CN118614868B - An experimental test method for estimating the bending strength and disturbance of rat femur - Google Patents

Abstract

Translated fromChinese

本发明公开了一种推算大鼠股骨弯曲强度与扰度的实验测试方法，通过高速摄影机与三点弯曲试验获得大鼠股骨的弯曲强度，随后可以电镜扫描图进行二值化处理获得大鼠股骨断裂面的精准截面面积，依据材料力学公式计算大鼠股骨的弯曲强度与扰度，然后进行大鼠股骨的生物力学性能评价，可以从力学的角度上很好地表征不同血糖浓度造模处理对大鼠生命体征的影响作用；本发明可以精准计算大鼠股骨断裂面的弯曲强度、扰度、位移场及应变场等实验数据，测试的大鼠股骨力学强度数据广，测试精度高，可以多方面对大鼠股骨生物力学性能进行评价。

The invention discloses an experimental test method for estimating the bending strength and disturbance of rat femur. The bending strength of rat femur is obtained by a high-speed camera and a three-point bending test. Subsequently, an electron microscope scanning image can be binarized to obtain the precise cross-sectional area of the rat femur fracture surface. The bending strength and disturbance of the rat femur are calculated according to a material mechanics formula. Then, the biomechanical performance of the rat femur is evaluated. The method can well characterize the influence of modeling treatments with different blood sugar concentrations on the vital signs of the rat from a mechanical point of view. The method can accurately calculate experimental data such as the bending strength, disturbance, displacement field and strain field of the rat femur fracture surface. The tested rat femur mechanical strength data is wide and the test accuracy is high. The biomechanical performance of the rat femur can be evaluated in many aspects.

Description

Experimental test method for calculating bending strength and deflection of rat femur

Technical Field

The invention relates to the technical field of rat femur biomechanical strength test, in particular to an experimental test method for calculating rat femur bending strength and disturbance.

Background

Various studies have been made by some students on the methods for testing the tensile strength, compressive strength and torsional strength of the femur of a rat, but these mechanical strengths are different from the stress characteristics in real life, for example, the chinese patent application No. 201610102091.9 discloses a stress loading device and loading system and method for constructing a stress fracture animal model, in which the moving wheelbase of a tissue fixing unit is adjusted by a linear guide, so that the bone to be tested of an experimental animal is placed in the tissue fixing unit, and the displacement and speed of the motion of a linear actuator are set by a manual control part of a LabVIEW control program to apply a certain preload.

On the one hand, the representation of the bending strength of the femur of the rat is the most form, and on the other hand, a large amount of blank exists for the accurate measurement of the bending strength of the femur of the rat, on the other hand, because the internal part of the femur of the rat has partial marrow condition, which is generally of a hollow structure, the influence of the hollow section of the femur on the bending strength needs to be fully considered, and the cross-sectional area of the femur needs to be accurately measured, and then the inertia cross-sectional area of the fracture surface of the femur needs to be represented. On the other hand, when the thigh femur of a human body is subjected to a load such as a certain impact force, the stress characteristic of the thigh femur is in a three-point bending state or an eccentric bending stress state, so that the stress state of the thigh femur of a rat can be idealized to be similar to the stress state of the thigh femur of the human body, and therefore, the bending strength characterization of the thigh femur of the rat generally adopts a three-point bending experiment, particularly the bending strength test experiment adopts a high-speed camera to simultaneously perform a simultaneous air evolution test on the displacement field and the strain field of the femur of the mouse, and the accurate test on the bending strength and the deflection of the femur of the rat cannot be realized.

The present invention provides a new solution to this problem.

Disclosure of Invention

Aiming at the situation, in order to overcome the defects of the prior art, the invention aims to provide an experimental test method for estimating the bending strength and the deflection of the femur of a rat.

The technical scheme is that the experimental test method for calculating the bending strength and the deflection of the femur of the rat comprises the following steps:

1) Preparing a plurality of normal rats, carrying out model building treatment on part of the rats with type 2 diabetes to obtain a model group, equally dividing the rats subjected to the model building treatment into three groups, feeding two groups of rats with traditional Chinese medicine reagents and western medicine reagents, and obtaining four groups of rat models with different blood sugar concentrations, namely a normal group, a model group, a traditional Chinese medicine group and a western medicine group;

2) Drawing materials of rat thighbones of the four groups of rat models in the step 1), removing muscle tissues, and then placing the muscle tissues into phosphate buffer salt solution for culture treatment;

3) Taking out the rat femur from the phosphate buffer salt solution for drying treatment, and then spraying black-and-white speckles on the upper surfaces of the four groups of rat femur integrally for digital image correlation method treatment;

4) Placing four groups of rat thighbones on a compression load loading device to respectively perform three-point bending tests, simultaneously shooting the fracture process of the rat thighbones in real time by matching with a high-speed camera, and importing test data into a computer for processing;

5) According to the test data obtained in the step 4), a rat femur load time course curve is derived, and a displacement field and a strain field between rat femur fracture points are analyzed;

6) Scanning and analyzing the fracture surface of the femur of the rat by using an electron microscope, inputting scanned Image information into Image J software for binarization treatment, accurately calculating the diameter and the area of the fracture surface of the femur of the rat according to the proportion of black and white pixels of a binarized picture to a scale of the electron microscope scanning picture after conversion is completed, then calculating the bending strength according to a mechanical bending strength theoretical formula of a material, and then analyzing the bending strength and the disturbance degree by combining the Image information of a high-speed camera;

7) And (3) analyzing according to the bending strength of the thighbones of the four groups of rats, and evaluating the mechanical strength of the biomechanics of the thighbones of the rats.

Further, the traditional Chinese medicine reagent and the western medicine reagent in the step 1) are respectively a ginseng and astragalus compound reagent and a saxagliptin tablet reagent.

Further, the specific analysis process in the step 5) is as follows:

a. Randomly selecting a point P (x_i,y_i) to be measured in a reference image of the femur of the rat, and selecting a square sub-image with the size of (2N+1) x (2N+1) pixels, namely a reference subset, by taking the point P (x_i,y_i) to be measured as a center;

b. selecting a square sub-image (M > N) with the size of (2M+1) x (2M+1) pixels from the deformed image by taking the corresponding pixel point as a center, namely searching the subset;

c. Selecting a deformation subset from the search subsets at will, wherein the deformation subset is expressed by g ' (x ', y '), and the size of the deformation subset is (2N+1) x (2N+1) pixels;

d. then, carrying out correlation calculation on f (x, y) and g ' (x ', y ') according to a correlation coefficient formula to obtain a correlation coefficient distribution diagram of the whole field;

e. The peak value of the correlation coefficient distribution diagram is the best matching point of f (x, y) and g ' (x ', y '), and the difference between the coordinates of the central point P ' (x_i′,y_i ') of the deformation subset and the central point of the reference subset is the displacement vector of the point P (x_i,y_i) to be detected;

f. By adopting the same method, the whole displacement and the whole strain of the femur of the rat can be obtained by carrying out the related operation on each pixel point in the whole speckle pattern, and then the displacement field and the strain field of the femur of the rat can be further analyzed.

Further, the compression load loading device in the step 4) is an electrohydraulic servo press provided with a three-point bending clamp.

Further, the three-point bending test in the step 4) may be a centrosymmetric loading or an eccentric asymmetric three-point bending loading.

Through the technical scheme, the invention has the beneficial effects that:

1. The invention can accurately calculate the experimental data such as bending strength, disturbance degree, displacement field, strain field and the like of the fracture surface of the femur of the rat, the tested mechanical strength data of the femur of the rat is wide, the disturbance degree of the femur of the rat can be tested by utilizing a high-speed camera in combination with a digital image correlation method, and the experimental value is compared and analyzed with the theoretical value of a theoretical formula, so that the bending strength of the femur of the rat can be corrected;

2. the invention can accurately test the displacement field and strain field data of the fracture point of the femur of the rat, which is always the limitation of experimental test data of the femur of the rat, and the precision range of the displacement field and strain field of the femur of the rat can reach 0.001mm;

3. The test method can evaluate the biomechanical property of the rat femur from the bending strength of the rat femur, can evaluate the biomechanical property of the rat femur according to the disturbance value of the rat femur, and can respectively perform mutual verification and evaluation from two aspects.

Drawings

FIG. 1 is a flow chart of a test method of the present invention;

FIG. 2 is a schematic view of a compression load loading apparatus according to the present invention;

FIG. 3 is a schematic illustration of the force-displacement curve of the femur of a normal group of rats;

FIG. 4a is a schematic representation of loading points of a normal group of rat femur;

FIG. 4b is a graph showing load point bending moment calculation of a normal group of rat femur;

FIG. 4c is a schematic cross-sectional view of a femur of a normal group of rats;

FIG. 5a is an electron microscope scan of a femur of a normal group of rats;

FIG. 5b is a diagram of electron microscope scan binarization of the femur of a normal group of rats;

fig. 6 is a graph showing the displacement time course of the loaded femur section monitoring points of the femur of the normal group of rats.

Detailed Description

The foregoing and other features, aspects and advantages of the present invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures 1 to 6. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

The principle of application of the present invention will be described in detail with reference to the following examples.

Example 1:

1) 3 healthy male Wistar normal rats with the age of 10-13 weeks and 9 healthy male GK rats with the age of 10-13 weeks are selected, the rats are adaptively fed for two weeks, random blood sugar is measured once during the feeding period to know the blood sugar condition of the rats, the feeding environment temperature is 19-22 ℃, the relative humidity is 50% -70%, the 12-hour bright/dark circadian rhythm change (darkness, 7:00am to 7:00pm; illumination, 7:00pm to 7:00 am) is maintained, and all the rats can drink water and ingest freely;

Establishing a type 2 diabetes model group, wherein Wistar rats are fed with common growth propagation feed serving as a normal control group, the common growth propagation feed formula comprises 66% of carbohydrate, 22% of protein and 12% of fat, all GK rats are fed with high-fat feed, the high-fat feed formula comprises 88.2% of common animal feed, 10% of refined lard, 1.5% of cholesterol and 0.3% of pig bile salt, and the random blood sugar of each group of animals is measured 1-2 times per week (frequency is adjusted according to the blood sugar value) until the measured value of blood sugar of the model GK rats is more than or equal to 11.1mmol/L for 3 times continuously, thereby establishing the type 2 diabetes model group;

randomly grouping 9 GK rats which are incorporated into the experiment according to blood sugar, and dividing the GK rats into a model group (n=3), a western medicine group-saxagliptin group (n=3) and a traditional Chinese medicine group-ginseng and astragalus compound group (n=3);

2) After animals are sacrificed, model groups (type 2 diabetes), western medicine groups (saxagliptin tablets) and traditional Chinese medicine groups (ginseng and astragalus compound) and normal group rat thighbones are separated, muscle tissues are removed, specimens are wrapped by normal saline wet gauze, and the obtained rat thighbones are put into phosphate buffer saline solution with the temperature of 4 ℃ and the PH value of 7.2-7.4 for preservation treatment;

3) Before the three-point bending test, taking out a model group (type 2 diabetes), a western medicine group (saxagliptin tablets), a traditional Chinese medicine group (ginseng and astragalus compound) and a normal group rat femur from a phosphate buffer salt solution to carry out drying treatment, and then spraying black and white scattered spots for processing by a digital image correlation method;

4) Placing a normal group of rat thighbones on a three-point bending clamp of an electrohydraulic servo press, wherein the upper end is contacted with a loading pressure head 2, the lower end is contacted with two support supports 3, and the distance between the two ends of the loading supports is set to be l=25 mm according to the rat thighbones, as shown in fig. 2;

5) The hydraulic loading system 4 is adopted for loading, the loading speed is selected to be 0.1mm/min, the computer 7 is used for automatically collecting data of force measurement and displacement, the collecting frequency is 60Hz, then a load stress time course curve of the femur of the rat can be obtained, and further a peak load value of fracture of the femur of the rat can be obtained according to the load time course curve of the femur of the rat, so that a load peak value is 126.61N, as shown in figure 3;

6) Idealized assumption is carried out on a rat femur, the stress state of a three-point bending simple support beam is simplified, a bending moment envelope diagram is obtained, as shown in fig. 4a and 4B, wherein C is a loading point, x is the distance between a loading pressure head and a support A on the left side of the simple support beam, a is the distance between a loading point and a support A on the left side, B is the distance between a loading point and a support B on the right side, l is the distance between the supports on the left side and the right side, F_R is a load value applied by the loading pressure head, F_RA and F_RB are support counter-force of the supports on the left side and the right side, and when the loading force of an electrohydraulic servo press is 1N, the maximum bending moment of the three-point bending loading point C can be expressed as ab/l;

7) Scanning the fracture surface of the femur of the rat by an electron microscope, inputting ImageJ software to perform binarization treatment to obtain the outer diameter D₁ and the inner diameter D₂ of the femur of the rat, as shown in fig. 4c, and then calculating the cross-sectional area a= (pi D₁²－πD₂²)/4＝4.83mm²) of the fracture surface of the femur of the rat, wherein the cross-sectional bending cross-sectional coefficient is shown in formula (1), as shown in fig. 5a and 5 b;

wherein D₁ is the outer diameter, and alpha is the ratio of the inner diameter to the outer diameter;

then according to the formula (2) of the mechanical bending strength of the material, the maximum bending stress value of the fracture surface of the normal group of bones is 0.493MPa, and the formula is as follows

8) Calculating the bending stress of the loading point according to the formulas (1) and (2) to obtain an allowable stress value range [ sigma ] of the femur of the rat, then continuously calculating the disturbance omega of the loading point according to the load value, wherein the disturbance formula is shown in the formula (3), and then obtaining an allowable displacement value u₁＝ω_C = 0.52mm of the femur of the rat;

Wherein the method comprises the steps ofE represents the elastic modulus of the femur of the rat, and F_P represents the load value to which the femur of the rat is subjected;

9) According to the image information obtained by the high-speed camera shooting 5 and the light system 6, a numerical image correlation method (DIC) system 7 is utilized to obtain a displacement value u₂ =0.50 mm tested in the loading process, as shown in fig. 6, and then error ranges of u₁ and u₂ values are subjected to comparative analysis to remove average values, so that more accurate maximum allowable disturbance degree of the rat femur can be obtained to be 0.51mm;

examples 2 to 4:

Repeating the steps 3) to 9), obtaining a maximum bending stress value of the rat femur of the model group, the traditional Chinese medicine group and the western medicine group according to the step 7) and the step 9), and obtaining a maximum deflection value of the rat femur of the ninth step, respectively carrying out biomechanical property analysis on the rat femur under different blood sugar concentrations from the stress and displacement aspects as shown in table 1, and then analyzing the biomechanical property of the rat femur from the biomechanical aspect.

TABLE 1 Experimental data on rat femur flexural Strength and maximum disturbance values between different groups of rat femur

The evaluation method of the femoral pathology mechanism of the rats after different modeling treatments is as follows:

If the maximum bending stress value of the rat femur of the western medicine group (saxagliptin tablets) and the traditional Chinese medicine group (ginseng and astragalus compound) is smaller than that of the normal group and larger than that of the rat femur of the model group (type 2 diabetes), the biological mechanical property of the rat femur is improved by the medicament treatment, if the maximum bending stress value of the rat femur of the western medicine group (saxagliptin tablets) and the traditional Chinese medicine group (ginseng and astragalus compound) is smaller than that of the rat femur of the model group (type 2 diabetes), the biological mechanical property of the rat femur is attenuated by the medicament treatment, and if the maximum bending stress value of the rat femur of the western medicine group (saxagliptin tablets) is larger than that of the rat femur of the traditional Chinese medicine group (ginseng and astragalus compound), the biological mechanical property of the rat femur is improved by the western medicine group is larger than that of the traditional Chinese medicine group, and vice versa;

If the maximum disturbance value of the rat femur of the traditional Chinese medicine group and the western medicine group is smaller than the normal group and larger than the maximum bending maximum disturbance value of the rat femur of the model group (type 2 diabetes), the biological mechanical property of the rat femur is improved by the medicament treatment, if the maximum disturbance value of the rat femur of the traditional Chinese medicine group and the western medicine group is smaller than the maximum bending maximum disturbance value of the rat femur of the model group (type II diabetes), the biological mechanical property of the rat femur is attenuated by the medicament treatment, if the maximum disturbance value of the rat femur of the western medicine group (saxagliptin tablets) is larger than the maximum disturbance value of the rat femur of the traditional Chinese medicine group (ginseng-astragalus compound), the biological mechanical property of the rat femur is improved by the western medicament group is larger than the traditional Chinese medicine group, and vice versa;

Experimental results show that the maximum bending stress value of the rat femur of the traditional Chinese medicine group (0.418 MPa) and the western medicine group (0.408 MPa) is smaller than 0.493MPa and larger than 0.377MPa, which indicates that the medicament treatment has a better improving effect on the biomechanical property of the rat femur, but does not exceed the normal group;

The maximum disturbance value of the rat femur of the traditional Chinese medicine group (0.432 mm) and the western medicine group (0.422 mm) is smaller than 0.510mm and larger than 0.377mm, which indicates that the medicament treatment has a better promotion effect on the biomechanical property of the rat femur, but does not exceed the normal group, and the maximum disturbance value of the rat femur of the traditional Chinese medicine group is larger than the western medicine group by 0.432mm, which indicates that the traditional Chinese medicine group has a better promotion effect on the biomechanical property of the rat femur.

In summary, according to the experimental test method for estimating the bending strength and the deflection of the femur of the rat provided by the invention, the bending strength of the femur of the rat is obtained through a high-speed camera and a three-point bending test, then the accurate cross-sectional area of the fracture surface of the femur of the rat can be obtained through binarization processing of an electron microscope scanning image, the bending strength and the deflection of the femur of the rat are calculated according to a material mechanics formula, and then the biomechanical property evaluation of the femur of the rat is carried out, so that the influence of modeling treatment of different blood glucose concentrations on vital signs of the rat can be well represented from the mechanical angle.

The method can accurately calculate experimental data such as bending strength, disturbance degree, displacement field, strain field and the like of the fracture surface of the femur of the rat, the tested rat femur mechanical strength data are wide, the high-speed camera is combined with a digital image correlation method to carry out experimental value test on the disturbance degree of the femur of the rat, the experimental value test is compared with a theoretical value of a theoretical formula, the bending strength of the femur of the rat can be finally corrected, in addition, the testing range can be popularized to measurement of the femur of the rat and can also be applied to testing of bones of biological materials such as rabbits, the displacement field and strain field data of the fracture point of the femur of the rat can be accurately tested, the limitation of experimental test data of the femur of the rat is always reached, the precision range of the displacement field and the strain field of the femur of the rat can be up to 0.001mm, the testing method not only can carry out evaluation on the biomechanical property of the femur of the rat from the femur of the rat, but also can carry out evaluation on the biomechanical property of the femur of the rat according to the disturbance degree value of the femur of the rat, and mutual verification evaluation can be carried out from two aspects.

The above is a further detailed description of the present invention with reference to specific embodiments, and it should not be construed that the specific embodiments of the present invention are limited thereto, and that the expansion, the operation method and the data substitution performed on the basis of the technical solution idea of the present invention should fall within the protection scope of the present invention for those skilled in the art to which the present invention pertains.

Claims (5)

Translated fromChinese

1.一种推算大鼠股骨弯曲强度与扰度的实验测试方法，其特征在于，该方法包括以下步骤：1. An experimental test method for estimating the bending strength and disturbance of rat femur, characterized in that the method comprises the following steps:1）准备若干个正常大鼠，并对部分大鼠进行2型糖尿病造模处理得到模型组，然后将造模处理后的大鼠平均分为三组，并对其中两组分别进行中药试剂和西药试剂喂养，然后得到正常组、模型组、中药组和西药组四组不同血糖浓度的大鼠模型；1) Prepare a number of normal rats, and perform type 2 diabetes modeling on some of the rats to obtain a model group, then divide the modeled rats into three groups on average, and feed two of the groups with Chinese medicine reagents and Western medicine reagents respectively, and then obtain four groups of rat models with different blood glucose concentrations: normal group, model group, Chinese medicine group, and Western medicine group;2）对步骤1）中的四组大鼠模型的已死亡大鼠股骨进行取材，剔除肌肉组织然后放入磷酸缓冲盐溶液中进行培养处理；2) The femurs of the deceased rats in the four groups of rat models in step 1) were collected, the muscle tissues were removed, and then the femurs were placed in a phosphate buffered saline solution for culture treatment;3）从磷酸缓冲盐溶液中取出大鼠股骨进行干燥处理，随后在四组大鼠股骨上表面整体喷射黑白散斑，用于数字图像相关法处理；3) The rat femurs were removed from the phosphate buffered saline solution and dried, and then black and white speckles were sprayed on the upper surface of the femurs of the four groups of rats for digital image correlation processing;4）将四组大鼠股骨放置于压缩载荷加载装置上分别进行三点弯曲试验，同时搭配高速摄影机对大鼠股骨的断裂过程进行实时拍摄，并将试验数据导入计算机中进行处理；4) The femurs of the four groups of rats were placed on a compression load loading device for three-point bending tests. A high-speed camera was used to take real-time photos of the fracture process of the femurs of the rats, and the test data were imported into a computer for processing;5）根据步骤4）获取的试验数据导出大鼠股骨载荷时程曲线，并对大鼠股骨断裂点之间位移场与应变场进行分析；5) deriving the rat femur load time history curve according to the test data obtained in step 4), and analyzing the displacement field and strain field between the fracture points of the rat femur;6）利用电镜对大鼠股骨断裂面进行扫描分析，将扫描的图像信息输入Image J软件中进行二值化处理，转换完成后可以根据二值化图片的黑白像素点与电镜扫描图片的标尺比例进行大鼠股骨断裂面的直径与面积的精确计算，随后根据材料力学弯曲强度理论公式进行弯曲强度计算，随后结合高速摄影机的图像信息进行弯曲强度与扰度分析；6) Scan and analyze the rat femoral fracture surface using an electron microscope, input the scanned image information into Image J software for binarization processing, and after the conversion is completed, the diameter and area of the rat femoral fracture surface can be accurately calculated based on the black and white pixel points of the binary image and the scale ratio of the electron microscope scanned image, and then the bending strength is calculated according to the bending strength theory formula of material mechanics, and then the bending strength and disturbance analysis are performed in combination with the image information of the high-speed camera;7）根据四组大鼠股骨弯曲强度进行分析，对大鼠股骨的生物力学性能进行力学强度评价。7) Based on the analysis of the bending strength of the femurs of the four groups of rats, the biomechanical properties of the rat femurs were evaluated by mechanical strength.2.根据权利要求1所述一种推算大鼠股骨弯曲强度与扰度的实验测试方法，其特征在于：所述步骤1）中药试剂和西药试剂分别为参芪复方试剂和沙格列汀片试剂。2. An experimental test method for estimating the bending strength and disturbance of rat femur according to claim 1, characterized in that: the Chinese medicine reagent and the Western medicine reagent in step 1) are respectively a Shenqi compound reagent and a Saxagliptin tablet reagent.3.根据权利要求1所述一种推算大鼠股骨弯曲强度与扰度的实验测试方法，其特征在于：所述步骤5）中具体分析过程为：3. The experimental test method for estimating the bending strength and disturbance of rat femur according to claim 1, characterized in that the specific analysis process in step 5) is as follows:a、在大鼠股骨的基准图像中随机选择待测点P(x_i,y_i)，并以待测点P(x_i,y_i) 为中心选取一个大小为 (2N+1)×(2N+1) 像素的正方形子图像，即参考子集；a. Randomly select a test pointP (x_i ,y_i ) in the reference image of the rat femur, and select a square sub-image with a size of (2N+1)×(2N+1) pixels with the test pointP (x_i ,y_i ) as the center, i.e., the reference subset;b、用f(x,y) 表示；同时从变形后的图像中，以相应的像素点为中心选取一个大小为 (2M+1)×(2M+1) 像素的正方形子图像 (M > N)，即搜索子集；b. Denote it byf (x ,y ); at the same time, from the deformed image, select a square sub-image (M > N) of size (2M+1)×(2M+1) pixels with the corresponding pixel as the center, i.e., the search subset;c、在搜索子集中任意选取变形子集，用g′(x′,y′) 表示，变形子集的大小为 (2N+1)×(2N+1) 像素；c. Randomly select a deformed subset in the search subset, denoted byg ′(x ′,y ′), and the size of the deformed subset is (2N+1)×(2N+1) pixels;d、然后将f(x,y) 和g′(x′,y′) 按照相关系数公式进行相关性计算，得到全场的相关系数分布图；d. Then,f (x ,y ) andg ′(x ′,y ′) are correlated according to the correlation coefficient formula to obtain a correlation coefficient distribution diagram of the entire field;e、相关系数分布图的峰值，即为f(x,y) 和g′(x′,y′) 的最佳匹配点；而变形子集的中心点P′(x_i′,y_i′) 和参考子集的中心点坐标之差即为待测点P(x_i,y_i) 的位移矢量；e. The peak value of the correlation coefficient distribution graph is the best matching point off (x ,y ) andg ′(x ′,y ′); and the difference between the coordinates of the center pointP ′(x_i ′,y_i ′) of the deformed subset and the center point of the reference subset is the displacement vector of the measured pointP (x_i ,y_i ) ;f、采用同样的方法，对整个散斑图中的每个像素点进行上述相关操作，即可得到大鼠股骨全场位移与全场应变，随后进一步可以对大鼠股骨的位移场与应变场进行分析。f. Using the same method, the above related operations are performed on each pixel point in the entire speckle pattern to obtain the full-field displacement and full-field strain of the rat femur, and then the displacement field and strain field of the rat femur can be further analyzed.4.根据权利要求1所述一种推算大鼠股骨弯曲强度与扰度的实验测试方法，其特征在于：所述步骤4）中压缩载荷加载装置为装设有三点弯曲夹具的电液伺服压力机。4. The experimental test method for estimating the bending strength and disturbance of rat femur according to claim 1, characterized in that: the compression load loading device in step 4) is an electro-hydraulic servo press equipped with a three-point bending fixture.5.根据权利要求4所述一种推算大鼠股骨弯曲强度与扰度的实验测试方法，其特征在于：所述步骤4）中三点弯曲试验可以是中心对称加载，也可以是偏心非对称三点弯曲加载。5. An experimental test method for estimating the bending strength and disturbance of rat femur according to claim 4, characterized in that: the three-point bending test in step 4) can be a central symmetrical loading or an eccentric asymmetrical three-point bending loading.