Metal implantable material mechanical property testing device

Abstract

The utility model relates to the technical field of determination of physical and chemical properties of materials, in particular to a mechanical property testing device for a metal implantable material. The metal implantable material mechanical property testing device comprises a static side fixing seat for fixing one end of a simulated broken bone and a movable side fixing seat for fixing the other end of the simulated broken bone, and the two broken parts of the simulated broken bone are fixed together through a bone fracture plate and a bone fracture nail. The testing device comprises a pressure detection device used for detecting the pressure between the simulated broken bone and the bone fracture plate, and the movable side fixing seat is connected with a loading device used for applying an alternating load to the movable side fixing seat so as to enable the simulated broken bone and the bone fracture plate to move relatively to generate friction. A pressure value can be obtained through the pressure detection device, the pressure value can be adjusted by adjusting the number of screwing turns of the bone setting nail, the pressure is in positive correlation with friction force, the friction degrees are different when the pressure is different, and therefore the influence of different degrees of fretting friction on the mechanical property of the simulated broken bone can be tested.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of determining material physical and chemical properties, and specifically relates to a mechanical property testing device for metal implantable material. BACKGROUND

[0002] Metal implantable material is a material widely used in orthopedic surgery, and currently, bone screws and bone plates are often used to connect broken bones in orthopedic surgery. Bone screws and bone plates belong to metal implants, and the bone screw is screwed into the broken bone through the bone plate, so that the bone plate is fixed with the two parts of the broken bone. Such metal implants are subjected to stress due to body movement and electrochemical corrosion in body fluid in the body, so in order to study the reliability of metal implants during use, it is usually necessary to test the mechanical properties of metal implants.

[0003] At present, the experiment for evaluating the mechanical properties of metal implantable material under the coupling action of stress and corrosion is mainly stress corrosion experiment. Generally, the metal implantable material sample is immersed in a container containing corrosive liquid, and a tensile testing machine is used to apply tensile stress to the sample. After a certain period of time, the force at which the sample is pulled apart is measured to obtain the strength change. Although the existing testing device can simulate the stress condition of metal implantable material in the human body to a certain extent, it still has deficiencies compared with the actual in-vivo use environment. For bone plates, they are not only affected by alternating loads and corrosive media, but also by the micro-motion friction between the material and the bone. The broken bone affected by tensile and compressive stress will produce relative movement with the bone plate to form friction. The tighter the bone screw presses the bone plate and the broken bone, the greater the friction when the broken bone and the bone plate move relative to each other, and the more serious the wear of the bone plate. Micro-motion friction has a great influence on the strength of the bone plate, and the conventional testing device in the prior art is only suitable for stress corrosion test and cannot test the influence of micro-motion friction on the mechanical properties of the bone plate. SUMMARY

[0004] The utility model aims at providing a mechanical property testing device for metal implantable material to solve the problem that the conventional testing device cannot be used to test the influence of micro-motion friction on the mechanical properties of the bone plate.

[0005] The technical scheme of the mechanical property testing device for metal implantable material of the utility model is as follows:

[0006] The utility model provides a metal implantable material mechanical property testing device, the testing device includes the static side fixed base of one end of simulating broken bone is fixed and the dynamic side fixed base with the other end of simulating broken bone is fixed, and the two parts of simulating broken bone are fixed together through the bone plate and the bone nail, and the testing device includes a pressure detection device for detecting the pressure between simulating broken bone and the bone plate, and the dynamic side fixed base is connected with a loading device for applying alternating load to the dynamic side fixed base to make the relative motion of simulating broken bone and the bone plate and generate friction.

[0007] Beneficial effects: the utility model innovatively provides a metal implantable material mechanical property testing device suitable for micro-tribological test, the two parts of simulating broken bone are fixed through the bone plate and the bone nail, the pressure between simulating broken bone and the bone plate is detected through the pressure detection device, one end of simulating broken bone is fixed through the static side fixed base of testing device, the other end is fixed with the dynamic side fixed base, alternating load is applied to the dynamic side fixed base through the loading device, the dynamic side fixed base can reciprocate, and then the corresponding part of simulating broken bone is driven to move relative to the bone plate, so that simulating broken bone and the bone plate form micro-tribological test under corresponding pressure, the pressure value can be obtained through the pressure detection device, the pressure value can be adjusted by adjusting the screwing number of the bone nail, the pressure and the friction force are positively correlated, the friction degree is different under different pressure, so that the influence of different degree micro-tribological test on the mechanical property of simulating broken bone can be realized.

[0008] Further, the testing device includes a simulated body fluid container and an electrochemical corrosion testing equipment for electrochemical corrosion test of the bone plate, and the bone plate is located in the simulated body fluid container.

[0009] Further, the static side fixed base is fixed at the bottom of the simulated body fluid container, and the dynamic side fixed base is located above the static side fixed base and is movably arranged relative to the simulated body fluid container.

[0010] Further, the dynamic side fixed base is located outside the simulated body fluid container.

[0011] Further, the simulated body fluid container includes a main tank body and an upper cover arranged on the top of the main tank body, the static side fixed base is arranged at the bottom of the main tank body, and the dynamic side fixed base is located above the upper cover, and the upper cover is provided with an avoiding hole through which the upper end of simulating broken bone is adapted to pass.

[0012] Further, the simulated body fluid container is provided with an openable upper cover, and the upper cover is provided with a liquid injection hole for injecting simulated body fluid into the inside of the simulated body fluid container.

[0013] Further, the simulated body fluid container is provided with a heat preservation structure.

[0014] Further, the simulation body fluid container side wall is a double-layer structure, a water bath cavity is formed between the inner layer and the outer layer, and the heat preservation structure comprises the water bath cavity and a water bath circulation pipeline connected with the water bath cavity.

[0015] Further, the test device comprises an alternating load measuring device for measuring the alternating load.

[0016] Further, the static side fixing seat and / or the dynamic side fixing seat is a clamp for clamping and fixing the simulation broken bone. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a structural schematic view of an embodiment of the metal implantable material mechanical property test device.

[0018] In the figure: 100, simulation broken bone; 101, bone plate; 102, bone nail; 1, bearing base; 2, tank bottom; 3, tank wall; 4, upper cover; 5, static side fixing seat; 6, dynamic side fixing seat; 7, three-dimensional force sensor; 8, ball screw; 9, speed reducer; 10, servo motor; 11, load analysis computer; 12, pressure sensor; 13, pressure display instrument; 14, electrochemical workstation; 15, electrochemical analysis computer; 16, beaker; 17, reference electrode; 18, salt bridge; 19, auxiliary electrode; 20, water pump; 21, constant temperature water bath pot. DETAILED DESCRIPTION

[0019] The simulation broken bone and the bone plate form micro-tribology under corresponding pressure through the pressure detection device and the loading device, the friction degree is different due to different pressure, and thus the influence of different degrees of micro-tribology on the mechanical property of the simulation broken bone can be realized.

[0020] The embodiment of the metal implantable material mechanical property test device of the utility model:

[0021] The metal implantable material mechanical property test device is used for simulating and testing the performance of the bone plate fixed to the simulation broken bone through the bone nail, the test device comprises a static side fixing seat for fixing one end of the simulation broken bone and a dynamic side fixing seat for fixing the other end of the simulation broken bone, the two parts of the simulation broken bone are fixed together through the bone plate and the bone nail, the test device comprises a pressure detection device for detecting the pressure between the simulation broken bone and the bone plate, the dynamic side fixing seat of the test device is connected with a loading device for applying alternating load to the dynamic side fixing seat so that the simulation broken bone and the bone plate relatively move to generate friction, and the micro-tribology test requirement can be realized.

[0022] Specifically, as Figure 1As shown, the metal implantable material mechanical property testing device comprises a simulated broken bone 100, a bone plate 101 and a bone nail 102. The simulated broken bone 100 comprises two broken parts. The bone plate 101 is fixed at the broken part of the simulated broken bone 100 by the bone nail 102. The bone nail 102 penetrates the bone plate 101 and is screwed on the simulated broken bone 100 to press the bone plate 101 on the simulated broken bone 100. The two broken parts of the simulated broken bone 100 are connected together by the bone plate 101 and the bone nail 102 to simulate the cooperation state of the bone plate 101 with the human bone.

[0023] The testing device comprises a simulated body fluid container for simulating the state of the metal implantable material in the human body. The simulated body fluid container is used to contain simulated body fluid. The simulated body fluid container comprises a tank bottom 2, a tank wall 3 and an upper cover 4. The simulated body fluid container is fixed on a bearing base 1 which is used to be fixed on a corresponding test bench. The testing device comprises a static side fixing seat 5 for fixing one end of the simulated broken bone 100 and a dynamic side fixing seat 6 for fixing the other end of the simulated broken bone 100. The static side fixing seat 5 is fixed on the tank bottom 2 of the simulated body fluid container. The dynamic side fixing seat 6 is located above the upper cover 4 of the simulated body fluid container. The simulated broken bone 100 penetrates the upper cover 4 and is fixed with the dynamic side fixing seat 6. The broken part of the simulated broken bone 100 is located in the simulated body fluid container. Correspondingly, the bone plate 101 and the bone nail 102 are located in the simulated body fluid container to be soaked in the simulated body fluid.

[0024] The testing device comprises a pressure detection device and a loading device. The loading device comprises a ball screw 8, a speed reducer 9 and a servo motor 10. The loading device is in transmission connection with the dynamic side fixing seat 6 to apply alternating load to the dynamic side fixing seat 6 to make the simulated broken bone 100 and the bone plate 101 move relatively to generate friction. The pressure detection device comprises a pressure sensor 12 and a pressure display instrument 13. The pressure sensor 12 is arranged between the simulated broken bone 100 and the bone plate 101 to detect the pressure between the simulated broken bone 100 and the bone plate 101.

[0025] The simulation broken bone 100 is vertically arranged, the upper end of the simulation broken bone 100 is fixed with the moving side fixed seat 6, the lower end is fixed with the static side fixed seat 5, and the alternating load applied by the loading device can act on the upper part of the simulation broken bone 100, so that the upper part of the simulation broken bone 100 reciprocates relative to the bone plate 101, the pressure sensor 12 is arranged between the upper part of the simulation broken bone 100 and the bone plate 101, so as to detect the pressure between the upper part of the simulation broken bone 100 and the bone plate 101, the greater the pressure, the greater the friction, and the pressure is adjustable between 0-200N. The loading device is used to apply alternating load to the moving side fixed seat 6, and under the action of the alternating load, the moving side fixed seat 6 can reciprocate, the moving side fixed seat 6 drives the upper part of the simulation broken bone 100 to move relative to the bone plate 101, so that the simulation broken bone 100 and the bone plate 101 form a slight friction under the corresponding pressure, and the pressure value can be known through the pressure detection device, the pressure value is positively correlated with the friction degree, and the set pressure value can represent the set friction degree, the tightening degree of the bone nail 102 determines the pressure between the simulation broken bone 100 and the bone plate 101, the pressure value can be adjusted by adjusting the screwing number of the bone nail 102, the friction degree is different due to different pressures, the different friction degrees make the force different when the bone plate 101 is pulled off, so that the influence of different degrees of slight friction on the mechanical properties of the simulation broken bone 100 can be tested under the condition of alternating load and test time, and the influence of slight friction on the strength of the bone plate 101 can be evaluated.

[0026] The test device comprises an alternating load measuring device for measuring the alternating load, the alternating load measuring device comprises a three-dimensional force sensor 7 and a load analysis computer 11, the alternating load can be measured by using the three-dimensional force sensor 7, the three-dimensional force sensor 7 is connected with the load analysis computer 11 through a data line, and the load analysis computer 11 can display the load size. The servo motor 10 of the loading device is in transmission connection with the speed reducer 9, the speed reducer 9 is in transmission connection with the ball screw 8, the ball screw is provided with a sliding block nut, the sliding block nut is connected with the three-dimensional force sensor 7 through a connecting rod, and the three-dimensional force sensor 7 is fixedly installed on the moving side fixed seat 6, so as to drive the moving side fixed seat 6 to move up and down through the servo motor 10 and the screw nut mechanism, alternating load is applied to the simulation broken bone 100 in the vertical direction, the alternating load is 0-10KN, the frequency is 0-10Hz and is adjustable. In order to keep the movement track of the moving side fixed seat 6, a guide rail for guiding the movement of the moving side fixed seat 6 can be arranged. The loading device and the alternating load measuring device can be used to test the material performance under the condition of alternating load, and the influence of different alternating loads on the strength of the bone plate 101 can be tested. In other embodiments, the alternating load measuring device can also not be arranged, which is suitable for the case that the material performance is not tested under the condition of alternating load.

[0027] The static side fixing base 5 and the dynamic side fixing base 6 are clamps for clamping and fixing the simulated broken bone 100, and the clamps can be made of resin. The broken bone in the embodiment is a rod with a diameter of 20 mm. Correspondingly, the clamp includes three clamping jaws, and the simulated broken bone 100 is clamped and fixed by the three clamping jaws. Such a clamp belongs to a conventional technology, and thus will not be described here. After the simulated broken bone 100 is clamped, it will not move relative to the fixing base during the test. In other embodiments, the broken bone can also be provided in a plate shape according to needs, with a length of 20 mm and a width of 4 mm. Correspondingly, the clamp includes two clamping jaws for clamping and fixing the simulated broken bone. In other embodiments, the simulated broken bone can be directly fixed to the fixing base by a screw. In other embodiments, one of the fixing bases is a clamp, and the other is directly fixed to the simulated broken bone by a screw.

[0028] The test device includes an electrochemical corrosion test device for performing an electrochemical corrosion test on the bone plate 101. The electrochemical corrosion test device includes an electrochemical workstation 14, an electrochemical analysis computer 15, a beaker 16, a reference electrode 17, a salt bridge 18, and an auxiliary electrode 19. The beaker 16 contains a saturated potassium chloride solution. The bone plate 101, the reference electrode 17, and the auxiliary electrode 19 are respectively connected to corresponding interfaces of the electrochemical workstation 14 through corresponding wires. The electrochemical workstation 14 is connected to the electrochemical analysis computer 15 through a data line. The method and principle of the electrochemical corrosion test are prior art, and thus will not be described here. In other embodiments, when the electrochemical corrosion test is not needed, the electrochemical corrosion test device can be omitted. Correspondingly, the simulated body fluid container is also omitted, and the simulated broken bone and the bone plate are exposed to air to test the influence of micro-tribological friction alone on the materials.

[0029] The bottom 2 and the upper cover 4 of the simulated body fluid container are made of resin, the wall 3 is made of acrylic, the lower end of the wall 3 is fixed with the bottom 2, and the upper end is fixed with the upper cover 4. The static side fixing seat 5 is fixed at the bottom of the simulated body fluid container, and the dynamic side fixing seat 6 is located above the static side fixing seat 5 and can be movably arranged relative to the simulated body fluid container, so that the dynamic side fixing seat 6 is arranged above and below the static side fixing seat 5, which is simple in structure and saves space. The dynamic side fixing seat 6 is located outside the simulated body fluid container, which can avoid the dynamic side fixing seat 6 from contacting the simulated body fluid and save the amount of simulated body fluid. The wall 3 and the bottom 2 jointly constitute the main tank body of the simulated body fluid container, the upper cover 4 is used to cover the top of the main tank body, the static side fixing seat 5 is arranged at the bottom of the main tank body, and the dynamic side fixing seat 6 is located above the upper cover 4. The upper cover 4 is provided with an avoiding hole for the upper end of the simulated broken bone 100 to pass through to ensure that the simulated broken bone 100 enters the simulated body fluid container and the upper end is fixed with the dynamic side fixing seat 6. The upper cover 4 can be opened, which is convenient for placing the simulated broken bone 100. In other embodiments, the simulated broken bone can also be arranged horizontally, and the static side fixing seat and the dynamic side fixing seat are arranged at the horizontal two ends of the simulated body fluid container. In other embodiments, the dynamic side fixing seat can also have a part extending into the simulated body fluid container. In other embodiments, the upper cover can also not be provided, and the upper end of the simulated body fluid container is open. In order to support the salt bridge and the auxiliary electrode, a support can be arranged at the top end of the wall.

[0030] The avoiding hole of the upper cover 4 for avoiding the simulated broken bone 100 is located at the center and is matched with the shape and size of the simulated broken bone 100. The upper cover 4 is provided with through holes for avoiding the corresponding parts of the electrochemical corrosion test equipment. The upper cover 4 is provided with a liquid injection hole for injecting simulated body fluid into the inside of the simulated body fluid container, and the liquid injection hole on the upper cover 4 is convenient for connecting the liquid injection equipment. In other embodiments, the liquid injection hole can also be arranged on the wall.

[0031] The simulation body fluid container is provided with a heat preservation structure, the tank wall 3, i.e. the side wall of the simulation body fluid container, is a double-layer structure, the inner layer contacts the simulation body fluid, and a water bath cavity is formed between the inner layer and the outer layer, the heat preservation structure comprises the water bath cavity and a water bath circulation pipeline connected with the water bath cavity, a water pump 20 and a constant temperature water bath kettle 21 are arranged on the water bath circulation pipeline. The double-layer structure of the tank wall 3 can realize solution separation, and cooperates with the upper cover 4 and the tank bottom 2 to prevent water leakage. The outer layer of the tank wall 3 has a diameter of 160 mm and a height of 150 mm, the inner layer of the tank wall 3 has a diameter of 120 mm and a height of 150 mm, the outer layer of the tank wall 3 is provided with a water outlet and a water inlet matched with the water bath circulation pipeline, and the water outlet and the water inlet are respectively connected with the water pump 20 and the constant temperature water bath kettle 21 through a hose. Deionized water is circulated in the hose, so that the temperature of the simulation body fluid is maintained in a water bath heating mode, the structure is simple, the heat preservation effect is good, and the accuracy of the test result is favorable. In other embodiments, an electric heating structure can be arranged on the periphery of the simulation body fluid container to maintain the temperature. In other embodiments, when the ambient temperature is constant, the heat preservation structure can also be omitted.

[0032] The test device can be used to evaluate the mechanical properties of bone plate 101 (metal implant material) under the action of alternating load-corrosion medium-micro-motion friction coupling. The pressure between the simulated broken bone 100 and the bone plate 101 is adjusted by adjusting the number of rotations of the bone screw 102, the pressure is tested by using the pressure sensor 12 and the pressure display instrument 13, and the micro-motion friction experiment requirement is realized. The simulated broken bone 100 passes through the upper cover 4, the static side fixing seat 5 fixes the lower end of the simulated broken bone 100, the simulated broken bone 100 is placed in the simulation body fluid container, the upper end of the container is covered with the upper cover 4, and the upper end of the simulated broken bone 100 is clamped with the dynamic side fixing seat 6. The simulation body fluid (corrosion medium) is injected into the inner layer space surrounded by the inner layer of the tank wall 3 of the container through the liquid injection hole in the upper cover 4, and the deionized water is circulated in the outer layer space of the container through the water pump 20 and the constant temperature water bath kettle 21 and the container side wall joint and the connecting hose. The upper cover 4 is provided with a circular hole matched with the salt bridge 18 and the auxiliary electrode 19 for electrochemical corrosion test, so that the test under corrosion condition can be realized. The vertical alternating load is applied to the simulated broken bone 100 through the servo motor 10, the speed reducer 9, the ball screw 8 and the dynamic side fixing seat 6, and the pressure value is tested through the three-dimensional force sensor 7, the data line and the load analysis computer 11, so that the material performance under alternating load condition can be tested. The purpose of evaluating the mechanical properties of metal implant material under the action of alternating load-corrosion medium-micro-motion friction coupling can be realized in one device, so that the test result is closer to the actual situation. The traditional stress corrosion experiment is improved, the experimental method and data for evaluating the mechanical properties of metal implant material in vitro are closer to the actual situation, and the reliability of the experiment is further improved.

[0033] Finally, it needs to be explained that the above is only the preferred embodiment of the present application, and is not used to limit the present application, although the present application is described in detail with reference to the foregoing embodiments, for those skilled in the art, it still can modify the technical solutions recorded in the foregoing embodiments without paying creative labor, or make equivalent replacement for part of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A device for testing the mechanical properties of metallic implantable materials, characterized in that it comprises: The testing device comprises a static side fixing base for fixing one end of the simulated broken bone and a dynamic side fixing base for fixing the other end of the simulated broken bone, the two parts of the simulated broken bone are fixed together by the bone plate and the bone nail, the testing device comprises a pressure detection device for detecting the pressure between the simulated broken bone and the bone plate, and the dynamic side fixing base is connected with a loading device for applying an alternating load to the dynamic side fixing base to cause the relative movement of the simulated broken bone and the bone plate to generate friction.

2. The device for testing the mechanical properties of metallic implantable materials according to claim 1, characterized in that, The testing device comprises a simulated body fluid container and an electrochemical corrosion testing device for electrochemical corrosion testing of the bone plate, the bone plate is located in the simulated body fluid container, and the simulated body fluid container is used for containing simulated body fluid.

3. The apparatus for testing the mechanical properties of metallic implantable materials according to claim 2, wherein The static side fixing base is fixed at the bottom of the simulated body fluid container, and the dynamic side fixing base is located above the static side fixing base and is movably arranged relative to the simulated body fluid container.

4. The apparatus for testing the mechanical properties of metallic implantable materials according to claim 3, wherein The dynamic side fixing base is located outside the simulated body fluid container.

5. The apparatus for testing the mechanical properties of metallic implantable materials according to claim 4, wherein The simulated body fluid container comprises a main tank body and an upper cover arranged on the top of the main tank body, the static side fixing base is arranged at the bottom of the main tank body, and the dynamic side fixing base is located above the upper cover, and the upper cover is provided with a avoiding hole through which the upper end of the simulated broken bone is adapted to pass.

6. The device for testing the mechanical properties of a metallic implantable material according to claim 2 or 3 or 4, characterized in that, The simulated body fluid container is provided with an openable upper cover, and the upper cover is provided with a liquid injection hole for injecting simulated body fluid into the inside of the simulated body fluid container.

7. The apparatus for testing the mechanical properties of a metallic implantable material according to claim 2 or 3 or 4 or 5, wherein The simulated body fluid container is provided with a heat preservation structure.

8. The apparatus for testing the mechanical properties of metallic implantable materials according to claim 7, wherein The side wall of the simulated body fluid container is a double-layer structure, a water bath cavity is formed between the inner layer and the outer layer, and the heat preservation structure comprises the water bath cavity and a water bath circulation pipeline connected with the water bath cavity.

9. The apparatus of any one of claims 1-5, wherein the apparatus is configured to test the mechanical properties of a metallic implantable material. The testing device comprises an alternating load measuring device for measuring the alternating load.

10. The device for testing the mechanical properties of a metallic implantable material according to any one of claims 1 to 5, characterized in that, The static side fixing base and / or the dynamic side fixing base is a clamp for clamping and fixing the simulated broken bone.

Images