• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Cyclic loading machine. Cyclic loading machine (1) comprising: a motor (2) eccentrically attached to a crank (3); a connecting rod (4) attached to said crank (3) and immobilized at its second end in all directions except in a single free direction: two test tubes (6 and 8) and intended to accommodate a test tube (7) of a sample to be studied : means (9) for measuring the force, means (5) for measuring linear displacement and joining means that allow the test tube (7) to rotate, which allow the movement of the connecting rod (4) along the direction free and that restrict movement in the remaining directions. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2738953A1
    申请号:ES201830766
    申请日:2018-07-26
    公开日:2020-01-27
    发明作者:Sánchez Raúl López；Herrero David Baza；López Alicia Salazar；Pérez Jesús Rodríguez
    申请人:Consejo Superior de Investigaciones Cientificas CSIC；Universidad Rey Juan Carlos；
    IPC主号:
    专利说明:

    [0001]
    [0002]
    [0003]
    [0004] FIELD OF THE INVENTION
    [0005]
    [0006] The field of application of the present invention is that of the mechanical tests of fatigue, or fracture, of solid propellants and other elastomers.
    [0007]
    [0008] Such tests are commonly used in various technical sectors, for example and without limitation, the aerospace and materials engineering sector with dual use (civil and military) within the field of defense and security.
    [0009]
    [0010] OBJECT OF THE INVENTION
    [0011]
    [0012] The invention, as described and claimed herein, relates to a cyclic loading machine (in English, Fatigue Machine = FM) for performing fatigue tests (or cyclic loading) on different materials or solid components, is that is, tests to determine the behavior of said materials or solid components under cyclic dynamic loads, or cyclic dynamic displacements.
    [0013]
    [0014] The cyclic loading machine as presented, offers advantages and innovative features that will be described in detail below and that represent a remarkable novelty compared to the systems currently known.
    [0015]
    [0016] More particularly, the object of the invention is centered on a cyclic loading machine, designed and constructed to perform constant fatigue, or displacement fatigue tests (in English, Fixed Force -F F - or Fixed Grip -FG-),
    [0017]
    [0018] BACKGROUND OF THE INVENTION
    [0019]
    [0020] Cyclic loading machines that are commonly used for the characterization of fatigue behavior in solid materials are usually hydraulic systems that allow studying the effect of loads, or displacements, cyclic in materials or solid components. Dimensionally, these machines are bulky (on the order of 2 meters high), heavy (on the order of 3 tons in weight), and with a high economic cost.
    [0021]
    [0022] Said cyclic loading machines, corresponding to the current state of the art, usually consist of a series of control and registration systems of test variables such as force and displacement (from which deformation is usually deduced), some of These machines can include accessories to record temperature and humidity, as well as incorporate a coupled oven.
    [0023]
    [0024] Cyclic loading machines of the state of the art are widely used in material characterization laboratories, usually known as "dynamic universal testing machines." When using these machines in the study of solid and elastomeric propellants, they observe some problems inherent to the size and cost of the testing machines, as well as to their insufficient flexibility to configure the test together with a high cost associated with any adaptation that is desired to be made on the original configuration of the machine. they make some adaptations of the equipment impracticable for the measurement of a property of the material with unusual values, precisely this being the reason why these strategic materials are used, so the use of cyclic loading machines of the state of the art is not advisable in tests for the study of samples with low mechanical resistance, such as solid propellants of composite material, since the configuration of said cyclic loading machines, of the state of the art, are usually not prepared for samples with low stiffness such as solid propellants of composite material. In the same way, the high variability in the different configurations of the test, the result of the heterogeneity of the material studied, can seriously jeopardize the integrity of some elements of the machines, such as, for example, the load cells usually used to the registration of the force in this type of tests. For all the above, there is an absence in the market of equipment specifically designed and constructed to perform fatigue tests on materials of low mechanical resistance, such as, for example, solid propellants of composite material.
    [0025]
    [0026] For the purposes of the present invention, it should be understood that a solid propellant is a solid state energy material commonly used to generate gases or release energy and whose use is related to the shelling of rockets and missiles. A solid propellant of composite material is usually constituted by an elastomeric matrix and loads, usually ceramic, around 80% by mass.
    [0027]
    [0028] There is also a need in the sector to develop cyclic loading machines to perform fatigue tests on samples of materials of low mechanical resistance in order to reduce the test time necessary for the study of the behavior of the material, the machine being easy to calibrate. and that it provides reduced uncertainties associated with the quantitative result of the test, thus facilitating the performance of quality controls on the material under study, that is, on the solid or elastomeric propellant.
    [0029]
    [0030] Not having adapted equipment has the consequence that the tests carried out cause an increase in the associated costs, an increase in the uncertainties associated with the results obtained, as well as difficulties and operational delays in the studies on the mechanical state of solid and elastomeric propellants.
    [0031]
    [0032] On the other hand, it is convenient to develop a cyclic loading machine that also complies with international norms and standards for the study of fatigue behavior of materials, paying special attention to the measure of force, displacement and growth of the crack during the test in specimens of small dimensions obtained from the material under study. The ASTM E647-15: 2015 (Standard Test Method for Measurement of Fatigue Crack Growth Rates, ASTM International, West Conshohocken, PA, www. Stands out among the most commonly used standards within the security and defense sector). astm.org).
    [0033]
    [0034] There are few scientific publications that perform fatigue tests on solid propellant samples, mainly due to their low mechanical strength and difficult mechanization. Using the equipment of the prior art would imply a very high cost (economic and temporary). It should be taken into account that the characterization of fatigue behavior requires the repetition of tests, an aspect that is limited by the experimental difficulties of the equipment of the prior art, mainly due to the necessary processing of the data obtained. Given the duration of each individual test, up to several weeks, it is also necessary that the cyclic loading machine to be developed is able to work in a fully automated way 24 hours a day, with a reduced intervention by the operator (for example, 30 minutes / day), allowing to obtain fatigue curves that fully characterize the material studied.
    [0035]
    [0036] DESCRIPTION OF THE INVENTION
    [0037]
    [0038] The present invention is therefore intended to address the problems and disadvantages of the prior art indicated above, providing a solution to the problem of performing fatigue tests on low mechanical strength materials, in particular, low stiffness materials, that is, that change their original form against not very high efforts. Examples of these materials are rubbers and solid propellants of composite material, where it is highly advisable to use equipment specifically designed for this purpose.
    [0039] For the purpose of the present invention, a material with low stiffness is a material that has a stiffness in the range of rubbers, preferably whose elastic modulus (Young's modulus) is between 1 and 40 MPa, more preferably between 1 and 20 MPa, even more preferably between 1 and 10 MPa, when measured in uniaxial tensile tests with elongations between 100 and 400%, measured by NATO STANAG-4506 (March 29, 2000).
    [0040] More particularly, a first object of the present invention refers to a cyclic loading machine as exemplified in Figures 1 and 2, described below, comprising:
    [0041] - a motor (2) attached to a crank (3) provided with two ends, so that it transmits a circular movement to the first end of said crank;
    [0042] - a connecting rod (4) provided with two ends and joined by a first end to the second end of said crank, describing an eccentric path with the second end of the crank at the first of its ends when the motor is activated. The second end of the connecting rod is immobilized in all directions except in a single free direction. In this way, the circular movement of the first end of the crank (3) (driven by the motor) produces a reciprocating linear movement of the second end of the connecting rod, along the free direction;
    [0043] - two specimen holders (6 and 8), one of them attached to the free end of the connecting rod (4) and the other to the load measuring means (9), the specimen holder being adapted to accommodate a specimen (7) of the sample a study;
    [0044] - means (9) for measuring the force applied, such as load cells; and - means (5) for measuring linear displacement, such as linear potentiometers;
    [0045]
    [0046] characterized because
    [0047] - a first specimen holder (6) is connected to the second end of the connecting rod by means of attachment that do not prevent the rotation of the specimen (7) during the test (that is, they allow the specimen to be rotated), this rotation occurs with respect to the central axis of the specimen holder (6) (where a central axis of the specimen holder refers to an axis extending in a vertical direction), for example of a rotating mooring system such as a bolt passing through the specimen holder and the sample, and the second end of the connecting rod (4) can still move along the free direction with its restricted movement in the remaining directions (i.e., the movement of the second end of the connecting rod is allowed along the free direction); Y
    [0048] - a second specimen holder (8) attached to the means (9) for measuring the force applied, preferably by means of attachment that do not prevent the rotation of the specimen (7) during the test, this rotation occurs with respect to the central axis of the test holder (8); Y
    [0049] - because the specimen is housed between the first specimen holder (6) and the second specimen holder (8).
    [0050]
    [0051] Throughout the present specification it should be understood that an "end" refers to the fulcrum or pivot located near an edge of a machine part, where a first end is that terminal of said part that first receives (directly or indirectly) ) the force transmitted by the engine, while a second end is another terminal that is also driven by the movement applied to the first end, for example, the first end of the crank is that terminal that is coupled to the engine, the second end of the crank is that terminal that is coupled with the first end (terminal) of the connecting rod, and the second end of the connecting rod is that terminal that is coupled with the first cylinder holder (6), said cylinder holder is coupled with the first end of the test tube (7).
    [0052]
    [0053] Said cyclic loading machine according to the invention is a machine which, as noted above, comprises a motor that transmits a reproducible circular movement at an angle and / or rotational speed to a crank. The crank is attached to a connecting rod that has restricted movement in all directions except in one (free address). This free direction is the one that will be controlled in distance and speed of movement, allowing to ensure a uniform and reproducible movement, an essential requirement for the performance of a fatigue test.
    [0054]
    [0055] The crank-crank system of the cyclic loading machines according to the present invention, by comparison with the state-of-the-art machines provided with spindle systems, has a restricted minimum and maximum movement. This means that the means of measurement of the applied force cannot be damaged by the positioning of the specimen in the specimen holders, since the second specimen holder (8, the one attached to the load cell) cannot be reached by the first specimen holder. (6, attached to the second end of the connecting rod).
    [0056]
    [0057] The present invention contemplates, in some possible embodiments, that the displacement of the connecting rod along the free direction corresponds to a function: triangular, sinusoidal, or square wave versus time (or displacement function). Preferred embodiments of the invention also contemplate triangular or sinusoidal displacement functions at low frequencies (around 1 Hz) to avoid changing the behavior of the material of which the specimen is composed of, among other causes, heating due to the thermal hysteresis that affects rubbers and elastomers.
    [0058]
    [0059] The motor provided in a cyclic loading machine according to the invention can be, for example and without limitation, a continuous motor, a stepper motor or a servomotor. In a preferred embodiment of the invention, the free direction, along which the connecting rod travels, is a horizontal direction. The usual in commercial machines already known is that they work vertically due to their size, weight and configuration.
    [0060]
    [0061] Throughout the present specification it should be understood that a "horizontal direction" is all that direction parallel to the plane defined by the ground, that is, an direction parallel to the plane defined by the circular movement of the first end of the crank (perpendicular to the axis of rotation of the motor.) Also, a "vertical direction" is that perpendicular to the ground (parallel to the axis of rotation of the motor).
    [0062]
    [0063] Being able to work horizontally, it is easier to combine 2 and 3 cyclic loading machines, according to the invention, to allow photographic registration of the test and the subsequent extension of the test to bi and triaxial loads.
    [0064] In a more preferred embodiment of the invention the first end of the connecting rod is attached to the crank with the interposition of at least one bearing.
    [0065]
    [0066] In another even more preferred embodiment of the invention, the joining means, interposed between the first cylinder holder and the second end of the connecting rod, comprise at least one bearing.
    [0067]
    [0068] In another even more preferred embodiment of the invention, the joining means, interposed between the first cylinder holder and the second end of the connecting rod, comprise a bearing attached to the second end of the connecting rod. The joining means preferably further comprise a rotating mooring system, such as a bolt, attached to the bearing and supporting the first specimen holder. In this particular configuration of the invention, the rotating or bolt mooring system is mounted on the connecting rod through a bearing that allows it to rotate, but which restricts all other movements except that of linear displacement in the free direction of the first test-tube holder.
    [0069]
    [0070] In a further embodiment of the invention, the joining means are also provided with bolt closing means, which leave the specimen trapped inside the specimen holders, preventing displacement in directions other than the direction of the fatigue test. defined by the free direction of the connecting rod, totally undesirable aspect in this type of tests.
    [0071]
    [0072] In yet another much more preferred embodiment of the invention, the connecting means, interposed between the first cylinder holder and the second end of the connecting rod, comprise a bolt disposed inside a bearing, the bolt of closing means of being also provided with pin that immobilize the test piece between both test tubes, so that it is possible to impose a reciprocating motion on the test piece uniaxially when using the machine.
    [0073]
    [0074] In an even more preferred embodiment, there are two rotating mooring systems, preferably bolts, one per specimen holder, which crosses (each of them) to the specimen holder and the specimen, thereby incorporating the specimen into the system's freight train, with an unbroken chain of elements from the engine to the load cell. Each rotating or bolt mooring system has a rotation axis that matches the central axis of each specimen holder, where said axis extends in a vertical direction. In the reciprocating movement imposed on the second end of the connecting rod, that is to say of the first cylinder holder (6), the movement is transmitted to the first end of the cylinder (7, located inside the first cylinder holder and crossed by the rotating clamping system or bolt ). The second test tube holder (8) with its corresponding rotating or bolt mooring system also holds the second end of the test piece in the freight train and, together with the second test piece, connects the test piece with the load cell, in this way it is allowed the measure of the force during the test. The type of mooring described, by means of individual probes and their corresponding rotating or bolt mooring systems, allows the rotation of the ends (edges) of the specimen (not the specimen) around the vertical axis (perpendicular to the motor movement ) of each specimen holder, in this way the reciprocating movement of the second end of the connecting rod becomes a uniaxial effort in the crack front of the specimen and can be measured through the load cell located in the second of the specimen holder .
    [0075]
    [0076] The above-described embodiments utilize rotating tie systems that are joining means that do not prevent the rotation of the specimen (7) during the test. Preferably said rotating mooring systems are part of the specimen holders and may comprise bolts, shafts, or bolts, more preferably bolts. Other types of mooring usually used in materials such as those that use jaws or through adhesives on the faces of the specimen, prevent the rotation of the ends of the specimen and transmit stress to the bottom of the crack that are inappropriate for the precise determination of toughness of the material, in particular the rigidity, according to the Mechanics of the Fracture.
    [0077]
    [0078] The previously described embodiments in which the crank-connecting rod and bielaportaprobeta joints are made with bearings, make the gaps with the time of use considerably reduced. Other motion transmission systems, such as those provided by the rack-and-pinion and Scotch-Yoke systems, introduce clearances far superior to the proposed system, especially when changes in the direction of rotation of the engine occur. These gaps affect the accuracy and reproducibility of the assay.
    [0079]
    [0080] In another very preferred embodiment of the invention, the means for measuring linear displacement are attached to the second end of the connecting rod.
    [0081] The means for measuring the linear displacement in the machine, according to the invention, can be of the mechanical type (eg displacement gauges), electrical (eg with piezoelectric coatings), laser (eg with optical systems distance measurement), or by ultrasound.
    [0082]
    [0083] Said means for measuring linear displacement allow the position of one of the bolts attached to the specimen to be known at all times, this value being usually considered as the displacement of the test.
    [0084]
    [0085] In one embodiment of the invention, the means of measuring the force applied to the specimen is a load cell.
    [0086]
    [0087] As for the materials that can be tested with this system, the machine is specially designed to test fracture and fatigue specimens based on solid propellants, preferably on solid elastomeric propellants, in uniaxial tests.
    [0088]
    [0089] The machine thus configured is optimal for performing fracture and fatigue tests based on Fracture Mechanics following the guidelines of the standards of polymers and elastomers collected in, for example, ISO 13586: 2000 or ASTM D5045-99: 1999 ( Standard Test Methods for Plane-Strain Fracture Toughness and Strain Energy Release Rate of Plastic Materials, ASTM International, West Conshohocken, PA, www.astm.org).
    [0090]
    [0091] The machine according to the invention can be used with specimens of the samples to be analyzed, two being the most commonly used types in the field of knowledge of Fracture Mechanics, such as, preferably, sharpened bending specimens on one side (in English, SENB: Single Edge Notch Bending), in the form of a parallelepiped, used, for example, in tests with a three-point bending configuration, or compact square-shaped (CT) specimens, more preferably the specimens defined in ISO13586: 2000 and ISO13586: 2003. Each of the types of specimens would be consistent with their corresponding type of jaw (or closing means) that are required to immobilize said specimens within the two specimen holders.
    [0092]
    [0093] The cyclic loading machine according to the present invention may optionally be provided with crack size measuring means, said means being able to be, by example and without limitation, optical or electrical type. In the latter case, for example, the crack size is determined based on changes in the electrical conductivity of the material itself or electrically active coatings (eg with piezoelectric effect).
    [0094]
    [0095] Finally, it should be noted that the machine described allows to obtain properties inherent to the materials tested, facilitating the performance of intercomparison studies between homogeneous groups of laboratories, and the subsequent development of specific regulations for solid propellants of composite material as recommended by the NATO publication AOP-46 of July 2006, and that with the current state of the art of the available testing machines it has not been possible due to the experimental and economic difficulties indicated above. The machine described as a mechanical properties characterization system for the indicated materials represents an innovative contribution to the state of the art that is currently non-existent.
    [0096]
    [0097] DESCRIPTION OF THE DRAWINGS
    [0098]
    [0099] To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, a set of figures is attached to this descriptive report, as an integral part thereof, in which, by way of illustration and not limiting the following has been represented:
    [0100]
    [0101] Figure 1. It shows an isometric view of a possible embodiment of a machine according to the invention, showing in it the main parts and elements that compose it.
    [0102]
    [0103] Figure 2. Shows a plan view of the machine of Fig. 1, coupled to the specimen in its support on the connecting rod and on the load cell.
    [0104]
    [0105] Figure 3. Shows an example of a record obtained on a real sample after being subjected to cyclic loading tests with a machine according to the present invention. Fig. 3 is composed of 4 registration details (Figures 3A, 3B, 3C and 3D).
    [0106]
    [0107] Figure 4. It shows two analysis of the register shown in Fig. 3, which characterizes two solid propellant specimens subjected to cyclic loading tests with a machine according to the present invention.
    [0108] PREFERRED EMBODIMENT OF THE INVENTION
    [0109]
    [0110] In view of the aforementioned figures and in accordance with the numbering adopted, a preferred but not limiting example of the cyclic loading machine according to the invention can be observed, which comprises the parts and elements indicated and described. in detail below, the following configuration being an example of preferred, non-exclusive, embodiment of other combinations with the limits already defined.
    [0111]
    [0112] As can be seen in Figures 1 and 2, the cyclic loading machine (1) according to the invention is provided with a motor (2) which can be a continuous motor, a servomotor or a stepper motor attached to a crank (3) to which it transmits a circular motion. The circular movement of the crank becomes linear reciprocating by means of a connecting rod (4) joined by both parts (connecting rod and crank) by means of bearings. The second end of the connecting rod (4) is connected to a means for measuring linear displacement, which in this embodiment of the invention is a displacement gauge (5) and ends in one of the holders (6), in this case a bolt, which allows the test tube to rotate, but limits the other movements, except for the reciprocating linear movement of the second end of the connecting rod (4), so reciprocating movement on the specimen allows the application of uniaxial stresses in fracture tests and fatigue The test piece (7) is the only piece that physically connects the first test holder (6) with the second test holder (8). This second test tube holder (8) is connected to a system capable of measuring the force involved during the test, which in the preferred embodiment of the invention is a load cell (9).
    [0113]
    [0114] When using the loading machine of the present invention in a fracture and fatigue test, all movements are restricted except that of linear displacement in the free direction of the first specimen holder (6), and as the system is configured, other movements and clearances disappear due to the use of bolts and bearings. Thus, there is no torsion in the specimen.
    [0115]
    [0116] In the embodiment of the invention disclosed in Figures 1 and 2, the machine (1) is provided with a means (10) for measuring crack size in the form of an optical recording system based on CCD sensors (in English, Charge Coupled Devices). It can also be provided in the embodiment of the invention disclosed in Fig. 1 of a second crack size measurement means, such as an electrical crack measuring system 11 by electrical conductivity or another based on the effect piezoelectric.
    [0117] In the embodiment of the invention disclosed in Fig. 1, means for recording the environmental conditions of ambient temperature, pressure and humidity (12) or of the atmosphere, and conditions, in which it is desired to study the mechanical behavior of the material.
    [0118]
    [0119] The specimens (7) used in this specific embodiment of the invention have the following characteristics:
    [0120]
    [0121] - Type of test tube: The test piece will be designed and manufactured to measure, although it is usual to use the compact test piece (CT), with test tube sizes around 20x20x5 mm being common, although the size will depend on the material to be studied and the behavior mechanical present depending on its state of degradation. - Type of material: Solid propellants of composite material and elastomers.
    [0122] - Test conditions:
    [0123]
    [0124] o Temperatures (Ta) from - 80 ° C to 80 ° C
    [0125] ■ Accuracy in Ta; 0.1 ° C
    [0126]
    [0127] o Pressures (P o ): from ambient to 100 Bar
    [0128] ■ Accuracy in P o : 0.1 Bar
    [0129]
    [0130] o Displacements (d o ): from 10pm to 10 cm
    [0131] ■ Precision in d o ; 10 pm
    [0132]
    [0133] o Forces (F); from 0.01 N
    [0134] ■ Precision in F; 0.01 N
    [0135] ■ Full scale; 0.05 N
    [0136]
    [0137] o Crack lengths (a or ); from 5 pm
    [0138] ■ Accuracy in a or ; 5 pm
    [0139]
    [0140] o Frequency of data acquisition; usually from 80 Hz to 250 Hz
    [0141] o Test frequencies; usually 0.5 Hz to 10 Hz
    [0142]
    [0143] In this embodiment of the invention, the cyclic loading machine (1) is provided with electronic control means that make it completely autonomous (capable of carrying the test to the end without human intervention) once the test conditions have been introduced into the system, and the test piece (7) rests between the two test pieces (6) and (8) located at the two ends of the test piece. More particularly, the electronic control means are responsible for automatically connecting, disconnecting and controlling the motor speed (2), as well as recording the values of the test variables (eg force, displacement and crack size), detected by means (5) for measuring linear displacement, means (9) for measuring applied force, optical means (10) for measuring crack size or electrical means (11 ) of measurement of the crack size, as well as the values detected by any combination of said means (5), (9), (10) and (11) of measurement.
    [0144]
    [0145] In the present preferred embodiment of the invention, the electronic control means impose such a speed on the motor (2), which induces a linear displacement at the second end of the connecting rod, which as a function of time can impose triangular shifts on the two probes , sinusoidal or square wave. This is possible because - as mentioned above - said motor (2) is connected to the crank (3) and the crank (3) is connected, in turn, to the connecting rod (4).
    [0146]
    [0147] An example of the record obtained on a real sample of solid propellant of composite material is shown in Fig. 3, after being subjected to cyclic loading tests with the machine according to the present invention of Figs. 1 and 2. The force recorded in Newtons is represented on the ordinate axis. The time elapsed in milliseconds is represented on the abscissa axis of the graph. Fig. 3 consists of 1 record and 4 record details, the first (Fig. 3A) shows a 1-day trial, the second (Fig. 3B) the beginning of the trial with a series of calibration points in force, the third (Fig. 3C) is a detail of the test at a given time, showing 5 cycles, the frequency of the test, the frequency of data collection and the reproducibility of the system, the fourth (Fig. 3D) is a detail of the precision in the full scale with the variations of a real heterogeneous sample.
    [0148]
    [0149] Two analyzes of the register shown in Fig. 3 are shown in Fig. 4, characterizing two solid propellant specimens of composite material. On the ordinate axis, the crack growth rate (da / dN in mm / cycle) is shown and on the abscissa axis the energy release rate associated with the maximum charge cycle, Gmax in kJm-2.
    [0150]
    [0151] LIST OF NUMERICAL REFERENCES USED IN THE FIGURES
    [0152]
    [0153] (1): Cyclic loading machine;
    [0154] (2): Engine;
    [0155] (3): Crank;
    [0156] (4): Crank;
    [0157] (5): Means of measurement of linear displacement;
    [0158] (6): First test holder;
    [0159] (7): Test tube;
    [0160] (8): Second test holder;
    [0161] (9): Measuring means of applied force;
    [0162] (10): Optical means for measuring crack size;
    [0163] (11): Electric means for measuring crack size; (12): Means for detecting environmental conditions.
    权利要求:
    Claims (14)
    [1]
    1. Cyclic loading machine (1) comprising:
    - a motor (2) attached to a crank (3) provided with two ends, so that it transmits a circular movement to the first end of said crank (3);
    - a connecting rod (4) provided with two ends and connected by its first end to the second end of said crank (3), the second end of the connecting rod (4) being immobilized in all directions except in a single free direction, so that the circular movement of the first end of the crank (3) produces a reciprocating linear movement at the second end of the connecting rod (4), along said free direction;
    - two specimen holders (6 and 8), one of them attached to the second end of the connecting rod (2) and the other to the load measuring means (9), the specimen holder being adapted to accommodate a specimen (7) of a sample a study;
    - means (9) for measuring the force applied; Y
    - means (5) for measuring linear displacement;
    characterized because
    - a first test tube holder (6) is connected to the second end of the connecting rod (4) by means of connection that allow the test piece (7) to rotate, with the second end of the connecting rod (4) being able to move along the direction free and with its restricted movement in the remaining directions; Y
    - a second test holder (8) attached to the means (9) for measuring the force applied; Y
    - because the specimen (7) is housed between the first specimen holder (6) and the second specimen holder (8).
    [2]
    2. Cyclic loading machine (1) according to claim 1, characterized in that the motor (2) is a continuous motor, a stepper motor or a servomotor.
    [3]
    3. Cyclic loading machine (1) according to any of the preceding claims, characterized in that the free direction of the connecting rod (4) is a horizontal direction.
    [4]
    4. Cyclic loading machine (1) according to any of the preceding claims, characterized in that the first end of the connecting rod (4) is connected to the crank (3) with the interposition of at least one bearing.
    [5]
    5. Cyclic loading machine (1) according to any of the preceding claims, characterized in that the joining means, interposed between the first specimen holder (6) and the second end of the connecting rod (4), comprise at least one bearing.
    [6]
    6. Cyclic loading machine (1) according to claim 5, characterized in that the joining means comprise a bearing attached to the second end of the connecting rod (4), the joining means further comprising a bolt attached to said bearing and which supports the first test holder (6).
    [7]
    7. Cyclic loading machine (1) according to claim 6, characterized in that the joining means are also provided with bolt closing means.
    [8]
    8. Cyclic loading machine (1) according to claim 5, characterized in that the joining means comprise a bolt disposed inside a bearing, the bolt also being provided with bolt closing means that immobilize the specimen (7) .
    [9]
    9. Cyclic loading machine (1) according to any of the preceding claims, characterized in that the means (5) for measuring linear displacement are connected to the second end of the connecting rod (4).
    [10]
    10. Cyclic loading machine (1) according to any of the preceding claims, characterized in that the means (5) for measuring linear displacement are a displacement gauge.
    [11]
    11. Cyclic loading machine (1) according to any of the preceding claims, characterized in that the means (9) for measuring the force applied to the specimen are a load cell.
    [12]
    12. Cyclic loading machine (1) according to any of the preceding claims, characterized in that it is provided with means (10, 11) for measuring crack size.
    [13]
    13. Cyclic loading machine (1) according to any of the preceding claims, characterized in that it is provided with control by electronic control means for automatically connecting, disconnecting and controlling the motor speed (2), and for recording the values detected by the means (5) for measuring linear displacement, means (9) for measuring the applied force, optical means (10) for measuring crack size and electrical means (11) for measuring crack size, as well Like any combination of them.
    [14]
    14. Cyclic loading machine (1) according to claim 13, characterized in that the electronic control means induce, through the motor (2), a function, with respect to time, of triangular, sinusoidal or square wave displacement to the second end of the connecting rod (4).
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    同族专利:
    公开号 | 公开日
    ES2738953B2|2020-06-01|
    引用文献:
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    BRPI0803266A2|2008-07-17|2010-06-08|Charles Leonardo Israel|hip joint full denture wear testing machine|
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    RU2015151600A|2015-12-01|2017-06-06|Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Ухтинский государственный технический университет" |Installation for testing a material sample for bending and shock compression fatigue|
    CN205506371U|2016-01-29|2016-08-24|廊坊辰兴机械有限公司|Slider -crank mechanism in use of shield ventral brush fatigue test bench|
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