CN107085659B - A kind of preparation method of biomimetic material with soft and hard phase morphology based on friction properties - Google Patents

Abstract

The invention belongs to the field of bionic materials, and particularly relates to a preparation method of a soft and hard interphase morphology bionic material based on friction performance. The method comprises the following steps: step one, determining the proportion of two materials with different elastic moduli; secondly, determining the basic body size of the material with large elastic modulus; and step three, preparing the soft and hard interphase bionic material by adopting laser processing, 3D printing and physical blending methods according to the ratio and the basic body size of the two materials with different elastic moduli obtained in the step one and the step two. The soft and hard alternate morphology bionic material prepared by the invention is simple in method and has excellent wear resistance, tensile property and impact resistance, wherein the bionic material which takes the body surfaces of dung beetles, earthworms and other soil animals as a prototype and is distributed with bionic coupling unit bodies with a certain rule on the surface shows excellent resistance reduction and wear resistance, and is used in engineering practice to obtain better economic benefit and social benefit.

Description

A kind of preparation method of biomimetic material with soft and hard phase morphology based on friction properties

technical field

The invention belongs to the field of biomimetic materials, in particular to a preparation method of a biomimetic material with a soft-hard phase morphology based on friction performance.

Background technique

In the co-evolution of billions of years, natural organisms constantly adapt to the environment to meet the needs of survival, and their structures and functions have reached a near-perfect level. The body surface is an important organ for organisms to exchange energy and substances with the outside world, and at the same time protect the organism from the external environment. Organisms constantly adjust their body surface morphology in evolution according to their environment, creating a variety of soft and hard morphologies and structures, which are endowed with excellent drag reduction and wear resistance properties. The tribological properties of natural biomaterials such as bamboo, intertidal shellfish and snake-bellied scales are far beyond people's imagination.

The biomimetic material between soft and hard phases is a material formed by arranging two materials with different elastic moduli in a certain ratio in an orderly or disorderly manner based on the characteristics of the organism. By imitating the morphology, structure, The material ratio, size, distribution law and other factors are used for bionic design. Using laser, 3D printing and physical blending methods, a bionic structure with a certain distribution law between soft and hard phases is prepared on the surface of the mold, which can effectively reduce the adhesion between the mold and the casting, and has both wear resistance and thermal fatigue resistance. At the same time, the use of laser processing technology to process the soft and hard bionic morphology on the surface of the material improves the toughness, wear resistance and lubricity of the material. We define a material with a small elastic modulus as a soft material, and a material with a large elastic modulus as a hard material. The design of biomimetic materials between soft and hard phases involves many aspects, such as the properties of soft and hard materials, the "soft-hard" phase structure, soft The differences in the ratio of hard materials and the basic dimensions of soft and hard materials will affect the friction properties of the biomimetic materials with soft and hard phases.

In modern industry, friction has two sides, both harmful and beneficial. It is generally considered that friction is harmful, because friction must be accompanied by wear and tear, and 60% of the failure of production equipment is caused by wear and tear, and friction will consume a lot of energy, 1/2-1/3 of the world's energy is wasted due to friction . However, friction also has a beneficial side. There are many examples of using friction and increasing friction to serve human beings in engineering, such as friction transmission, brake valves, clutches, vehicle driving wheels, bolts and nuts, etc. Therefore, it is very important to reasonably design the friction coefficient of materials in engineering practice. Therefore, it is also worth studying to prepare biomimetic materials with soft and hard interphase morphology according to the required friction coefficient.

SUMMARY OF THE INVENTION

The invention provides a method for preparing a biomimetic material with soft and hard phase morphology based on friction performance. The morphological biomimetic material exhibits controllable friction performance, which solves the blank of designing new soft and hard biomimetic materials in the existing market.

The technical scheme of the present invention is described as follows in conjunction with the accompanying drawings:

A method for preparing a biomimetic material with a soft-hard phase morphology based on friction properties, the method comprises the following steps:

Step 1: Determine the ratio of two materials with different elastic moduli; define the material with a small elastic modulus as a soft material and a material with a large elastic modulus as a hard material; according to the expected soft-hard phase morphology of the biomimetic material material properties And the required friction coefficient, the ratio of soft and hard materials can be calculated according to the following formula:

Among them, c% is the volume percentage of the soft material; f is the friction coefficient of the soft and hard bionic material; f _s is the friction coefficient of the soft material, f _h is the friction coefficient of the hard material; E _s is the elastic modulus of the soft material; E _h is the elastic modulus of the hard material;

Step 2: Determine the basic body size of the material with a large elastic modulus; it can be obtained according to the specific form and surface topography size of the desired soft-hard phase topography biomimetic material;

Step 3: According to the ratio of the two materials with different elastic moduli and the basic body size obtained in Step 1 and Step 2, the method of laser processing, 3D printing, and physical blending is used to prepare a soft-hard biomimetic material.

The desired soft-hard interphase morphology biomimetic material described in step 2 has a point-like arrangement of materials with a large elastic modulus, that is, a series of point-like materials with a large elastic modulus are uniformly distributed on the soft material with a small elastic modulus. For hard materials, the lateral distance between hard materials is defined as a ₁ , and the longitudinal distance between them is b ₁ . According to experience, the range of a ₁ and b ₁ is between 1-2 mm. The calculation method of the radius r of the basic body of the point-like hard material includes: The following steps:

21) Determine the relationship between the size of the soft and hard materials and the ratio of the two materials; the surface area of the material in the local area is a ₁ b ₁ , and the surface area of the soft material is a ₁ b ₁ -πr ² ; relationship, to determine the volume percent of the soft material, with:

22) Calculate the radius of the hard material basic body; the radius of the point-like hard material basic body is expressed as:

The desired biomimetic material between the soft and hard phases described in the second step is a striped arrangement of the soft and hard phases, and the stripe spacing is a ₂ . According to experience, the range of a ₂ is between 1-2 mm. _The calculation method of the width b2 consists of the following steps:

31) Determine the relationship between the size of the soft and hard material and the ratio of the two materials, and determine the volume percentage of the soft material according to the relationship between the surface morphology and size, as follows:

32) Calculate the width of the hard material basic body, and express the stripe width of the strip-shaped hard material basic body as:

b ₂ =a ₂ -c%*a ₂ .

The hard material of the desired soft-hard phase biomimetic material described in step 2 is arranged in a grid, and the grid spacing is a ₃ . According to experience, the range of a ₃ is between 1-2 mm. _The b3 calculation method of grid width consists of the following steps:

41) Determine the relationship between the size of the soft and hard material and the ratio of the two materials, and determine the volume percentage of the soft material according to the relationship between the surface morphology and size, as follows:

42) To calculate the width of the hard material basic body, the grid width of the hard material basic body can be expressed as:

b ₃ =a ₃ -sqrt(a ₃ *a ₃ -c%a ₃ *a ₃ )

Two materials with different elastic moduli are both polymer materials or metal materials.

The beneficial effects of the invention are as follows: the method of preparing the biomimetic material with soft and hard phase morphology is simple. Among them, the surface of soil animals such as dung beetles, earthworms and other soil animals is used as the prototype, and the bionic material of the bionic coupling unit body with a certain regular distribution on the surface shows controllable friction performance, and is used in engineering practice, and has achieved good economic benefits and social benefit.

Description of drawings

Fig. 1a is a surface schematic diagram of a biomimetic material with a soft-hard phase morphology;

Fig. 1b is a schematic diagram of the surface of another biomimetic material with soft and hard phase morphology;

Figure 1c is a schematic diagram of the surface of the third biomimetic material with soft and hard phase morphology;

Figure 2 is a schematic diagram of the microscopic uneven surface of a biomimetic material with a soft and hard phase morphology;

Figure 3 is a schematic diagram of the contact situation of the friction pair during the friction process of the biomimetic material with the soft and hard phase morphology;

Figure 4 is a schematic diagram of the structural interaction between soft and hard phases;

5 is a schematic diagram of the basic size of a biomimetic material with a soft and hard phase morphology;

Figure 6 is a schematic diagram of the basic size of another soft-hard phase biomimetic material;

Figure 7 is a schematic diagram of the surface of the third biomimetic material with soft and hard interphase morphology.

Detailed ways

The biomimetic material between soft and hard phases mentioned in the present invention refers to two materials with different elastic moduli, and the material with a small elastic modulus is defined as a soft material, and the material with a large elastic modulus is defined as a hard material.

Refer to Fig. 1a-Fig. 1c, Fig. 1a-Fig. 1c are several common biomimetic materials with soft and hard morphology. The surface of the biomimetic material with the soft and hard phase morphology involved in the present invention is a macroscopically smooth biomimetic surface. Referring to Figure 2, the microscopic surface of the biomimetic material with soft and hard topography is uneven. Referring to Figure 3, when the surfaces of two soft and hard topographic bionic materials are in contact with each other under load, contact occurs only at the top of a few asperities. Since the actual contact surface is actively small, the contact pressure on the asperities is extremely large. Under the action of load, instantaneous temperature and other factors, adhesion occurs at the contact peak. After that, the stress of the contact point does not change, and it can only rely on expanding the contact area to withstand the increasing load. In the friction process, the sticking point is sheared under the action of tangential force to produce sliding. The shearing force is the sticking friction force. In most dry friction cases, the sticking friction force can be regarded as the total friction force. Referring to Figure 4, the soft-hard interphase material has a "soft-hard" interphase structure, and the interaction between the soft material and the hard material during the friction process makes the friction process much more complicated than that of a single material. Under the same load of a single-component soft material or hard material, the actual contact area of the soft material is much larger than that of the hard material. However, for soft-hard biomimetic materials, the actual contact area between soft and hard materials will be affected due to the synergistic effect of soft and hard materials.

Based on the above adhesion friction mechanism, the present invention provides a new method for preparing a biomimetic material with a corresponding soft and hard phase morphology according to a required friction coefficient, and the specific method is as follows:

Step 1: Determine the ratio of two materials with different elastic moduli; define a material with a small elastic modulus as a soft material, and a material with a large elastic modulus as a hard material; the soft-hard phase material has a "soft-hard" phase structure, In the friction process, the interaction between soft materials and hard materials makes the friction process much more complicated than that of a single material. Under the same load of a single-component soft material or hard material, the actual contact area of the soft material is much larger than that of the hard material. However, for the soft-hard biomimetic material, in the adhesion generation stage, due to the soft-hard interphase structural characteristics of the soft-hard biomimetic material, the relative compression of the soft and hard material must be kept the same, so the actual contact area of the soft and hard material will be changed, further cause a redistribution of the load. The characteristics of soft and hard biomimetic materials can be represented by two parameters, the elastic modulus E _s (soft material elastic modulus) and E _h (hard material elastic modulus). In order to analyze the influence of elastic modulus E _s and E _h on the friction process, it can be assumed that the volume percentage of soft material is c%, and the volume percentage of hard material is 1-c%. Due to the synergistic effect of soft and hard materials, the actual contact area of soft materials and hard materials will be affected. According to statistical methods, it can be expressed as:

_Among them, A is the total contact area, and As and _Ah are the respective actual contact areas of the soft material and the hard material.

According to the stick friction mechanism, the total normal load (W) can be expressed as:

W=Ws+ _Wh =c% _AEsε +(1- _c %) _AEhε

where ε is the average strain at the sticking point, W _s is the normal load of the soft material, and W _h is the normal load of the hard material;

A tangential force is applied to the upper surfaces that are in contact with each other and loaded. When the tangential force is large enough, the adhesive point is sheared, and the upper and lower surfaces slide relative to each other. The tangential force at this time is the adhesive friction force. For soft-hard biomimetic materials, in the shearing stage of the adhesion point, due to the different adhesion conditions of soft and hard materials and the different conditions for shearing of soft and hard materials by tangential force, the friction force can be expressed as:

F=A _s τ _s +A _h τ _h =c%Aτ _s +(1-c%)Aτ _h

Among them, τ _s and τ _h are the shear limits of soft and hard materials, respectively.

According to Coulomb's friction law, the friction coefficient f of the soft-hard biomimetic material can be obtained:

where f _s is the friction coefficient of the soft material, and f _h is the friction coefficient of the hard material.

According to the material properties of the biomimetic material between the soft and hard phases, the required friction coefficient and the known friction coefficients of the soft and hard materials, the ratio of the soft and hard materials can be calculated according to the following formula:

Among them, c% is the volume percentage of the soft material; f is the friction coefficient of the soft and hard bionic material; f _s is the friction coefficient of the soft material, f _h is the friction coefficient of the hard material; E _s is the elastic modulus of the soft material; E _h is the elastic modulus of the hard material;

Step 2: Determine the size of the basic body of the hard material. It can be obtained according to the specific form and surface topography size of the desired soft-hard phase morphology biomimetic material;

Step 3. According to the ratio and basic size of the two materials with different elastic moduli obtained in Step 1 and Step 2, laser processing, 3D printing, physical blending and other methods can be used to prepare them under the same working conditions. Soft and hard biomimetic material.

The desired soft-hard phase biomimetic material described in step 2 has a large elastic modulus in a point-like arrangement, and the lateral distance of the material with large elastic modulus is defined as a ₁ , and the longitudinal distance is b ₁ . According to experience a The range of ₁ and b ₁ is between 1-2mm. The calculation method of the basic body size of a material with a large elastic modulus includes the following steps:

21) Determine the relationship between the size of the soft and hard materials and the ratio of the two materials. As shown in Figure 1a and Figure 5, the surface structure of the biomimetic material with the soft and hard phase morphology (the hard material in the figure is a black circle), it can be seen that its structure is the superposition of the structure in the virtual frame. According to the size of the structure in the virtual frame The surface area of the material is a ₁ b ₁ , and the surface area of the soft material is a ₁ b ₁ -πr ² . According to the relationship between the surface topography and size, the volume percentage of soft material is determined, as follows:

22) Calculate the radius of the point-like hard material basic body, and the radius of the point-like hard material basic body is expressed as:

The desired soft-hard interphase biomimetic material described in step 2 with a large elastic modulus is arranged in stripes, and the stripe spacing is defined as a ₂ , and the range of a ₂ is between 1-2 mm according to experience. The calculation method of the basic body size of a material with a large elastic modulus includes the following steps:

31) Determine the relationship between the size of the soft and hard materials and the ratio of the two materials. As shown in Figure 1b and Figure 6, the surface structure of the biomimetic material with the topography between the soft and hard phases (the hard material is a black bar in the figure), according to the relationship between the surface topography and size, the volume percentage of the soft material is determined, as follows:

32) To calculate the stripe width of the point-like hard material base body, the stripe width of the point-like hard material base body can be expressed as:

b ₂ =a ₂ -c%*a ₂

The desired soft-hard interphase biomimetic material described in the second step has a large elastic modulus in a grid-like arrangement, and the fringe spacing is defined as a ₃ . According to experience, the range of a ₃ is between 1-2 mm. The calculation method of the basic body size of a material with a large elastic modulus includes the following steps:

41) Determine the relationship between the size of the soft and hard materials and the ratio of the two materials. As shown in Figure 1c and Figure 7, the surface structure of the biomimetic material with the morphology of the soft and hard phases (the hard material in the figure is a black bar), according to the relationship between the surface morphology and size, the volume percentage of the soft material is determined, as follows:

42) Calculate the grid width of the hard material basic body, and the grid width of the hard material basic body can be expressed as:

b ₃ =a ₃ -sqrt(a ₃ *a ₃ -c%a ₃ *a ₃ )

Example 1

It is known that the elastic modulus of the soft material is 160Mpa, the friction coefficient is 0.2, the elastic modulus of the hard material is 1200Mpa, and the friction coefficient is 0.1. The biomimetic material with the soft and hard phase as shown in Figure 1a and Figure 5 is selected. If you want to prepare the friction coefficient A biomimetic material with a soft-hard phase morphology of 0.15, the specific preparation method is as follows:

Step 1: Determine the ratio of soft and hard materials. According to the requirements of the friction characteristics of the material, that is, the friction coefficient f of the biomimetic material with the soft and hard phase morphology, select the appropriate ratio of soft and hard materials. The ratio of soft and hard materials can be calculated according to the following formula:

where c% is the volume percentage of the soft material, f is the friction coefficient of the soft-hard topographic biomimetic material, f _s is the friction coefficient of the soft material, f _h is the friction coefficient of the hard material, and E _s is the elastic modulus of the soft material _Eh is the elastic modulus of the hard material. According to the characteristics of biomimetic materials with soft and hard topography, the size of f should be between f _s and f _h .

Putting the specific parameters into the above formula, the volume percentage of the soft material can be obtained:

Step 2: Determine the size of the basic body of the hard material (the hard material is a black circle in the figure). As shown in Figure 1a and Figure 5, the surface structure of the biomimetic material with the soft and hard phase morphology is shown in Figure 1. It can be seen that its structure is the superposition of the structure in the virtual frame. According to the relationship between the structure dimensions in the virtual frame, the surface area of the material is a ₁ b ₁ , the surface area of the soft material is a ₁ b ₁ -πr ² . The volume percentage of soft material determined according to the above formula is:

The radius of a point-like hard material primitive can be expressed as:

Step 3: Using a 3D printing method to prepare the soft-hard biomimetic material obtained in Step 1 and Step 2 under the same working conditions as in Step 1.

Embodiment 2

It is known that the elastic modulus of the soft material is 180Mpa, the friction coefficient is 0.21, the elastic modulus of the hard material is 1000Mpa, and the friction coefficient is 0.11. The biomimetic material with the soft and hard phase as shown in Figure 1b and Figure 6 is selected. If the friction coefficient is expected to be 0.14 The soft and hard phase morphology biomimetic material, the specific preparation method is as follows:

Step 1: Determine the ratio of soft and hard materials. According to the requirements of the friction characteristics of the material, that is, the friction coefficient f of the biomimetic material with the soft and hard phase morphology, select the appropriate ratio of soft and hard materials. The ratio of soft and hard materials can be calculated according to the following formula:

where c% is the volume percentage of the soft material, f is the friction coefficient of the soft-hard topographic biomimetic material, f _s is the friction coefficient of the soft material, f _h is the friction coefficient of the hard material, and E _s is the elastic modulus of the soft material _Eh is the elastic modulus of the hard material. According to the characteristics of biomimetic materials with soft and hard topography, the size of f should be between f _s and f _h .

Putting the specific parameters into the above formula, the volume percentage of the soft material can be obtained:

Step 2: Determine the basic size of the hard material (the hard material in the figure is a black bar). As shown in Figure 1b and Figure 6, the surface structure of the biomimetic material with the soft and hard phase morphology is determined according to the relationship between the surface morphology and size, and the volume percentage of the soft material is determined as follows:

The width of the strip-like hard material primitive can be expressed as:

b ₂ =a ₂ -0.7042a ₂ =0.2958a ₂

Step 3: Using a laser processing method to prepare the soft-hard biomimetic material obtained in Step 1 and Step 2 under the same working conditions as in Step 1.

Embodiment 3

It is known that the elastic modulus of the soft material is 150Mpa, the friction coefficient is 0.19, the elastic modulus of the hard material is 1100Mpa, and the friction coefficient is 0.12. The biomimetic material shown in Figure 1c and Figure 7 is selected. If the friction coefficient is expected to be 0.16 The soft and hard phase morphology biomimetic material, the specific preparation method is as follows:

Step 1: Determine the ratio of soft and hard materials. According to the requirements of the friction characteristics of the material, that is, the friction coefficient f of the biomimetic material with the soft and hard phase morphology, select the appropriate ratio of soft and hard materials. The ratio of soft and hard materials can be calculated according to the following formula:

where c% is the volume percentage of the soft material, f is the friction coefficient of the soft-hard topographic biomimetic material, f _s is the friction coefficient of the soft material, f _h is the friction coefficient of the hard material, and E _s is the elastic modulus of the soft material _Eh is the elastic modulus of the hard material. According to the characteristics of biomimetic materials with soft and hard topography, the size of f should be between f _s and f _h .

Putting the specific parameters into the above formula, the volume percentage of the soft material can be obtained:

Step 2: Determine the basic size of the hard material (the hard material in the figure is a black bar). As shown in Figure 1c and Figure 7, the surface structure of the biomimetic material with the soft and hard phase morphology is determined according to the relationship between the surface morphology and size, and the volume percentage of the soft material is determined as follows:

The mesh width of hard material primitives can be expressed as:

b ₃ =a ₃ -sqrt(a ₃ *a ₃ -0.8462a ₃ *a ₃ )

Step 3: Using a laser processing method to prepare the soft-hard biomimetic material obtained in Step 1 and Step 2 under the same working conditions as in Step 1.

The above-prepared biomimetic material with soft and hard phase morphology is simple in method, and exhibits excellent wear resistance, tensile properties, and impact resistance. The bionic material of the bionic coupling unit body shows excellent drag reduction and wear resistance properties, and is used in engineering practice, achieving good economic and social benefits.

Claims (5)

1. a kind of preparation method based on the soft-hard phase morphology bionic material based on frictional performance, it is characterised in that the method comprises the following steps: Step 1: Determine the ratio of two materials with different elastic moduli; define the material with a small elastic modulus as a soft material and a material with a large elastic modulus as a hard material; according to the expected soft-hard phase morphology of the biomimetic material material properties And the required friction coefficient, the ratio of soft and hard materials can be calculated according to the following formula:

Among them, c% is the volume percentage of the soft material; f is the friction coefficient of the soft and hard bionic material; f _s is the friction coefficient of the soft material, f _h is the friction coefficient of the hard material; E _s is the elastic modulus of the soft material; E _h is the elastic modulus of the hard material; Step 2: Determine the basic body size of the material with a large elastic modulus; it can be obtained according to the specific form and surface topography size of the desired soft-hard phase topography biomimetic material; Step 3: According to the ratio of the two materials with different elastic moduli and the basic body size obtained in Step 1 and Step 2, the method of laser processing, 3D printing, and physical blending is used to prepare a soft-hard biomimetic material. 2. the preparation method of a kind of biomimetic material with soft-hard phase morphology based on friction performance according to claim 1, it is characterized in that, the elastic modulus of the desired soft-hard phase morphology biomimetic material described in step 2 is large The material is point-like arrangement, that is, _a series of point _- like hard materials with large elastic modulus are evenly distributed on the soft material with small elastic modulus. , according to experience, the range of a ₁ and b ₁ is between 1-2mm, the calculation method of the radius r of the point-like hard material basic body includes the following steps: 21) Determine the relationship between the size of the soft and hard materials and the ratio of the two materials; the surface area of the material in the local area is a ₁ b ₁ , and the surface area of the soft material is a ₁ b ₁ -πr ² ; relationship, to determine the volume percent of the soft material, with:

22) Calculate the radius of the hard material basic body; the radius of the point-like hard material basic body is expressed as:

3. the preparation method of a kind of biomimetic material of soft and hard phase morphology based on friction performance according to claim 1, it is characterized in that, the expected soft and hard phase morphology biomimetic material described in step 2 is soft and hard phase stripe The stripe spacing is a ₂ . According to experience, the range of a ₂ is between 1-2mm. The calculation method of the stripe width b ₂ of the strip-shaped hard material basic body includes the following steps: 31) Determine the relationship between the size of the soft and hard material and the ratio of the two materials, and determine the volume percentage of the soft material according to the relationship between the surface morphology and size, as follows:

32) Calculate the width of the hard material basic body, and express the stripe width of the strip-shaped hard material basic body as: b ₂ =a ₂ -c%*a ₂ . 4. the preparation method of a kind of biomimetic material with soft-hard phase morphology based on friction performance according to claim 1, it is characterized in that, the hard material of the desired soft-hard phase morphology biomimetic material described in step 2 is a mesh Grid-like arrangement, the grid spacing is a ₃ , and the range of a ₃ is between 1-2mm according to experience, the calculation method of b ₃ of the grid width of the hard material basic body includes the following steps: 41) Determine the relationship between the size of the soft and hard material and the ratio of the two materials, and determine the volume percentage of the soft material according to the relationship between the surface morphology and size, as follows:

42) To calculate the width of the hard material basic body, the grid width of the hard material basic body can be expressed as: b ₃ =a ₃ -sqrt(a ₃ *a ₃ -c%a ₃ *a ₃ ). 5 . The method for preparing a biomimetic material with soft and hard phase morphology based on friction performance according to claim 1 , wherein the two materials with different elastic moduli are both polymer materials or metal materials. 6 .

Images