SI25679A

SI25679A - Flat workpieces clamping device for mechanical strength cyclic test

Info

Publication number: SI25679A
Application number: SI201800151A
Authority: SI
Inventors: eruga Domen Ĺ; Marko Nagode; Vili MalnariÄŤ; Jernej Klemenc
Original assignee: Tpv D.D.
Priority date: 2018-07-02
Filing date: 2018-07-02
Publication date: 2020-01-31

Abstract

Namen izuma je zasnovati karseda preprosto pripravo za vpenjanje ploščatih preizkušancev (8) med izvajanjem cikličnih obremenitev za potrebe ugotavljanja mehanske trdnosti materiala. Tovrstna priprava naj bi bila po eni strani dovolj toga in naj bi obenem preprečevala uklon preizkušanca, kadar je le-ta med preizkušanjem tlačno obremenjen, po drugi strani pa naj bi prisotnost protiuklonske podpore (9) načeloma ne vplivala na potek samih meritev, če pa že bi, naj bi bilo te vplive možno izmeriti in jihupoštevati pri določanju samih merilnih rezultatov. Po izumu je predlagana priprava za vpetje ploščatega preizkušanca (8) med izvajanjem cikličnega preizkusa mehanske trdnosti materiala, ki je prirejena za vpetje preizkušanca (8) v čeljusti (7) vsakokratne preizkuševalne naprave, in ki obsega protiuklonsko podporo (9), sestoječo iz dvojice med seboj razmaknjenih togih stoj in (1), izmed katerih je vsaka togo povezana s togima pasnicama (2), vsakokratni pasnici (2) pa sta s pomočjo vijakov (3) povezljivi spasnicama (2) vsakokrat preostale stojine, pri čemer je med omenjenima stojinama (2) na voljo vrzel, skozi katero je vstavljiv vsakokraten preizkušanec (8). Vsaka izmed stojin (1) in pasnic (2) uklonske podpore (9) je v območju omenjene vrzeli, skozi katero je vstavljiv preizkušanec (8), na vseh tistih površinah, ki bi med regularno uporabo priprave lahko prišle v stik s preizkušancem (8), opremljena s prevleko (5) z izrazito nizkim tornim koeficientom, in da je vsaka izmed stojin (1) opremljena z vsajenim skoznjim prehodom (4) za vgradnjo vsaj enega senzorja (11) za merjenje specifičnih deformacij preizkušanca (8).The purpose of the invention is to design as simple as possible a device for clamping flat test pieces (8) while performing cyclic loads for the purpose of determining the mechanical strength of a material. Such preparation should, on the one hand, be sufficiently rigid and at the same time prevent damping of the test subject when it is pressurized during the test and, on the other hand, the presence of anti-clamp support (9) should not in principle affect the course of the measurements, but if already, these impacts could be measured and taken into account in determining the measurement results themselves. According to the invention, a device for clamping a flat test piece (8) is proposed while performing a cyclic mechanical strength test of a material adapted for clamping a test piece (8) in the jaw (7) of each test device and comprising a counter-support (9) consisting of two rigid stands and (1) spaced apart, each of which is rigidly connected to rigid webs (2), and each webbing (2) is connected to each other by webs with screws (3). a gap is provided to the webs (2) through which each test piece (8) is inserted. Each of the stands (1) and the bands (2) of the support support (9) is in the area of said gap through which the test piece (8) is inserted, on all those surfaces which, during regular use of the device, may come into contact with the test piece (8 ), which is provided with a coating (5) with extremely low friction coefficient, and that each of the racks (1) is provided with an implanted through passage (4) for mounting at least one sensor (11) to measure specific deformations of the test piece (8).

Description

Priprava za vpetje ploščatega preizkušanca med izvajanjem cikličnega preizkusa mehanske trdnosti materialaPreparation for mounting a flat test piece during the cyclic mechanical strength test of a material

Izum se nanaša na pripravo za vpetje ploščatega preizkušanca med izvajanjem cikličnega preizkusa mehanske trdnosti materiala. Tovrstni izumi po Mednarodni klasifikaciji patentov v okviru fizike, namreč merjenja in preizkušanja, spadajo v domeno preiskovanja materialov z ugotavljanjem njihovih kemičnih in fizikalnih lastnosti, zlasti mehanske trdnosti s pomočjo mehanskih obremenitev, in so na tej osnovi razvrščeni v razred G 01 N 03/00.The invention relates to a device for mounting a flat test piece during a cyclic test of the mechanical strength of a material. Such inventions according to the International Classification of Patents in the Field of Physics, namely Measurement and Testing, fall within the domain of investigation of materials by determining their chemical and physical properties, in particular mechanical strength through mechanical loads, and are therefore classified in class G 01 N 03/00 .

Pri tem je izum osnovan na problemu, kako zasnovati karseda preprosto pripravo za vpenjanje ploščatih preizkušancev med izvajanjem cikličnih obremenitev za potrebe ugotavljanja mehanske trdnosti materiala, pri čemer naj bi bila tovrstna priprava po eni strani dovolj toga in naj bi obenem preprečevala uklon preizkušanca, kadar je le-ta med preizkušanjem tlačno obremenjen, po drugi strani pa naj bi prisotnost podpore načeloma ne vplivala na potek samih meritev, če pa že bi, naj bi bilo te vplive možno izmeriti in jih upoštevati pri določanju samih merilnih rezultatov.The invention is based on the problem of how to design a simple device for clamping flat test pieces during cyclic loading for the purpose of determining the mechanical strength of the material, while such preparation should be sufficiently rigid on the one hand and at the same time preventing the test pieces from collapsing when it is pressurized during testing, but on the other hand, the presence of support does not in principle affect the course of the measurements themselves, but if so, these effects could be measured and taken into account in determining the measurement results themselves.

Priprava za vpenjanje preizkušanca med izvajanjem preizkusa mehanskih lastnosti zlasti laminatnih materialov iz umetnih snovi je opisana v GB 2 197 489 B. Naprava obsega dve med seboj vzporedni podpori, izmed katerih je vsaka zasnovana v obliki črke U in med katerima je na voljo vrzel za vstavljanje preizkuševanca. Pasnici prve podpore sta preko distančnikov togo povezana s pasnicama druge podpore, med omenjenimi pasnicami pa sta pri eni od izvedb priprave na voljo tudi uklonski podpori, ki sta razporejeni vsaka na svoji strani preizkušanca in sta namenjeni za preprečevanje uklona preizkušanca med izvajanjem preizkusa. Uklonski podpori sta prilagodljivi, tako da je možno preizkušati preizkušance različnih debelin in izvedeni na tak način, da se ob pojavu uklona preizkušanec opre na vsakokratno podporo. Tovrstna podpora je predvidena za uporabo v preizkuševalnih napravah ta izvajanje statičnih preizkusov, razen tega pa ne omogoča niti ugotavljanja pogreškov pri merjenju niti kompenzacije napak, ki so posledica napetosti ali deformacij zaradi samega vpetja preizkušanca, trenja in drugih motilnih veličin.A device for clamping a test piece while performing the mechanical properties test, in particular of laminate materials of plastics, is described in GB 2 197 489 B. The device comprises two parallel supports, each of which is U-shaped and with a gap for insertion the test subject. The first support lanes are rigidly connected to the second support lanes via spacers, and in one of the embodiments preparation supports are provided, each arranged on its side of the subject and intended to prevent the test subject from being diverted during the test. The slope supports are flexible, so that it is possible to test subjects of different thicknesses and be designed in such a way that, when the slope occurs, the tester relies on the appropriate support. Such support is intended to be used for testing purposes in the performance of static tests, in addition to which neither measurement errors nor compensation for errors due to stress or deformation due to the very engagement of the test piece, friction and other disturbing quantities can be compensated for.

Nadalje je v US 3,795 134 opisana naprava za preizkušanje vzdržljivosti preizkušanca, ki je izpostavljen tlačni napetosti, obenem pa tudi cikličnim temperaturnim spremembam. Tovrstna priprava je konstrukcijsko zelo zapletena in sestoji iz množice sestavnih delov, ki niso zgolj zahtevni in dragi za izdelavo in sestavljanje pred vsakokratnim preizkusom, temveč vsak po svoje prispevajo tudi h generiranju merilnih pogreškov, zaradi katerih so rezultati meritev potem manj natančni.Further, U.S. Pat. No. 3,795,134 describes an apparatus for endurance testing of a subject subjected to compressive stress, as well as cyclical temperature changes. This type of preparation is very complex in design and consists of a multitude of components, which are not only demanding and expensive to produce and assemble before each test, but each also contribute to the generation of measurement errors, which make the measurement results less accurate.

Se nadaljnje naprave za vpenjanje preizkušancev so opisane med drugim v US 3 795 134, CN 202013310 U, KR 20170035719 A, CN 103967151 A in US 3 559 473.Further test clamping devices are described, inter alia, in US 3 795 134, CN 202013310 U, KR 20170035719 A, CN 103967151 A and US 3 559 473.

Pričujoči izum se nanaša na napravo za vpetje ploščatega preizkušanca med izvajanjem cikličnega preizkusa mehanske trdnosti materiala, ki je prirejena za vpetje preizkušanca v čeljusti vsakokratne preizkuševalne naprave. Tovrstna priprava obsega protiuklonsko podporo, ki sestoji iz dvojice med seboj razmaknjenih togih stojin, izmed katerih je vsaka togo povezana s togima pasnicama, pasnici pa sta s pomočjo vijakov povezljivi s pasnicama vsakokrat preostale stojine. Med omenjenima stojinama je na voljo vrzel, skozi katero je vstavljiv vsakokraten preizkušanec.The present invention relates to a device for clamping a flat test piece while performing a cyclic mechanical strength test of a material adapted for clamping a test piece into the jaws of each test device. Such preparation comprises a counter-support, consisting of two rigid webs spaced apart, each of which is rigidly connected to the rigid webs, and the webs are connected to the webs of the remaining webs by means of screws. There is a gap between the two stands, through which each test piece is inserted.

Po izumu je predlagano, da je vsaka izmed stojin in pasnic uklonske podpore na vseh tistih površinah, ki bi med regularno uporabo priprave lahko prišle v stik s preizkušancem, zlasti v območju omenjene vrzeli, skozi katero je vstavljiv preizkušanec, opremljena s prevleko z izrazito nizkim tornim koeficientom, še zlasti s prevleko iz teflona. Obenem je vsaka izmed stojin opremljena z vsaj enim skoznjim prehodom za vgradnjo vsaj enega senzorja za merjenje specifičnih deformacij preizkušanca. Še nadalje sta na vsaki stojini na voljo vsaj dva med seboj razmaknjena zatiča, izmed katerih vsak omogoča po eni strani ponovljivo sestavljivost uklonske podpore in po drugi strani pritrditev vzmeti, ki je po drugi strani pripeta na čeljusti preizkuševalne naprave.According to the invention, it is proposed that each of the stands and bands of the supporting support on all those surfaces which, during regular use of the device, may come into contact with the test piece, especially in the area of said gap through which the test piece is inserted, is provided with a very low coating friction coefficient, especially with Teflon coating. At the same time, each of the racks shall be provided with at least one through passage for mounting at least one sensor for measuring specific deformations of the subject. In addition, there are at least two spaced pins on each stand, each of which enables, on the one hand, the reproducible compatibility of the mounting support and, on the other, the attachment of a spring secured to the jaws of the test fixture.

Pri prednostni izvedbi izuma sta na vsaki stojini predvidena vsaj dva med seboj razmaknjena prehoda, pri čemer je še zlasti prednostno, vsakokraten prehod predstavlja podolgovata skoznja luknja. Prav tako je prednostno, če je omenjena vzmet na voljo kot natezna vzmet. Nadalje je med omenjeno protiuklonsko podporo in vsakokrat pripadajočo čeljust preizkuševalne naprave prednostno vgradljiv tudi senzor za zaznavanje sile trenja med preizkušancem in protiuklonsko podporo.In a preferred embodiment of the invention, at least two spaced aisles are provided on each stand, in particular, each passage being an elongated through hole. It is also preferred if said spring is available as a tensile spring. Further, a friction force sensor between the test subject and the anti-clamp support is preferably incorporated between said anti-tilt support and the respective jaw of the test device.

Izum bo v nadaljevanju konkretiziran s primerom izvedbe, ki je shematično ponazorjen na priloženi skici, kjer kažejoThe invention will hereinafter be concretized with an embodiment which is schematically illustrated in the accompanying drawing showing

Sl. 1 v narisu ponazorjeno protiuklonsko podporo priprave po izumu;FIG. 1 illustrates an anti-clamping support of the device according to the invention;

Sl. 2 protiuklonsko podporo v prerezu v ravnini A - A po Sl. 1;FIG. 2 is a cross-sectional view of the cross section in plane A - A according to FIG. 1;

Sl. 3 pritrditev protiuklonske podpore po Sl. 1 in 2 na čeljusti preizkuševalne naprave;FIG. 3 is a view showing the mounting of the anti-tilt support according to FIG. 1 and 2 on the jaws of the test rig;

Sl. 4 namestitev senzorja za merjenje specifičnih deformacij na omenjeno protiuklonsko podporo; inFIG. 4 installing a sensor for measuring specific deformations on said anti-tilt support; and

Sl. 5 namestitev senzorja za merjenje sile na omenjeno protiuklonsko podporo.FIG. 5 installing a force-sensing sensor on said counter-support.

Priprava za vpetje ploščatega preizkušanca 8 med izvajanjem cikličnega preizkusa mehanske trdnosti materiala je prirejena za vpetje preizkušanca 8 v čeljusti 7 vsakokratne preizkuševalne naprave. Tovrstna priprava obsega protiuklonsko podporo 9, ki sestoji iz dvojice med seboj razmaknjenih togih stojin 1, izmed katerih je vsaka togo povezana s togima pasnicama 2. Vsakokratni pasnici 2 sta s pomočjo vijačne zveze 3, jo v prikazanem primeru tvorijo štirje vijaki, povezljivi s pasnicama 2 vsakokrat preostale stojine 1, pri čemer je med omenjenima stojinama 1 na voljo vrzel, skozi katero je vstavljiv vsakokraten preizkušanec 8.The device for clamping the flat test piece 8 while performing the cyclic mechanical strength test of the material is adapted to clamp the test piece 8 in the jaw 7 of each test device. Such a device comprises a counter-support 9 consisting of two rigidly spaced webs 1, each of which is rigidly connected to the rigid webs 2. The webs 2 are each formed by means of a screw connection 3, which in the example shown is formed by four screws connected to the webs. 2 in each of the remaining stands 1, with a gap between said stands 1 through which the test piece 8 is inserted.

Vsaka izmed stojin 1 in pasnic 2 uklonske podpore 9 na vseh tistih površinah, ki bi med regularno uporabo priprave lahko prišle v stik s preizkušancem 8, v območju omenjene vrzeli, skozi katero je vstavljiv preizkušanec 8, opremljena s prevleko 5 z izrazito nizkim tornim koeficientom, v obravnavanem primeru izvedbe pa omenjena prevleka 5 sestoji iz teflona. Nadalje je vsaka izmed stojin 1 opremljena z vsaj enim skoznjim prehodom 4 za vgradnjo vsaj enega senzorja 11 za merjenje specifičnih deformacij preizkušanca 8. V prikazanem primeru sta na voljo dva prehoda 4 v obliki podolgovatih lukenj, kar zagotavlja ustrezno premakljivost senzorja 11 med izvajanjem meritev. Razen tega sta na vsaki stojini 1 na voljo vsaj dva med seboj razmaknjena zatiča 6, izmed katerih vsak omogoča po eni strani ponovljivo sestavIjivost uklonske podpore 9 in po drugi strani pritrditev vzmeti 10, v prikazanem primeru natezne vzmeti, ki je po drugi strani pripeta na čeljusti 7 preizkuševalne naprave in s tem preprečuje premikanje podpore 9 med potekom preizkusa zaradi trenja med njo in preizkušancem 8. Med protiuklonsko podporo 9 in vsakokrat pripadajočo čeljust 7 preizkuševalne naprave vgradljiv senzor 12 za zaznavanje sile trenja med preizkušancem 8 in protiuklonsko podporo 9.Each of the stands 1 and lane 2 of the support support 9 on all those surfaces which, during regular use of the device, may come into contact with the test piece 8, in the region of said gap through which the test piece 8 is inserted, is provided with a coating 5 with an extremely low friction coefficient , in the present embodiment, said coating 5 consists of Teflon. Further, each of the racks 1 is provided with at least one through passage 4 for mounting at least one sensor 11 to measure the specific deformations of the subject 8. In the example shown, there are two passageways 4 in the form of elongated holes, which ensure adequate movement of the sensor 11 during the measurements. In addition, at least two spaced pins 6 are provided on each stand 1, each of which enables, on the one hand, the reproducible compatibility of the mounting support 9 and, on the other, the attachment of a spring 10, in the case shown, of a tensile spring attached to the other. of the test device's jaws 7, thereby preventing the support 9 from moving during the course of the friction test between the test device and the test device 8. There is a built-in sensor 12 for the friction support 9 and the corresponding test device jaw 7 for detecting the friction force between the test device 8 and the support 9.

Protiuklonska podpora 9 sestoji iz dveh razmeroma širokih stojin 1, med kateri je vstavljiv vsakokraten preizkušanec 8. Vsaka izmed stojin 1 je togo povezana s pasnicama 2, ki preko vijačne zveze 3, ki jo v prikazanem primeru tvorijo štirje vijaki, omogoča nastavitev ali odpravo zračnosti med stojinama 1 in preizkušancem 8. Stojini 1 sta opremljeni s prevleko 5 iz materiala z nizkim koeficientom trenja, tako da se s s pomočjo omenjene prevleke 5 zniža silo trenja v primeru, kadar se med preizkusom preizkušanec 8 nasloni na podporo 9. Omenjena prevleka 5 prednostno sestoji iz teflona, kar ob ustrezni izbiri senzorjev 11, 12 omogoča tudi izvajanje meritev pri povišanih temperaturah.The counter-support 9 consists of two relatively wide webs 1, each of which has a test piece 8. Each of the webs 1 is rigidly connected to the belts 2, which, through the screw connection 3 formed by the four screws in the example shown, allows for adjustment or removal of play. between the stands 1 and the test piece 8. The stands 1 are provided with a cover 5 made of low friction material such that the force of friction 5 is reduced by means of said cover 5 when the support 8 is supported by the test piece 8 during said test. it consists of Teflon, which, with the proper selection of sensors 11, 12, also allows measurements at elevated temperatures.

V podolgovatih luknjah 4 je vstavljen senzor 11 za merjenje specifične deformacije preizkušanca 8 med izvajanjem meritev. Ponovljivost sestavljanja protiuklonske podpore 9 je zagotovljena zahvaljujoč zatičema 6, ki pa razen tega omogočata tudi vpetje vzmeti 10, s katerima je protiuklonska podpora 9 pritrjena na čeljusti 7 preizkuševalne naprave, tako da se med izvajanjem preizkusa ne more premikati skupaj s preizkušancem 8 zaradi sile trenja.In the elongated holes 4, a sensor 11 is inserted to measure the specific deformation of the test piece 8 while performing the measurements. The repetitiveness of the assembly of the counter support 9 is ensured by the pins 6, which in addition allow the spring 10 to be secured by which the counter support 9 is secured to the jaws 7 of the test device so that it cannot move with the test member 8 due to the force of friction during the test .

Izvedba priprave s protiuklonsko podporo 9 že s svojo obliko zagotavlja potrebno togost, razen tega pa zahvaljujoč prisotnosti skoznjih prehodov 4 v obliki podolgovatih lukenj omogoča vgradnjo senzorja 11 in premikanje le-tega med izvajanjem preizkusa, s čimer je potem omogočeno merjenje deformacij preizkušanca 8. Pri tem vijačna zveza 3 omogoča nastavitev in odpravo zračnosti med preizkušancem 8 in omenjeno podporo 9. V primeru, ko se preizkušanec 8 pod obremenitvijo nasloni na protiuklonsko podporo 9, prevleka 5 občutni zmanjša trenje med preizkušancem 8 in podporo 9. Zatiča 6 omogočata ponovljivost sestavljanja podpore in omogočata namestitev pritrdilnih vzmeti 10 med protiuklonsko podporo 9 in vsakokratno preizkuševalno napravo. Z namestitvijo dodatnega senzorja 12 v območje med protiuklonsko podporo 9 in vsakokratno preizkuševalno napravo je možno izmeriti silo trenja, ki se pojavi med preizkušancem in protiuklonsko podporo 9, na osnovi česar je potem možno ustrezno korigirati z meritvijo pridobljene rezultate.The design of the counter-support device 9 already provides the necessary rigidity with its shape, and thanks to the presence of elongated holes 4 through the passageways, it allows the sensor 11 to be mounted and moved during the test, which in turn allows the measurement of the deformations of the test specimen 8. thus, the screw connection 3 allows adjustment and clearance of the gap between the test piece 8 and said support 9. In case the test piece 8 rests against the tilt support 9 under load, the coating 5 significantly reduces the friction between the test piece 8 and the support 9. The pins 6 allow for the repetition of the support assembly. and allow the mounting springs 10 to be fitted between the anti-roll support 9 and the respective test device. By placing an additional sensor 12 in the area between the support 9 and the respective test device, it is possible to measure the friction force that occurs between the support 9 and the support 9, which can then be corrected accordingly by measuring the results obtained.

Tovrstna rešitev po izumu omogoča natančno določanje napetostnodeformacijskega odziva vsakokratnega materiala preizkušanca 8 in njegove vzdržljivosti pri cikličnem obremenjevanju, pri čemer je omenjeni material preizkušanca 8 na voljo v obliki plošče, pri kateri je ena dimenzija bistveno večja od obeh preostalih. Izvajanje tovrstnih meritev brez prisotnosti protiuklonske podpore 9 je v večini primerov praktično nemogoče, ker se preizkušanec 8 med izvajanjem preizkusa pod obremenitvijo ukloni še pred doseženjem želenega napetostno-deformacijskega stanja. Zahvaljujoč primerno širokima stojinama 1 dosežemo zadostno togost, da deformacije podpore 9, kadar se nanjo nasloni tlačno obremenjen preizkušanec 8, ne more signifikantno vplivati na rezultate meritve. Zaradi omenjene širine stojin 1 je optimalno, če je vsakokraten skoznji prehod 4 na voljo kot podolgovata luknja.Such a solution according to the invention makes it possible to accurately determine the stress-strain response of each material of test specimen 8 and its durability under cyclic loading, said material of test specimen 8 being available in the form of a plate in which one dimension is substantially larger than the two remaining. In most cases it is practically impossible to perform such measurements without the presence of anti-tilt support 9, because the test piece 8 is removed during the load test even before reaching the desired stress-strain state. Thanks to the sufficiently wide stands 1, sufficient rigidity is achieved so that the deformation of the support 9, when supported by a pressure laden specimen 8, cannot significantly affect the measurement results. Due to the aforementioned width of the webs 1, it is optimal if the respective through passage 4 is available as an elongated hole.

Claims

PATENT APPLICATIONS

A device for clamping a flat test piece (8) while performing a cyclic mechanical strength test of a material adapted for clamping a test piece (8) in the jaw (7) of each test device, such preparation comprising a counter-support (9) consisting of two rigid webs (1) spaced apart, each of which is rigidly connected to rigid webs (2) and the respective webs (2) are connected to the webs (2) by each of the remaining webs (1) by means of screws (3), wherein a gap is provided between said stands (1) through which a test piece (8) is inserted, characterized in that each of the stands (1) and the belts (2) of the supporting support (9) is in the region of said gap through which is a test piece (8). on all those surfaces which, during regular use of the device, may come into contact with the test piece (8), equipped with a coating (5) with a very low friction coefficient, and with each of the stands (1) being provided with at least one through (4) the installation of at least one sensor (11) for measuring the specific deformations of the test specimen (8), except that at least two spaced pins (6) are provided on each stand (1), each of which allows one on the other hand, the reproducible compatibility of the supporting support (9) and, on the other hand, the attachment of a spring (10), which, in turn, is attached to the jaws (7) of the test device.

Device according to claim 1, characterized in that at least two spaced aisles (4) are provided on each stand (1).

Device according to claim 1 or 2, characterized in that each passage (4) is an elongated through hole.

Device according to any one of claims 1-3, characterized in that said spring (10) is a tensile spring.

Device according to any one of the preceding claims, characterized in that said coating (5) consists of Teflon.

Device according to any one of the preceding claims, characterized in that a friction sensor (12) for sensing the friction force between the test piece (8) and the counter-support (9) is provided between the counter-support (9) and the respective jaw (7) of the test device. .