GB2394062A - Mechanical testing of material samples - Google Patents
Mechanical testing of material samples Download PDFInfo
- Publication number
- GB2394062A GB2394062A GB0223607A GB0223607A GB2394062A GB 2394062 A GB2394062 A GB 2394062A GB 0223607 A GB0223607 A GB 0223607A GB 0223607 A GB0223607 A GB 0223607A GB 2394062 A GB2394062 A GB 2394062A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sample
- tested
- camera
- air
- controlling
- 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.)
- Withdrawn
Links
- 238000004154 testing of material Methods 0.000 title description 2
- 238000012360 testing method Methods 0.000 claims abstract description 19
- 230000003287 optical effect Effects 0.000 claims abstract description 8
- 238000012544 monitoring process Methods 0.000 claims abstract description 7
- 239000003570 air Substances 0.000 description 16
- 239000000463 material Substances 0.000 description 5
- 238000012545 processing Methods 0.000 description 3
- 238000009864 tensile test Methods 0.000 description 3
- 239000012080 ambient air Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000010408 sweeping Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/02—Mechanical
- G01N2201/023—Controlling conditions in casing
- G01N2201/0233—Gas purge
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0017—Tensile
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0025—Shearing
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/022—Environment of the test
- G01N2203/0236—Other environments
- G01N2203/0238—Inert
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/022—Environment of the test
- G01N2203/0236—Other environments
- G01N2203/0242—With circulation of a fluid
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/0641—Indicating or recording means; Sensing means using optical, X-ray, ultraviolet, infrared or similar detectors
- G01N2203/0647—Image analysis
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
An apparatus for testing of samples comprising means for holding a sample 11 to be tested, means for altering the strain in the sample, an optical arrangement 12 for monitoring the sample to be tested, and means for controlling the environment in the space between the optical arrangement and the sample to be tested, wherein the environment controlling means is a tubular member 16, and a fan 17 to produce homogenously mixed air to the interior of the tube.
Description
TESTING OF SAMPLES
The present invention relates to the testing of samples and more particularly to the mechanical testing of materials, or of components.
5 It is common when testing materials to undertake tensile tests of materials by forming a standard sample, marking the sample with one or more datum points and applying an increasing load to the sample while monitoring movement of the datum point or points. It is known to utilise video cameras for the purposes of monitoring the movement and by using a suitable mathematical algorithm, the 10 distance between the marks can be determined. This technique results in an apparatus which is reliable and cost effective. However, there is a demand for more accurate measurement techniques which can currently only be satisfied with expensive equipment.
It is an object of the present invention to improve the accuracy of the 15 existing apparatus.
The present invention provides testing apparatus comprising means for holding a sample to be tested, means for altering the strain in the sample to be tested, an optical arrangement for monitoring the sample to be tested, and processing means for processing the signals resulting from the monitoring of the 20 sample under test characterised in that the environment between the optical arrangement and the sample under test is controlled.
Preferably, a characteristic of the atmosphere in the space between the camera and the sample is controlled. The characteristic is preferably the density of the air but may additionally or alternatively be the temperature, humidity or other 25 characteristic which will adversely affect the accuracy of the signals resulting from the monitoring.
In the preferred embodiment, the control of the environment between the camera and the sample under test is achieved by inducing a controlled flow of air in the said region. Preferably, the air is processed so that its refractive index in the region is constant which is a result of the air in the controlled environment having 5 a constant density.
In order that the present invention be more readily understood, an embodiment thereof will now be described by way of example only with reference to the accompanying drawing which shows a diagrammatic representation of apparatus according to the present invention.
10 The preferred embodiment will be described in relation to its use as a test apparatus for tensile testing a metal sample but it will be appreciated that the material of the sample is not significant and any suitable material or component can be tested. Additionally, compression or shear testing could be undertaken rather than tensile testing.
IS The test apparatus comprises the basic components of a sample holder 10 for holding a sample 1 1 of the material to be tested which sample is provided with marks in the usual fashion. The sample holder is conventional and is arranged to enable varying loads to be placed on the sample under test in a manner which is not shown but is conventional in the art. The sample 11 under test is monitored by 20 an optical arrangement in the form of a camera 12 which in this case is a video camera. Video cameras are useful because of their high effective shutter speed but it will be appreciated that a still camera could equally well be used if desired. It is preferred to utilise digital cameras.
The output from the camera is fed to a signal processing computer (14) 25 where an algorithm is used to determine the mark separation and to produce the results for the sample under test which are output in any convenient form.
We have found that the accuracy now required of the apparatus is such that the accuracy of the measurements was being affected by the properties of the air in the space between the camera and the sample under test. For this reason, the present embodiment controls one or more characteristics of the air in the region S between the camera and the sample. We have found that one important characteristic is the density of the air which should be maintained constant and uniform in order to control the refractive index of the air. This is most conveniently achieved by providing a tube 16 through which the camera 12 views the sample 1 1 under test. The tube 16 is supplied with ambient air via one or more lO fans 17 and one or more filters for removing dust from the air which results in the atmosphere in the tube 16 having uniform characteristics throughout the length of the tube. The fan 17 produces homogenously mixed air to the interior of the tube at a pressure above atmospheric pressure sufficient to promote mixing and flow. It is not necessary to seal the ends of the tube in view of the fact that air flows out of 15 the tube and so has the effect of sweeping away any ambient air from the front of the camera and the sample.
The location and orientation of the fan 17 is not critical. AS shown, the fan 17 directs air at an angle into the tube 16. It is equally possible to have one or more fans fitted to the tube 16 adjacent the camera 12 so as to blow air axially 20 along the length of the tube.
Likewise, the cross-sectional shape of the tube 16 is not critical eg the cross-section may be oval or rectangular with the long axis parallel to the length dimension of the sample 11. A1SO7 the tube need not be of constant cross-section throughout its length. It may be of rectangular cross-section with the area of the 25 cross-section increasing with distance from the camera 12. Preferably the increase is linear.
Using the above apparatus, we have found that by utilising a video camera having a CCD array with approximately 1000 lines and a field of view of 1 OOmn,,
the accuracy of the apparatus can be improved so that the separation between two datum points (marks) in a sample under test can be measured within a precision of 5 + lam. Even if a high resolution CCD and optics are used in an attempt to improve accuracy, we have found that noise due to variations in the atmospheric conditions cause distortion of the light to such an extent that the full benefit of upgrading the quality of the camera and optics is not achieved.
Various modifications may be made to the above apparatus. For example, 10 the fan and filter can be replaced by a source of purified air such as from a pressure cylinder. This might require a baffle of some sort to ensure a constant, even flow. It is also conceivable that an air line fitted with appropriate air flow conditioning apparatus might be used.
Also, although the above description assumes visible light, light of other
15 wavelengths such as ultra-violet or infra-red can be used as can laser light.
Although we refer to marks being applied, inherently visible features of the surface can be used instead or indeed an optical image can be used within which image locations can be identified and monitored.
Claims (7)
1. Test apparatus comprising means for holding a sample to be tested, means for altering the strain in the sample, an optical arrangement for 5 monitoring the sample to be tested, and means for controlling the environment in the space between the optical arrangement and the sample to be tested.
2. Apparatus according to claim 1, wherein the environment controlling 10 means includes a tubular member extending between the camera and the sample to be tested, the camera viewing the sample to be tested through the tubular member.
3. Apparatus according to claim 1 or 2, wherein a gaseous medium is 15 present in the space and a characteristic of the gaseous medium is controlled.
4. Apparatus according to claim 3, wherein the gaseous medium is air.
20
5. Apparatus according to claim 4, wherein the controlling means comprises means for supplying air of constant density into the space between the camera and the sample to be tested.
6. Apparatus according to claim 5, wherein the air supply means comprises 25 one or more fans for providing homogenously mixed air.
7. Apparatus according to claim 1, wherein the output of the camera is processed to produce results of the test.
Priority Applications (12)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0223607A GB2394062A (en) | 2002-10-10 | 2002-10-10 | Mechanical testing of material samples |
| ES03256385T ES2279068T3 (en) | 2002-10-10 | 2003-10-09 | SAMPLE TEST |
| DE60335306T DE60335306D1 (en) | 2002-10-10 | 2003-10-09 | sample tests |
| AT03256385T ATE348324T1 (en) | 2002-10-10 | 2003-10-09 | MECHANICAL MATERIAL TESTING |
| EP03256385A EP1424547B1 (en) | 2002-10-10 | 2003-10-09 | Testing of samples |
| PT03256385T PT1424547E (en) | 2002-10-10 | 2003-10-09 | Testing of samples |
| DK03256385T DK1424547T3 (en) | 2002-10-10 | 2003-10-09 | Testing of samples |
| AT06076084T ATE491145T1 (en) | 2002-10-10 | 2003-10-09 | SAMPLE TESTS |
| EP06076084A EP1739403B1 (en) | 2002-10-10 | 2003-10-09 | Testing of samples |
| DE60310349T DE60310349T2 (en) | 2002-10-10 | 2003-10-09 | Mechanical material testing |
| US10/683,072 US7047819B2 (en) | 2002-10-10 | 2003-10-10 | Testing of samples |
| US11/410,686 US7610815B2 (en) | 2002-10-10 | 2006-04-24 | Testing of samples |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0223607A GB2394062A (en) | 2002-10-10 | 2002-10-10 | Mechanical testing of material samples |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0223607D0 GB0223607D0 (en) | 2002-11-20 |
| GB2394062A true GB2394062A (en) | 2004-04-14 |
Family
ID=9945697
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0223607A Withdrawn GB2394062A (en) | 2002-10-10 | 2002-10-10 | Mechanical testing of material samples |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2394062A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112098211A (en) * | 2020-09-17 | 2020-12-18 | 山东大学 | An experimental device and method for simulating multi-anchor coupling |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2205396A (en) * | 1987-04-27 | 1988-12-07 | Yokohama Rubber Co Ltd | Tension tester |
| GB2223319A (en) * | 1988-10-03 | 1990-04-04 | Rolls Royce Plc | Method & means fatigue testing |
-
2002
- 2002-10-10 GB GB0223607A patent/GB2394062A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2205396A (en) * | 1987-04-27 | 1988-12-07 | Yokohama Rubber Co Ltd | Tension tester |
| GB2223319A (en) * | 1988-10-03 | 1990-04-04 | Rolls Royce Plc | Method & means fatigue testing |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112098211A (en) * | 2020-09-17 | 2020-12-18 | 山东大学 | An experimental device and method for simulating multi-anchor coupling |
| CN112098211B (en) * | 2020-09-17 | 2021-08-06 | 山东大学 | An experimental device and method for simulating multi-anchor coupling |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0223607D0 (en) | 2002-11-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |