficients in two main stress directions corresponding to the depth increment of the corresponding milling ring groove; μ is the Poisson's ratio of the material.
and f, calculating to obtain a residual stress value corresponding to the depth of each milling ring groove according to the simplified residual stress release coefficient calculated in the step e. The method for calculating the residual stress value in the embodiment comprises the following steps:
In the formula, σ1‘、σ2' residual stress values in two principal stress directions corresponding to the depths of the corresponding milling ring grooves; e is the Young's modulus of the material; delta epsilon0、Δε90Is the strain increment of two main stress directions; Δ a, Δ B are simplified residual stress relief coefficients.
Therefore, the residual stress release coefficients and the residual stress values corresponding to different milling ring groove depths can be obtained more simply and conveniently by adopting a numerical calculation method. Compared with the existing ring core method which is used for determining the residual stress release coefficient in the theoretical calculation formula by experiments and only corresponds to the specific milling ring groove depth, the method for measuring the residual stress based on the numerical calculation of the ring core method in the embodiment can represent the characteristic more effectively, particularly when the gradient of the residual stress in the depth direction of the milling ring groove is large, the residual stress release coefficients corresponding to different milling ring groove depths can be effectively obtained, and the residual stress corresponding to different milling ring groove depths can be calculated, so that the distribution characteristics of the residual stress in the depth direction can be measured more accurately. The advantages of this embodiment are particularly apparent in the case of varying inner and outer diameters of the milling ring groove. In addition, the invention has the advantage of simple and feasible implementation.
the above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.
Claims (6)
1. A method for measuring residual stress by a ring core method based on numerical calculation is characterized by comprising the following steps:
Step a, establishing a homogeneous material stress-free flat plate model in numerical calculation software, and applying a unidirectional tensile load on the flat plate model to obtain a stress field and a strain field which are uniformly distributed in the flat plate model;
B, removing materials at the milling ring grooves layer by layer in the center of the flat plate model, and obtaining stress values and strain increments at the ring core corresponding to the depths of the milling ring grooves after each layer of materials at the milling ring grooves is removed through balance calculation;
Step c, calculating a residual stress release coefficient corresponding to the depth of each milling ring groove according to the stress value and the strain increment calculated in the step b;
D, calculating to obtain an equivalent residual stress release coefficient corresponding to the depth increment of each milling ring groove after removing the material at each layer of milling ring groove according to the residual stress release coefficient obtained by calculation in the step c;
E, calculating a simplified residual stress release coefficient according to the equivalent residual stress release coefficient calculated in the step d;
And f, calculating to obtain a residual stress value corresponding to the depth of each milling ring groove according to the simplified residual stress release coefficient calculated in the step e.
2. The method for measuring residual stress by using a numerical calculation-based ring core method according to claim 1, wherein in the step a, the strain gauge on the flat plate model is a cross-shaped strain gauge and is attached along principal stress directions, wherein the principal stress directions are axial and circumferential directions of the flat plate model.
3. The method for measuring residual stress based on the numerical calculation ring core method according to claim 2, wherein in the step c, the residual stress relief coefficient is calculated by:
in the formula, Δ ε0、Δε90is the strain increment of two main stress directions; delta z is the milling ring groove depth increment; k is a radical of1、k2Residual stress release coefficients in two main stress directions corresponding to the depths of the corresponding milling ring grooves; sigma1、σ2Stress values in two main stress directions corresponding to the depths of the corresponding milling ring grooves; e is the Young's modulus of the material; μ is the Poisson's ratio of the material.
4. The method for measuring residual stress based on the numerical calculation ring core method according to claim 3, wherein in the step d, the method for calculating the equivalent residual stress relief coefficient is as follows:
In the formula, delta z is the depth increment of the milling ring groove; k1、K2equivalent residual stress release coefficients in two main stress directions corresponding to the depth increment of the corresponding milling ring groove; k is a radical of1、k2Residual stress relief in two principal stress directions for respective milling pocket depthsAnd (5) amplifying the coefficient.
5. The method for measuring residual stress based on the numerical calculation ring core method according to claim 4, wherein in the step e, the simplified method for calculating the residual stress relief coefficient is as follows:
In the formula, delta A and delta B are simplified residual stress release coefficients; delta z is the milling ring groove depth increment; k1、K2Equivalent residual stress release coefficients in two main stress directions corresponding to the depth increment of the corresponding milling ring groove; μ is the Poisson's ratio of the material.
6. the method for measuring residual stress based on the numerical calculation ring core method according to claim 5, wherein in the step f, the residual stress value is calculated by:
In formula (II), sigma'1、σ‘2Residual stress values in two main stress directions corresponding to the depths of the corresponding milling ring grooves; e is the Young's modulus of the material; delta epsilon0、Δε90Is the strain increment of two main stress directions; Δ a, Δ B are simplified residual stress relief coefficients.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611185415.6A CN106599496B (en) | 2016-12-20 | 2016-12-20 | Method for measuring residual stress by ring core method based on numerical calculation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611185415.6A CN106599496B (en) | 2016-12-20 | 2016-12-20 | Method for measuring residual stress by ring core method based on numerical calculation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106599496A CN106599496A (en) | 2017-04-26 |
| CN106599496B true CN106599496B (en) | 2019-12-17 |
Family
ID=58600337
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201611185415.6A Active CN106599496B (en) | 2016-12-20 | 2016-12-20 | Method for measuring residual stress by ring core method based on numerical calculation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106599496B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115165182A (en) * | 2022-06-13 | 2022-10-11 | 长三角先进材料研究院 | High-efficiency and high-spatial-resolution residual stress measurement method |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102072877A (en) * | 2010-12-13 | 2011-05-25 | 清华大学 | System and method for measuring residual stress in real time |
| CN105117547A (en) * | 2015-08-25 | 2015-12-02 | 大连理工大学 | Simulation method for residual stress prediction of micro-milling nickel-based superalloy |
| CN105784960A (en) * | 2016-03-17 | 2016-07-20 | 清华大学 | Steel part and experiment research method of turning residual stress distribution of steel part |
| CN105825025A (en) * | 2016-03-30 | 2016-08-03 | 清华大学 | Plate-shaped part processing deformation simulation prediction method |
-
2016
- 2016-12-20 CN CN201611185415.6A patent/CN106599496B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102072877A (en) * | 2010-12-13 | 2011-05-25 | 清华大学 | System and method for measuring residual stress in real time |
| CN105117547A (en) * | 2015-08-25 | 2015-12-02 | 大连理工大学 | Simulation method for residual stress prediction of micro-milling nickel-based superalloy |
| CN105784960A (en) * | 2016-03-17 | 2016-07-20 | 清华大学 | Steel part and experiment research method of turning residual stress distribution of steel part |
| CN105825025A (en) * | 2016-03-30 | 2016-08-03 | 清华大学 | Plate-shaped part processing deformation simulation prediction method |
Non-Patent Citations (1)
| Title |
|---|
| 大型汽轮机、发电机转子残余应力测量新方法—环芯法及国外应用实例;陈惠南;《大型铸锻件》;19970228(第01期);第40-45页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106599496A (en) | 2017-04-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103808438B (en) | A kind of measuring method of plate sheet welding residual stress | |
| GB2592775A (en) | Rotating blade non-contact dynamic strain field measurement method and system | |
| CN106370334B (en) | A kind of internal residual stress measurement method based on stepped hole method | |
| CN104236768A (en) | Residual stress measuring method through hole drilling method based on finite element correction coefficient | |
| CN109870258B (en) | Instrumented spherical indentation detection method for plane random residual stress | |
| CN109855971B (en) | Measurement method for simulating buoyancy loss of buoyancy material in deep sea environment | |
| CN104296901A (en) | Welding residual stress small hole measuring method | |
| CN103148971B (en) | Method for testing local stress field of end part structure of thermal jacket of ultrahigh-pressure tubular reactor | |
| CN111982377A (en) | Deep hole differential stress evaluation method based on secondary sleeve core | |
| CN104655505B (en) | Instrumented-ball-pressing-technology-based residual stress detection method | |
| CN112036059B (en) | Method for detecting working stress based on blind hole method | |
| CN108844824B (en) | Known material residual stress measuring method based on conical pressure head | |
| CN107677403A (en) | A kind of residual stress blind hole detection method | |
| Ghaedamini et al. | A comparative experimental study for determination of residual stress in laminated composites using ring core, incremental hole drilling, and slitting methods | |
| Chakraborty et al. | Experimental determination of mode I stress intensity factor in orthotropic materials using a single strain gage | |
| CN106599496B (en) | Method for measuring residual stress by ring core method based on numerical calculation | |
| CN103994842B (en) | Based on the compound substance ring-type part residual stress measuring method cutting off bending method | |
| CN109733641A (en) | A kind of aircraft full size structure part multiaxle fatigue experimental method | |
| CN115165629A (en) | Method for evaluating rock burst type tendency | |
| CN109507040B (en) | Honeycomb sandwich structure panel compression stress assessment method | |
| CN105067187A (en) | Hole-drilling method residual stress calibrating device | |
| CN207066755U (en) | The experimental rig of tunnel bottom structure accumulated damage under a kind of cyclic load | |
| WO2015103571A1 (en) | System and methodology for determining forces acting on components | |
| CN104596695A (en) | Loading device for accurately controlling rivet preload of riveting member | |
| CN205561699U (en) | Utensil is examined to blind hole locations degree |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |