CN-121977906-A - Preparation method of flexible speckles for biological soft tissues, composite test body and application thereof

Abstract

The invention relates to the technical field of mechanical property test, and provides a preparation method of flexible speckles for biological soft tissues, a composite test body and application thereof. The invention carries out spraying and curing on the surface of biological soft tissues to obtain the flexible speckles. The flexible speckles prepared by the method have excellent elasticity and adhesive force, can be cooperatively deformed with tissues under a large tensile strain condition without obvious cracking, peeling or relative sliding, can meet the requirements of biological soft tissue large-deformation mechanical tests, and simultaneously have the advantages of simple operation, no need of complex pretreatment such as priming paint, polishing and the like, good repeatability and wide application range.

Inventors

• LI ZHENGDONG
• YANG SHENGPEI
• SHEN SIHUI
• WANG JIAN
• XU ZONGSHI
• XING YUAN
• ZOU DONGHUA
• SHI JING
• WANG JINMING
• ZHANG JIANHUA
• YUAN RUNZE

Assignees

• 司法鉴定科学研究院

Dates

Publication Date

20260505

Application Date

20260211

Claims (10)

1. 1. A method for preparing flexible speckles for biological soft tissues, comprising the steps of: and spraying and then curing the double-component polyurethane coating on the surface of the biological soft tissue to obtain the flexible speckles, wherein the double-component polyurethane resin comprises an A component and a B component, the A component is a polyurethane main agent, and the B component is an isocyanate curing agent.
2. 2. The method for preparing the flexible speckles according to claim 1, wherein the two-component polyurethane coating has a coating-4 viscosity cup outflow time of 280 to 320 seconds.
3. 3. The method for preparing flexible speckles according to claim 2, wherein the volume ratio of the component A to the component B is (7-9): 1.
4. 4. The method for preparing flexible speckles according to claim 1, wherein the spraying pressure is 0.15-0.25 mpa.
5. 5. The method for preparing flexible speckles according to claim 1, wherein the caliber of the spray nozzle is 0.7-1.0 mm.
6. 6. The method for preparing flexible speckles according to claim 1, wherein the distance of spraying is 10-20 cm.
7. 7. The method of claim 1, wherein the curing temperature is 20-30 ℃.
8. 8. A composite test body is characterized by comprising a substrate layer and a flexible speckle layer positioned on the surface of the substrate layer, wherein the flexible speckle layer is prepared by the method of any one of claims 1-7, and the substrate layer is biological soft tissue to be tested.
9. 9. The composite test body of claim 8, wherein the biological soft tissue is skin, an organ, fascia, tendon, or a blood vessel.
10. 10. Use of the composite test body according to claim 8 or 9 for testing mechanical properties of biological soft tissue by digital image correlation.

Description

Preparation method of flexible speckles for biological soft tissues, composite test body and application thereof Technical Field The invention relates to the technical field of mechanical property testing of materials, in particular to a preparation method of flexible speckles for biological soft tissues, a composite test body and application thereof. Background The digital image correlation method (DIC) is a non-contact full-field deformation measurement method based on image gray scale correlation, and is widely applied to the fields of material mechanics, structural engineering, biomechanics and the like. In biomechanical studies, the mechanical properties of biological soft tissues such as skin, organs, fascia, tendons, blood vessels, etc. often need to be tested and characterized over a large strain range (more than 50%). The DIC technology has the basic premise that a layer of speckle pattern which has good randomness and high contrast and can cooperatively deform along with a substrate exists on the surface of a measured object. If the speckle is cracked, peeled off or relatively slipped during loading, the image gray field of the relevant area is not truly changed, and the DIC calculation is invalid or the result is seriously distorted. However, for biological soft tissues that are moist, soft, have low surface energy and need to undergo large deformations, the preparation of a stable and reliable speckle pattern on their surface has been a challenge in the art. At present, the methods for preparing the speckles on the surface of biological soft tissues mainly comprise the following steps: The physical adsorption method uses carbon powder, ink powder and the like as raw materials, and the particles are attached to the surface of the tissue to form speckle patterns by means of physical adsorption acting force between the particles such as the carbon powder, the ink powder and the like and the surface of biological soft tissue. The speckle prepared by the method has weak binding force with the surface of biological tissues, is easy to fall off under large deformation, has unstable speckle shape, is difficult to form patterns with controllable size and clear edges, causes tracking and measurement failure, has poor repeatability, and is difficult to meet the requirements of systematic experiments and high-precision DIC calculation. Dye staining, in which ink, dye, marker pen and the like are used to write or dot on the surface of tissue directly, is generally suitable for materials with small rigidity or deformation, and for moist soft tissue, diffusion, halation and blurring of speckle outline are easy to occur, enough gray contrast cannot be formed, and DIC identification is difficult. Meanwhile, the dye is difficult to bear large deformation, and the dye is easy to peel off or irregularly migrate along with the epidermis under large strain. One-component paint film method the speckle pattern is produced using commercially available self-spray paints (hand-shake paints, typically acrylic or alkyd one-component paints). The method is convenient to operate, but has the fundamental defects that a single component is formed into a film by solvent volatilization and physical method, the extensibility is limited, the method is suitable for designing rigid or medium rigid base materials such as metal, plastic and the like, and when the strain is large (more than 20% -30%), the paint film itself is subjected to brittle fracture before soft tissues, speckle patterns are destroyed, and DIC cannot be tracked continuously. "Primer+topcoat" multilayer paint film method to improve contrast, researchers have attempted to form speckles with a black primer sprayed first, followed by a white or other colored topcoat. However, the paint is still a brittle material, the interlayer bonding force is limited, the failure strain limit is not improved substantially under large strain, and the process steps are increased, so that the repeatability and the efficiency are poor. In summary, the speckle patterns prepared by the method are difficult to achieve both strong adhesive force and high flexibility, the requirement of DIC measurement of large-deformation biological soft tissues cannot be met, and how to prepare a flexible speckle layer on the surface of the biological soft tissues, which has excellent adhesive force and can undergo large deformation along with the tissues without breaking, is a technical problem to be solved in the art. Disclosure of Invention In view of the above, the invention provides a method for preparing flexible speckles for biological soft tissues, a composite test body and application thereof. The flexible speckles prepared by the invention have excellent elasticity and adhesive force, can be cooperatively deformed with tissues under a large tensile strain condition without obvious cracking, peeling or relative sliding, and can meet the requirements of biological soft tissue large deformation mech