CN110074503A - A kind of shock resistance structure optimum design method - Google Patents

Abstract

The invention discloses an optimal design method of an impact-resistant structure based on the impact-resistant principle of a woodpecker head. It is characterized in that: learning from the structural characteristics of the cancellous bone in the woodpecker skull that tends to be plate-shaped and the uneven distribution of the cancellous bone in the skull, combined with the design of structural microscopic parameters and the protection requirements of different parts of the protective equipment, it is formed in the entire protective equipment. Gradient structural design and distribution; by controlling the microscopic parameters of the structure at the part of the impact, increase the strength of the structure, improve the impact resistance and the ability to resist deformation, and adjust the centroid position of the protective equipment through the layout and distribution of the structure; While ensuring the impact effect, improve the utilization rate of materials, reduce the quality of protective equipment, and improve the stability of protective equipment. It can be applied in the design of helmets and other protective equipment for athletes and pilots. The present invention does not relate to the specific material and manufacturing process of the impact-resistant structure, nor does it relate to the specific way of structure distribution.

Description

An Optimal Design Method for Shock Resistant Structures

technical field

The invention relates to the field of impact-resistant structure design and the field of bionics, in particular to an optimal design method of an impact-resistant structure based on the impact-resistant principle of a woodpecker head.

Background technique

Collisions and impacts are very common phenomena in everyday life. In the field of transportation, collisions are almost inevitable, and such collisions are very easy to cause damage to passengers; in the field of aerospace, pilots will also be constantly collided under various load conditions, which will seriously threaten flight safety; The impact protection of the head and brain is also an important issue in sports competitions where violent collisions occur. In recent decades, people have carried out a series of researches on impact protection. In order to reduce human body injury or component damage caused by various collisions, impact-resistant equipment is generally used to protect the human body or related components. The key to the impact resistance of these protective equipment lies in its internal impact-resistant structural design. At present, the basic principle of impact-resistant structure design is: under the action of external impact, the impact-resistant structure deforms, absorbs the energy of collision and impact through deformation or internal viscoelastic dissipation, increases the impact time, and reduces the impact force. Thereby play a protective role.

However, there are some deficiencies in the design methods of impact-resistant structures at present. First of all, in the layout of the protective structure, the impact characteristics of the protective parts are not considered, and the method of uniform distribution is often used. This method is designed to protect the maximum impact. Although it can protect the protective equipment, it also increases the protection. The use of structures and materials, and unnecessary structural arrangements increase the quality of the overall structure and cause the center of mass to shift. The increase in mass and the shift of the center of mass will not only seriously affect the protection effect, but will even cause serious damage to the protected parts or human body. additional risk of injury. Especially in pilot helmets, under high-speed overload, the increase in helmet mass and the offset of the center of mass will cause excessive fatigue or even damage to the pilot's helmet, increasing the risk of accidents. Secondly, in order to increase the impact time and the energy absorption of the structure, materials and structures that can undergo large deformation are generally used in the existing impact protection, such as polystyrene foam is used as the buffer layer of the helmet in the general helmet design, which is of great importance. Increasing the size and volume of the structure, excessive deformation will also affect the distribution of the center of mass of the impact structure, thereby also reducing the stability of the protective equipment. Therefore, how to optimize the design of impact-resistant structures and propose new design methods is particularly important.

Bionic research provides us with new ideas and methods for designing impact-resistant structures and equipment. Bionic research on woodpeckers is a good example. Woodpeckers peck wood up to 12,000 times a day, with a pecking speed of 6-7m/s and a maximum acceleration of 2170g. Under the impact of such high frequency, high speed and high load, the woodpecker did not get a "concussion". This miraculous phenomenon has attracted the attention of researchers. Since 2009, our research group has focused on the impact resistance mechanism of the woodpecker head, using various research methods to study the reasons why woodpeckers do not have "concussions", and found that the cancellous bone in the woodpecker skull played a huge role in the impact resistance process. The role of cancellous bone in the woodpecker skull: First, the structural model index of the cancellous bone in the woodpecker skull is higher and more plate-like, and has a higher bone volume fraction and elastic modulus. Compared with other birds, the cancellous bone has a stronger Good impact resistance; Secondly, the cancellous bone in the woodpecker skull is unevenly distributed, and there is a large amount of cancellous bone near the forehead, temporal part, occipital part and hyoid bone that bear the impact. The remaining parts that bear less impact force contain little or no cancellous bone, while the cancellous bone of other birds is evenly distributed, and most of them are rod-shaped structures. This feature makes the woodpecker skull optimized. Design, while improving the impact resistance, it also greatly reduces the mass of the skull. The microstructure and uneven distribution of woodpecker cancellous bone provide a unique natural cushioning layer that allows it to survive high-speed impacts. Inspired by this, the present invention starts from the protection mechanism of the microstructure and uneven distribution characteristics of the cancellous bone in the woodpecker skull to its head, and proposes a method for optimizing the design of the impact-resistant structure, which provides support for the structural design and optimization of protective equipment. new ideas. In the specific implementation, the structural optimization design of a certain protective equipment is taken as an example to introduce.

SUMMARY OF THE INVENTION

The purpose of the present invention is to propose a structural optimization design method based on the impact resistance principle of the cancellous bone of the woodpecker head. By optimizing the microscopic morphology and distribution characteristics of the impact-resistant structure, the method improves the impact-resistant performance and increases the efficiency of impact-resistant protection, and provides a new idea and method for the design and optimization of impact-resistant protective equipment.

The present invention is achieved through the following technical solutions:

The present invention is mainly implemented on the two aspects of design of the microcosmic parameters of the impact-resistant structure and the distribution of the structure. The design of the microscopic parameters of the impact-resistant structure mainly involves the morphology characteristics and structural parameters of the impact-resistant structure, which can be realized through the microscopic morphology and structural parameters of the bionic woodpecker cancellous bone; the distribution optimization of the impact-resistant structure mainly involves the The distribution and arrangement of the impact structure in different parts of the protective equipment can be optimized by referring to the distribution of the cancellous bone of the woodpecker skull;

Among them, the above-mentioned micro-morphological features of the impact-resistant structure specifically refer to the shape of the basic unit pores that make up the impact-resistant structure, combined with the shape of the plate-shaped pores of the micro-porous structure of the woodpecker cancellous bone, imitating the shape of the pores. appearance characteristics to guide the design of impact-resistant structures;

The structural parameters of the impact-resistant structure mentioned above mainly refer to the structural model index, volume fraction and other parameters of the impact-resistant structure that control the design of the structure. The design can be guided by referring to the plate-like structural characteristics of the woodpecker cancellous bone structure; through the control Structural parameters, it is possible to design plate-shaped, rod-shaped or rod-shaped and plate-shaped structures with different impact resistance properties, combined to meet the needs of various impact resistance properties;

Regarding the distribution optimization of the impact-resistant structure mentioned above, it mainly refers to the arrangement of the designed impact-resistant structure inside the equipment in the design of the impact-resistant equipment. Arrange structures with higher strength and better toughness in places where there is less or no impact, and place structures with lower strength or no impact structures;

Regarding the above-mentioned microscopic morphology characteristics and distribution optimization of the impact-resistant structure, it mainly refers to combining the structural microscopic parameter design and the protection requirements of different parts of the protective equipment to form a gradient structural design and distribution in the entire protective equipment; For large parts, by controlling the microscopic parameters of the structure, the strength, impact resistance and deformation resistance of the structure can be increased, and the position of the center of mass of the protective equipment can be adjusted through the layout and distribution of the structure; the utilization rate of materials can be improved while ensuring the impact effect, Reduce the quality of protective equipment and improve the stability of protective equipment.

Inspired by the impact resistance of the head of woodpeckers in nature, the present invention proposes an optimal design method for impact-resistant structure without involving specific The advanced impact-resistant structure and specific materials and manufacturing processes can be applied in the design of helmets for athletes and pilots, as well as in the design of other protective equipment.

Description of drawings

In order to clearly show the uneven distribution and microscopic features of the cancellous bone in the woodpecker skull, the following is an introduction to the characteristics of the cancellous bone in the woodpecker skull. The following is only an introduction to the characteristics of the cancellous bone in the woodpecker skull. The optimization method can be Reference is made to the methods presented in the Summary of the Invention.

Fig. 1 is a schematic diagram of the sagittal plane of the woodpecker skull in the present invention, showing the uneven distribution characteristics of the cancellous bone in the woodpecker skull in the sagittal plane, one is the forehead position, and the other is the occipital bone position, and these two positions are rich in Cancellous bone, almost no cancellous bone in the top part of the head;

Figure 2 shows the microstructure and morphology of the cancellous bone in the woodpecker skull. The white area is the bony part. It can be seen that the cancellous bone in the woodpecker skull forms a plate-like structure;

Fig. 3 is a schematic diagram of the coronal plane of the woodpecker skull in the present invention, which shows the uneven distribution characteristics of the cancellous bone in the woodpecker skull in the coronal plane, one is the part wrapped by the hyoid bone, two are the temporal part, and three are the occipital parts , these three parts are rich in cancellous bone, and there is almost no cancellous bone in the top of the skull;

Figure 4 is a schematic diagram of the coronal plane of the cranium of a lark, which shows the uniform distribution of cancellous bone in the cranium of a lark in the coronal plane. The inner cancellous bone is rod-shaped;

Detailed ways

In order to present the purpose and technical solution of the present invention more clearly, the application of this method will be further described in detail in conjunction with the design of a certain impact-resistant equipment:

The impact resistance design of protective equipment is mainly carried out on the microscopic parameter design and distribution optimization of its internal structure; by optimizing the internal microstructural parameters and the distribution position of the structure, the overall impact resistance of the protective equipment is increased, and the The utilization rate of materials reduces the quality of equipment and improves the stability of equipment.

First of all, aiming at the design of the microscopic parameters of the internal structure of the protective equipment, combined with the porous morphology and microstructural characteristics of the cancellous bone in the woodpecker skull, the structural parameters such as the model index and volume fraction of the structure are controlled, and the design has a plate shape, a rod shape or a rod shape. Different impact resistance structures combined with plates can use different structures for different impact resistance requirements. The plate structure can meet the needs of higher impact resistance, while the rod structure can meet the needs of lower impact resistance. ;

Secondly, according to the optimization design of the protective structure distribution of the impact-resistant equipment, according to the protection requirements and protection levels of each part of the protective equipment, the protective equipment is divided into different protective areas, and the structural parameters are designed for different protective areas. For parts that are impacted and have a strong impact, structures that can resist strong impacts such as woodpecker plate structures can be designed; for parts that are not easily impacted or withstand small impacts, rod-shaped structures can be used for layout. Through the structure The design makes the structure form a gradient distribution in the protective equipment, so as to optimize the distribution of the structure and meet different impact requirements;

Taking the design of the helmet buffer layer as an example, according to the load characteristics of the human skull, the buffer layer is divided into four parts: the front part, the top part, the side part and the rear part. According to the impact characteristics and the maximum load allowed by each part, buffer structures with different impact resistance are arranged in different parts. Increase the layout of the impact-resistant buffer structure for parts that are prone to impact, and reduce the layout of the buffer structure layer for parts that are less or even non-impact, and form a plate-shaped rod-shaped gradient distribution in the helmet to meet the impact resistance. At the same time, increase the material utilization rate, reduce the quality of the helmet, and improve the stability.

Claims (6)

1. An impact-resistant structure optimization design method, characterized in that: it is based on the impact-resistant structure optimization design method of cancellous bone microscopic features and uneven distribution characteristics in the woodpecker skull. 2. according to the described impact-resistant structure optimal design method of claim 1, it is characterized in that: the designed impact-resistant structure is to learn from the woodpecker skull internal cancellous bone plate shape feature, guide the design of impact-resistant structure, design plate Shape, rod or rod and plate combined structure with different impact resistance, combined to meet the needs of a variety of impact resistance. 3. The impact-resistant structure optimization design method according to claim 1, characterized in that: according to the characteristics of uneven distribution of cancellous bone in the woodpecker skull, structures with higher strength and better toughness are arranged at the parts that are vulnerable to impact , Arrange lower-strength structures or no impact structures at places with less impact or no impact. 4. The method for optimizing the design of an impact-resistant structure according to claim 1, characterized in that: in combination with the structural microscopic parameter design and the protection requirements of different parts of the protective equipment, a gradient structural design and distribution are formed in the entire protective equipment; By controlling the microscopic parameters of the structure, the parts with greater impact can increase the strength, impact resistance and deformation resistance of the structure, and adjust the center of mass position of the protective equipment through the layout and distribution of the structure; while ensuring the impact effect, improve the utilization of materials Efficiency, reduce the quality of protective equipment, and improve the stability of protective equipment. 5. The impact-resistant structure optimization design method according to claim 1, characterized in that: the impact-resistant structure optimization design method has a wide range of applications, and equipment related to impact protection can apply this method according to the corresponding situation. 6. The impact-resistant structure optimization design method according to claim 1, characterized in that: impact-resistant structure shape design and impact-resistant structure distribution optimization are two different methods, both of which can be used alone or in combination .