TWI900082B - Curved surface friction testing device - Google Patents

Abstract

A curved surface friction testing device has a first clamp applied to provide a pulling force to an object along a length direction; a second clamp applied to provide a clamping force to the object; a testing space with a bionic liquid therein, at least one part of the second clamp is immersed in the bionic liquid to simulate a usage environment of the object; and a sensor applied to detect a sensing data which is generated when the object is pulled by the first clamp.

Description

Arc surface friction test device

A friction testing device, in particular a curved surface friction testing device.

Current technology primarily refers to "ASTM D1894 Test Method for Static and Dynamic Coefficients of Friction of Plastic Film and Sheeting," which is used to measure the static and dynamic coefficients of friction on the surfaces of sheet/plate materials such as plastic film, sheet, and rubber. Surface friction is typically measured using a universal testing machine or tensile testing equipment, where the sheet/plate material is dragged against a test plate to calculate the static and dynamic coefficients of friction.

However, the aforementioned testing methods mostly target flat plate materials and employ flat friction methods to determine the surface's static and kinetic friction coefficients. Test items with curved surfaces (such as invasive medical catheters or guidewires) require additional processing of the same material into a flat surface for surface friction testing. This not only increases manufacturing costs and processing steps, but the resulting surface is also not identical to the actual test item, making it difficult to verify the quality of the test item.

In view of this, in order to develop a friction testing technology that can avoid manufacturing costs and process burdens and is suitable for testing objects with curved surfaces, the present invention provides a curved surface friction testing device, comprising a stretching portion, a clamping portion, and a simulation device arranged in a longitudinal direction from top to bottom. The stretching portion includes a first clamp that is movable relative to the clamping portion along the longitudinal direction. The first clamp is used to provide a The curved surface exerts a pulling force on an object to be tested along the longitudinal direction; the clamping portion includes a second clamp, the second clamp being configured to provide a clamping force on the object to be tested; the simulation device includes a receiving space, a biomimetic fluid disposed within the receiving space, and at least a portion of the second clamp being immersed in the biomimetic fluid to simulate a usage scenario of the object to be tested; and a sensor is configured to detect sensing data generated when the first clamp pulls the object to be tested.

The second fixture includes a bionic pad on a side corresponding to the object to be tested.

The bionic pad is an elastic body, including rubber or silicone.

The surface of the bionic pad includes a concave-convex structure.

Furthermore, a temperature control device is included to provide the second fixture and/or the simulation device with a temperature condition corresponding to the usage scenario.

Furthermore, a control center provides a test command to the stretching unit, the clamping unit, and the simulation device via wired or wireless communication. The test command includes the tension of the first clamp, a displacement speed of the first clamp, the clamping force of the second clamp, and a temperature condition corresponding to the usage scenario provided to the second clamp and/or the simulation device.

The control center includes a database recording at least one test condition corresponding to the usage scenario, including the bionic pad corresponding to the test condition, a pad friction coefficient corresponding to the bionic pad, the clamping force, the type of bionic fluid, the position of the second clamp relative to the bionic fluid, the temperature condition, and a test logic. The control center provides the test instruction based on the test condition and the test logic.

The clamping force of the second clamp corresponds to the pressure applied to the object under test in the usage scenario.

The pulling force and/or displacement speed of the first clamp corresponds to the pulling force or speed of the object to be tested in the usage scenario.

The stretching unit is a common universal material machine or a stretching device.

The advantages of this invention are:

1. By immersing at least a portion of the second fixture in the bionic fluid, the use scenario of the object under test can be simulated.

2. The arc-shaped surface friction testing device can provide appropriate testing conditions for different test items, avoiding the problem of uncertainty about the quality of the test items due to standardized testing conditions.

3. Based on the test conditions, select the bionic gasket, the tension of the first clamp, the displacement speed of the first clamp, the clamping force of the second clamp, and the temperature conditions suitable for the test object to accurately detect the static friction and/or dynamic friction that may be generated by the bionic gasket during its intended use.

10: Stretching Section

11: First clamp

20: Clamping part

21: Second clamp

22: Bionic Pad

30:Simulation device

31: Storage Space

32: Bionic Fluid

40: Control Center

41:Database

42: Sensor

43: Temperature control equipment

A: Items to be tested

Figure 1 is a three-dimensional cross-sectional view of a preferred embodiment provided by the present invention.

Figure 2 is a diagram of the preferred embodiment of the present invention.

Figure 3 is a block diagram of a preferred embodiment system provided by the present invention.

Figure 4 is a diagram of experimental data from a preferred embodiment of the present invention.

Please refer to Figures 1 to 3, which illustrate a preferred embodiment of the arc surface friction testing device provided by the present invention. The device comprises a stretching section 10, a clamping section 20, and a simulation device 30, arranged longitudinally from top to bottom. A control center 40 provides test commands, either wired or wireless, to control the stretching section 10, the clamping section 20, and the simulation device 30.

The stretching section 10 includes a first clamp 11, which can be adjusted by the control center 40 to move along its length toward or away from the clamping section 20. The curved surface friction testing device uses the first clamp 11 of the stretching section 10 to clamp a test object A with a curved surface. The first clamp 11 applies a pulling force to displace the test object A along its length relative to the clamping section 20.

The clamping portion 20 includes a second clamp 21. At least a portion of the second clamp 21 is disposed within the simulation device 30. The second clamp 21 clamps the object A to be tested and applies a clamping force to the object A to be tested.

The object to be tested A can be a generally cylindrical material such as a rod or tube. Preferably, the object to be tested A is a medical catheter, guidewire, or prosthesis.

The stretching unit 10 can be a common universal material machine or a stretching device. The stretching unit 10, the clamping unit 20, the simulation device 30, and the control center 40 are a detachable assembly.

The second clamp 21 includes a bionic pad 22 on the side corresponding to the object A to be tested, to simulate the use scenario of the object A being pulled relative to a biological body.

For example, the bionic pad 22 can be an elastic material such as rubber or silicone to simulate the elastic characteristics of human skin or organs; or the surface of the bionic pad 22 can be formed with a concave-convex structure to simulate the concave-convex surface of the human body, such as the esophagus or intestines.

The simulation device 30 includes a housing 31 containing a biomimetic fluid 32. At least a portion of the second fixture 21 is immersed in the biomimetic fluid 32 to simulate the use scenario of the test object A.

For example, another portion of the second fixture 21 protrudes above the surface of the biomimetic fluid 32 to simulate the use scenario of the test object A moving from inside the organism to outside the organism (or vice versa), crossing different environments. Alternatively, the entire second fixture 21 can be immersed in the biomimetic fluid 32 to simulate the use scenario of the test object A moving inside the organism.

Referring to Figure 3 , the control center 40 includes a database 41 , at least one sensor 42 , and a temperature control device 43 . The temperature control device 43 provides a temperature condition for the second fixture 21 and/or the simulation device 30 to accurately simulate the usage scenario.

The database 41 records at least one test condition, which is determined based on the expected usage scenario of the test object A. The database 41 also records the bionic pad corresponding to the test condition, a pad friction coefficient corresponding to the bionic pad, the clamping force, the type of the bionic fluid 32, the position of the second clamp 21 relative to the bionic fluid 32, the temperature condition, and a test logic.

The sensor 42 is used to detect sensing data such as resistance or distance traveled per unit time generated when the first fixture 11 pulls the object A to be tested, and transmits the sensing data to the control center 40.

The control center 40 determines the test instructions based on the selected test conditions and the test logic. The test instructions include the tension of the first clamp 11, the displacement speed of the first clamp 11, the clamping force of the second clamp 21, and the temperature conditions of the second clamp 21 and/or the simulation device 30 provided by the temperature control device 43. By adjusting or changing the tension of the first clamp 11 and/or the clamping force of the second clamp 21 in the test instructions, the static and/or dynamic friction coefficients of the surface of the test object A corresponding to the test conditions can be measured.

It is worth noting that the clamping force of the second clamp 21 can be set to simulate the pressure exerted by the test object A in the test scenario, such as when it is wrapped, squeezed, or pressed against the biological tissue. The pulling force or displacement speed provided by the first clamp 11 can also simulate the force or speed exerted by medical personnel when pulling the test object A in the test scenario.

Furthermore, whether or not at least a portion of the second clamp 21 is immersed in the biomimetic fluid 32 can significantly affect the static and/or kinetic friction coefficients of the surface of the object under test (A). This invention examines the difference in friction coefficient measured on a polyvinyl chloride (PVC) tube at a point 2 cm below the biomimetic fluid 322 surface and 2 cm above the surface of the biomimetic fluid 32, when the PVC tube is displaced relative to the second clamp, using the same tension and displacement speed provided by the first clamp 11 and the same clamping force provided by the second clamp 21. The PVC tube is continuously displaced, and the kinetic friction coefficients of the PVC tube are measured at points 2 cm below the surface of the biomimetic fluid 32 and 2 cm above the surface of the biomimetic fluid 32, respectively, for every 1 cm of movement. As shown in Figure 4, the kinetic friction coefficient of the PVC tube measured 2 cm above the surface of the biomimetic fluid 32 during the first 4 cm of movement differs significantly from the kinetic friction coefficient measured below the surface of the biomimetic fluid 322. This indicates that the positional relationship between the second fixture 21 and the biomimetic fluid 32 is crucial in determining the usage scenario of the test object A. The values of the surface static friction coefficient and/or kinetic friction coefficient of the test object A measured by the second fixture 21 below the surface of the biomimetic fluid 322 and above the surface of the biomimetic fluid 32 can be used to select reference values for the surface static friction coefficient and/or kinetic friction coefficient based on the intended use of the test object A (e.g., in vivo or in vitro).

The advantages of this invention are:

1. By immersing at least a portion of the second fixture 21 in the bionic fluid 32, the use scenario of the test object A can be simulated.

2. The arc-shaped surface friction testing device can provide appropriate testing conditions for different test objects A, avoiding the problem of uncertainty about the quality of the test objects due to standardized testing conditions.

3. Based on the test conditions, select the bionic gasket, the tension of the first clamp 11, the displacement speed of the first clamp 11, the clamping force of the second clamp 21, and the temperature conditions suitable for the test object A to accurately detect the surface static friction and/or dynamic friction that may be generated by the bionic gasket during its intended use.

20: Clamping part

21: Second clamp

22: Bionic Pad

30:Simulation device

31: Storage Space

Claims (8)

A curved surface friction testing device comprises a stretching portion, a clamping portion, and a simulation device arranged from top to bottom along a longitudinal direction, wherein: the stretching portion comprises a first clamp, the first clamp being displaceable relative to the clamping portion along the longitudinal direction, the first clamp being used to provide a tensile force along the longitudinal direction to a test object having a curved surface; the clamping portion comprises a second clamp, the second clamp being used to provide a clamping force to the test object, wherein a side of the second clamp corresponding to the test object clamping comprises a bionic pad; the simulation device comprises a accommodating space, wherein a bionic fluid is disposed in the accommodating space, At least a portion of the second clamp is immersed in the bionic fluid to simulate a usage scenario of the object to be tested; a sensor is used to detect sensing data generated when the first clamp pulls the object to be tested; and a control center includes a database that records at least one test condition, which corresponds to the usage scenario, including the bionic pad corresponding to the test condition, a pad friction coefficient corresponding to the bionic pad, the clamping force, the type of bionic fluid, the position of the second clamp relative to the bionic fluid, the temperature condition, and a test logic. The control center provides the test instruction based on the test condition and the test logic. In the arc surface friction testing device as described in claim 1, the bionic pad is an elastic body comprising rubber or silicone. In the arc surface friction testing device as described in claim 1, the surface of the bionic pad includes a concave-convex structure. The arc surface friction testing device as described in claim 1 includes a temperature control device that provides the second fixture and/or the simulation device with a temperature condition corresponding to the usage scenario. As for the arc surface friction testing device as described in any one of claims 1 to 4, the control center provides a test instruction to the stretching part, the clamping part and the simulation device by wire or wirelessly, and the test instruction includes the pulling force of the first clamp, a displacement speed of the first clamp, the clamping force of the second clamp and a temperature condition corresponding to the usage scenario provided to the second clamp and/or the simulation device. In the arc surface friction testing device as described in claim 5, the clamping force of the second clamp corresponds to the pressure received by the object to be tested in the usage scenario. In the arc surface friction testing device as described in claim 5, the pulling force and/or displacement speed of the first clamp corresponds to the force or speed at which the object to be tested is pulled out in the usage scenario. In the arc surface friction testing device as described in claim 5, the stretching part is a common universal material machine or a stretching equipment.