A method and system for indentation testing of complex curved surface parts

Abstract

The application discloses a kind of indentation test method and system suitable for complex curved surface parts, it is related to the technical field of material mechanical property test, the method comprises: confirming initial space coordinate system;The surface of the part to be tested is scanned by three-dimensional profilometer, three-dimensional topography data is obtained, curved surface equation is obtained, and tangent plane equation at target measuring point on the part to be tested is calculated;Confirm the angle between the plane intersection line of tangent plane and the initial space coordinate system and horizontal plane, and according to the angle and the preset interval between the telescopic rod, two telescopic rods are calculated and controlled to move;The center point coordinate of spherical hinge moving assembly, the projection point coordinate of vertical projection on the plane where the positioning table is located is calculated to calculate the coordinate of the center of positioning table, and the coordinate difference between projection point coordinate and the center coordinate is calculated to carry out indentation test to the target measuring point, the application can quickly, accurately and non-destructively carry out indentation test to complex curved surface parts.

Description

Technical Field

[0001] This application relates to the technical field of material mechanical property testing, and in particular to an indentation testing method and system applicable to complex curved surface parts. Background Technology

[0002] Currently, indentation testing is an important method for testing the mechanical properties of materials. It involves pressing an indenter of a specific shape into the surface of the material being tested, simultaneously recording load and displacement data, and calculating key mechanical parameters such as hardness and elastic modulus based on the load-displacement curve. Due to its small sample size requirements and ease of testing, this technology is widely used in materials science, product quality control, and other fields.

[0003] In related technologies, indentation testing techniques and equipment are mainly designed for specimens with flat surfaces or regular symmetrical geometries. To conduct effective indentation testing at specific points on curved surfaces, the loading direction of the indenter must be strictly aligned with the surface normal at that test point; otherwise, significant testing errors will be introduced, potentially leading to test failure. Currently, when dealing with industrial parts with complex free-form surface features, the common practice to achieve this consistency is to design and manufacture dedicated positioning and clamping fixtures for specific parts. This process is not only time-consuming and costly, but the fixtures themselves lack versatility. Furthermore, for certain critical components where damage is not permissible or sampling is difficult, the traditional "cutting-sample preparation-grinding and polishing" pretreatment process cannot be implemented, resulting in the inability to effectively evaluate their local mechanical properties.

[0004] Therefore, there is an urgent need in this field for a method that can quickly, accurately, and non-destructively perform in-situ indentation testing on complex curved surface parts to overcome problems such as strong dependence on special fixtures, long testing cycles, highly destructive pretreatment, and difficulty in aligning the normal direction of the test points. Summary of the Invention

[0005] The purpose of this application is to provide an indentation testing method and system suitable for complex curved surface parts, which can quickly, accurately and non-destructively perform indentation testing on complex curved surface parts.

[0006] To achieve the above objectives, this application provides the following solution:

[0007] Firstly, this application provides an indentation testing method suitable for complex curved surface parts, employing an indentation testing device. The device includes: a base, a positioning stage mounted on the base, three telescopic rods for driving the positioning stage to adjust its spatial posture, an indenter and a three-dimensional profilometer mounted on the positioning stage, the top ends of the three telescopic rods being rotatably connected to the positioning stage via ball joint moving components. The method includes: placing the part to be tested on the base and confirming the initial spatial coordinate system; scanning the surface of the part to be tested using the three-dimensional profilometer to acquire three-dimensional shape data; fitting a surface equation based on the three-dimensional shape data; calculating the equation of the tangent plane at the target measurement point on the part to be tested based on the surface equation; and confirming the relationship between the tangent plane and the initial spatial coordinate system based on the tangent plane equation. The angle between the plane intersection line of the coordinate system and the horizontal plane is calculated, and based on the angle and the preset interval between the telescopic rods, the first and second displacements of the two telescopic rods are calculated and controlled. The coordinates of the center points of the three ball joint moving components are calculated based on the first and second displacements, and the coordinates of the projection point of the target measuring point on the plane of the positioning platform after movement are calculated based on the center point coordinates. The coordinates of the center of the positioning platform are calculated based on the center point coordinates and the projection point coordinates, and the coordinate difference between the projection point coordinates and the center coordinates is calculated to confirm the required movement offset of the indenter on the positioning platform plane. Based on the movement offset, the indenter is controlled to move to the position of the projection point to perform an indentation test on the target measuring point.

[0008] For example, confirming the initial spatial coordinate system specifically includes: defining the horizontal leftward direction as the Y-axis, the vertical upward direction as the Z-axis, and the direction perpendicular to the YZ plane inward as the X-axis to establish the initial spatial coordinate system, wherein the target measuring point is located on the Z-axis of the initial spatial coordinate system; calculating the equation of the tangent plane at the target measuring point on the part to be measured according to the surface equation includes: confirming the normal vector at the target measuring point according to the surface equation to obtain the equation of the tangent plane.

[0009] For example, determining the angle between the plane intersection line between the tangent plane and the initial spatial coordinate system and the horizontal plane according to the tangent plane equation includes: simultaneously solving the tangent plane equation and the equation of the YZ plane to calculate the straight line equation of the plane intersection line of the tangent plane in the YZ plane; determining the tangent value of the intersecting straight line and the XY plane according to the intersecting straight line equation; and determining the angle according to the tangent value; the first displacement and the second displacement of the telescopic rod are calculated through the preset interval and the tangent value, wherein the preset interval is a preset distance between the ball joint moving components at the top of the telescopic rod.

[0010] For example, the center points of the three ball joint moving components include a first center point, a second center point, and a third center point. Calculating the coordinates of the center points of the three ball joint moving components includes: determining the X-axis and Y-axis coordinates of the center points of the three ball joint moving components based on the fixed installation position of the telescopic rod and the first displacement and the second displacement; calculating the Z-axis coordinate of the first center point after displacement based on the first displacement and the second displacement; determining the plane equation of the positioning platform plane where the ball joint moving component is located after displacement, and calculating the Z-axis coordinate after displacement based on the plane equation and the tangent plane equation; and determining the coordinates of the first center point, the second center point, and the third center point corresponding to the three ball joint moving components based on the Z-axis coordinate after displacement.

[0011] For example, calculating the coordinates of the projection point of the target measuring point on the plane of the positioning platform after the movement, based on the coordinates of the center point, includes: connecting the target measuring point and the projection point to obtain a first vector; connecting the first center point and the second center point to obtain a second vector; and connecting the second center point and the third center point to obtain a third vector; establishing a system of equations based on the vector perpendicularity relationship and the condition that the projection point is located on the plane of the positioning platform, and solving the system of equations to obtain the coordinates of the projection point; wherein the vector perpendicularity relationship includes: the first vector being perpendicular to the second vector and the third vector respectively.

[0012] For example, the relative positional relationship between the positioning stage center, the projection point, and the first center point constitutes a geometric constraint relationship. The step of calculating the coordinates of the positioning stage center based on the coordinates of the center point and the coordinates of the projection point includes: confirming the X-axis coordinate of the positioning stage center based on the geometric constraint relationship, and constructing the coordinate equation of the positioning stage center; solving the Y-axis coordinate and Z-axis coordinate of the positioning stage center by simultaneously solving the coordinate equation and the plane equation of the positioning stage plane.

[0013] For example, calculating the coordinate difference between the projection point coordinates and the center coordinates to obtain the required movement offset of the indenter on the positioning stage plane includes: on the positioning stage plane, subtracting the corresponding components of the coordinates of the projection point and the coordinates of the center of the positioning stage to confirm the lateral movement offset of the indenter along the X direction and the longitudinal movement offset along the Y direction.

[0014] Secondly, this application provides an indentation testing system suitable for complex curved surface parts. The system includes: an indentation testing device; and a control processing unit, which is communicatively connected to the telescopic rod, the indenter, and the three-dimensional profilometer, respectively, for executing the indentation testing method for complex curved surface parts described above.

[0015] For example, the scanning center of the three-dimensional profilometer and the indenter center of the indenter both correspond to the center position of the positioning stage.

[0016] For example, the positioning platform is a frame structure or the positioning platform has a through hole in the middle. The indenter's indentation head drive mechanism is mounted on the positioning platform and configured to drive the indenter's indenter to move in a direction perpendicular to the plane of the positioning platform, and the movement path of the indenter passes through the through hole or frame space in the middle of the positioning platform.

[0017] According to the specific embodiments provided in this application, the following technical effects are disclosed:

[0018] This application provides an indentation testing method and system suitable for complex curved surface parts. By integrating a 3D profilometer to scan and fit the curved surface of the part, combined with subsequent geometric calculations, the surface normal direction at any target measurement point and the projection position of that point on the positioning stage plane can be automatically and accurately determined. An adjustable positioning stage driven by three telescopic rods and a ball joint moving assembly is used to simulate the attitude adjustment function of a special fixture. Based on the calculated displacement, the telescopic rods are driven to automatically adjust the positioning stage plane to be parallel to the tangent plane of the test point. Only the part needs to be fixed to the base, without any cutting, polishing, or sample pretreatment. It is suitable for parts with various curved surface features, eliminating the need to design and manufacture fixtures for each part, saving time and economic costs. The close integration of 3D scanning, spatial analytical geometric calculation, and motion control forms a closed-loop automated testing process. It can automatically calculate all control parameters based on the scanning data and drive the actuator to complete the positioning, greatly reducing the difficulty of operation and dependence on operator experience, improving testing efficiency and reliability, and obtaining more realistic and reliable local mechanical property data. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the initial state structure of the test device in the embodiments of this application.

[0021] Figure 2 This is a schematic diagram of the adjusted test device in the embodiments of this application.

[0022] Figure 3 This is a flowchart of the testing method in the embodiments of this application.

[0023] Figure 4 This is a schematic diagram of the initial position of the positioning stage in an embodiment of this application.

[0024] Figure 5 This is a schematic diagram showing the correspondence between the spatial coordinate system and the base position in an embodiment of this application.

[0025] Figure 6 This is a cross-sectional view of the positioning stage after positioning is completed in the embodiments of this application.

[0026] Figure 7 This is a schematic diagram showing the positional relationship between the telescopic rod and the base in an embodiment of this application.

[0027] Figure 8 This is a schematic diagram of the position of the telescopic rod after displacement in an embodiment of this application.

[0028] Figure 9 This is a schematic diagram of the center point of the ball joint moving component in an embodiment of this application.

[0029] Figure 10 This is a schematic diagram of the center point and projection point of the positioning stage in an embodiment of this application.

[0030] Figure 11 This is a schematic diagram of the displacement in an embodiment of this application.

[0031] Figure 12 This is a schematic diagram of the positioning platform after positioning is completed in an embodiment of this application.

[0032] Figure 13 This is a schematic diagram of vector relationships in an embodiment of this application.

[0033] Reference numerals in the attached drawings: 1. Base; 2. Telescopic rod II; 3. Ball joint moving assembly II; 4. Positioning platform; 5. Indenter; 6. Ball joint moving assembly IV; 7. Ball joint moving assembly I; 8. Telescopic rod IV; 9. Telescopic rod I; 10. Part to be measured; 11. 3D profilometer. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] This application provides an indentation testing method suitable for complex curved surface parts, employing an indentation testing device. For example... Figure 1 and Figure 2 As shown, the device includes: a base 1, a positioning platform 4 mounted on the base 1, three telescopic rods for adjusting the spatial attitude of the positioning platform 4, an indenter and a three-dimensional profilometer 11 mounted on the positioning platform 4, and the top ends of the three telescopic rods are rotatably connected to the positioning platform 4 via ball joint moving components. Figure 3 As shown, the method includes the following steps:

[0037] S310. Place the part to be tested on the base and confirm the initial spatial coordinate system.

[0038] S320. The surface of the part to be measured is scanned by a three-dimensional profilometer to obtain three-dimensional topographic data. The surface equation is obtained by fitting the three-dimensional topographic data, and the equation of the tangent plane at the target measuring point on the part to be measured is calculated based on the surface equation.

[0039] S330. Based on the equation of the tangent plane, determine the angle between the plane intersection line between the tangent plane and the initial spatial coordinate system and the horizontal plane, and calculate and control the first and second displacements of the two telescopic rods according to the angle and the preset interval between the telescopic rods.

[0040] S340. Calculate the coordinates of the center points of the three ball joint moving components based on the first displacement and the second displacement, and calculate the coordinates of the projection point of the target measuring point on the plane of the positioning platform after the movement based on the coordinates of the center points.

[0041] S350. Calculate the coordinates of the center of the positioning stage based on the center point coordinates and the projection point coordinates, and calculate the coordinate difference between the projection point coordinates and the center coordinates to confirm the required movement offset of the indenter on the positioning stage plane.

[0042] S360: Based on the movement offset, the indenter is moved to the position of the projection point to perform indentation testing on the target measurement point.

[0043] like Figure 1 and Figure 2The diagram shows different working states of the indentation testing device for complex curved surface parts in this application embodiment. The base 1 supports the part 10 to be tested. The positioning platform 4 is positioned above the base 1. Three telescopic rods are vertically positioned between the base 1 and the positioning platform 4. The top of each telescopic rod is hinged to the lower surface of the positioning platform 4 via a ball joint moving assembly, used to drive the positioning platform 4 to adjust its spatial posture. An indenter is positioned on the positioning platform 4 and can move on the plane of the positioning platform 4, used to perform indentation testing on the part 10 to be tested. A three-dimensional profilometer 11 is positioned above the positioning platform 4, used to perform three-dimensional morphological scanning of the part 10 to be tested. The telescopic rods include telescopic rod one 9, telescopic rod two 2, and telescopic rod four 8, and the corresponding top ball joint moving assemblies are ball joint moving assembly one 7, ball joint moving assembly two 3, and ball joint moving assembly four 6.

[0044] The scanning center of the 3D profilometer 11 and the center of the indenter head both correspond to the center position of the positioning platform 4. The positioning platform 4 is a frame structure or has a through hole in the middle. The indenter head drive mechanism is mounted on the positioning platform 4 and configured to drive the indenter head to move in a direction perpendicular to the plane of the positioning platform 4. The movement path of the indenter head passes through the through hole or frame space in the middle of the positioning platform 4 to facilitate the indentation test.

[0045] like Figures 4-6 The diagram shows the initial position of positioning stage 4, with the horizontal direction to the left defined as the Y-axis (within the left-hand side). Figure 1 The position shown is the main viewpoint. The vertical direction upwards is the Z-axis, and the direction perpendicular to the YZ plane inwards is the X-axis, establishing an initial spatial coordinate system. The part to be measured 10 is placed on the base 1, and the target measurement point K on the part to be measured 10 is located on the Z-axis, with its coordinates marked K(0, 0, Z0). The 3D profilometer 11 is moved along the Y-axis direction until it is directly above the part to be measured 10. The surface of the part to be measured 10 is scanned to acquire 3D topographic data. The surface equation is obtained by fitting the 3D topographic data, denoted as... After obtaining the surface equations described above, the equation of the tangent plane at the target measuring point K on the part to be measured 10 is calculated based on the surface equations. Specifically, the equation is as follows: .

[0046] Based on the equation of the tangent plane, the angle between the plane's intersection line with the initial spatial coordinate system and the horizontal plane is calculated. Specifically, this involves simultaneously solving the equations of the tangent plane and the YZ plane to obtain the equation of the straight line of the intersection line of the tangent plane and the YZ plane. L 1 Determine the tangent of the intersecting lines and the XY plane based on their equations, and then determine the included angle based on the tangent. .

[0047] The equations of the simultaneous equations are shown below:

[0048] ;

[0049] The equation of the line is further obtained as follows: Thus, the tangent of the included angle is obtained. .

[0050] like Figures 7-8 As shown, the three telescopic rods are telescopic rod 1 (9), telescopic rod 2 (2), and telescopic rod 4 (8). The line connecting telescopic rod 2 (2) and telescopic rod 4 (8) is located in the Y-axis direction, and the line connecting telescopic rod 1 (9) and the center point of this line is located in the X-axis direction. The displacement of the telescopic rods includes a first displacement of telescopic rod 2 (2) and a second displacement of telescopic rod 4 (8). These two displacements are calculated using a preset interval and a tangent value. The preset interval is the preset distance between the ball joint moving components at the top of the telescopic rods. The preset distance between the ball joint moving components at the top of telescopic rod 2 (2) and telescopic rod 4 (8) is... The distance that telescopic pole 2 moves is: The travel distance of telescopic pole 4 is .

[0051] like Figure 9 As shown, the center points of the three ball joint moving components at the top of the telescopic rod include the first center point A, the second center point B, and the third center point D. The process of calculating the coordinates of the center points of the three ball joint moving components in step S340 is as follows:

[0052] Based on the fixed installation position of the telescopic rod and the first and second displacements, determine the X-axis and Y-axis coordinates of the center points of the three ball joint moving components; calculate the Z-axis coordinate of the first center point after displacement based on the first and second displacements; determine the plane equation of the positioning platform plane where the ball joint moving components are located after displacement, and calculate the Z-axis coordinate after displacement based on the plane equation and the tangent plane equation; determine the coordinates of the first, second, and third center points corresponding to the three ball joint moving components based on the Z-axis coordinates after displacement.

[0053] Since the positions of telescopic rod 1 (9), telescopic rod 2 (2), and telescopic rod 4 (8) relative to base 1 are fixed, the horizontal and vertical coordinates of the first center point A, the second center point B, and the third center point D are determined. Combining the first and second displacements obtained in the above steps, the coordinates of the three center points are confirmed as follows: , , .in Since these are unknown quantities, the three-dimensional spatial coordinates of the three center points can be updated and confirmed after calculation.

[0054] The tangent plane has been confirmed in the previous text. Let the plane The positioning plane of the ball joint moving assembly after displacement can be determined from the spatial positional relationship. Therefore, we can assume The center points of all three ball joint moving components are on the positioning table plane. Above, the coordinates of the second center point B and the third center point D are known. Substitute the coordinates of point B into the positioning platform plane. From the plane equation, we obtain Then substitute the x and y coordinates of point A into the plane equation to obtain .

[0055] Based on this, after confirming the Z-axis coordinates of the first center point, the coordinates of the center points of the three ball joint moving components are obtained. Then, the steps in S340 above are executed to calculate the coordinates of the projection point of the target measuring point on the plane of the moved positioning platform 4, based on the center point coordinates. The specific process is as follows:

[0056] like Figures 10-13 As shown, connecting the target measurement point and the projection point yields the first vector; connecting the first center point and the second center point yields the second vector; and connecting the second center point and the third center point yields the third vector. Based on the perpendicular relationship between the vectors and the condition that the projection point lies on the positioning platform plane, a system of equations is established. Solving the system of equations yields the coordinates of the projection point. The perpendicular relationship between the vectors includes that the first vector is perpendicular to both the second and third vectors.

[0057] The coordinates of the target measuring point K have been confirmed as (0, 0, Z0) in the previous text. The coordinates of the first center point A, the second center point B, and the third center point D have also been confirmed. Let the coordinates of the projection point E be... The specific calculation method is as follows:

[0058] Connecting the target measurement point K and the projection point E yields the first vector. Connecting the first center point A and the second center point B yields the second vector. Connecting the second center point and the third center point yields the third vector. Based on spatial relationships, we can obtain: , Furthermore, the projection point lies on the plane of the positioning stage. Solving the system of equations, we obtain the following equation set:

[0059] ;

[0060] By solving for the three-dimensional coordinates using known parameters, we obtain:

[0061] ;

[0062] This allows us to solve for the three-dimensional coordinates of the projection point E.

[0063] After obtaining the projected coordinates and the center point coordinates, the coordinates of the positioning stage center can be calculated, and the coordinates of the positioning stage center are set as follows: The relative positional relationships between the positioning stage center, the projection point, and the first center point constitute geometric constraints. The specific calculation method is as follows:

[0064] The coordinate equation of the positioning stage center is constructed based on the geometric constraints; the Y-axis and Z-axis coordinates of the positioning stage center are obtained by solving the equations of the coordinate equations and the plane equation of the positioning stage plane.

[0065] The geometric constraints are as follows: the center of the positioning platform lies on the positioning platform plane; the line connecting the first center point A and the center F of the positioning platform is perpendicular to the line connecting the second center point and the fourth center point. Based on the spatial relationship, telescopic rods 2 and 8 are always fixed above the base 1, and the plane they form always lies within the ZY plane. The Y-axis of the positioning platform also lies within this plane. The X-axis coordinate of the center of the positioning platform... Since the line connecting the second and third center points is along the Y-axis, and the center point of the positioning stage is located at the center of the positioning stage plane, the coordinates of the positioning stage center satisfy: Combining the plane equation of the positioning platform mentioned above, we have: Solving these equations simultaneously, we obtain the following system of equations concerning the Y-axis and Z-axis coordinates:

[0066] ;

[0067] The adjusted equations for the Y-axis and Z-axis coordinates of point F are as follows:

[0068] ;

[0069] Based on the known data calculated above, the system of equations can be solved to confirm the coordinates of the positioning stage center. Then, the coordinate difference between the projection point coordinates and the positioning stage center coordinates is calculated to obtain the required displacement of the indenter 5 on the positioning stage plane. The process is as follows: on the positioning stage plane, the corresponding components of the projection point coordinates and the positioning stage center coordinates are subtracted to confirm the lateral displacement of the indenter 5 along the X direction and the longitudinal displacement along the Y direction.

[0070] Specifically, the coordinates of the projection point and the center of the positioning platform were calculated earlier and are as follows: and Calculate the vector: , , The difference between the X-axis and Y-axis coordinates is obtained through vector calculation, as shown below:

[0071] , ;

[0072] The X-axis and Y-axis coordinate differences calculated using the above method are used to represent the lateral displacement along the X-direction and the longitudinal displacement along the Y-direction, respectively. Based on the calculated displacement, the indenter 5 is moved to the position of the projection point for indentation testing of the target measurement point.

[0073] Because the aforementioned lateral and longitudinal offsets are relative to the center of the positioning stage, and the position of the positioning stage center has been confirmed, when moving the indenter 5, it first coincides with the center of the positioning stage, and then moves by applying lateral and longitudinal offsets. The indenter head at the bottom of the indenter 5 moves vertically along the Z-axis, so only the stroke of the indenter head needs to be controlled, and it is not necessary to re-drive the indenter 5 to move in the Z-axis direction. When using the indenter 5, the indenter head passes through the through hole in the center of the positioning stage, contacts and presses into the surface of the part, completes the standard loading-holding-unloading work cycle, and collects load-displacement data for calculating mechanical property parameters.

[0074] The following examples and data illustrate this point: For example, part 10 to be tested... Figure 1 and Figure 2 As shown, the complex curved surface with convex and concave points has a flat bottom surface. The specific steps for performing an indentation test on this specimen are as follows:

[0075] The part to be tested 10 is placed on the base 1, and the 3D profilometer 11 is placed on the positioning stage and moved along the Y-axis so that it is directly above the part to be tested 10. The shape of the part to be tested 10 is scanned to obtain its 3D shape information, and the fitted surface equation is obtained. .

[0076] The equation of the tangent plane of the surface at the target measurement point K(0, 0, -1) is: .

[0077] Based on the equation of the tangent plane obtained in the previous step, the equation of the line intersecting the ZY plane is obtained, and the simultaneous equations are: The equation of the line in the ZY plane is: Its tangent value is: Based on a preset distance The moving distances of telescopic pole 2 and telescopic pole 4 are determined to be respectively... , .

[0078] The coordinates of points A, B, and D are determined by their geometric positions. Since the positions of telescopic rod 1 (9), telescopic rod 2 (2), and telescopic rod 4 (8) relative to base 1 are fixed, the x and y coordinates of points A, B, and D are fixed. Combining this with the moving distances of telescopic rod 2 (2) and telescopic rod 4 (8) obtained in the previous step, their coordinates can be determined as follows: ,point ,point ,in The unknowns that need to be solved are shown in the following steps:

[0079] Based on spatial relationships, the tangent plane can be determined. and positioning platform plane The relationship between them is ,flat Let the plane of the positioning table where the ball joint is located after positioning be defined. Since points A, B, and D are all on the plane Above, points B and D are known points. Substitute the coordinates of point B into the plane equation. achievable Substituting the x and y coordinates of point A into the plane equation, we can obtain the y coordinates of point A. Then the coordinates of points A, B, and D can be determined.

[0080] Based on the calculated coordinates of points A, B, and D, determine the coordinates of the intersection point (projection point E) where the straight line passing through the measured point intersects the plane containing the positioning platform perpendicularly.

[0081] The coordinates of the center points A, B, and D, and the coordinates of the target measurement point K have been confirmed in the previous text. The vector has been calculated. , , Based on spatial relationships, it can be confirmed that: , And the projection point E is located on the positioning stage plane. The above equations are combined to form a system of equations, as shown below:

[0082] ;

[0083] Solving for the problem, we get:

[0084] ;

[0085] This completes the calculation of the coordinates of projection point E. Next, the center point of the positioning stage will be calculated. Based on the spatial relationship, it can be seen that telescopic rod 2 and telescopic rod 8 are always fixed above base 1. Therefore, the plane they form is always located in the ZY plane, and the Y-axis of the positioning platform center is also located in the ZY plane. Therefore, there is an X-axis coordinate. The projection point E is always located at the center of the positioning stage, that is Point F is in plane From the above, we obtain: vector Solving these equations simultaneously, we obtain a system of equations concerning the Y-axis and Z-axis coordinates, as shown below:

[0086] ;

[0087] The solution is obtained as follows: Therefore, the coordinates of the center F of the positioning platform are .

[0088] Based on the coordinates of point E and point F, calculate the distance the center of the indenter 5 has moved relative to the center of the positioning stage. ,point The calculation yields:

[0089] , ;

[0090] Therefore, the indenter 5 moves 15.63 mm and 175.60 mm relative to the positioning stage on the X and Y axes, respectively. Based on this, it is moved to point E for indentation testing.

[0091] This application also provides an indentation testing system suitable for complex curved surface parts, the system including the aforementioned indentation testing device (such as...). Figure 1 and Figure 2 (as shown) and a control processing unit. The control processing unit is communicatively connected to the telescopic rod, the indenter 5, and the three-dimensional profilometer 11, and is used to execute the above-described indentation test method applicable to complex curved surface parts.

[0092] It should be noted that the scanning center of the 3D profilometer 11 and the center of the indenter head of the indenter 5 both correspond to the center position of the positioning stage. In order to prevent the testing process of the indenter 5 from being interfered with by the positioning stage, in this embodiment, the positioning stage is a frame structure or has a through hole in the middle. The indenter head driving mechanism of the indenter 5 is mounted on the positioning stage and configured to drive the indenter head of the indenter 5 to move in a direction perpendicular to the plane of the positioning stage, and the movement path of the indenter head passes through the through hole or frame space in the middle of the positioning stage.

[0093] This application provides an indentation testing method and system suitable for complex curved surface parts. By integrating a 3D profilometer 11 to scan and fit the surface of the part, combined with subsequent geometric calculations, the surface normal direction at any target measurement point and the projection position of that point on the positioning stage plane can be automatically and accurately determined. An adjustable positioning stage driven by three telescopic rods and a ball joint moving assembly simulates the attitude adjustment function of a dedicated fixture. Based on the calculated displacement, the telescopic rods are driven, automatically adjusting the positioning stage plane to be parallel to the tangent plane of the test point. Only the part needs to be fixed to the base 1; no cutting, polishing, or sample pretreatment is required. This method is suitable for parts with various curved surface features, eliminating the need to design and manufacture fixtures for each part individually, saving time and economic costs. The close integration of 3D scanning, spatial analytical geometry calculation, and motion control forms a closed-loop automated testing process. It can automatically calculate all control parameters based on the scan data and drive the actuator to complete the positioning, greatly reducing the difficulty of operation and dependence on operator experience, improving testing efficiency and reliability, and obtaining more realistic and reliable local mechanical property data.

[0094] In one exemplary embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0095] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0096] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0097] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0098] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0099] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for indentation testing suitable for complex curved surface parts, employing an indentation testing device, characterized in that, The device includes: a base, a positioning platform mounted on the base, three telescopic rods for adjusting the spatial attitude of the positioning platform, an indenter and a three-dimensional profilometer mounted on the positioning platform, the top ends of the three telescopic rods being rotatably connected to the positioning platform via ball joint moving components; the method includes: Place the part to be tested on the base and confirm the initial spatial coordinate system; The surface of the part to be tested is scanned by a 3D profilometer to obtain 3D topographic data. The surface equation is obtained by fitting the 3D topographic data, and the equation of the tangent plane at the target measurement point on the part to be tested is calculated based on the surface equation. The angle between the plane intersection line between the tangent plane and the initial spatial coordinate system and the horizontal plane is determined according to the equation of the tangent plane. Based on the angle and the preset interval between the telescopic rods, the first and second displacements of the two telescopic rods are calculated and controlled. The coordinates of the center points of the three ball joint moving components are calculated based on the first and second displacements, and the coordinates of the projection point of the target measuring point on the plane of the positioning platform after the movement are calculated based on the center point coordinates. Calculate the coordinates of the center of the positioning stage based on the coordinates of the center point and the coordinates of the projection point, and calculate the coordinate difference between the coordinates of the projection point and the center coordinates to confirm the required offset of the indenter on the plane of the positioning stage. The indenter is moved to the position of the projection point based on the movement offset to perform indentation testing on the target measurement point.

2. The indentation testing method for complex curved surface parts according to claim 1, characterized in that, The confirmation of the initial spatial coordinate system specifically includes: defining the horizontal leftward direction as the Y-axis, the vertical upward direction as the Z-axis, and the direction perpendicular to the YZ plane inward as the X-axis, to establish the initial spatial coordinate system, wherein the target measuring point is located on the Z-axis of the initial spatial coordinate system; calculating the equation of the tangent plane at the target measuring point on the part to be measured according to the surface equation, including: confirming the normal vector at the target measuring point according to the surface equation, to obtain the equation of the tangent plane.

3. The indentation testing method for complex curved surface parts according to claim 2, characterized in that, The angle between the plane intersection line of the tangent plane and the initial spatial coordinate system and the horizontal plane is determined according to the equation of the tangent plane, including: solving the equation of the tangent plane and the equation of the YZ plane simultaneously to calculate the straight line equation of the plane intersection line of the tangent plane in the YZ plane; determining the tangent value of the plane intersection line and the XY plane according to the straight line equation of the plane intersection line; and determining the angle according to the tangent value; the first displacement and the second displacement of the telescopic rod are calculated through the preset interval and the tangent value, wherein the preset interval is the preset distance between the ball joint moving components at the top of the telescopic rod.

4. The indentation testing method for complex curved surface parts according to claim 2, characterized in that, The center points of the three ball joint moving components include a first center point, a second center point, and a third center point. Calculating the coordinates of the center points of the three ball joint moving components includes: Based on the fixed installation position of the telescopic rod and the first displacement and the second displacement, determine the X-axis and Y-axis coordinates of the center points of the three ball joint moving components; Calculate the Z-axis coordinate of the first center point based on the first displacement and the second displacement. Confirm the plane equation of the positioning platform plane where the ball joint moving component is located after displacement, and calculate the Z-axis coordinate after displacement based on the plane equation and the tangent plane equation. Based on the Z-axis coordinates after displacement, the coordinates of the first center point, the second center point, and the third center point corresponding to the three ball joint moving components are confirmed.

5. The indentation testing method for complex curved surface parts according to claim 4, characterized in that, Calculate the coordinates of the projection point of the target measuring point onto the plane of the positioning platform after the movement, based on the coordinates of the center point, including: A first vector is obtained by connecting the target measurement point and the projection point; a second vector is obtained by connecting the first center point and the second center point; and a third vector is obtained by connecting the second center point and the third center point. Based on the perpendicular relationship of the vectors and the condition that the projection point is located on the plane of the positioning platform, a system of equations is established, and the coordinates of the projection point are obtained by solving the system of equations; wherein the perpendicular relationship of the vectors includes: the first vector is perpendicular to the second vector and the third vector respectively.

6. The indentation testing method for complex curved surface parts according to claim 5, characterized in that, The relative positional relationship between the positioning stage center, the projection point, and the first center point constitutes a geometric constraint relationship. The step of calculating the coordinates of the positioning stage center based on the center point coordinates and the projection point coordinates includes: Based on the geometric constraints, the X-axis coordinates of the positioning stage center are determined, and the coordinate equation of the positioning stage center is constructed. By combining the coordinate equations and the plane equation of the positioning platform, the Y-axis and Z-axis coordinates of the center of the positioning platform can be obtained.

7. The indentation testing method for complex curved surface parts according to claim 1, characterized in that, The calculation of the coordinate difference between the projection point coordinates and the center coordinates to determine the required movement offset of the indenter on the positioning table plane includes: On the positioning platform plane, the coordinates of the projection point are subtracted from the corresponding components of the coordinates of the positioning platform center to confirm the lateral movement offset of the indenter along the X direction and the longitudinal movement offset along the Y direction.

8. An indentation testing system suitable for complex curved surface parts, characterized in that, The system includes: An indentation testing device; a control and processing unit, which is communicatively connected to a telescopic rod, an indenter, and a three-dimensional profilometer, for executing the indentation testing method applicable to complex curved surface parts as described in any one of claims 1-7.

9. The indentation testing system for complex curved surface parts according to claim 8, characterized in that, The scanning center of the three-dimensional profilometer and the indenter center of the indenter both correspond to the center position of the positioning stage.

10. The indentation testing system for complex curved surface parts according to claim 9, characterized in that, The positioning platform is a frame structure or has a through hole in the middle. The indenter's indentation head drive mechanism is mounted on the positioning platform and configured to drive the indenter's indenter to move in a direction perpendicular to the plane of the positioning platform. The movement path of the indenter passes through the through hole or frame space in the middle of the positioning platform.

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