Biology Coupling Characteristics Of Desert Lizard Epidermis

The bionics is technological science to study the structures, characters, elements, behavior, and interaction of the biologic system, in order to provide the new design idea, working principle, and system structure for the engineering. Nowadays, the bionics research mainly classified as five aspects including configuration bionics, morphology bionics, structure bionics, biomaterials and functional bionics, respectively. As the development of bionic research, complex problems have been found difficult to solve under the condition of using bionics method include one or two kinds of field. More and more research have presented that a private function of one animal was achieved by the cooperation of surface morphology, tissue structure and component material factors. We can also call this cooperation of factors which are advantage to the function's achievement as"biological coupling". Bionics based on the mechanisms and principles of biological coupling is"coupling bionics".Wear is the main failure form and the initial failure causes of the mechanical equipments. About 80% invalidation of components is caused by abrasion for materials. Abrasion not only consumes the energy and materials and decreases the equipment efficiency, but also accelerates the equipments discard and causes the parts replacement frequently.The friction and wear appears together with living body origin, and will always exist in all life activities. The bionic research results show that some of living body surface has unique function to reduce friction. The function improves wear resistance of the body surface. This function is the product of evolution for millions of years. Wear resistance of body surface was the synergetic effect of morphology, structure and materials respectively, namely the results of biological coupling. Desert lizard living in desert, the lizard body rubs against the sad frequently. To study on desert lizard, especially research the biology coupling characteristics of typical friction parts of desert lizard could provide fundamental information on further study of coupling bionics which about the development of anti friction technology. In this paper, the key factor of the living body function was found by using the idea of bionics and biological coupling. the function about adapting themselves to the environment have been studied in both entomology and bionics. The functions of every factors and the cooperation of factors were also considered.Taking the Laudakin stoliczkana and Phrynocephalus versicolor as the research objects, and the stereomicroscope and scanning electron microscope were chosen to observe and analyses the modality, structure and the HE staining sections of body surface. By comparing the two kinds of lizard which both living in desert, the coupling mode and coupling characteristics of the function of anti-friction were studied. The backside cuticle of Laudakin stoliczkana was studied by using the reverse engineering technology. The point cloud data of cuticle was obtained by 3D SCANNER laser scanner, and the data was processed with Imageware software. Finally, the 3D geometry entity model of part of backside cuticle was got. The 3D geometry entity model shown on which the modality backside cuticle of Laudakin stoliczkana is uudee. The undee modality is a system which combined with various squama.In this paper, the head, back, abdomen, leg and tail of the two kinds of desert lizard were chosen as typical parts with anti-friction function. After analysis behaviour of the desert lizard, found that the backside is the primary part of enduring wear. The form of wear is erosion which is the result of gas-sand two-phase flow impacting the cuticle. Therefore, we choose the backside cuticle of lizard as the research object and emphatically analyzed the biological coupling characteristics. There is a similarity of biological coupling characteristics between Laudakin stoliczkana and Phrynocephalus versicolor that is the component of two kinds of lizard squama both are gradient materials. From surface to interior, tissue are oberhautchen,β-keratin, mesos layer,α-keratin, stratum intermedium and stratum basale repectively, the property are becoming increasingly flexible. This kind of gradient materials could absorb the impact effectively, thus preventing erosion. In addition, the coupling characteristics between two kinds of desert lizard have different respectively.(1) The function of wear resistance of Laudakin stoliczkana's backside was achieved by synergistic effects of morphology, squama structure and micron-size micro ornamentation.The squamas on front backside of Laudakin stoliczkana arrange orderly with certain direction, thus forming some grooves with the direction of perpendicular to wind direction. These grooves could influence cuticle surface flow field, make airflow come into being overfall, thus alleviating the impact speed of sand. The middle backside of Laudakin stoliczkana covered with pentagonal or hexagonal squamas, and the squamas arrangement tight, are resulting in better mechanical conductivity. The system which composing of tight arranged squamas can transfer the impact force from one squama to another. As for the single squamas of backside, the surface layer is oberhautchen andβ-keratin which is more rigid then other layer. A crustiform composite structure was formed between surface layer and under layer. The surface layer mainly compose with oberhautchen andβ-keratin and the under layer which is flexibler then surface layer including mesos layer,α-keratina and stratum intermedium, et al. This kind of rustiform composite structure could enhance the impact resistance of single squama. From the microscopic level analysis, the surface of Laudakin stoliczkana's backside squama lack of microornamentation, but the squama top surface exist a loose tissue layer with lots of crannies. When the sand impact the squama surface, this loose tissue could absorb energy producing by impact, and the crannies could guide the crack which produces by impact to landscape orientation.(2) The scalelike morphology on surface in macro, microornamentation on squama and crustiform structure of squama cooperates to achieve the erosion wear function of the dorsum of Phrynocephalus versicolor.The arrange manner of squama on the dorsum of Phrynocephalus versicolor is tile piling. The tip of squama is upwarping, with 15 degree to horizontal surface. This kind of morphology can increase angle of attack, when the sand blowing. As attack angle increase, tangential impact and the damage of horny layer decrease. Micro ornamentation exists on squama. Many pits with edge processes connect at the edge to form microornamentation morphology. In pit, there are corneous cell granules in submicron, which can lubricate the surface in the situation of friction. The Phrynocephalus versicolor connect tightly with surface without any gap. Two squamas connect at the bottom. This structure not only can protect water of skin from vaporizing, but also separate attack from one squama to others around it. The observing of squama section indicates that the squama also has crustiform structure.The research found that the desert lizard's function of anti-friction is the results of multi-factor coupling. The results of this paper provide fundamental information on further study of coupling bionics which about the development of anti friction technology.